Complete metabolic response (CMR) in positron emission tomography–computed tomography (PET‐CT) scans may have prognostic significance in patients with marginal zone lymphomas (MZL)

Although clinical use of positron emission tomography–computed tomography (PET‐CT) scans is well established in aggressive lymphomas, its prognostic value in marginal zone lymphoma (MZL) remains yet unclear. Hence, we investigated potential role of PET‐CT in predicting MZL patients' outcomes following systemic chemotherapy. A total of 32 patients with MZL who received first‐line chemotherapy were included in the analysis. They all underwent pretreatment, interim, and posttreatment PET‐CT scans. The primary objective was to evaluate the role of complete metabolic response (CMR) in posttreatment PET‐CT scans in predicting progression‐free survival (PFS). Compared with non‐CMR group, 5‐year PFS rate was significantly higher in patients who achieved CMR in posttreatment PET‐CT (54.2% vs 0.0%, P = .003) and also in patients gaining CMR in interim PET‐CT scans (62.5% vs 15.6%, P = .026). Interestingly, early CMR group, who achieved and maintained CMR in both interim and posttreatment PET‐CT scans, showed significantly higher 5‐year PFS than those with delayed or never CMR group (62.5% vs 37.5% vs 0%, P = .008). Therefore, interim and/or posttreatment CMR can be prognostic at least in these subsets of patients with MZL treated with chemotherapy.     

Role of fluorine-18 fluoro-deoxyglucose positron emission tomography scan in the evaluation and follow-up of patients with low-grade lymphomas

BACKGROUND: Fluorine-18 fluoro-deoxyglucose positron emission tomography (FDG-PET) scanning has excellent sensitivity and specificity for staging non-Hodgkin lymphomas, but to the authors' knowledge few studies to date have evaluated FDG-PET in low-grade lymphomas only. METHODS: A retrospective study was performed on patients with biopsy-proven nontransformed and transformed follicular lymphoma (FL), B-cell small-cell lymphocytic lymphoma (SLL/CLL), or marginal zone lymphoma (MZL) who underwent PET and computed tomography (CT) scans within 3 weeks. Standard uptake values (SUV) of all abnormal foci were measured. RESULTS: In FL, PET demonstrated 94% sensitivity and 100% specificity for staging. PET was more specific than CT for detecting recurrence or assessing therapeutic responses (91% vs. 50%). FDG avidity among patients with WHO Grades 1, 2, and 3 disease was not significantly different (analysis of variance [ANOVA]). For MZL staging, PET had moderate sensitivity (71%) and outperformed CT alone in the depiction of extranodal sites (85% vs. 57% sensitivity). In SLL/CLL, PET sensitivity was 53% and underestimated disease extent in 5 of 19 patients (26%) compared with CT. PET did not affect initial management but confirmed suspected recurrences in 75% of patients. Nontransformed FL had a higher SUV (ANOVA, P < .05) compared with MZL and SLL/CLL. SUV was higher in transformed than in nontransformed tumors (P < .001, Student t test). CONCLUSIONS: PET usefulness in staging low-grade lymphomas varies depending on histology. PET sensitivity is excellent in FL and moderate in MZL. PET is more specific than CT for follow-up in all types. PET has limited usefulness for SLL/CLL staging. However, a suggestive pattern of hazy and mild uptake was often noted in positive scans. In all low-grade lymphomas, the emergence of foci of intense uptake should raise suspicion of conversion to high-grade disease.     

FDG PET/CT as a diagnostic and prognostic tool for the evaluation of marginal zone lymphoma

We evaluated the role of 18‐fluoro‐2‐deoxy‐d ‐glucose positron emission tomography (^[18F] FDG‐PET) with computed tomography (CT) (PET/CT) as a diagnostic and prognostic tool in newly diagnosed marginal zone lymphoma (MZL) patients. This is a retrospective cohort study of patients with newly diagnosed MZL, treated with immunotherapy, chemotherapy regimens, surgery, or Helicobacter pylori eradication between 2008 and 2016 in a single tertiary center. Only patients who had a pretreatment PET/CT (P‐PET/CT) were included. P‐PET/CT, interim (I‐PET/CT), and end‐of‐treatment PET/CT (E‐PET/CT) studies were reviewed. P‐PET/CT results were reported using two methods of evaluation, qualitative and semi quantitative: visual assessment (VAS) and maximal standardized uptake value (SUVmax), and I‐PET and E‐PET results were reported by Deauville 5‐point score (DS) evaluation as well. Avidity of PET/CT was defined as abnormal uptake in any of these methods. The primary outcome was the prognostic role of P‐PET/CT, I‐PET/CT, and E‐PET/CT on progression‐free survival (PFS) and overall survival (OS). Data of 196 patients with MZL were identified, 110 of which had P‐PET/CT and were included in this analysis. Median age was 67 years (range 18‐93). The median follow‐up period was 63 months (range 3‐278). The median OS and PFS for the whole cohort were 63 (interquartile range 39‐85) and 60 (interquartile range 37‐76) months, respectively. The avidity of PET at baseline for the whole cohort was 70% (77/110 patients), for MALT lymphoma, 62.5% (40/64 patients), for NMZL, 76.4% (13/17 patients), and for SMZL, 82.7% (24/29 patients). When adjusted for IPI, sex, and comorbidities, positive E‐PET/CT was associated with reduced PFS with a hazard ratio (HR) of 3.4 (95% CI, 1.27‐9.14, P = 0.02). Positive E‐PET/CT did not correlate with OS. However, there were only three events. P‐PET/CT was not predictive of PFS or OS. Our study demonstrates that above 70% of MZL are FDG avid. Positive E‐PET/CT is a strong prognostic factor for PFS.     

Role of 18F‐FDG‐PET/CT in the management of marginal zone B cell lymphoma

The use of PET in patients with marginal zone B cell lymphoma (MZL) is controversial because of variability of fluorodeoxyglucose (FDG) avidity. We analyzed 40 PET/CT in 25 consecutive patients to compare its performance with CT at staging and as a first‐line response assessment. Sensitivity of PET/CT and CT was 96 and 76%. Mean standard uptake value was 6.1, 6.9 and 3.4 (p = 0.3) in nodal, extranodal and splenic subtypes, respectively. Of 17 patients (extranodal: n = 9; nodal: n = 6; splenic subtype: n = 2) with both imaging tests available at diagnosis, 8 (47%) had more involved areas with PET/CT than with CT, 75% of which were extranodal lesions. PET/CT resulted in upstaging of five patients although treatment of only two of them was changed. Responses of 15 patients with post‐treatment PET/CT were the following: 9 negative and 6 positive of which 3 were isolated residual lesions. Progression was documented in two of these three patients. Response was also assessed by CT in 11 patients. Discrepancies were found in three: Two were in complete remission by CT while PET/CT detected localized residual disease; another patient was in partial remission by CT, whereas PET/CT showed only one positive lesion. Two of these three patients relapsed. Patients with negative post‐treatment PET/CT did not relapse. With a median follow‐up of 50 months (10–152 months), 3‐year overall survival was 100 and 80% for patients with negative and positive post‐treatment PET/CT (p = 0.2). Three‐year disease‐free survival was 86%; the negative predictive value (NPV) was 100%, and the positive predictive value (PPV) was 83.3%. Although a larger number of patients will be required to further confirm these data, we can conclude that PET/CT is a useful imaging tool for both staging and response assessment in patients with nodal and extranodal MZL as a result of its high sensitivity, NPV and PPV. Copyright © 2014 John Wiley & Sons, Ltd.     

High SUV uptake on FDG–PET/CT predicts for an aggressive B-cell lymphoma in a prospective study of primary FDG–PET/CT staging in lymphoma

BackgroundData assessing the role of positron emission tomography (PET)/computed tomography (CT) imaging in lymphoma staging is still being accumulated and current staging is based primarily on CT. This study aims to compare the value of PET/CT over conventional CT and bone marrow biopsy (BMB) in the initial evaluation of patients with lymphoma.MethodsData on 122 patients with PET/CT scans as part of their initial staging were prospectively collected and reviewed. All patients had complete staging, including BMB.ResultsAmong the 122 patients, 101 had non-Hodgkin's lymphoma (NHL) and 21 had Hodgkin's lymphoma (HL). Compared with conventional CT, PET/CT upstaged 21 (17%) cases [B-cell non-Hodgkin's lymphoma (B-NHL), 12; T-cell non-Hodgkin's lymphoma (T-NHL), 3; HL, 6]. Of significance, in 13 patients with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG)-avid splenic lesions, four had normal CT findings. A maximum FDG uptake of >10 standardized uptake value (SUV) seems to significantly correlate with an aggressive B-cell lineage (odds ratio 2.47, 95% confidence interval 2.23–2.70). Overall, PET scan was concordant with BMB results in 108 (89%) and discordant in 14 (11%) cases. In HL, our data show that PET scan and marrow results agreed in 19 of the cases (90%), being concordantly negative in 18 cases and concordantly positive in one, giving a negative predictive value (NPV) of 100%, sensitivity of 100% and specificity of 90%. Of note, all 13 with early-stage HL had negative PET/CT scan and BMB. In NHL, all 17 cases of T-NHL had concordant PET and BMB results. In patients with aggressive B-NHL, BMB and PET/CT agreed in 58 patients (92%) and disagreed in five (8%), while the corresponding rates in indolent B-cell lymphoma were 14 (67%) and seven patients (33%), respectively. All seven were falsely negative.ConclusionsPET/CT upstages 17% of cases and detects occult splenic involvement. This may have potential therapeutic and prognostic implications. SUV >10 may predict for an aggressive histology. Except for indolent B-NHL, our data show that PET scans have a good overall NPV in excluding lymphomatous bone marrow involvement. This is particularly true of early-stage HL, suggesting that BMB may be safely omitted in this group.     

FDG-PET scanning for detection and staging of extranodal marginal zone lymphomas of the MALT type: a report of 42 cases.

BACKGROUND: Although reports have suggested that FDG-PET scans were not useful for staging of extranodal marginal zone lymphomas (MZL), experience at our center suggests otherwise. Thus we reviewed the findings of FDG-PET scans in patients with extranodal MZL seen at our center. PATIENTS AND METHODS: A database of 175 patients with histologically-confirmed diagnoses of extranodal MZL was reviewed. Forty-two patients who had had FDG-PET scans for initial staging were identified. All information was obtained by retrospective review of medical records and PET scans. RESULTS: Thirty-four (81%) patients had focal tracer uptake within verified tumor sites, six (14%) patients did not, and two (5%) patients had indeterminate uptake. Seven of the 34 (21%) patients with uptake within verified tumor sites had uptake in regional lymph nodes and four patients were upstaged due to FDG-PET findings. Eight patients also obtained post-treatment FDG-PET scans. In five of those eight, the repeated FDG-PET scan indicated a complete response, and in three there was an indeterminate or mixed response. CONCLUSION: FDG-PET scans carried out for initial staging of extranodal MZL detected disease in a high proportion of patients. This study suggests that imaging with FDG-PET scans is useful for both initial staging and follow-up of patients with extranodal MZL.     

The value of routine bone marrow biopsy in patients with diffuse large B-cell lymphoma staged with PET/CT: a Danish-Canadian study

BackgroundThe added diagnostic and prognostic value of routine bone marrow biopsy (BMB) in patients with diffuse large B-cell lymphoma (DLBCL) undergoing positron emission tomography combined with computed tomography (PET/CT) staging is controversial.Patients and methodsPatients with newly diagnosed DLBCL who underwent both staging PET/CT and BMB were retrospectively identified in British Columbia, Aalborg, and Copenhagen. Original written PET/CT and pathology reports were retrospectively reviewed to determine Ann Arbor stage and outcomes, with and without the contribution of BMB.ResultsA total of 530 patients were identified: 146 (28%) had focal bone marrow (BM) lesions on PET/CT and 87 (16%) had positive BMB. Fifty-two of 146 patients (36%) with positive PET/CT had a positive BMB [39 DLBCL, 13 indolent non-Hodgkin lymphoma (iNHL)], while 35 of 384 patients (9%) with negative PET/CT had positive BMB (12 DLBCL, 23 iNHL). BMB upstaged 12/209 (6%) of stage I/II patients to stage IV, although this was the case for only 3 (1%) patients with DLBCL in the BMB. PET/CT identified BM involvement by BMB with sensitivity 60%, specificity 79%, positive predictive value 36%, and negative predictive value 91%. Concordant histological involvement of the BM by DLBCL was associated with worse overall survival and progression-free survival than discordant or no involvement in univariate and multivariate analyses.ConclusionsIn patients with DLBCL, staging PET/CT can miss BM involvement with concordant DLBCL (less common) or discordant iNHL (more common). Routine BMB does not add relevant diagnostic or prognostic value over PET/CT alone in the majority of patients with DLBCL.     

Positron emission tomography/computed tomography in the management of recurrent/metastatic breast cancer: a large retrospective study from the Royal Marsden Hospital

BackgroundDespite the increasing use of positron emission tomography/computed tomography (PET/CT) in the management of patients with breast cancer, its role is yet to be defined.Patients and methodsWe reviewed PET/CT scans carried out in breast cancer patients, the indication, concordance/discordance with other imaging and whether their use had altered patient management.ResultsPET/CT scans (233) were carried out in 122 patients between July 2004 and October 2008. Indications were as follows: staging (S) (91), response assessment (RA) (87), clarification (C) of findings on other imaging (32) and reassurance (ASS) (23). In the S group, positive scans were helpful in accurately defining the extent of disease and guided localised or systemic treatment. PET/CT was particularly useful for detecting lytic bone metastases. One-third of the scans was carried out for RA. PET/CT allowed early RA and in some cases appropriate discontinuation of ineffective treatment. PET/CT was used effectively for the clarification of indeterminate lesions on CT (18), magnetic resonance imaging (15) and bone scan (13). In the ASS group, all scans were negative.ConclusionsPET/CT is useful in accurately staging metastatic disease, assessing response to systemic treatment and clarifying equivocation on other imaging. Incorporation of PET/CT in these areas contributes to breast cancer management optimisation.     

[18F]-FDG–PET in clinical stage I/II non-seminomatous germ cell tumours: results of the German multicentre trial

PurposeThe aim of this study was to determine the predictive values of 2-[fluorine-18]fluoro-2-deoxy-D-glucose–positron emission tomography (FDG–PET) in primary staging in patients with newly diagnosed non-seminomatous germ cell tumour (NSGCT) clinical stage I/II.Patients and methodsThe hypothesis was that FDG–PET would improve the negative predictive value (NPV) from 70% to 90%, thus requiring a total of 169 patients. All scans underwent visual analysis by a reference team of nuclear medicine physicians. Results were validated by histology following retroperitoneal lymph node dissection.ResultsOnly 72 of the planned 169 patients were included, due to poor accrual. The prevalence of nodal involvement was 26%. Correct nodal staging by FDG–PET was achieved in 83% compared with correct computed tomography (CT) staging in 71%. CT had a sensitivity and specificity of 41% and 95%, respectively. Positive predictive value (PPV) and NPV were 87% and 67%, respectively. FDG–PET had a sensitivity and specificity of 66% and 98%, respectively. PPV was 95%. The primary end point was not reached, with an NPV of 78%.ConclusionFDG–PET as a primary staging tool for NSGCT yielded only slightly better results than CT. Both methods had a high specificity while false-negative findings were more frequent with CT. FDG–PET is mostly useful as a diagnostic tool in case of questionable CT scan.     

Diagnostic and Clinical Impact of Staging 18F-FDG PET/CT in Mantle-Cell Lymphoma: A Two-Center Experience

IntroductionThe diagnostic accuracy of fluorine-18–fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in staging mantle-cell lymphoma has not yet investigated. The aim of this 2-center retrospective study was to investigate the utility of ¹⁸F-FDG PET/CT in assessing nodal, splenic, bone marrow (BM), and gastrointestinal (GI) disease compared to CT, BM, and GI endoscopy; and to assess its clinical impact.Patients and MethodsOne hundred twenty-two patients with histologically proven mantle-cell lymphoma were included. PET/CT BM findings were considered positive if isolated/multiple focal uptake in the BM not explained by benign findings and/or diffuse BM uptake higher than liver with/without focal uptakes were present. PET/CT findings were considered positive for GI involvement in the presence of isolated/multiple focal uptake in the GI organ.ResultsAll patients had positive PET/CT showing the presence of at least one hypermetabolic lesion, with the exception of one case. PET/CT results, compared to CT, detected more nodal and/or splenic lesions in 26 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT for BM were 52%, 98%, 97%, 65%, and 74%; for GI 64%, 91%, 69%, 90%, and 85%; and for GI excluding diabetic patients, 78%, 92%, 72%, 94%, and 89%. PET/CT permitted upstaging of 21 cases and downstaging of 2.Conclusion¹⁸F-FDG PET/CT showed excellent detection rate in nodal and splenic disease—a rate better than CT. For BM and GI evaluation, in order to reach good accuracy, the selection of patients and the use of specific criteria for evaluation of these organs seems to be crucial. Moreover, PET/CT altered the management and therapeutic approach in about 20% of patients.     

To PET or not to PET? That is the question. Staging in anal cancer

BackgroundAnal cancer is a rare tumour accounting for ∼2% of all colorectal cancers between 1997 and 2000 in the UK. Staging is still dominated by DRE (digital rectal examination), computed tomography (CT) and magnetic resonance imaging (MRI) imaging. The role of PET as a definitive modality is still emerging and there are relatively few adequate studies in the literature.MethodsWe looked at patients treated radically for anal cancer at Mount Vernon Cancer Centre (UK) between 2009 and 2010. Eighty-eight patients underwent treatment according to data-based coding records of which 46 had positron emission tomography (PET)/CT scans. Notes were unavailable for three patients. We compared staging following conventional modalities (DRE, MRI and CT) and PET/CT scans for these 43 patients.ResultsIn 18 patients, the PET/CT stage differed from MRI. PET/CT altered the stage in 42% of patients but changes in subsequent management were not implemented.ConclusionsOur data show that PET/CT does alter staging in a significant number of cases although it did not lead to change in management under the current guidelines. Furthermore, there is agreement that PET/CT shows greater sensitivity for detection of lymph nodes and our study has demonstrated a distinct trend towards upstaging of anal cancer with PET/CT.     

The Pattern of Use of PET/CT Scans in the Clinical Management of Chronic Lymphocytic Leukemia

BackgroundThe study aimed to evaluate the utilization patterns of positron emission tomography/computed tomography (PET/CT) in chronic lymphocytic leukemia (CLL) patients and to investigate whether the results of these scans influenced treatment decisions.Patientsand Methods: In this observational study, we analyzed patients with CLL or small lymphocytic leukemia (SLL) who underwent at least one PET/CT scan from 2007 to 2018. Patients were divided into two groups: (1) patients who had at least one fluorodeoxyglucose-avid PET/CT scan, and (2) patients who had all negative scans. PET/CT results were retrieved from patients’ medical files and were revised by an expert radiologist according to visual score scale, SUVmax/SUVliver mean ratio, and the SUVmax.ResultsOf the 524 patients, 160 patients (30.5%) had PET/CT scans, and 120 patients met the inclusion criteria. A total of 219 eligible scans were analyzed; 62 of these scans (28.3%) were reported as positive, and 167 of these scans (76.3%) were performed for staging. There was a significant association between PET/CT results and change of therapy (P < .001); however, 62.9% of the positive PET/CT scans were not followed by a change of treatment. Survival time was not different between the two groups. The SUVmax/SUVliver mean ratio was negatively significantly associated with lymphocytes percent (r = –0.237, P = .042) and positively associated with lactate dehydrogenase levels (r = 0.338, P = .008) among CLL patients.ConclusionDespite the fact that the use of surveillance PET/CT for patients with CLL/SLL is not in the guidelines and that it is not useful for disease management, in practice the test is in frequent use in Israel.     

Stage Migration in Planning PET/CT Scans in Patients Due to Receive Radiotherapy for Non–Small-Cell Lung Cancer

IntroductionThis study examined rates of tumor progression in treatment-naive patients with non–small-cell lung cancer (NSCLC) as determined by repeat treatment-planning fluorine-18 (¹⁸F) fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).Methods and MaterialsThis study assessed patients who underwent PET/CT simulation for NSCLC stage II/III, radiation-naive, nonmetastatic NSCLC. It compared planning PET/CT with previous PET/CT images. Patients were analyzed for change in stage, treatment intent, or both. Progression was defined as a change in TNM status leading to upstaging, and standardized uptake value (SUV) velocity was defined as [(SUV_scan2 − SUV_scan1)/interscan interval in days].ResultsOf 149 consecutive patients examined between April 2009 and April 2011, 47 had prior PET/CT scans and were included. The median age was 68 years. New nodal disease or metastatic disease was identified in 24 (51%) of 47 patients. Fourteen (30%) had evidence of extrathoracic metastatic disease; the remaining 10 (21%) had new nodal disease that required substantial alteration of treatment fields. At a scan interval of 20 days, the rate of upstaging was 17%. SUV velocity was analyzed in the subset of patients who had their studies on the identical PET/CT scanner (n = 14). Nonupstaged patients had a mean SUV velocity of 0.074 units per day, compared with 0.11 units per day in patients that were upstaged by their second PET/CT scan (P = .020).ConclusionRadiation treatment planning with hybrid PET/CT scans repeated within 120 days of an initial staging PET/CT scan identified significant upstaging in more than half of patients. For a subset of patients who underwent both scans on the same instrument, SUV velocity predicts upstaging, and the difference between those upstaged and those not was statistically significant.     

Preoperative PET/CT in early-stage breast cancer

BackgroundThe aim of this study was to assess the diagnostic and therapeutic impact of preoperative positron emission tomography and computed tomography (PET/CT) in the initial staging of patients with early-stage breast cancer.Patients and methodsA total of 103 consecutive patients with newly diagnosed operable breast cancer with tumors ≥2 cm were independently examined preoperatively with conventional assessment (mammography, breast/axillary ultrasound, chest X-ray and blood samples) and PET/CT with no prior knowledge of the other.ResultsPET/CT identified a primary tumor in all but three patients (97%). PET/CT solely detected distant metastases (ovary, bones and lung) in 6 patients and new primary cancers (ovary, lung) in another two patients, as well as 12 cases of extra-axillary lymph node involvement. In 15 patients (15%), extra-axillary malignancy was detected by PET/CT only, leading to an upgrade of initial staging in 14% (14/103) and ultimately a modification of planned treatment in 8% (8/103) of patients.ConclusionsPET/CT is a valuable tool to provide information on extra-axillary lymph node involvement, distant metastases and other occult primary cancers. Preoperative ¹⁸F-fluorodeoxyglucose–PET/CT has a substantial impact on initial staging and on clinical management in patients with early-stage breast cancer with tumors ≥2 cm.     

18F‐FDG uptake and its clinical relevance in primary gastric lymphoma

We studied the clinical relevance of ¹⁸F‐fluorodeoxyglucose (¹⁸F‐FDG) uptake in patients with primary gastric lymphoma underwent positron emission tomography (PET)/ computed tomography (CT) scan. Forty‐two patients with primary gastric lymphoma were analysed: 32 diffuse large B‐cell lymphomas (DLBCL) and 10 extranodal marginal zone B‐cell lymphomas of mucosa‐associated lymphoid tissue (MALT lymphomas). The PET/CT scans were compared with clinical and pathologic features, and the results of CT and endoscopy. Nine patients were up‐staged based on the results of their PET/CT scan compared to CT (seven DLBCLs, two MALT lymphomas) while six patients were down‐staged by the PET/CT scan. The standard uptake value (SUV) was used as an indicator of a lesion with a high metabolic rate. The high SUVmax group, defined as an SUVmax ≥ median value, was significantly associated with an advanced Lugano stage (p < 0.001). Three patients with DLBCL, who showed an initially high SUVmax, died of disease progression. Among 24 patients for whom follow‐up PET/CT scan with endoscopy was performed, 11 patients with ulcerative or mucosal lesions showed residual ¹⁸F‐FDG uptake. All of these gastric lesions were grossly and pathologically benign lesions without evidence of lymphoma cells. In conclusion, PET/CT scan can be used in staging patients with primary gastric lymphoma; however, the residual ¹⁸F‐FDG uptake observed during follow‐up should be interpreted cautiously and should be combined with endoscopy and multiple biopsies of the stomach. Copyright © 2009 John Wiley & Sons, Ltd.     

Impact of 18F-FDG PET/CT staging on management and prognostic stratification in head and neck squamous cell carcinoma: A prospective observational study

BackgroundAccurate assessment of the extent of cancer is essential for appropriate treatment planning and outcome prediction. This study prospectively evaluated whether adding ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) to the routine initial staging practice in head and neck squamous cell carcinoma (HNSCC) improved management and prognosis.MethodsAll consecutive patients with newly diagnosed HNSCC who presented in October 2010 – December 2012 underwent conventional workups (CWU) followed by PET/CT. The clinical stage and management plans before and after PET/CT were compared. PET/CT was deemed to have no/low, moderate, and high impact on management planning depending on whether PET/CT changed the treatment modality or goal. The appropriateness of PET/CT staging and management impact was confirmed by histopathology and clinical follow-up, and its association with survival was analysed.FindingsOf the 248 patients, PET/CT changed the Tumour Node Metastasis (TNM) classification in 79 (31.9%). In the patients with discordant staging, PET/CT staging was significantly more sensitive and accurate than CWU staging (both P < 0.001). PET/CT had high or moderate impact on management in 39 (15.7%) patients. Patients with PET/CT upstaged disease had significantly worse progression-free survival (PFS) and overall survival (OS) than patients with no CWU-stage changes (3-year PFS = 56.8% versus 74.5%, P = 0.043; 3-year OS = 61.3% versus 85.3%, P = 0.006). Multivariate analyses revealed that PET/CT staging and second primary cancer were independent predictive factors for both PFS and OS (P < 0.05, each).Interpretations¹⁸F-FDG PET/CT added important staging information that improved management and prognostic stratification in HNSCC.     

Long-term metabolic evolution of brain metastases with suspected radiation necrosis following stereotactic radiosurgery: longitudinal assessment by F-DOPA PET

BackgroundThe evolution of radiation necrosis (RN) varies depending on the combination of radionecrotic tissue and active tumor cells. In this study, we characterized the long-term metabolic evolution of RN by sequential PET/CT imaging with 3,4-dihydroxy-6-[¹⁸F]-fluoro-l-phenylalanine (F-DOPA) in patients with brain metastases following stereotactic radiosurgery (SRS).MethodsThirty consecutive patients with 34 suspected radionecrotic brain metastases following SRS repeated F-DOPA PET/CT every 6 months or yearly in addition to standard MRI monitoring. Diagnoses of local progression (LP) or RN were confirmed histologically or by clinical follow-up. Semi-quantitative parameters of F-DOPA uptake were extracted at different time points, and their diagnostic performances were compared with those of corresponding contrast-enhanced MRI.ResultsNinety-nine F-DOPA PET scans were acquired over a median period of 18 (range: 12–66) months. Median follow-up from the baseline F-DOPA PET/CT was 48 (range 21–95) months. Overall, 24 (70.6%) and 10 (29.4%) lesions were classified as RN and LP, respectively. LP occurred after a median of 18 (range: 12–30) months from baseline PET. F-DOPA tumor-to-brain ratio (TBR) and relative standardized uptake value (rSUV) increased significantly over time in LP lesions, while remaining stable in RN lesions. The parameter showing the best diagnostic performance was rSUV (accuracy = 94.1% for the optimal threshold of 1.92). In contrast, variations of the longest tumor dimension measured on contrast-enhancing MRI did not distinguish between RN and LP.ConclusionF-DOPA PET has a high diagnostic accuracy for assessing the long-term evolution of brain metastases following SRS.     

Comparison of (11)C-choline PET/CT and enhanced CT in the evaluation of patients with pulmonary abnormalities and locoregional lymph node involvement in lung cancer

BackgroundThis study compares the diagnostic abilities of integrated ¹¹C-choline PET/CT imaging and contrast-enhanced helical CT imaging in pulmonary lesions and locoregional lymph node metastases in patients with lung cancer.Patients and MethodsOne hundred eight patients with proven or suspected lung cancer underwent integrated ¹¹C-choline PET/CT and contrast-enhanced CT, followed by surgical resection and nodal staging.ResultsThe ¹¹C-choline PET/CT and CT diagnoses of pulmonary lesions and locoregional lymph node metastases were compared with pathologic findings, which revealed benign lesions in 26 patients (tuberculoma [8 patients], inflammatory pseudotumor [7 patients], hamartoma [6 patients], sclerosing hemangioma [4 patients], and pulmonary sequestration [1 patient]) and lung cancers in 82 patients (adenocarcinoma [39 patients], squamous cell carcinoma [23 patients], carcinoid [7 patients], small-cell lung cancer [5 patients], adenosquamous carcinoma [5 patients], and large-cell lung cancer [3 patients]). The accuracy, sensitivity, and specificity of ¹¹C-choline PET/CT for diagnosing lung cancer were 82.4%, 85.4%, and 73.1%, respectively, compared with 73.1%, 76.8%, and 61.5%, respectively, for CT. Differences between ¹¹C-choline PET/CT and CT in diagnosing lung cancer were not statistically significant (p = .503, .118, and .375, respectively). We used receiver operating characteristic (ROC) curve for analysis, finding the ROC of standard uptake value (SUV_max) for diagnosing lung cancer. The cutoff value of SUV_max was 3.54. Preoperative nodal staging was compared with postoperative histopathologic staging. ¹¹C-choline PET/CT correctly staged 80.5% of patients, 12.2% were overstaged, and 7.3% were understaged; for CT these values were 58.5%, 24.4%, and 17.1%, respectively. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ¹¹C-choline PET/CT for lymph nodes were 83.8%, 82.4%, 84.1%, 50.3%, and 96.1%, respectively, compared with 69.3%, 63.7%, 71.2%, 30.2%, 91.0%, respectively, for CT.ConclusionDifferences in the accuracy, sensitivity, specificity, PPV, and NPV between ¹¹C-choline PET/CT and CT are thus statistically significant for nodal staging (p = .003, .007, .000, .000, and .004, respectively). Although ¹¹C-choline PET/CT is not significantly better at diagnosing pulmonary lesions than is enhanced CT, ¹¹C-choline PET/CT has improved sensitivity, specificity, accuracy, PPV, and NPV relative to enhanced CT in the evaluation of locoregional lymph nodes.     

Combined PET and low-dose,noncontrast CT scanning obviates the need for additional diagnostic contrast-enhanced CT scans in patients undergoing staging or restaging for lymphoma

BackgroundPositron emission tomography (PET) is more accurate than computed tomography (CT) in staging and restaging of lymphoma, but both are considered necessary. Increasingly, PET is carried out with a low-dose CT scan. Many patients undergo both PET/CT and standard diagnostic CT. The clinical utility of performing both studies in patients with lymphoma was evaluated.Patients and methodsPatients with lymphoma who underwent concurrent PET/CT and diagnostic CT (a scan pair) were identified, and findings detected in either scan but not both were documented. Discrepancies were considered significant if they were related to either lymphoma or another disease process which potentially required intervention.ResultsEighty-seven scan pairs were identified. PET/CT detected additional lesions over diagnostic CT in 30 patients, of which 11 demonstrated increased clinical stage. Lymphoma therapy changed based on PET/CT in two patients, and one occult rectal cancer was detected. In contrast, diagnostic CT detected five relevant findings, including two incidental findings (venous thrombosis) and three patients with splenic lesions, none of which could be confirmed as lymphoma. No patient had change of stage or lymphoma therapy based on diagnostic CT.ConclusionIn our series, diagnostic CT did not add value to staging or restaging of lymphoma when carried out concurrently with PET/CT.     

18F]fluorodeoxyglucose positron emission tomography scanning for staging, response assessment, and disease surveillance in patients with mantle cell lymphoma

BackgroundPositron emission tomography (PET) is an important imaging modality in the staging and response assessment of patients with lymphoma, but data on its specific use in mantle cell lymphoma (MCL) are lacking.Patients and MethodsThe records of 28 patients with MCL who had a total of 123 [¹⁸F]fluorodeoxyglucose (FDG) PET scans between March 1999 and November 2005 were reviewed. Nine patients had staging scans. The other scans were performed for response assessment or relapse surveillance.ResultsFDG-PET sensitivity was 100% for nodal disease in the 9 patients studied at baseline. Positron emission tomography scans performed for response assessment were concordant with conventional imaging in 47% and discordant in 53% of cases. Positron emission tomography scanning led to earlier diagnosis of relapse in 1 of 17 patients but produced a high rate of false-negative findings in the evaluation of gastrointestinal involvement.ConclusionFDG-PET appears to be a sensitive modality for staging and for response assessment in MCL but was not found to be useful in relapse surveillance or in the evaluation of gastrointestinal disease.