Usefulness of dual-time point imaging after carbonated water for the fluorodeoxyglucose positron emission imaging of peritoneal carcinomatosis in colon cancer

Role of 18F-FDG PET-derived parameters for predicting complete response to chemoradiotherapy in squamous cell anal carcinoma

PURPOSE

We aimed to evaluate the accuracy of metabolic parameters, calculated on pretreatment positron emission computed tomography (PET/CT) with fluorodeoxyglucose (F-FDG), for predicting complete response to chemoradiotherapy (CRT) of patients affected by squamous cell anal carcinoma (SCAC).

PATIENTS AND METHODS

Clinical records of 20 patients affected by SCAC and treated with CRT were retrospectively evaluated. F-FDG PET/CT was performed at time 0 (baseline) and time 1 (12 weeks after CRT). The following parameters were extracted from PET at time 0: standardized uptake values (SUVmax and SUVmean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). Response was assessed according to PET response criteria in solid tumors and classified as complete metabolic response (CMR), partial metabolic response (PMR) and progressive metabolic disease (PMD). Receiver operating characteristic analysis was performed to analyze the predictive value of each PET-derived parameter on CMR.

RESULTS

Sixteen patients were finally enrolled. All presented increased F-FDG uptake in the primary tumor and 11 (68.7%) also showed metastatic lymph nodes. At PET/CT performed at time 1, 11 subjects (68.7%) presented CMR, three (18.7%) had PMR and the remaining two (12.5%) showed PMD (i.e. hepatic metastases). Among baseline PET-derived parameters, both MTV and TLG efficiently predicted response to CRT with an area under the curve of 0.9 (cutoff 62.3 cm, sensitivity 80%, specificity 100%, P = <0.0001) and 0.87 (cutoff 654.1 g, sensitivity 80%, specificity 100%, P = 0.004), respectively.

CONCLUSION

Among PET-derived parameters, both MTV and TLG presented a high predictive value on subjects' outcome after CRT.

Diagnostic accuracy of 18F-FDG PET/CT for detection of peritoneal carcinomatosis; a systematic review and meta-analysis

OBJECTIVE

The current review aimed to investigate the performance of the diagnostic accuracy of ¹⁸F- fludeoxyglucose positron emission tomography/CT (PET/CT) in detecting peritoneal carcinomatosis (PC) through a systematic review and meta-analysis.

METHODS

The MEDLINE via PubMed and EMBASE from the earliest available date of indexing to 31 March 2017, were searched for studies evaluating the diagnostic performance of ¹⁸F-FDG PET/CT in detecting PC. We evaluated the pooled sensitivities and specificities across included studies, calculated positive and negative likelihood ratios (LR+ and LR-), and plotted summary receiver operating characteristic curves. Deek's funnel plot asymmetry tests were used to assess the possible underlying publication bias.

RESULTS

The current meta-analysis demonstrated no significant publication bias (p = 0.21). Across 14 studies (671 patients), the overall sensitivity of ¹⁸F-FDG PET/CT was 0.87 [95% CI (0.77-0.93)] with heterogeneity (χ² = 94.2, p = 0.00) and a pooled specificity of 0.92 [95% CI; (0.89-0.94)] with heterogeneity (χ² = 20.6, p = 0.08). LR syntheses gave an overall LR+ of 10.4 [95% CI (7.5-14.5)] and LR- of 0.14 [95% CI (0.08-0.26)]. The pooled diagnostic odds ratio was 73 [95% CI (34-159)]. In univariate meta-regression analysis, publication year and cohort homogeneity were the potent sources of heterogeneity. However, in multivariate meta-regression, no definite variable was the source of the study heterogeneity.

CONCLUSION

¹⁸F-FDG PET/CT demonstrated good sensitivity and specificity for the detection of PC. Further large multicentre studies would be necessary to substantiate the diagnostic accuracy of ¹⁸F-FDG PET/CT for the diagnosis of PC in various cancers. Advances in knowledge: ¹⁸F-FDG PET/CT showed good diagnostic performance in the evaluation of PC and could provide additional information for that purpose in various cancers.

Change in total lesion glycolysis and clinical outcome after (90)Y radioembolization in intrahepatic cholangiocarcinoma

INTRODUCTION

Our aim was to assess the prognostic value of post-treatment decrease in total lesion glycolysis (ΔTLG) assessed by 2-[(18)F]-fluorodeoxyglucose ([(18)F] FDG) PET-CT performed 6weeks after (90)Y radioembolization ((90)Y RE) in patients affected by intrahepatic cholangiocarcinoma (ICC).

METHODS

A total of 18 patients were accepted into our department for (90)Y RE. Before the procedure, all patients underwent [(18)F] FDG PET-CT, and total lesion glycolysis was calculated. Six weeks after (90)Y administration, PET scan was performed, and ΔTLG was determined. Patients underwent follow up by imaging and laboratory at quarterly intervals until death or for at least 24 months from (90)Y RE. Furthermore, subjects were divided in 2 groups (group 1: 6 weeks ΔTLG>50%, group 2: ΔTLG<50%). Kaplan-Meier method was used to achieve time to progression (TTP) and overall survival (OS) curves for each group. TTP and OS curves were compared to demonstrate eventual relevant differences between the 2 groups.

RESULTS

Seventeen patients underwent (90)Y RE, and one subject was considered ineligible. According to PET Response Criteria in Solid Tumors, partial response was found in 14 patients (82.4%), stable disease in 3 (17.6%). No patient showed complete metabolic response. The mean OS for all patients was 64.5±5.0 weeks. Subjects with a ΔTLG>50% and ΔTLG<50% had a mean OS of 79.6±3.6 and 43.1±2.0 weeks, respectively (p<0.001). TTP resulted of 28.9±3.8 weeks for the whole cohort. Patients with ΔTLG>50% had a significantly longer TTP (mean 36.9±3.6 weeks) than those with ΔTLG<50% (mean 13.7±1.7 weeks, p=0.001).

CONCLUSION

Our results indicate that (90)Y RE can be an effective and safe therapy for ICC. ΔTLG calculated on post-treatment [(18)F] FDG PET-CT agrees with patients' final outcome.

Tumor thrombus in the renal vein from an adrenal metastasis of lung cancer: 18FDG PET/CT findings

Tumor thrombus is a rare complication of solid cancer. The authors report a case of a 76-year-old woman presenting a thick walled cystic mass in the lower lobe of the left lung. 18FDG positron emission tomography (PET)/computed tomography (CT) was performed, showing tracer accumulation in the wall of the pulmonary lesion and in the mediastinal and hilar lymph nodes. Moreover, PET/CT depicted a gross mass in the left adrenal gland and a hypermetabolic focus corresponding to the anatomic location of the left renal vein. Contrast-enhanced CT, subsequently performed, confirmed PET findings in the lung, lymph nodes, and adrenal glands, also demonstrating marginal enhancement and intraluminal filling defect in the left renal vein, which was interpreted as tumor thrombus due to the 18FDG uptake at PET scan. CT-guided biopsy of the mass was positive for poorly differentiated carcinoma. 18FDG PET can be useful to diagnose tumor thrombus in oncological patients.

Diagnosis and evaluation of gastric cancer by positron emission tomography

Gastric cancer is the second leading cause of cancer mortality worldwide. The diagnosis of gastric cancer has been significantly improved with the broad availability of gastrointestinal endoscopy. Effective technologies for accurate staging and quantitative evaluation are still in demand to merit reasonable treatment and better prognosis for the patients presented with advanced disease. Preoperative staging using conventional imaging tools, such as computed tomography (CT) and endoscopic ultrasonography, is inadequate. Positron emission tomography (PET), using ¹⁸F-fluorodeoxyglucose (FDG) as a tracer and integrating CT for anatomic localization, holds a promise to detect unsuspected metastasis and has been extensively used in a variety of malignancies. However, the value of FDG PET/CT in diagnosis and evaluation of gastric cancer is still controversial. This article reviews the current literature in diagnosis, staging, response evaluation, and relapse monitoring of gastric cancer, and discusses the current understanding, improvement, and future prospects in this area.