18F-FDG PET/CT and lung cancer: value of fourth and subsequent posttherapy follow-up scans for patient management.

UNLABELLED: The Centers for Medicare and Medicaid Services recently ruled that only 3 posttherapy follow-up (18)F-FDG PET/CT scans are funded for a tumor type per patient and any additional follow-up PET/CT scans will be funded at the discretion of the local Medicare administrator. The purpose of this study was to evaluate the added value of 4 or more follow-up PET/CT scans to clinical assessment and impact on patient management. METHODS: This was an institutional review board-approved, retrospective study. A total of 1,171 patients with biopsy-proven lung cancer who had undergone (18)F-FDG PET/CT at a single tertiary center from 2001 to 2013 were identified. Among these, 85 patients (7.3%) had undergone 4 or more follow-up PET/CT scans, for a total of 285 fourth and subsequent follow-up PET/CT scans. Median follow-up from the fourth follow-up PET/CT scan was 31.4 mo (range, 0-155.2 mo). The follow-up PET/CT scan results were correlated with clinical assessment and treatment changes. RESULTS: Of the 285 fourth and subsequent follow-up PET/CT scans, 149 (52.28%) were interpreted as positive and 136 (47.7%) as negative for recurrence or metastasis. A total of 47 patients (55.3%) died during the study period. PET/CT identified recurrence or metastasis in 44.3% of scans performed without prior clinical suspicion and ruled out recurrence or metastasis in 24.2% of scans performed with prior clinical suspicion. The PET/CT scan resulted in a treatment change in 28.1% (80/285) of the patients. New treatment was initiated for 20.4% (58/285) of the scans, treatment was changed in 5.6% (16/285), and ongoing treatment was stopped in 2.1% (6/285). CONCLUSION: The fourth and subsequent (18)F-FDG PET/CT scans performed during follow-up after completion of primary treatment added value to clinical assessment and changed management 28.1% of the time.

Two-time-point FDG PET/CT: liver SULmean repeatability.

OBJECTIVE. The purpose of this study was to evaluate the repeatability of liver mean standardized uptake value normalized to lean body mass (SULmean) in the same patients at different time points within the right lobe of the liver at (18)F-FDG PET/CT, in a clinical setting. MATERIALS AND METHODS. Two PET/CT studies performed on two different dates from each of 130 patients who had normal livers according to structural imaging were included in this reader study. The mean (± SD) length of time between the studies was 235 ± 192 days. SULmean was measured with a 30-mm diameter spherical volume of interest (VOI) placed within the right lobe of the liver (above, below, and at the level of the main portal vein) by two expert readers. ANOVA, intraclass correlation coefficient (ICC), and Bland-Altman analysis were performed. RESULTS. The ICC for the first and second set of studies varied between 0.487 and 0.535 for reader 1 and between 0.472 and 0.545 for reader 2. The mean percentage variation for SULmean between the two time scans for the VOIs placed above, below, and at the level of the main portal vein were 3.55% ± 23.19%, 4.65% ± 23.87%, and 4.30% ± 23.03%, respectively, for reader 1 and 4.49% ± 23.23%, 4.33% ± 23.74%, and 4.48% ± 23.01%, respectively, for reader 2. Using 95% CI, the reference range for intrapatient variations between the studies in liver SULmean was -0.5 to 0.60. CONCLUSION. There is only fair repeatability of liver SULmean measured between two time points in the same patient in a clinical setting. Scan-to-scan intrapatient variation in absolute liver SULmean was -0.5 to 0.60.

FDG volumetric parameters and survival outcomes after definitive chemoradiotherapy in patients with recurrent head and neck squamous cell carcinoma.

OBJECTIVE: The purpose of this study was to establish the predictive value of (18)F-FDG parameters for overall survival in biopsy-proven recurrent head and neck squamous cell cancer (HNSCC) patients after definitive chemoradiotherapy. MATERIALS AND METHODS: We conducted a retrospective study including 34 patients with HNSCC who had biopsy-proven recurrence between April 2004 and March 2012 and underwent FDG PET/CT at our institution at the time of recurrence. Maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. The primary outcome measure was overall survival. ROC analysis, univariate and multivariate Cox regression models, and Kaplan-Meir survival curves were performed. RESULTS: In univariate analyses, human papillomavirus (HPV) status (p = 0.04), primary site recurrence of MTV (p = 0.03), metastasis of MTV (p = 0.02), metastasis of TLG (p = 0.02), total MTV (p = 0.002), and total TLG (p = 0.04) were significantly associated with overall survival outcome. Total MTV remained as significant independent prognostic factor when adjusted for all other covariates except for primary site recurrence SUVmax and SUVpeak and lymph node SUVmax and SUVpeak. There was a significant difference in time to survival between patients with total MTV above and below the 50th percentile (Mantel-Cox log-rank test, p = 0.05 and Gehan-Breslow-Wilcoxon test, p = 0.03) and the optimum threshold of 16.8 mL (Mantel-Cox log-rank test, p = 0.01 and Gehan-Breslow-Wilcoxon test, p = 0.01; hazard ratio [HR], 0.25). CONCLUSION: FDG PET/CT-based total MTV and clinical HPV status may be significant prognostic markers for overall survival of patients with recurrent HNSCC after definitive chemoradiotherapy.

Interreader agreement and variability of FDG PET volumetric parameters in human solid tumors.

OBJECTIVE: The purpose of this article is to evaluate the interreader agreement and variability of two (18)F-FDG PET parameters, metabolic tumor volume and total lesion glycolysis, in human solid tumors. MATERIALS AND METHODS: One hundred eleven patients (mean [± SD] age, 61.9 ± 12.5 years) with baseline staging FDG PET/CT scans were included. Two readers independently read the scans and segmented metabolic tumor volume and total lesion glycolysis using two fixed thresholds, 40% and 50% of the lesion's maximum standardized uptake value (SUVmax). The impact of the lesion's FDG avidity and location on reader agreement and variability was established. Intraclass correlation coefficient (ICC), precision, and Bland-Altman analysis were used to evaluate agreement and variability. RESULTS: The ICCs for 40% and 50% SUVmax segmentations of metabolic tumor volume between the readers were 0.987 and 0.995, and the corresponding values for 40% and 50% SUVmax segmentations of total lesion glycolysis were 0.987 and 0.986, respectively (p = 0.0001). The corresponding precisions were 0.5%, 0.2%, 0.5%, and 0.5%, respectively. The mean biases between the readers for 40% and 50% SUVmax segmentations of metabolic tumor volume were -1.78 ± 8.42 mL and -0.46 ± 2.1 mL and for 40% and 50% SUVmax segmentations of total lesion glycolysis were -7.3 ± 31.6 g and -2.97 ± 12.86 g, respectively. Subgroup analysis showed better precision and lesser variability for 50% SUVmax segmentations of metabolic tumor volume and total lesion glycolysis in patients with the highest and lowest FDG-avid primary tumors. The precision was highest and variability was lowest for lung tumors. CONCLUSION: There is excellent interreader agreement for measurement of metabolic tumor volume and total lesion glycolysis with 40% and 50% SUVmax threshold segmentations in human solid tumors.

Addition of 18F-FDG PET/CT to clinical assessment predicts overall survival in HNSCC: a retrospective analysis with follow-up for 12 years.

UNLABELLED: (18)F-FDG PET/CT is used in the follow-up of patients with head and neck squamous cell cancer (HNSCC). However, its impact on clinical decision making and patient outcome is not fully established. The objective of this study was to determine the prognostic value of (18)F-FDG PET/CT for overall survival (OS) of HNSCC patients when performed in addition to clinical assessment between 4 and 24 mo after treatment. METHODS: This was a retrospective study at a single tertiary center. The institutional review board approved this study, and the requirement to obtain informed consent was waived. The study included 134 biopsy-proven HNSCC patients with 227 follow-up PET/CT scans. The primary outcome measure was OS. Median follow-up was 40 mo (range, 7-145 mo). Survival is presented as Kaplan-Meier plots with Mantel-Cox log-rank test. The multivariate Cox model included clinical covariates. RESULTS: Of the 227 PET/CT scans, 41 (18%) were positive for tumor and 186 (82%) were negative for tumor. PET/CT identified recurrence in 5% (9/194) of scans performed without prior clinical concern and ruled out tumor in 51.5% (17/33) of scans performed to evaluate clinical suspicion or uncertainty of recurrence. The median survival of PET-positive and -negative groups from the date of the scan was 20 and 30.5 mo, respectively (P < 0.0001). There was a significant difference in OS from the scan date between patients who had a positive PET/CT result for tumor and those who had a negative result (log-rank, P < 0.0001), with a hazard ratio of 29.74. Human papillomavirus status (P = 0.001) and PET/CT result (P = 0.04) were the only factors significantly associated with OS, adjusted for all other covariates. CONCLUSION: (18)F-FDG PET/CT performed between 4 and 24 mo after treatment adds value to clinical assessment at the time of the study, especially when there is clinical suspicion or uncertainty, and can serve as a prognostic marker of OS in HNSCC.

Impact of concurrent diagnostic level CT with PET/CT on the utilization of stand-alone CT and MRI in the management of head and neck cancer patients.

PURPOSE OF THE REPORT: This study aims to determine if the expansion of a PET/CT service to include simultaneous contrast-enhanced CT with PET (PET/DCT) leads to a reduction of supplemental diagnostic CT (sCT) performed within a 6-month period centered around PET/CT for initial treatment planning of patients with head and neck cancers. PATIENTS AND METHODS: There were 91 patients with head and neck cancers who had a non-contrast-enhanced PET/CT with CT (PET/aCT), and 153 patients had a PET/DCT. We compared the utilization of sCT before and after PET/aCT or PET/DCT. Logistic regression analysis, unpaired t test, and analysis of variance were performed. RESULTS: Among the 75 patients who had sCT scans in the 3 months before their PET/CT, 44 (58.7%) scans were performed in patients who had a PET/aCT and 31 (41.3%) scans were performed in patients who had a PET/DCT (P < 0.001). Among the 36 patients who had a CT in the 3 months after their baseline PET/CT, 23 (63.9%) were performed in patients who had a baseline PET/aCT and 13 (36.1%) were performed in patients who had a baseline PET/DCT (P < 0.001). The adjusted odds ratio for performing an sCT within 3 months before and after baseline PET/DCT scan as opposed to a PET/aCT scan was 0.24 (P < 0.001) and 0.31 (P < 0.01), respectively. CONCLUSIONS: The opportunity to order simultaneous diagnostic CT imaging with PET/CT (PET/DCT) reduced the referrals for stand-alone CT neck imaging in the initial treatment plan of head and neck cancer patients when compared to a service that only offered the PET/CT scan with CT for attenuation correction (PET/aCT).

FDG PET/CT in the management of primary pleural tumors and pleural metastases.

OBJECTIVE. FDG PET/CT is emerging as an important modality in the evaluation of pleural tumors. PET/CT has an established role in the diagnosis and staging and shows promise in therapy planning, therapy response assessment, and providing prognostic information in patients with malignant pleural mesothelioma. This modality has distinct advantages in characterizing other primary pleural tumors and pleural metastases. CONCLUSION. FDG PET/CT is a useful imaging modality in the management of patients with primary pleural tumors and pleural metastases.

FDG-PET/CT imaging biomarkers in head and neck squamous cell carcinoma.

This article discusses the value of 18F-fluoro-2-deoxyglucose PET/CT imaging biomarkers in head and neck squamous cell carcinoma. 18F-fluoro-2-deoxyglucose PET/CT is valuable at baseline staging, radiotherapy planning, therapy response assessment and in the follow-up of patients with head and neck squamous cell carcinoma. Maximum and peak standardized uptake value (SUVmax and SUVpeak), metabolic tumor volume and total lesion glycolysis are the common 18F-fluoro-2-deoxyglucose quantitative parameters that have been studied, along with qualitative assessments. These parameters will be evaluated with respect to their established or potential role as noninvasive biomarkers for patient risk stratification, treatment response and survival outcome.