Assessment of histological response of paediatric bone sarcomas using FDG PET in comparison to morphological volume measurement and standardized MRI parameters

Purpose

The objective of this study was to evaluate positron emission tomography (PET) using ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) in comparison to volumetry and standardized magnetic resonance imaging (MRI) parameters for the assessment of histological response in paediatric bone sarcoma patients.

Methods

FDG PET and local MRI were performed in 27 paediatric sarcoma patients [Ewing sarcoma family of tumours (EWS), n?=?16; osteosarcoma (OS), n?=?11] prior to and after neoadjuvant chemotherapy before local tumour resection. Several parameters for assessment of response of the primary tumour to therapy by FDG PET and MRI were evaluated and compared with histopathological regression of the resected tumour as defined by Salzer-Kuntschik.

Results

FDG PET significantly discriminated responders from non-responders using the standardized uptake value (SUV) reduction and the absolute post-therapeutic SUV (SUV2) in the entire patient population (?SUV, p?=?0.005; SUV2, p?=?0.011) as well as in the subgroup of OS patients (?SUV, p?=?0.009; SUV2, p?=?0.028), but not in the EWS subgroup. The volume reduction measured by MRI/CT did not significantly discriminate responders from non-responders either in the entire population (p?=?0.170) or in both subgroups (EWS, p?=?0.950; OS, p?=?1.000). The other MRI parameters alone or in combination were unreliable and did not improve the results. Comparing diagnostic parameters of FDG PET and local MRI, metabolic imaging showed high superiority in the subgroup of OS patients, while similar results were observed in the population of EWS.

Conclusion

FDG PET appears to be a useful tool for non-invasive response assessment in the group of OS patients and is superior to MRI. In EWS patients, however, neither FDG PET nor volumetry or standardized MRI criteria enabled a reliable response assessment to be made after neoadjuvant treatment.     

Clinical and survival impact of FDG PET in patients with suspicion of recurrent cervical carcinoma

Purpose

The aim of this retrospective study was to evaluate the contribution of ¹⁸F-FDG PET to the clinical management and survival outcome of patients suspected of recurrent cervical carcinoma and in line with the hypothesis that early diagnosis of recurrent cervical cancer may improve overall survival.

Methods

A total of 40 patients underwent conventional imaging (CI) and FDG PET/CT for suspected cervical cancer. Clinical management decisions were recorded with CI and additional PET/CT. Discordances and concordances between CI and PET/CT results were compared to the final diagnosis as based on histopathology analysis or follow-up considered as the gold standard.

Results

The final diagnosis was established pathologically (n?=?25) or by median clinical follow-up for 48 months after the PET (n?=?15). The PET/CT was positive in 76% (20/26) of patients compared to 19% (6/26) with CI. Globally PET/CT modified the treatment plan in 55% (22/40) of patients and in 75% (18/24) when the CI was negative prior to PET/CT. These changes led to the use of previously unplanned therapeutic procedures in 37.5% (15/40). When FDG PET was positive for recurrence (>?3 foci), the median overall survival was 12 months (2–70) compared to patients with PET findings with ≤?1 focus for which the median survival was not attained (p?=?0.007). A multivariate analysis of prognostic factors demonstrated that abnormal FDG uptake (>?3 foci) was the most significant factor (p?<?0.03) for death from cervical cancer.

Conclusion

FDG PET is a valuable tool in the case of suspected recurrence of cervical cancer on account of its impact on treatment planning and especially in predicting patient outcome.     

Diagnostic performance of 18F-fluorothymidine PET/CT for primary colorectal cancer and its lymph node metastasis: comparison with 18F-fluorodeoxyglucose PET/CT

Purpose

To examine the diagnostic performance of ¹⁸F-fluorothymidine (FLT) PET/CT in primary and metastatic lymph node colorectal cancer foci in comparison with ¹⁸F-fluorodeoxyglucose (FDG) PET/CT.

Methods

The study population comprised 28 patients with 30 newly diagnosed colorectal cancers who underwent surgical resection of the primary lesion and regional lymph nodes after both FLT and FDG PET/CT. The associations between SUVmax levels and pathological factors were evaluated using the Mann-Whitney U or Kruskal-Wallis test. Differences in diagnostic indexes for detecting nodal metastasis between the two tracers were estimated using the McNemar exact or χ ² test.

Results

All 30 primary cancers (43.0?±?20.0 mm, range 14 – 85 mm) were visualized by both tracers, but none of the FLT SUVmax values exceeded the FDG SUVmax values in any of the primary cancers (6.6?±?2.4 vs. 13.6?±?5.8, p?<?0.001). The sensitivity, specificity and accuracy for detecting nodal metastasis were 41 % (15/37), 98.8 % (493/499) and 94.8 % (508/536) for FDG PET/CT, and 32 % (12/37), 98.8 % (493/499) and 94.2 % (505/536) for FLT PET/CT, respectively. The sensitivity (p?=?0.45), specificity (p?=?0.68) and accuracy (p?=?0.58) were not different between the tracers. Nodal uptake of FLT and FDG was discordant in 7 (19 %) of 37 metastatic nodes. There were ten concordant true-positive nodes of which six showed higher FDG SUVmax and four showed higher FLT SUVmax, but the difference between FDG and FLT SUVmax was not significant (5.56?±?3.55 and 3.62?±?1.45, respectively; p?=?0.22).

Conclusion

FLT has the same potential as FDG in PET/CT for the diagnosis of primary and nodal foci of colorectal cancer despite significantly lower FLT uptake in primary foci.     

Evaluation of early response to concomitant chemoradiotherapy by interim 18F-FDG PET/CT imaging in patients with locally advanced oesophageal carcinomas

Purpose

The best way to assess the response to chemoradiotherapy of locally advanced oesophageal carcinomas is not known. We used ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to evaluate the metabolic response during chemoradiotherapy and tried to correlate this response to survival.

Methods

Patients with biopsy-proven oesophageal carcinoma underwent FDG PET/CT with evaluation of the standardized uptake value (SUV) before any treatment (SUV1) and during chemoradiotherapy after two cycles of 5-fluorouracil (FU)/cisplatin and 20 Gy (SUV2). Metabolic response was defined as 1?(SUV2/SUV1). Surgery was discussed after 40 Gy and three cycles of chemotherapy. Results of interim PET were not considered for the therapeutic decision.

Results

Among 72 patients who underwent a first FDG PET/CT before any treatment, 59 (82 %) could receive the second FDG PET/CT examination. Median survival was 22.2 months with 1-year and 2-year survivals of 70 and 46 %, respectively. Nineteen patients (32 %) underwent surgery. Mean SUV1 and SUV2 were 12.3?±?6.2 and 6?±?4.1, respectively (p?<?0.001). Using a cut-off for metabolic response of 50 %, sensitivity and specificity for survival were 0.7 and 0.58. The 2-year overall survival of good responders was 62 % as compared to 27 % for poor metabolic responders. A multivariate analysis was performed, including T and N stages, surgery, histology and metabolic response: only metabolic response was significantly (p?=?0.009) associated with 2-year survival.

Conclusion

Early evaluation of metabolic response had a great prognostic value and could help identify good responders to chemoradiotherapy.     

18F-FDG PET/CT-based treatment response evaluation in locally advanced rectal cancer: a prospective validation of long-term outcomes

Purpose

To prospectively evaluate the usefulness of ¹⁸F-FDG PET/CT) imaging for predicting histopathological response and long-term clinical outcomes in locally advanced rectal cancer (LARC).

Methods

This prospective study included 38 patients with a confirmed diagnosis of LARC (cT3-4 or cN+) who underwent ¹⁸F-FDG PET/CT before and after neoadjuvant therapy (NAT). Total mesorectal excision was scheduled 6 weeks after NAT and was followed by an expert histopathological analysis of the surgical specimen. Baseline variables and previously identified maximum FDG standardized uptake value (SUVmax) cut-off values before NAT (SUVmax_PRE ≥6) and after NAT (SUVmax_POST ≥2), and the absolute and percentage reductions from baseline SUVmax (?SUVmax <4 and ?SUVmax% <65 %, respectively) were applied to differentiate patients showing a metabolic tumour response from nonresponders. These features were correlated with tumour regression grade (TRG), disease-free survival (DFS) and overall survival (OS).

Results

Significantly higher 5-year DFS and OS were seen in 19 responders (TRG 3 or 4) than in 19 nonresponders (TRG 0–2; 94.4 vs. 48.8 %, p?=?0.001; 94.7 vs. 63.2 %, p?=?0.02, respectively). In multivariate analysis the only PET/CT SUVmax-based parameter significantly correlated with the likelihood of recurrence and survival was ?SUV% <65 % (HR?=?5.95, p?=?0.02, for DFS; HR?=?5.26, p?=?0.04, for OS)

Conclusion

This prospective study proved that ¹⁸F-FDG PET/CT is a valuable imaging tool for assessing rectal cancer TRG and long-term prognosis, and could potentially serve as an intermediate endpoint in treatment optimization research and rectal cancer patient care.     

Breast cancer detection using high-resolution breast PET compared to whole-body PET or PET/CT

Purpose

To compare the performance characteristics of positron emission mammography (PEM) with those of whole-body PET (WBPET) and PET/CT in women with newly diagnosed breast cancer.

Methods

A total of 178 women consented to PEM for presurgical planning in an IRB-approved protocol and also underwent either WBPET (n?=?69) or PET/CT (n?=?109) imaging, as per usual care at three centers. Tumor detection sensitivity, positive predictive values, and ¹⁸F-fluorodeoxyglucose (FDG) uptake were compared between the modalities. The effects of tumor size, type, and grade on detection were examined. The chi-squared or Fisher’s exact tests were used to compare distributions between groups, and McNemar’s test was used to compare distributions for paired data within subject groups, i.e. PEM versus WBPET or PEM versus PET/CT.

Results

The mean age of the women was 59?±?12 years (median 60 years, range 26–89 years), with a mean invasive index tumor size of 1.6?±?0.8 cm (median 1.5 cm, range 0.5–4.0 cm). PEM detected more index tumors (61/66, 92 %) than WBPET (37/66, 56 %; p?<?0.001) or PET/CT (95/109, 87 % vs. 104/109, 95 % for PEM; p?<?0.029). Sensitivity for the detection of additional ipsilateral malignancies was also greater with PEM (7/15, 47 %) than with WBPET (1/15, 6.7 %; p?=?0.014) or PET/CT (3/23, 13 % vs. 13/23, 57 % for PEM; p?=?0.003). Index tumor detection decreased with decreasing invasive tumor size for both WBPET (p?=?0.002) and PET/CT (p?<?0.001); PEM was not significantly affected (p?=?0.20). FDG uptake, quantified in terms of maximum PEM uptake value, was lowest in ductal carcinoma in situ (median 1.5, range 0.7–3.0) and invasive lobular carcinoma (median 1.5, range 0.7–3.4), and highest in grade III invasive ductal carcinoma (median 3.1, range 1.4–12.9).

Conclusion

PEM was more sensitive than either WBPET or PET/CT in showing index and additional ipsilateral breast tumors and remained highly sensitive for tumors smaller than 1 cm.     

18F-FDG PET/CT imaging versus dynamic contrast-enhanced CT for staging and prognosis of inflammatory breast cancer

Purpose

Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer with a poor prognosis. Locoregional staging is based on dynamic contrast-enhanced (DCE) CT or MRI. The aim of this study was to compare the performances of FDG PET/CT and DCE CT in locoregional staging of IBC and to assess their respective prognostic values.

Methods

The study group comprised 50 women (median age: 51?±?11 years) followed in our institution for IBC who underwent FDG PET/CT and DCE CT scans (median interval 5?±?9 days). CT enhancement parameters were net maximal enhancement, net early enhancement and perfusion.

Results

The PET/CT scans showed intense FDG uptake in all primary tumours. Concordance rate between PET/CT and DCE CT for breast tumour localization was 92 %. No significant correlation was found between SUVmax and CT enhancement parameters in primary tumours (p?>?0.6). PET/CT and DCE CT results were poorly correlated for skin infiltration (kappa?=?0.19). Ipsilateral foci of increased axillary FDG uptake were found in 47 patients (median SUV: 7.9?±?5.4), whereas enlarged axillary lymph nodes were observed on DCE CT in 43 patients. Results for axillary node involvement were fairly well correlated (kappa?=?0.55). Nineteen patients (38 %) were found to be metastatic on PET/CT scan with a significant shorter progression-free survival than patients without distant lesions (p?=?0.01). In the primary tumour, no statistically significant difference was observed between high and moderate tumour FDG uptake on survival, using an SUVmax cut-off of 5 (p?=?0.7 and 0.9), or between high and low tumour enhancement on DCE CT (p?>?0.8).

Conclusion

FDG PET/CT imaging provided additional information concerning locoregional involvement to that provided by DCE CT on and allowed detection of distant metastases in the same whole-body procedure. Tumour FDG uptake or CT enhancement parameters were not correlated and were not found to have any prognostic value.     

Clinical value of 11C-methionine PET/CT in patients with plasma cell malignancy: comparison with 18F-FDG PET/CT

Purpose

PET/CT using FDG has been widely used for the imaging of various malignant tumours, including plasma cell malignancy (PCM), but ¹¹C-methionine (MET), as a radiolabelled amino acid tracer, may also be useful because PCM is able to activate protein synthesis. The purpose of this study was to evaluate the clinical value of PET/CT imaging using MET in PCM, including multiple myeloma, compared with that of FDG PET/CT.

Methods

The study group comprised 20 patients with histologically proven PCM who underwent FDG PET/CT and MET PET/CT scans before (n?=?6) or after (n?=?14) treatment. Semiquantitative analysis was performed on a lesion basis. We also visually evaluated the scans qualitatively using a five-point scale (0, negative; 1, probably negative; 2, equivocal; 3, probably positive; 4, positive) on a lesion and a patient basis. The results were compared between the two scans.

Results

Active PCM was confirmed in 15 patients, including two patients with extramedullary lesions. Uptake of MET tended to be higher (maximum standardized uptake value 10.3 ± 5.6, mean ± SD) than that of FDG (3.4 ± 2.7, p?<?0.001), and more lesions of grade 3 or 4 were depicted by MET (MET 156 lesions vs. FDG 58 lesions). On a patient basis, two patients were accurately diagnosed only by MET. In the remaining 18 patients, consistent results were obtained, but potential upgrade of staging or restaging was necessary in 6 of 11 positive patients because more abnormal lesions were demonstrated by MET. The patient-based sensitivity, specificity and accuracy of MET for restaging were 89 %, 100 % and 93 %, respectively, while those of FDG were 78 %, 100 % and 86 %, respectively.

Conclusion

MET revealed an equal or greater number of lesions in PCM than FDG. MET may be especially useful when negative or inconclusive findings are obtained by FDG despite highly suspicious indications of recurrence.     

Role of 18FDG PET/CT in patients treated with 177Lu-DOTATATE for advanced differentiated neuroendocrine tumours

Purpose

The prognostic value of FDG PET for neuroendocrine tumours (NETs) has been reported. In this study we evaluated the role of FDG PET in predicting response and progression-free survival (PFS) after ¹⁷⁷Lu-DOTATATE peptide receptor radionuclide therapy (Lu-PRRT) in patients with advanced well-differentiated grade 1/2 NETs.

Methods

We retrospectively evaluated 52 patients with progressive advanced NETs overexpressing somatostatin receptors and treated with Lu-PRRT with a cumulative activity up to 27.7 GBq divided into five courses. According to WHO 2010/ENETS classification, patients were stratified into two groups: those with grade 1 tumour (Ki-67 index ≤2 %, 19 patients), and those with grade 2 tumour (Ki-67 index >3 % to <20 %, 33 patients). On the basis of the FDG PET scan, 33 patients were classified as PET-positive (PET+) and 19 as PET-negative (PET?).

Results

FDG PET was positive in 57 % of patients with grade 1 NET and in 66 % of patients with grade 2 NET, and the rates of disease control (DC, i.e. complete response + partial response + stable disease) in grade 1 and grade 2 patients were 95 % and 79 %, respectively (P?=?0.232). In PET? and PET+ patients, the DC rates were 100 % and 76 % (P?=?0.020) with a PFS of 32 and 20 months, respectively (P?=?0.033). Of the PET+ patients with grade 1 NET, 91 % showed disease control, whereas about one in three PET+ patients with grade 2 NET (32 %) progressed after Lu-PRRT (DC rate 68 %).

Conclusion

These results suggest that FDG PET evaluation is useful for predicting response to Lu-PRRT in patients with grade 1/2 advanced NETs. Notably, none of PET? patients had progressed at the first follow-up examination after Lu-PRRT. Grade 2 NET and PET+ (arbitrary SUV cutoff >2.5) were frequently associated with more aggressive disease. PET+ patients with grade 2 NET, 32 % of whom did not respond to Lu-PRRT monotherapy, might benefit from more intensive therapy protocols, such as the combination of chemotherapy and PRRT.     

Integration of 2-deoxy-2-[18F] fluoro-d-glucose PET/CT into clinical management of patients with Wegener’s granulomatosis

Objective

Wegener’s granulomatosis (WG) is a rare disorder characterized by granulomatous necrotizing vasculitis which mainly affects small- and medium-sized vessels. While the classical triad of involvement is upper and lower respiratory system and glomerulonephritis, WG may involve any organ or system in the body. The aim of our study was to investigate the role of positron emission tomography/computerized tomography (PET/CT) both in the initial evaluation and follow-up of patients with WG.

Methods

We retrospectively evaluated PET/CT data from 13 patients (6 males; 7 females) with a mean age of 45 ± 12.4 years (range 28–63) who underwent either initial evaluation (n = 12) or response evaluation (n = 2) by conventional imaging methods and FDG with PET/CT. PET/CT images were both visually and quantitatively evaluated. The demographic data, clinical and laboratory findings of each patient were also recorded from the hospital files.

Results

Lung (n = 13), parapharyngeal space (n = 8), nose (n = 8), and ear (n = 3) were the most common disease sites detected on PET/CT. The entire initial evaluation patients had either solitary or multiple pulmonary nodular/mass lesions with marked increased FDG uptake (mean SUVmax 12 ± 4, range 3.53–19.51) on PET/CT. There was no significant pathological FDG uptake in patients consistent with complete treatment response after appropriate immunosuppressive therapy. PET/CT clearly demonstrated unexpected disease sites besides the respiratory system, with WG involvement except kidneys. Possibly due to physiological urinary excretion of FDG, urine analysis, BUN and creatinine levels were accepted still the best way for diagnosis of renal involvement.

Conclusion

FDG with PET/CT is a valuable tool in the management of patients with WG for a more accurate clinical evaluation regarding disease extension and treatment response.     

Efficacy and Safety of Transarterial Radioembolization Versus Chemoembolization in Patients With Hepatocellular Carcinoma

Purpose

Intermediate-stage hepatocellular carcinoma (HCC) is usually treated with locoregional therapy using transarterial chemoembolization (TACE). Transarterial radioembolization (TARE) using β-emitting yttrium-90 integral to the glass matrix of the microspheres is an alternative to TACE. This retrospective case-control study compared the outcomes and safety of TARE versus TACE in patients with unresectable HCC.

Materials and Methods

Patients with unresectable HCC without portal vein thrombosis treated with TARE between 2005 and 2008 (n = 61) were retrospectively frequency-matched by age, sex, and liver dysfunction with TACE-treated patients (n = 55) in the Mayo Clinic Hepatobiliary Neoplasia Registry. Imaging studies were reviewed, and clinical and safety outcomes were abstracted from the medical records.

Results

Complete tumor response was more common after TARE (12 %) than after TACE (4 %) (p = 0.17). When complete response was combined with partial response and stable disease, there was no difference between TARE and TACE. Median survival did not differ between the two groups (15.0 months for TARE and 14.4 months for TACE; p = 0.47). Two-year survival rates were 30 % for TARE and 24 % for TACE. TARE patients received fewer treatments (p < 0.001). Fifty-nine (97 %) TARE patients received outpatient treatment. In contrast, 53 (98 %) TACE patients were hospitalized for ≥1 day (p < 0.001). Compared with TACE, TARE was more likely to induce fatigue (p = 0.003) but less likely to cause fever (p = 0.02).

Conclusion

There was no significant difference in efficacy between TARE and TACE. TARE patients reported more fatigue but had less fever than TACE patients. Treatment with TARE required less hospitalization than treatment with TACE. These findings require confirmation in randomized trials.     

PET/CT assessment in follicular lymphoma using standardized criteria: central review in the PRIMA study

Purpose

We aimed to compare the standardized central review of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scans performed after induction therapy for follicular lymphoma (FL) in the PRIMA study (Salles et al., Lancet 377:42–51, 2011; Trotman et al., J Clin Oncol 29:3194–3200, 2011) to scan review at local centres.

Methods

PET/CT scans were independently evaluated by two nuclear medicine physicians using the 2007 International Harmonization Project (IHP) criteria (Cheson et al., J Clin Oncol 25:579–586, 2007; Juweid et al., J Clin Oncol 25:571–578, 2007; Shankar et al., J Nucl Med 47:1059–1066, 2006) and Deauville 5-point scale (5PS) criteria (Meignan et al., Leuk Lymphoma 50:1257–1260, 2009; Meignan et al., Leuk Lymphoma 51:2171–2180, 2010; Barrington et al., Eur J Nucl Med Mol Imaging 37:1824–1833, 2010). PET/CT status was compared with prospectively recorded patient outcomes.

Results

Central evaluation was performed on 119 scans. At diagnosis, 58 of 59 were recorded as positive, with a mean maximum standardized uptake value (SUV_max) of 11.7 (range 4.6–35.6). There was no significant association between baseline SUV_max and progression-free survival (PFS). Sixty post-induction scans were interpreted using both the IHP criteria and 5PS. Post-induction PET-positive status failed to predict progression when applying the IHP criteria [p?=?0.14; hazard ratio (HR) 1.9; 95 % confidence interval (CI) 0.8–4.6] or 5PS with a cut-off ≥3 (p?=?0.12; HR 2.0; 95 % CI 0.8–4.7). However, when applying the 5PS with a cut-off ≥4, there was a significantly inferior 42-month PFS in PET-positive patients of 25.0 % (95 % CI 3.7–55.8 %) versus 61.4 % (95 % CI 45.4–74.1 %) in PET-negative patients (p?=?0.01; HR 3.1; 95 % CI 1.2–7.8). The positive predictive value (PPV) of post-induction PET with this liver cut-off was 75 %. The 42-month PFS for patients remaining PET-positive by local assessment was 31.1 % (95 % CI 10.2–55.0 %) vs 64.6 % (95 % CI 47.0–77.6 %) for PET-negative patients (p?=?0.002; HR 3.3; 95 % CI 1.5–7.4), with a PPV of 66.7 %.

Conclusion

We confirm that FDG PET/CT status when applying the 5PS with a cut-off ≥4 is strongly predictive of outcome after first-line immunochemotherapy for FL. Further efforts to refine the criteria for assessing minimal residual FDG uptake in FL should provide a reproducible platform for response assessment in future prospective studies of a PET-adapted approach.     

The association of 18F-FDG PET/CT parameters with survival in malignant pleural mesothelioma

Purpose

Malignant pleural mesothelioma (MPM) is a disease with poor prognosis despite multimodal therapy but there is variation in survival between patients. Prognostic information is therefore potentially valuable in managing patients, particularly in the context of clinical trials where patients could be stratified according to risk. Therefore we have evaluated the prognostic ability of parameters derived from baseline 2-[¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

Methods

In order to determine the relationships between metabolic activity and prognosis we reviewed all ¹⁸F-FDG PET/CT scans used for pretreatment staging of MPM patients in our institution between January 2005 and December 2011 (n?=?60) and measured standardised uptake values (SUV) including mean, maximum and peak values, metabolic tumour volume (MTV) and total lesion glycolysis (TLG). Overall survival (OS) or time to last censor was recorded, as well as histological subtypes.

Results

Median follow-up was 12.7 months (1.9–60.9) and median OS was 14.1 months (1.9–54.9). By univariable analysis histological subtype (p?=?0.013), TLG (p?=?0.024) and MTV (p?=?0.038) were significantly associated with OS and SUV_max was borderline (p?=?0.051). On multivariable analysis histological subtype and TLG were associated with OS but at borderline statistical significance (p?=?0.060 and 0.058, respectively). No statistically significant differences in any PET parameters were found between the epithelioid and non-epithelioid histological subtypes.

Conclusion

¹⁸F-FDG PET/CT parameters that take into account functional volume (MTV, TLG) show significant associations with survival in patients with MPM before adjusting for histological subtype and are worthy of further evaluation to determine their ability to stratify patients in clinical trials.     

The Role of F-18 FDG PET/CT in Intrahepatic Cholangiocarcinoma

Purpose

The aim of this study was to evaluate the diagnostic and prognostic role of metabolic parameters of FDG PET/CT in patients with intrahepatic cholangiocarcinoma (ICC).

Methods

From December 2008 to December 2013, 76 FDG PET/CT scans performed for initial staging of ICC in a single institution (57 male and 19 female; mean age 68?±?9 years) were retrospectively reviewed. Patients with history of other known malignancy were excluded. Detection rates of regional lymph node and distant metastasis by FDG PET/CT were analyzed in comparison with conventional imaging modalities such as CT or MRI. Metabolic parameters including maximum, peak and mean standardized uptake values (SUVmax, SUVpeak, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), glucose corrected SUV (SUVgluc), and glucose corrected TLG (TLGgluc) were measured for the primary tumor. Cut-off values for the metabolic parameters were calculated by ROC curve analysis, and used to dichotomize the patient groups. The overall survival time (OS) was calculated and compared using the Cox proportional hazard regression analysis.

Results

The median duration of follow-up period was 5.4 months (interquartile range: 1.45～15.45). FDG PET/CT showed higher sensitivity than conventional imaging modalities in detection of regional node involvement (74.5 % vs. 61.8 %, p?=?0.013). In six patients, distant metastasis was identified only by FDG PET/CT. The mean SUVmax, SUVpeak, SUVmean, MTV, and TLG for the primary tumor were 8.2?±?3.1, 6.8?±?2.5, 4.0?±?0.8, 192.7?±?360.5 cm³, and 823.7?±?1615.4, respectively. Patients with higher (≥7.3, HR: 4.280, p?=?0.001), higher SUVpeak (≥6.5, HR: 2.333, p?=?0.020), higher SUVmean (≥3.9, HR: 2.799, p?=?0.004), higher SUVgluc (≥8.1, HR: 2.648, p?=?0.012), and higher TLGgluc (≥431.6, HR: 2.186, p?=?0.030) showed significantly shorter survival time. By multivariate study, operability was an independent prognostic factor for longer survival (HR: 4.113, p?=?0.005).

Conclusion

FDG PET/CT is an important diagnostic imaging tool in the nodal staging and detection of distant metastasis in ICC patients. Metabolic parameters may have a significant role as prognostic factors in patients with ICC.

     

Usefulness of partial volume effect-corrected F-18 FDG PET/CT for predicting I-131 accumulation in the metastatic lymph nodes of patients with thyroid carcinoma

Purpose

The purpose of this study was to evaluate the clinical usefulness of partial volume effect (PVE)-corrected F-18 FDG PET/CT for predicting I-131 accumulation in metastatic lymph nodes (mLNs) during I-131 therapy for papillary thyroid carcinoma (PTC).

Methods

Sixty-five mLNs in 31 PTC patients who underwent F-18 FDG PET/CT in an initial radioiodine therapy (RIT) were retrospectively evaluated. Of these, 25 mLNs were I-131-positive and 40 were I-131-negative. SUVmax and SUVmax with PVE correction (cSUVmax) were measured for each mLN, where PVE correction was performed utilizing a simple table lookup correction method. Then, SUVmax/cSUVmax was compared between I-131-positive and I-131-negative mLNs, including the analyses for the mLNs with small-sized (<1 cm) and weak FDG accumulation (SUVmax <3.5). The predictability for I-131 accumulation with SUVmax/cSUVmax was also compared.

Results

For all 65 mLNs, SUVmax/cSUVmax was significantly higher in I-131-negative than I-131-positive mLNs (p < 0.0001). Only in cSUVmax, I-131-negative mLNs were significantly higher than I-131-positive, in terms of the 30 small-sized mLNs (p = 0.0001) and 14 mLNs with weak FDG uptake (p = 0.007). The highest accuracy in predictability for I-131 accumulation was significantly better with cSUVmax (92 %) than SUVmax (62 %) (p < 0.0001).

Conclusion

PVE-corrected F-18 FDG PET/CT is a valuable predictor of I-131 accumulation in mLNs during RIT.     

Performance of intra-procedural 18-fluorodeoxyglucose PET/CT-guided biopsies for lesions suspected of malignancy but poorly visualized with other modalities

Purpose

We sought to evaluate the safety and the diagnostic success rate of percutaneous biopsies performed under intra-procedural ¹⁸?F-deoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT) guidance for lesions difficult to see with conventional cross-sectional imaging.

Methods

From 2011 to 2013, consecutive clinically indicated percutaneous PET/CT-guided biopsies of 106 masses (mean size, 3.3 cm; range, 0.7–15.9 cm; SD, 2.9 cm) in bones (n?=?33), liver (n?=?26), soft tissues (n?=?18), lung (n?=?15) and abdomen (n?=?14) were reviewed. The biopsy procedures were performed following injection of a mean of 255 MBq (SD, 74) FDG. Mean maximal standardized uptake value (SUV) of lesions was 8.8 (SD, 6.3). A systematic review of the histopathological results and outcomes was performed.

Results

Biopsies were positive for malignancy in 76 cases (71.7 %, 76/106) and for benign tissue in 30 cases (28.3 %, 30/106). Immediate results were considered adequate for 100 PET/CT biopsies (94.3 %, 100/106) requiring no further exploration, and for the six others (5.7 %, 6/106) benign diagnoses were confirmed after surgery (n?=?4) or follow-up (n?=?2). The consequent overall sensitivity and the diagnostic success of biopsy were therefore 100 %. No significant differences in terms of detection of malignancy were observed between the different locations. Lesions > 2 cm or with SUV?>?4 were not significantly more likely to be malignant. Complications occurred after four biopsies (3.7 %, 4/106).

Conclusion

Intra-procedural PET/CT guidance appears as a safe and effective method and allows high diagnostic success of percutaneous biopsies for metabolically active lesions.     

Recurrent bladder carcinoma: clinical and prognostic role of 18 F-FDG PET/CT

Aim

A small number of studies evaluated the detection rate of lesions from bladder carcinoma (BC) of 18 F-FDG PET/CT in the restaging process. However, the prognostic role of FDG PET/CT still remains unclear. The aim of the present study was to evaluate the accuracy, the effect upon treatment decision, and the prognostic value of FDG PET/CT in patients with suspected recurrent BC.

Materials and Methods

Forty-one patients affected by BC underwent FDG PET/CT for restaging purpose. The diagnostic accuracy of visually interpreted FDG PET/CT was assessed compared to histology (n?=?8), other diagnostic imaging modalities (contrast-enhanced CT in 38/41 patients and MRI in 15/41) and clinical follow-up (n?=?41). Semiquantitative PET values (SUVmax, SUVmean, SUL, MTV, TLG) were calculated using a graph-based method. Progression-free survival (PFS) and overall survival (OS) were assessed by using Kaplan-Meier curves. The risk of progression (hazard ratio, HR) was computed by Cox regression analysis by considering all the available variables.

Results

PET was considered positive in 21 of 41 patients. Of these, recurrent BC was confirmed in 20 (95 %). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET/CT were 87 %, 94 %, 95 %, 85 %, 90 %. AUC was 0.9 (95 %IC 0.8-1). Bayesian positive and negative likelihood ratios were 14.5 and 0.13, respectively. FDG PET/CT findings modified the therapeutic approach in 16 patients (modified therapy in 10 PET-positive patients, watch-and-wait in six PET-negative patients). PFS was significantly longer in patients with negative scan vs. those with pathological findings (85 % vs. 24 %, p?<?0.05; HR?=?12.4; p?=?0.001). Moreover, an unremarkable study was associated with a longer OS (88 % vs. 47 % after 2 years and 87 % vs. 25 % after 3 years, respectively, p?<?0.05). Standardized uptake value (SUV)max?>?6 and total lesion glycolysis (TLG)?>?8.5 were recognized as the most accurate thresholds to predict PFS (2-year PFS 62 % for SUVmax?<?6 vs. 15 % for SUVmax?>?6, p?=?0.018; 2-year PFS 66 % for TLG?<?8.5 vs. 18 % for TLG?>?8.5, p?=?0.09).

Conclusion

A very good diagnostic performance for FDG PET/CT was confirmed in patients with suspected recurrent BC. FDG PET/CT allowed for a change in treatment decision in about 40 % of cases and showed an important prognostic value in assessing PFS and OS.

     

Prognostic value of 18 F-FDG uptake by regional lymph nodes on pretreatment PET/CT in patients with resectable colorectal cancer

Purpose

We evaluated the ability of pretreatment ¹⁸?F-FDG uptake by regional lymph nodes to predict the survival of patients with resectable colorectal cancer.

Methods

The records of 78 patients with AJCC stage III colorectal cancer (pathologically confirmed node-positive disease without evidence of distant metastasis) treated with surgery and adjuvant chemotherapy were retrospectively reviewed. The maximum standardized uptake values of the primary tumor (SUVp) and regional lymph nodes (SUVn) were measured by pretreatment ¹⁸?F-FDG PET/CT. The ROC curve analyses and the Cox proportional hazard model were used to analyze whether SUVp, SUVn, and clinicopathologic parameters could predict disease-free survival.

Results

Although there were no significant differences between the median SUVp in the event group and that in the non-event group, the median SUVn was significantly higher in the event group (1.7) than in the non-event group (0.8, p?=?0.023). Based on the ROC curve analysis, SUVn predicted the event for disease-free survival (AUC?=?0.668, p?=?0.02) with the optimal criterion, sensitivity, specificity, and accuracy of?>?1.2, 71 %, 63 %, and 65 %, respectively. However, SUVp did not predict disease-free survival (AUC?=?0.570, p?=?0.349). Univariate analysis revealed that SUVn (p?=?0.011) and venous invasion (p?=?0.016) were associated with disease-free survival, but pathologic N stage was not (p?=?0.09). By multivariate analysis, only SUVn?>?1.2 independently shortened the disease-free survival (relative risk, 2.97; 95 % CI, 1.14–7.74, p?=?0.026).

Conclusion

SUVn before surgery may be a useful prognostic marker in patients with AJCC stage III colorectal cancer.     

Detection of underlying malignancy in patients with paraneoplastic neurological syndromes: comparison of 18F-FDG PET/CT and contrast-enhanced CT

Purpose

To determine the value of combined ¹⁸F-FDG PET/CT with diagnostic contrast-enhanced CT (CECT) in detecting primary malignancies and metastases in patients with paraneoplastic neurological syndromes (PNS) and to compare this with CECT alone.

Methods

PET/CT scans from 66 patients with PNS were retrospectively evaluated. Two blinded readers initially reviewed the CECT portion of each PET/CT scan. In a second session 3 months later, the readers analysed the combined PET/CT scans. Findings on each study were assessed using a four-point-scale (1 normal/benign; 2 inconclusive, further diagnostic work-up may be necessary; 3 malignant; 4 inflammatory). Sensitivity and specificity for malignant findings were calculated for PET/CT and CECT. Interreader agreement was determined by calculating Cohen’s kappa. Pooled data from clinical follow-up (including histopathology and follow-up imaging, median follow-up 20.0 months) served as the reference gold standard.

Results

Both readers classified 12 findings in ten patients (15 %) as malignant on the PET/CT scans (two patients had two primary tumours). One such imaging finding (suspected thymic cancer) was false-positive (i.e. benign histology). The most common tumours were bronchial carcinoma (n?=?3), lymph node metastases of gynaecological tumours (n?=?3) and tonsillar carcinoma (n?=?2). Three of 12 findings (25 %) were not detected by CECT alone (cervical carcinoma, lymph node metastasis and tonsillar carcinoma). In a per-patient analysis, sensitivity and specificity for malignant findings were 100 % and 90 % for PET/CT and 78 % and 88 % for CECT. In 24 % (reader 1) and 21 % (reader 2) of the patients, the PET/CT findings were inconclusive. Of these findings, 57 % (reader 1) and 56 % (reader 2) were only diagnosed with PET (e.g. focal FDG uptake of the thyroid, gastrointestinal tract and ovaries). On follow-up, none of these findings corresponded to malignancy. Overall agreement between the two readers was excellent with a Cohen’s kappa of 0.95?±?0.04 (p?<?0.001) for PET/CT and 0.97?±?0.03 (p?<?0.001) for CECT alone.

Conclusion

In this cohort of patients with PNS, PET/CT exhibited improved detection of underlying malignancy versus CECT alone. While hybrid imaging produces a greater number of inconclusive findings, sensitivity is increased for the detection of head and neck and gynaecological malignancies as well as metastatic lymph node involvement.     

Prognostic value of 18F-FDG PET/CT in patients with soft tissue sarcoma: comparisons between metabolic parameters

Objectives

To investigate the relationship between volume-based PET parameters and prognosis in patients with soft tissue sarcoma (STS).

Methods

We retrospectively reviewed 55 patients with pathologically proven STS who underwent pretreatment with ¹⁸?F-Fluorodeoxyglucose (¹⁸F-FDG) PET/CT. The maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary tumors were measured using a threshold SUV as liver activity for determining the boundary of tumors. Univariate and multivariate survival analyses for overall survival were performed according to the metabolic parameters and other clinical variables.

Results

Cancer-related death occurred in 19 of 55 patients (35 %) during the follow-up period (29?±?23 months). On univariate analysis, AJCC stage (stage IV vs. I-III, hazard ratio (HR)?=?2.837, p?=?0.028), necrosis (G2 vs. G0-G1, HR?=?3.890, p?=?0.004), SUV_max (1 unit - increase, HR?=?1.146, p?=?0.008), SUV_avg (1 unit - increase, HR?=?1.469, p?=?0.032) and treatment modality (non-surgical therapy vs. surgery, HR?=?4.467, p?=?0.002) were significant predictors for overall survival. On multivariate analyses, SUV_max (HR?=?1.274, p?=?0.015), treatment modality (HR?=?3.353, p?=?0.019) and necrosis (HR?=?5.985, p?=?0.006) were identified as significant independent prognostic factors associated with decreased overall survival.

Conclusions

The SUV_max of the primary tumor is a significant independent metabolic prognostic factor for overall survival in patients with STS. Volume-based PET parameters may not add prognostic information outside of the SUV_max.