18F‐Fluorodeoxyglucose positron emission tomography/computed tomography for the detection of recurrent bone and soft tissue sarcoma

BACKGROUND:

The clinical utility of modern hybrid imaging modalities for detecting recurrent bone or soft tissue sarcoma remains to be determined. In this report, the authors present a clinical study on the diagnostic accuracy and incremental value of integrated ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) in patients with a history of sarcoma who have clinically suspected disease recurrence.

METHODS:

Forty‐three patients who had a history of bone or soft tissue sarcoma and had documented complete remission underwent ¹⁸F‐FDG PET/CT. Image analysis was performed independently for ¹⁸F‐FDG PET (n = 43) and for contrast‐enhanced spiral CT (CE‐CT) (n = 30) by 2 separate readers, whereas combined ¹⁸F‐FDG PET/CT (n = 43) images were analyzed in consensus by both readers. Imaging findings were rated on a 5‐point scale and finally were reported as malignant, benign, or equivocal. Imaging findings were validated either by histopathology (n = 24) or by clinical follow‐up (n = 19).

RESULTS:

¹⁸F‐FDG PET/CT had greater sensitivity and specificity compared with CE‐CT alone (94% and 92% vs 78% and 67%, respectively), resulting in significantly greater accuracy (93% vs 73%; P = .03). ¹⁸F‐FDG PET/CT was particularly superior regarding detection of local recurrence or soft tissue lesions (sensitivity and specificity: 83% and 100% vs 50% and 100%, respectively) or bone metastases (100% and 100% vs 85% and 88%, respectively).

CONCLUSIONS:

¹⁸F‐FDG PET/CT had greater diagnostic accuracy in the detection of recurrent bone or soft tissue sarcoma compared with CE‐CT alone. The detection of local recurrence was the most evident advantage of ¹⁸F‐FDG PET/CT over CE‐CT. Cancer 2013. © 2012 American Cancer Society.     

High rates of tumor growth and disease progression detected on serial pretreatment fluorodeoxyglucose‐positron emission tomography/computed tomography scans in radical radiotherapy candidates with nonsmall cell lung cancer

BACKGROUND:

The authors studied growth and progression of untreated nonsmall cell lung cancer (NSCLC) by comparing diagnostic and radiotherapy (RT) planning fluorodeoxyglucose (FDG)‐positron emission tomography (PET)/computed tomography (CT) scans before proposed radical chemo‐RT.

METHODS:

Patients enrolled on a prospective clinical trial were eligible for this analysis if they underwent 2 pretreatment whole body FDG‐PET/CT scans, >7 days apart. Scan 1 was performed for diagnosis/disease staging and scan 2 for RT planning. Interscan comparisons included disease stage, metabolic characteristics, tumor doubling times, and change in treatment intent.

RESULTS:

Eighty‐two patients underwent planning PET/CT scans between October 2004 and February 2007. Of these, 28 patients (61% stage III, 18% stage II) had undergone prior staging PET/CT scans. The median interscan period was 24 days (range, 8‐176 days). Interscan disease progression (TNM stage) was detected in 11 (39%) patients. The probability of upstaging within 24 days was calculated to be 32% (95% confidence interval [CI], 18%‐49%). Treatment intent changed from curative to palliative in 8 (29%) cases, in 7 because of PET. For 17 patients who underwent serial PET/CT scans under standardized conditions, there was a mean relative interscan increase of 19% in tumor maximum standardized uptake value (SUV) (P = .022), 16% in average SUV (P = .004), and 116% in percentage injected dose (P = .002). Estimated doubling time of FDG avid tumor was 66 days (95% CI, 51‐95 days).

CONCLUSIONS:

Rapid tumor progression was detected in patients with untreated, predominantly stage III, NSCLC on serial FDG‐PET/CT imaging, highlighting the need for prompt diagnosis, staging, and initiation of therapy in patients who are candidates for potentially curative therapy. Cancer 2010. © 2010 American Cancer Society.     

Plasma Epstein-Barr virus DNA screening followed by ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography in detecting posttreatment failures of nasopharyngeal carcinoma

BACKGROUND:

The authors investigated the clinical implication of plasma Epstein‐Barr virus (EBV) DNA assay and ¹⁸F‐fluoro‐2‐deoxy‐D‐glucose (¹⁸F‐FDG) positron emission tomography (PET) in the detection of recurrent nasopharyngeal carcinoma (NPC).

METHODS:

Two hundred forty‐five patients with NPC who had previously received treatment and were in a state of remission were monitored prospectively using a plasma EBV DNA assay every 3 to 6 months. ¹⁸F‐FDG PET studies were obtained when abnormal EBV DNA or clinically suggestive signs of recurrence were noted.

RESULTS:

Thirty‐six of 245 patients (14.7%) patients had abnormal EBV DNA tests and underwent PET scans. In the remaining 209 patients, 3658 blood tests were negative. PET scans also were obtained in 5 patients who had undetectable EBV DNA levels but signs that were clinically suggestive of disease recurrence. Subsequent analyses focused on 41 patients who had PET studies. In lesion‐based analyses, the sensitivity, specificity, and accuracy of PET by visual interpretation were 81.8%, 77.1%, and 79.2%, respectively, for all 125 lesions. In patient‐based analyses, the accuracy of PET by visual interpretation was 51.2%. All 36 patients who had detectable plasma levels of EBV DNA had demonstrable NPC recurrences, whereas no recurrences were noted in 5 patients who had undetectable EBV DNA levels but signs that clinically mimicked a recurrence. Compared with annual PET, the annual cost of blood tests every 3 to 6 months per patient saved approximately 77% ～ 88% in expenses.

CONCLUSIONS:

The plasma EBV DNA assay correctly predicted all NPC recurrences, and PET had high capacity to localize potential lesion sites. The authors concluded that applying the strategy of EBV DNA screening followed by PET scanning may guide appropriate further treatment planning in a cost‐effective manner. Cancer 2011;. © 2011 American Cancer Society.     

A prospective evaluation of the utility of 2‐deoxy‐2‐[18F]fluoro‐D‐glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer

BACKGROUND:

The aim of this study was to examine prospectively the utility of adding preoperative [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG‐PET)/computed tomography (CT) to routine CT, endoscopic ultrasound (EUS), and laparoscopic staging of localized gastric cancer.

METHODS:

Patients with locally advanced gastric/gastroesophageal cancer were screened for 2 institutional review board–approved Memorial Sloan‐Kettering Cancer Center neoadjuvant chemotherapy protocols. Locally advanced disease was defined as T3 or T4, or lymph node–positive, based on EUS and high‐resolution CT scan. All patients underwent both standard FDG‐PET/CT and laparoscopy with cytological examination of washings. The sensitivity and specificity of FDG‐PET/CT for the identification of metastatic disease not seen on CT was determined. An economic model using Medicare/Medicaid reimbursement charges was developed to assess the cost‐effectiveness of these interventions.

RESULTS:

A total of 113 patients were enrolled from 2003 to 2010. All patients were assessed as having locally advanced disease by CT/EUS. FDG uptake in the primary tumor was associated with male sex, proximal tumors, and nondiffuse Lauren's subtype. 31 (27%) patients had occult metastatic disease detected by PET/CT (n = 11, 10%) and/or laparoscopy (n = 21, 19%), with a single overlap. Economic modeling suggests that the addition of FDG‐PET/CT to the standard staging evaluation of patients with locally advanced gastric cancer resulted in an estimated cost savings of ～US $13,000 per patient.

CONCLUSIONS:

FDG‐PET/CT identifies occult metastatic lesions in approximately 10% of patients with locally advanced gastric cancer. Because of reduced morbidity from fewer futile surgeries and lower patient care costs, PET/CT should be considered as a component of the standard staging algorithm for localized gastric cancer. Cancer 2012. © 2012 American Cancer Society.     

Detection of hematogenous bone metastasis in cervical cancer

BACKGROUND:

In this large‐scale, retrospective study, the authors evaluated the diagnostic performances of computed tomography (CT), magnetic resonance (MR) imaging, and ¹⁸F‐fluorodeoxyglucose‐positron emission tomography (¹⁸F‐FDG–PET) in detecting hematogenous bone metastasis in patients with cervical cancer. The associated risk factors also were analyzed.

METHODS:

Patients with invasive cervical cancer who had both ¹⁸F‐FDG–PET studies and CT or MR imaging studies were selected. Patients who had either International Federation of Gynecology and Obstetrics (FIGO) stage III/IV disease or positive lymph node metastasis at the time of primary staging and patients who had suspected recurrent disease were included in the analyses. The diagnostic performances of PET was compared with the performance of CT and MR imaging by using the area under the receiver‐operating‐characteristic curve (AUC). Both univariate and multivariate analyses were applied to assess the risk factors for hematogenous bone metastasis at primary staging.

RESULTS:

PET was more sensitive than CT (P = .004) and was more specific than MR imaging (P = .04). The diagnostic performance of PET was significantly superior to the performance CT (AUC, 0.964 vs 0.662; P < .001) and MR (AUC, 0.966 vs 0.833; P = .033). Both FIGO stage and the extent of lymph node metastases were associated with hematogenous bone metastasis in univariate analysis. However, the extent of lymph node metastases was the only significant risk factor in multivariate analysis (P = .025).

CONCLUSIONS:

The current study demonstrated the superiority of ¹⁸F‐FDG–PET over CT and MR imaging for detecting hematogenous bone metastasis in patients with advanced cervical cancer. Hematogenous bone metastasis in cervical cancer was associated with the extent of lymph node metastases rather than with FIGO stage. Cancer 2009. © 2009 American Cancer Society.     

The role of FDG PET/CT in patients with locoregional breast cancer recurrence: A comparison to conventional imaging techniques

Purpose

The aim of this study was to evaluate the impact of ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) on clinical management in patients with locoregional breast cancer recurrence amenable for locoregional treatment and to compare the PET/CT results with the conventional imaging data.

Patients and methods

From January 2006 to August 2008, all patients with locoregional breast cancer recurrence underwent whole-body PET/CT. PET/CT findings were compared with results of the conventional imaging techniques and final pathology. The impact of PET/CT results on clinical management was evaluated based on clinical decisions obtained from patient files.

Results

56 patients were included. In 32 patients (57%) PET/CT revealed additional tumour localisations. Distant metastases were detected in 11 patients on conventional imaging and in 23 patients on PET/CT images (p < 0.01). In 25 patients (45%), PET/CT detected additional lesions not visible on conventional imaging. PET/CT had an impact on clinical management in 27 patients (48%) by detecting more extensive locoregional disease or distant metastases. In 20 patients (36%) extensive surgery was prevented and treatment was changed to palliative treatment. The sensitivity, specificity, accuracy, positive and negative predictive values of FDG PET/CT were respectively 97%, 92%, 95%, 94% and 96%.

Conclusions

PET/CT, in addition to conventional imaging techniques, plays an important role in staging patients with locoregional breast cancer recurrence since its result changed the clinical management in almost half of the patients. PET/CT could potentially replace conventional staging imaging in patients with a locoregional breast cancer recurrence.     

Impact of positron emission tomography/computed tomography surveillance at 12 and 24 months for detecting head and neck cancer recurrence

BACKGROUND:

In head and neck cancer (HNC), 3‐month post‐treatment positron emission tomography (PET)/computed tomography (CT) reliably identifies persistent/recurrent disease. However, further PET/CT surveillance has unclear benefit. The impact of post‐treatment PET/CT surveillance on outcomes is assessed at 12 and 24 months.

METHODS:

A 10‐year retrospective analysis of HNC patients was carried out with long‐term serial imaging. Imaging at 3 months included either PET/CT or magnetic resonance imaging, with all subsequent imaging comprised of PET/CT. PET/CT scans at 12 and 24 months were evaluated only if preceding interval scans were negative. Of 1114 identified patients, 284 had 3‐month scans, 175 had 3‐ and 12‐month scans, and 77 had 3‐, 12‐, and 24‐month scans.

RESULTS:

PET/CT detection rates in clinically occult patients were 9% (15 of 175) at 12 months, and 4% (3 of 77) at 24 months. No difference in outcomes was identified between PET/CT‐detected and clinically detected recurrences, with similar 3‐year disease‐free survival (41% vs 46%, P = .91) and 3‐year overall survival (60% vs 54%, P = .70) rates. Compared with 3‐month PET/CT, 12‐month PET/CT demonstrated fewer equivocal reads (26% vs 10%, P < .001). Of scans deemed equivocal, 6% (5 of 89) were ultimately found to be positive.

CONCLUSIONS:

HNC patients with negative 3‐month imaging appear to derive limited benefit from subsequent PET/CT surveillance. No survival differences were observed between PET/CT‐detected and clinically detected recurrences, although larger prospective studies are needed for further investigation. Cancer 2013. © 2012 American Cancer Society.     

Functional imaging of neuroendocrine tumors with combined PET/CT using 68Ga-DOTATATE (DOTA-DPhe1,Tyr3-octreotate) and 18F-FDG

BACKGROUND.

The aim was to assess the relevant distribution of the novel PET tracer ⁶⁸Ga‐DOTATATE in neuroendocrine tumors (NETs) with combined positron emission tomography / computed tomography (PET/CT) and compare its performance with that of ¹⁸F‐FDG PET/CT.

METHODS.

The imaging findings with ⁶⁸Ga‐DOTATATE and ¹⁸F‐FDG on 38 consecutive patients with a diagnosis of primary or recurrent NET were compared and correlated with tumor grade on histology based on ki67 and mitotic index.

RESULTS.

The sensitivity of ⁶⁸Ga‐DOTATATE PET/CT was 82% (31 of 38) and that of ¹⁸F‐FDG PET/CT was 66% (25 of 38). The sensitivity of combined ⁶⁸Ga‐DOTATATE and ¹⁸F‐FDG PET/CT was 92% (35 of 38). There was greater uptake of ⁶⁸Ga‐DOTATATE than ¹⁸F‐FDG in low‐grade NET (median SUV 29 vs 2.9, P < .001). In high‐grade NET there was higher uptake of ¹⁸F‐FDG over ⁶⁸Ga‐DOTATATE (median SUV 11.7 vs 4.4, P = .03). There was a significant correlation with predominant tumor uptake of ⁶⁸Ga‐DOTATATE or ¹⁸F‐FDG and tumor grade on histology (P < .0001).

CONCLUSIONS.

⁶⁸Ga‐DOTATATE PET/CT is a useful novel imaging modality for NETs and is superior to ¹⁸F‐FDG for imaging well‐differentiated NET. Functional imaging with both ⁶⁸Ga‐DOTATATE and ¹⁸F‐FDG has potential for a more comprehensive tumor assessment in intermediate‐ and high‐grade tumors. Cancer 2008. ©2008 American Cancer Society.     

18F‐fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT) imaging in the staging and prognosis of inflammatory breast cancer

BACKGROUND:

To prospectively assess fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT) staging and prognosis value in patients with suspected inflammatory breast cancer (IBC).

METHODS:

Sixty‐two women (mean age 50.7 ± 11.4 years) presenting with unilateral inflammatory breast tumors (59 invasive carcinomas; 3 mastitis) underwent a PET/CT scan before biopsy.

RESULTS:

PET/CT scan was positive for the primary malignant tumor in 100% and false positive in 2 of 3 benign mastitis. In 59 IBC patients, FDG nodal foci were detected in axillary (90%; n = 53) and extra‐axillary areas (56%; n = 33) ipsilateral to the cancer. Compared with clinical examination, the axillary lymph node status by PET/CT was upstaged and downstaged in 35 and 5 patients, respectively. In 7 of 9 N0 patients, the axillary lymph node positivity on PET/CT was correct, as revealed by pathological postsurgery assessment (not available in the 2 remaining patients). The nodal foci were compared with preoperative fine needle aspiration and/or pathological postchemotherapy findings available in 44 patients and corresponded to 38 true positive, 4 false‐negative, and 2 false‐positive cases. In 18 of 59 IBC patients (31%), distant lesions were found. On the basis of a univariate analysis of the first enrolled patients (n = 42), among 28 patients who showed intense tumoral uptake (standard uptake value_max>5), the 11 patients with distant lesions had a worse prognosis than the 17 patients without distant lesions (P = .04).

CONCLUSIONS:

FDG‐PET/CT imaging provides additional invaluable information regarding nodal status or distant metastases in IBC patients and should be considered in the initial staging. It seems also that some prognostic information can be derived from FDG uptake characteristics. Cancer 2009. © 2009 American Cancer Society.     

The diagnostic and prognostic utility of positron emission tomography/computed tomography‐based follow‐up after radiotherapy for head and neck cancer

BACKGROUND:

The detection of subclinical head and neck cancer recurrence or a second primary tumor may improve survival. In the current study, the authors investigated the clinical value of a follow‐up program incorporating serial ¹⁸F?fluorodeoxyglucose?positron emission tomography integrated with computed tomography (PET/CT) in the detection of recurrent disease in patients with head and neck cancer.

METHODS:

A total of 240 PET/CT scans were reviewed in 80 patients with head and neck cancer who were treated with radiotherapy (RT) from July, 2005 through August, 2007. All patients were followed with clinical examination, PET/CT, and correlative imaging for a minimum of 11 months (median follow?up, 21 months).

RESULTS:

The sensitivity, specificity, and positive and negative predictive values of PET/CT‐based follow‐up for detecting locoregional recurrence were 92%, 82%, 42%, and 98%, respectively. Corresponding values for distant metastases or second primary tumors were 93%, 96%, 81%, and 98%, respectively. Eight patients (10%) developed disease recurrences or second primary tumors that were amenable to salvage surgery with negative surgical margins. The 2‐year progression‐free survival and 2‐year overall survival rates were significantly different between patients who had a negative and those with a positive PET/CT result within 6 months of the completion of RT (93% vs 30% [P<.001] and 100% vs 32% [P<.001], respectively).

CONCLUSIONS:

Although post‐therapy follow‐up using PET/CT is reportedly associated with a high false‐positive rate in the irradiated head and neck, PET/CT appears to be a highly sensitive technique for the detection of recurrent disease. Furthermore, negative PET/CT results within 6 months of the completion of RT offer significant prognostic value. Cancer 2009. © 2009 American Cancer Society.     

Ability of integrated positron emission and computed tomography to detect significant colonic pathology

BACKGROUND:

The ability of integrated positron emission tomography and computed axial tomography (PET‐CT) to detect colonic pathology is not fully defined. The purpose of this study was to assess the ability of PET‐CT to detect colonic pathology and to determine the significance of (¹⁸F)2‐fluoro‐2‐deoxyglucose (¹⁸F‐FDG) activity noted incidentally in the colon on PET‐CT.

METHODS:

Records for all patients who underwent PET‐CT and colonoscopy at our institution were reviewed. Patients with history of colonic malignancy or colon surgery were excluded.

RESULTS:

Fifty‐eight patients had incidental colonic ¹⁸F‐FDG activity on PET (Group A) and 272 had none (Group B). In Group A, 65% of patients had pathologic findings detected on colonoscopy that corresponded to the site of PET activity. Standardized uptake value (SUV) readings were not helpful in distinguishing true‐positives from false‐positives. In Group B, 11.8% of patients were found to have significant colonic findings. Lesions not detected by PET‐CT included 4 colon cancers, 7 advanced adenomas, and 10 patients with colonic lymphoma. Overall, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET‐CT for detecting significant pathology were 53%, 93%, 65%, 89%, and 85%, respectively. For detecting colon cancer and adenomas 10 mm or more, the sensitivity, specificity, PPV, NPV, and accuracy of PET‐CT were 72%, 90%, 45%, 96%, and 88%, respectively.

CONCLUSIONS:

Incidental colonic activity detected by PET‐CT warrants further evaluation with colonoscopy. However, negative PET‐CT does not rule out significant colonic pathology including colon cancer, advanced adenomas, or lymphoma. Cancer 2010. © 2010 American Cancer Society.     

¹⁸F-fluoro-deoxyglucose positron emission tomography in assessment of myeloma-related bone disease: a systematic review

BACKGROUND:

The goal of this study was to conduct a comparative analysis of whole body X‐ray (WBXR) and ¹⁸F‐fluoro‐deoxyglucose positron emission tomography (¹⁸FDG PET) in staging and response assessment of multiple myeloma.

METHODS:

We performed a systematic review of studies comparing ¹⁸FDG PET with WBXR and/or magnetic resonance imaging in terms of sensitivity for myeloma‐related bone disease at staging and during follow‐up.

RESULTS:

Eighteen studies involving 798 patients met the inclusion criteria. The mean Quality Assessment of Diagnostic Accuracy Studies (QUADAS) score, expressed as a percentage of the maximum score, was 61%. In 7 studies (n = 242 patients), concordance assessment between WBXR and ¹⁸FDG PET scan was possible, showing a higher sensitivity of the ¹⁸FDG PET in the detection of myeloma bone lesions in 6 studies. The only study reporting on the prognostic value of ¹⁸FDG PET at staging found that the number of FDG‐avid focal lesions was an independent prognostic parameter. In addition, the limited studies on response monitoring showed that normalization of ¹⁸FDG PET during treatment correlated with a superior clinical outcome.

CONCLUSIONS:

In general, ¹⁸FDG PET has a superior sensitivity for myeloma bone lesions compared with WBXR. Future studies have to validate the additive value of myeloma‐related bone disease detected on ¹⁸FDG PET–computed tomography (CT) in predicting outcome. Response monitoring with the use of ¹⁸FDG PET‐CT during treatment is promising, allowing more precise prediction of prognosis compared with the standard response monitoring. In view of the expanding treatment options for multiple myeloma, this may provide important information for treatment decisions in the future. Cancer 2012. © 2011 American Cancer Society.     

High frequency of neurolymphomatosis as a relapse disease of intravascular large B-cell lymphoma

BACKGROUND:

Intravascular large B‐cell lymphoma (IVL) is characterized by lymphoma cell proliferation in the lumina of small vessels in various organs. A high incidence of neurologic symptoms associated with the central nervous system has been reported, but peripheral nerve involvement (neurolymphomatosis [NL]) rarely has been described.

METHODS:

The medical records from patients who were diagnosed with IVL over the past 4 years were reviewed. A diagnosis of NL was made based on the combination of neurologic symptoms and their correspondence with imaging studies, such as magnetic resonance imaging (MRI), ¹⁸F‐fluoro‐2‐deoxy‐D‐glucose (FDG)‐positron emission tomography/computed tomography (PET/CT), and/or the histologic confirmation of lymphoma cells within the peripheral nerves, nerve root/plexuses, or cranial nerves.

RESULTS:

Four patients with NL were identified among 11 patients who had IVL. All cases of NL occurred as relapsed disease during or shortly after the completion of chemotherapy. Although MRI studies of the brains and whole spines revealed nerve infiltration by gadolinium enhancement in 2 patients, the technology was not sensitive enough to detect such infiltration in the remaining 2 patients. In contrast, FDG‐PET/CT studies successfully revealed cranial or peripheral nerve lesions in all 4 patients and was useful for evaluating therapeutic response. Patients received treatment with high‐dose methotrexate with or without other systemic chemotherapy, which achieved varied success. Further studies will be needed to determine the optimal treatment.

CONCLUSIONS:

Considering the rarity of IVL and NL, the current observations suggested that IVL may have a predilection not only for the vessels but also for both the central and peripheral nervous systems. Cancer 2011. © 2011 American Cancer Society     

S-100B as an extra selection tool for FDG PET/CT scanning in follow-up of AJCC stage III melanoma patients

Background and Objectives

This current study assessed the value of S-100B measurement to guide fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scanning for detecting recurrent disease in stage III melanoma patients.

Methods

This study included 100 stage III melanoma patients in follow-up after curative lymph node dissection. Follow-up visits included physical examination and S-100B monitoring. FDG PET/CT scanning was indicated by clinical symptoms and/or elevated S-100B.

Results

Of 100 patients, 13 (13%) had elevated S-100B without clinical symptoms, of whom 7 (54%) showed disease evidence upon FDG PET/CT scanning. Twenty-six patients (26%) had clinical symptoms with normal S-100B and FDG PET/CT revealed metastasis in 20 (77%). Three patients had clinical symptoms and elevated S-100B, and FDG PET/CT revealed metastasis in all three (100%). Overall, FDG PET/CT scanning revealed metastasis in 30 of the 42 patients (71.4%). For seven recurrences, elevated S-100B prompted early detection of asymptomatic disease; 10% of all asymptomatic patients in follow-up, 23% of all patients with recurrent disease.

Conclusion

S-100B cannot exclude recurrent disease during follow-up of stage III melanoma. However, adding S-100B measurement to standard clinical assessment can guide FDG PET/CT scanning for detecting recurrent melanoma.     

Prevalence of non 18F‐fluorodeoxyglucose‐avid incidental findings of clinical significance on whole body positron emission tomography/computed tomography: A review of 500 consecutive cases

Introduction

The prevalence of incidental ¹⁸F‐fluorodeoxyglucose (FDG)‐avid findings on positron emission tomography–computed tomography (PET/CT) has been extensively described. Few studies, however, have assessed the prevalence and significance of non‐FDG‐avid findings; pathology that is identified on review of the low‐dose, non‐contrast CT. The aim of this study was to determine the overall prevalence of non FDG‐avid incidental findings on PET/CT and the prevalence of ‘clinically significant’ non FDG‐avid pathology.

Methods

Five hundred consecutive whole body PET/CT studies performed in 2016 at a university affiliated tertiary hospital were retrospectively reviewed by two radiologists experienced in reporting PET/CT. Findings were categorized according to potential clinical relevance, and a targeted follow‐up of clinically significant incidental findings was performed.

Results

Incidental findings were encountered in 463 of 500 (92.6%) patients. In 226 patients, these findings had been detected on previous imaging studies, with unknown incidental findings present in 237 of 500 (47.4%) patients. 113 of 500 (22.6%) patients had non‐avid incidental findings of potentially major clinical significance, and in 35 patients (7.0%) these findings were considered previously unknown. The most common non‐avid findings of potentially major significance were pulmonary nodules (6 mm or larger), moderate or large size pleural effusions, and vascular aneurysms. Unknown incidental findings of potentially major clinical significance were significantly higher in patients imaged for melanoma staging (P= 0.004).

Conclusion

The prevalence of incidental findings of clinical significance that do not accumulate FDG in PET/CT is not insignificant. Routine systematic review of the low‐dose CT is required to avoid missing potentially clinically important findings, in particular pleural effusions, vascular aneurysms and metastatic pulmonary nodules.     

Coregistered whole body magnetic resonance imaging‐positron emission tomography (MRI‐PET) versus PET‐computed tomography plus brain MRI in staging resectable lung cancer

BACKGROUND:

The objective of this study was to assess whether coregistered whole brain (WB) magnetic resonance imaging‐positron emission tomography (MRI‐PET) would increase the number of correctly upstaged patients compared with WB PET‐computed tomography (PET‐CT) plus dedicated brain MRI in patients with nonsmall cell lung cancer (NSCLC).

METHODS:

From January 2010 through November 2011, patients with NSCLC who had resectable disease based on conventional staging were assigned randomly either to coregistered MRI‐PET or WB PET‐CT plus brain MRI (ClinicalTrials.gov trial NCT01065415). The primary endpoint was correct upstaging (the identification of lesions with higher tumor, lymph node, or metastasis classification, verified with biopsy or other diagnostic test) to have the advantage of avoiding unnecessary thoracotomy, to determine appropriate treatment, and to accurately predict patient prognosis. The secondary endpoints were over staging and under staging compared with pathologic staging.

RESULTS:

Lung cancer was correctly upstaged in 37 of 143 patients (25.9%) in the MRI‐PET group and in 26 of 120 patients (21.7%) in the PET‐CT plus brain MRI group (4.2% difference; 95% confidence interval, ?6.1% to 14.5%; P = .426). Lung cancer was over staged in 26 of 143 patients (18.2%) in the MRI‐PET group and in 7 of 120 patients (5.8%) in the PET‐CT plus brain MRI group (12.4% difference; 95% confidence interval, 4.8%‐20%; P = .003), whereas lung cancer was under staged in 18 of 143 patients (12.6%) and in 28 of 120 patients (23.3%), respectively (?10.7% difference; 95% confidence interval, ?20.1% to ?1.4%; P = .022).

CONCLUSIONS:

Although both staging tools allowed greater than 20% correct upstaging compared with conventional staging methods, coregistered MRI‐PET did not appear to help identify significantly more correctly upstaged patients than PET‐CT plus brain MRI in patients with NSCLC. Cancer 2013. © 2013 American Cancer Society.     

Gastric cancers with microsatellite instability exhibit high fluorodeoxyglucose uptake on positron emission tomography

Background

Gastric cancers exhibit various degrees of ¹⁸F-fluorodeoxyglucose (FDG) uptakes on positron emission tomography/computed tomography (PET/CT) imaging. The aim of this study was to evaluate whether FDG uptake in gastric cancer varies according to the microsatellite instability (MSI) status.

Methods

Consecutive gastric cancer patients who underwent PET/CT imaging and MSI analysis were included in the study. The maximum standardized uptake value (SUV_max) of gastric cancer was assessed using PET/CT imaging.

Results

Of 131 gastric cancers, 16 exhibited a high incidence of MSI (MSI-H) and 3 exhibited a low incidence of MSI (MSI-L). In 29 subjects who showed no uptake on PET/CT imaging the gastric cancers were all microsatellite stable (MSS). Gastric cancers with MSI were related to age older than 60 years (p = 0.002), cancer volume larger than 10 cm³ (p = 0.015), and the presence of FDG uptake on PET/CT imaging (p = 0.001). A higher SUV_max of gastric cancer was linked to the presence of MSI (p < 0.001).

Conclusion

The presence of MSI is related to FDG uptake in gastric cancer. Care should be taken with MSS gastric cancers, because they show lower SUV_max on PET/CT imaging than MSI gastric cancers.     

Comparison of magnetic resonance spectroscopy and positron emission tomography in detection of tumor recurrence in posttreatment of glioma: A diagnostic meta‐analysis

It is important to distinguish between tumor recurrence and treatment effects in posttreatment patients with high‐grade gliomas. Several imaging modalities have been reported in differentiating between tumor recurrence and treatment effects. However, there were no consistent conclusions between different studies. We performed a meta‐analysis of 23 studies that compared the diagnostic values of fluorine‐18‐fluorodeoxyglucose (¹⁸F‐FDG) and ¹¹C‐methionine (¹¹C‐MET) PET (positron emission tomography) or PET/CT (computed tomography) and magnetic resonance spectroscopy (MRS) in predicting tumor recurrence of gliomas. The pooled estimated sensitivity, specificity, positive likelihood ratios, negative likelihood ratios and summary receiver operating characteristic curves of ¹⁸F‐FDG and ¹¹C‐MET PET or PET/CT and MRS in detecting tumor recurrence were calculated. In conclusion, MRS is highly sensitive in the detection of tumor recurrence in glioma.¹⁸F‐FDG PET or PET/CT is highly specific in recurrence diagnosis. ¹¹C‐MET does not have noticeable advantage over ¹⁸F‐FDG. The current evidence shows no statistical difference between MRS and PET on the accuracy.     

Indeterminate pulmonary nodules on CT images in breast cancer patient: The additional value of 18F-FDG PET/CT

Aim: To assess the potential role of 18F‐Fluorodeoxiglucose (FDG) Positron Emission Tomography (PET)/Computed Tomography (CT) in characterizing indeterminate lung nodules detected at CT scan in patients previously treated for a breast cancer (BC). Materials and Methods: Twenty‐nine consecutive BC patients (28 females, mean age 65 ± 12 years) with evidence of indeterminate lung nodules at contrast‐enhanced CT (CECT) scan (lesions with axial diameter ≥8 mm) were retrospectively analysed: all patients underwent 18F‐FDG PET/CT within a mean 2 ± 1 months from CECT imaging. PET/CT was considered positive in the presence of abnormal FDG uptake in the pulmonary nodules and/or in other organs. The nature of lung nodules was defined at histopathology and/or imaging follow‐up. Results: Fourteen (48%) patients showed negative and 15 (52%) positive PET/CT scan in the lungs: of these 15 patients, 7 (47%) had pathologic FDG‐uptake in lungs only, whereas 8 (53%) showed abnormal FDG‐uptake also in sites different from lungs. At histology and/or imaging follow‐up, five (17%) patients were considered positive for BC lung metastases while in seven (24%) a second cancer was diagnosed. In this subset of patients, the sensitivity and specificity for FDG PET/CT in revealing lung lesions were 17% and 100%, respectively, for nodules <8 mm in diameter, and 77% and 85%, respectively, for nodules with diameter ≥8 mm. The therapeutic planning was changed to surgery in seven patients, chemotherapy in one patient and continued hormonal therapy in five. The inclusion of PET/CT in the diagnostic algorithm of the evaluated patients helped avoid unnecessary over‐treatment in 12 of 29 patients. Conclusion: FDG PET/CT appears useful in characterizing indeterminate lung nodules found at CECT scan in BC patients, with a sensitivity that is proportional to nodule size. In addition, PET/CT helped in avoiding over‐treatment in a significant proportion of patients.     

The impact of positron emission tomography (PET) on expected management during cancer treatment

BACKGROUND:

Positron emission tomography (PET) performed during cancer therapy (treatment monitoring) has shown promise for predicting treatment outcome. However, when used for this purpose, PET generally is not considered standard care. Under the Medicare ‘coverage with evidence development’ policy, PET (and integrated PET/computed tomography) became a covered service for treatment monitoring if prospective registry data were collected.

METHODS:

The National Oncologic PET Registry collected questionnaire data on intended patient management before and after PET. Data were available from 8240 patients who had 10,497 treatment‐monitoring PET scans at 946 centers; these studies were used to monitor chemotherapy alone (82%), radiation therapy alone (6%), or combined‐modality treatment (12%). Ovarian, pancreatic, and lung cancers accounted for 37% of the cohort. In 54% of scans, the pre‐PET summary stage was metastatic disease.

RESULTS:

If PET had not been available, then the pre‐PET plan would have been other imaging (53%), ongoing treatment (41%), or biopsy or watching (6%). Change in the post‐PET intended management was similar in the imaging and treatment groups: 26% to 28% of scans to switching to another therapy, and 16% to 19% scans led to adjustment of the dose or duration of therapy. Changes in management were more frequent if the referring physician judged that the post‐PET prognosis was worse rather than improved or unchanged (78% vs 40%). The physicians indicated that PET enabled 91% of their patients to avoid future tests.

CONCLUSIONS:

Physicians often report plans to modify their therapeutic plans in elderly cancer patients when PET is used for treatment monitoring. Cancer 2009. © 2009 American Cancer Society.