FDG-PET as a predictive biomarker for therapy with everolimus in metastatic renal cell cancer

PET/Computed Tomography Transformation of Oncology: Kidney and Urinary Tract Cancers

Renal cell carcinoma (RCC) and urothelial carcinoma (UC) are two of the most common genitourinary malignancies. 2-deoxy-2-[18F]fluoro-d-glucose (18F-FDG) can play an important role in the evaluation of patients with RCC and UC. In addition to the clinical utility of 18F-FDG PET to evaluate for metastatic RCC or UC, the shift in molecular imaging to focus on specific ligand-receptor interactions should provide novel diagnostic and therapeutic opportunities in genitourinary malignancies. In combination with the rise of artificial intelligence, our ability to derive imaging biomarkers that are associated with treatment selection, response assessment, and overall patient prognostication will only improve.

Biomarkers for the Detection and Surveillance of Renal Cancer

Renal cell carcinoma (RCC) is a heterogeneous disease characterized by a broad spectrum of disorders in terms of genetics, molecular and clinical characteristics. There is an urgent need for noninvasive tools to stratify and select patients for treatment accurately. In this review, we analyze serum, urinary, and imaging biomarkers that have the potential to detect malignant tumors in patients with RCC. We discuss the characteristics of these numerous biomarkers and their ability to be used routinely in clinical practice. The development of biomarkers continues to evolve with promising prospects.

Molecular and functional imaging in cancer-targeted therapy: current applications and future directions

Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy. The Response Evaluation Criteria in Solid Tumor (RECIST) system has been used to assess tumor response to therapy via changes in the size of target lesions as measured by calipers, conventional anatomically based imaging modalities such as computed tomography (CT), and magnetic resonance imaging (MRI), and other imaging methods. However, RECIST is sometimes inaccurate in assessing the efficacy of targeted therapy drugs because of the poor correlation between tumor size and treatment-induced tumor necrosis or shrinkage. This approach might also result in delayed identification of response when the therapy does confer a reduction in tumor size. Innovative molecular imaging techniques have rapidly gained importance in the dawning era of targeted therapy as they can visualize, characterize, and quantify biological processes at the cellular, subcellular, or even molecular level rather than at the anatomical level. This review summarizes different targeted cell signaling pathways, various molecular imaging techniques, and developed probes. Moreover, the application of molecular imaging for evaluating treatment response and related clinical outcome is also systematically outlined. In the future, more attention should be paid to promoting the clinical translation of molecular imaging in evaluating the sensitivity to targeted therapy with biocompatible probes. In particular, multimodal imaging technologies incorporating advanced artificial intelligence should be developed to comprehensively and accurately assess cancer-targeted therapy, in addition to RECIST-based methods.

Efficacy of Pre-operative 18F-FDG PET/CT in Prognostic Prediction in Patients With Renal Cell Carcinoma

BACKGROUND/AIM

This study analyzed the parameters provided by preoperative ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for prognostic prediction of renal cell carcinoma (RCC).

PATIENTS AND METHODS

FDG-PET/CT data from 66 clear cell RCC and 19 non-clear cell RCC cases between January 2015 and October 2018 were reviewed retrospectively. We compared the two groups according to recurrence/metastasis to determine prognosis-influencing factors. Multivariate Cox hazard regression models were constructed to evaluate factors potentially predicting disease-free survival (DFS) after adjustment for confounders. DFS was then compared between groups.

RESULTS

Standardized uptake values (SUV) of the PET/CT scan were independent predictors of prognosis after adjusting for confounders. RCC cases were divided into two groups by optimal cut-off values. Differences between DFS percentages in high and low SUV groups were significant. Similar results were obtained in clear cell RCC groups.

CONCLUSION

Increased SUV of the PET/CT scan are significant predictors of worse prognoses in patients with surgically resected RCC.

Non-invasive molecular imaging of kidney diseases

In nephrology, differential diagnosis or assessment of disease activity largely relies on the analysis of glomerular filtration rate, urinary sediment, proteinuria and tissue obtained through invasive kidney biopsies. However, currently available non-invasive functional parameters, and most serum and urine biomarkers, cannot capture intrarenal molecular disease processes specifically. Moreover, although histopathological analyses of kidney biopsy samples enable the visualization of pathological morphological and molecular alterations, they only provide information about a small part of the kidney and do not allow longitudinal monitoring. These limitations not only hinder understanding of the dynamics of specific disease processes in the kidney, but also limit the targeting of treatments to active phases of disease and the development of novel targeted therapies. Molecular imaging enables non-invasive and quantitative assessment of physiological or pathological processes by combining imaging technologies with specific molecular probes. Here, we discuss current preclinical and clinical molecular imaging approaches in nephrology. Non-invasive visualization of the kidneys through molecular imaging can be used to detect and longitudinally monitor disease activity and can therefore provide companion diagnostics to guide clinical trials, as well as the safe and effective use of drugs.

Role of F-18 FDG PET/CT in the follow-up of asymptomatic renal cell carcinoma patients for postoperative surveillance: based on conditional survival analysis

PURPOSE

This study investigated the clinical usefulness of F-18 fluorodeoxylucose (FDG) positron emission tomography/computed tomography (PET/CT) for postoperative surveillance in the RCC patients in terms of detectability of recurrence and radiation exposure.

METHODS

Three-hundred-and-forty- three RCC patients who underwent surgery and postoperative surveillance were retrospectively included. Conditional recurrent free survival (CRFS) was investigated and diagnostic performance of conventional imaging (CI) which include abdominopelvic CT or/and chest CT was compared to the FDG PET/CT.

RESULTS

At a median follow-up of 4.3 years (0.5-13.0 years), thirty-nine patients (11.4%) developed recurrence. CRFS of the patients increased over time with greater increment in advanced stage. The sensitivity, specificity, positive-predictive value, negative-predictive value, and accuracy of FDG PET/CT were 92.3%, 97%, 80%, 99.0%, and 96.5% in detecting recurrence, while those values for CI were 89.7%, 97.7%, 83.3%, 98.7%, and 96.8%, respectively. There were no significant differences in these values between FDG PET/CT and CI (McNemar test, p = 0.581). The average radiation dose from FDG PET/CT was around 16.9 ± 3.08 mSv at each follow-up time point. For early stage patients, the average radiation dose from CI was around 26.5 ± 8.57 mSv at each follow-up time point, while this was about 33.0 ± 9.76 mSv for advanced stage patients.

CONCLUSION

FDG PET/CT exhibited good diagnostic performance in asymptomatic RCC patients after surgery, of a level comparable to that of CI, but with a lower radiation dose.

[18F]FDG-PET/CT and long-term responses to everolimus in advanced neuroendocrine neoplasia

PURPOSE

This study aims to identify in patients with neuroendocrine neoplasia (NEN) the potential correlation between FDG-PET findings and responses to everolimus therapy to identify predictors of long-term efficacy.

METHODS

Retrospective analysis of patients with sporadic, advanced, progressive NEN treated with everolimus was performed based on the available data on FDG-PET patients obtained before commencing therapy. Data are expressed as the median (25-75th IQR). Risk factor analysis and survival analysis were performed by logistic regression and Cox proportional hazard regression and the determination of Kaplan-Meier curves, as appropriate.

RESULTS

Sixty-six patients were evaluated (NET G1 19.7%, NET G2 75.7%, and NET G3 4.6%), including 45.4% with positive FDG-PET findings. Overall, disease stabilization and a partial response were achieved for 71.2% and 6% of patients, respectively. A long-term response (> 24 months) was observed in 33% of patients. Ki67 was the only predictor of tumor progression (p = 0.03). No significant difference in clinical outcomes was observed between patients with positive or negative FDG-PET findings (median PFS was 24 months and 18 months, respectively, p = 0.337; the disease control rate was 83.3% and 70%, respectively, p = 0.245).

CONCLUSIONS

Everolimus is a valid therapeutic option for advanced, progressive, well-differentiated NEN, even in patients with positive FDG-PET findings.

Central nervous system tumors in 2-year rat carcinogenicity studies: perspectives on human risk assessment

Rodent in vivo carcinogenicity bioassays are required for human risk assessment and have been utilized in this capacity for decades. Accordingly, there is an abundance of data that could be accessed and analyzed to better understand the translatability of xenobiotic-induced rodent tumors to human risk assessment. In the past decade, various groups have published assessments of the value garnered by these life-time rodent studies. Results and recommendations from the International Council for Harmonization Expert Working Group (ICH-S1 EWG) on the predictability of the current testing paradigm and proposal for an integrated approach to human carcinogenicity risk assessment are pending. Central nervous system (CNS) tumors in rats are rare and translatability to human remains unknown. This review focuses on microglial cell tumors (MCT) of the CNS in rats including its classification, nomenclature, incidence and translatability to human risk assessment. Based on emerging immunohistochemistry (IHC) characterization, glial tumors previously thought of astrocytic origin are more likely MCTs. These may be considered rodent specific and glucose dysregulation may be one component contributing to their formation. Based on review of the literature, MCTs are rarely diagnosed in humans, thus this tumor type may be rat-specific. We propose to include MCTs as a tumor type in revised International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) classification and all glial tumors to be classified as MCTs unless proven otherwise by IHC.

Everolimus Exposure and Early Metabolic Response as Predictors of Treatment Outcomes in Breast Cancer Patients Treated with Everolimus and Exemestane

BACKGROUND

Treating breast cancer patients with everolimus and exemestane can be challenging due to toxicity and suboptimal treatment responses.

OBJECTIVE

We investigated whether everolimus exposure and early metabolic response are predictors for toxicity and effectiveness in these patients.

PATIENTS AND METHODS

We performed pharmacokinetic assessments 14 and 35 days after starting treatment. [¹⁸F]fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG-PET) was performed at baseline, and 14 and 35 days after the start of the therapy. We recorded toxicity, defined as dose interventions within 3 months, and progression-free survival (PFS).

RESULTS

Among 44 evaluable patients, the geometric mean (GM) C_trough was higher in patients with toxicity compared to patients without (17.4 versus 12.3 μg/L (p = 0.02)). The optimal cut-off value to predict toxicity was C_trough > 19.2 μg/L. GM C_trough of patients with and without progressive disease (PD) within 3 months was not significantly different (12.0 versus 15.2 μg/L (p = 0.118)). In 28 evaluable patients, PD within 3 months could best be predicted using the percentage decrease in peak standardized uptake value normalized by lean body mass of the lesion with highest FDG uptake (SUL_{peak high}) at day 14. Patients with <11% versus >11% decrease in SUL_{peak high} at day 14 had a median PFS of 90 days versus 411 days, respectively (p = 0.0013) and more frequently had PD within 3 months: 70 vs 11%, respectively.

CONCLUSIONS

Our results show that everolimus toxicity is related to everolimus C_trough. No relation was observed between everolimus exposure and treatment effectiveness. An early FDG-PET can identify patients at high risk of nonresponse. These results warrant further validation. Clinicaltrials.gov identifier: NCT01948960.

Role of Positron Emission Tomography Imaging in Metabolically Active Renal Cell Carcinoma

PURPOSE OF REVIEW

The clinical role of fluorine-18 fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) in renal cell carcinoma (RCC) is still evolving. Use of FDG PET in RCC is currently not a standard investigation in the diagnosis and staging of RCC due to its renal excretion. This review focuses on the clinical role and current status of FDG PET and PET/CT in RCC.

RECENT FINDINGS

Studies investigating the role of FDG PET in localized RCC were largely disappointing. Several studies have demonstrated that the use of hybrid imaging PET/CT is feasible in evaluating the extra-renal disease. A current review of the literature determines PET/CT to be a valuable tool both in treatment decision-making and monitoring and in predicting the survival in recurrent and metastatic RCC. PET/CT might be a viable option in the evaluation of RCC, especially recurrent and metastatic disease. PET/CT has also shown to play a role in predicting survival and monitoring therapy response.

FDG PET/CT as a survival prognostic factor in patients with advanced renal cell carcinoma

Accurate prediction of the outcome of molecular target-based treatment in advanced renal cell carcinoma (RCC) is an important clinical problem. Positron emission tomography/computed tomography using [18F]-2-fluoro-2-deoxyglucose (FDG PET/CT) is a noninvasive tool for the assessment of glucose accumulation which can be a marker of the biological characteristics of the tumor. In this paper, we assess FDG PET/CT as a survival prognostic marker in patients with advanced RCC. The study included 121 patients treated in the years 2011–2016 with a diagnosis of advanced renal cell carcinoma (stage IV, multifocal metastases in all patients). Assessment using FDG PET/CT was conducted by measuring the maximum standard uptake value (SUVmax) for the marker used (the highest SUV measurement result for each patient in a single examination). SUVmax measurements were compared with various clinical risk factors used as prognostic markers. The median follow-up period was 19 months (ranging from 3 to 61 months). SUVmax measurements in all patients ranged from 1.3 to 30.0 (median 6.9). Higher SUVmax was correlated with poorer prognosis. Multi-way analysis with standard risk factors revealed that SUVmax was an independent factor for overall survival (OS; p < 0.003, hazard ratio 1.312, 95% CI 1.147–1.346). For SUVmax < 7.0, median OS was 32 months. For 7.0 ≤ SUVmax < 12.0, median OS was 12.5 months. For SUVmax ≥ 12.0, median OS was 10 months. The differences were statistically significant. A preliminary SUVmax assessment conducted using FDG PET/CT can provide information useful in the prediction of survival of patients with advanced RCC.

Metabolic Pathways in Kidney Cancer: Current Therapies and Future Directions

BACKGROUND

Renal cell carcinoma (RCC) has become known as a metabolic disease, owing to the diverse array of metabolic defects and perturbations that occur as a result of the unique genetics that can drive these tumors. Recent attention to this feature of RCCs has fueled interest in targeting metabolism as a therapeutic strategy.

METHODS

We conducted a literature search to develop themes around discrete pathways or processes of cellular metabolism, provide a framework for understanding emerging therapeutic strategies, and consider future interventions.

RESULTS

Defects occur in metabolic pathways ranging from glycolysis to mitochondrial function and affect not only the tumor cell functionality, but also the local environment. We identified opportunities for therapeutic intervention associated with each pathway.

CONCLUSION

The metabolism of RCC cells presents a special environment of tumor susceptibilities, with opportunities for novel imaging applications and treatment paradigms that are being tested in monotherapy or as adjuncts to targeted or immune-based strategies.

Comparison of DWIBS/T2 image fusion and PET/CT for the diagnosis of cancer in the abdominal cavity

Fusion images of diffusion-weighted whole-body imaging with background body signal suppression and T2-weighted image (DWIBS/T2) demonstrate a strong signal for malignancies, with a high contrast against the surrounding tissues, and enable anatomical analysis. In the present study, DWIBS/T2 was compared with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for diagnosing cancer in the abdomen. Patient records, including imaging results of examination conducted between November 2012 and May 2014, were analyzed retrospectively. In total, 10 men (age, 73.6±9.6 years) and 8 women (age, 68.9±7.1 years) were enrolled into the current study. Of the enrolled patients, 2 were diagnosed with hepatocellular carcinoma, 1 with cholangiocellular carcinoma, 1 with liver metastasis, 2 with pancreatic ductal adenocarcinoma, 1 with renal cell carcinoma and 1 with malignant lymphoma. Benign lesions were also analyzed, including adenomyomatosis of the gallbladder (5 patients), intraductal papillary mucinous neoplasm (4 patients) and right adrenal adenoma (1 case). All the patients with cancer showed positive results on DWIBS/T2 images. However, only 7 out of 8 patients were positive with PET/CT. One patient with right renal cellular carcinoma was positive with DWIBS/T2, but negative with PET/CT. All the patients with benign lesions were negative with DWIBS/T2 and PET/CT. In conclusion, DWIBS/T2 was more sensitive in diagnosing cancer of organs in the abdominal cavity compared with PET/CT. Furthermore, negative results with DWIBS/T2 and PET/CT were useful for the diagnosis of benign lesions, such as adenomyomatosis of the gallbladder and intraductal papillary mucinous neoplasm.

A Case Report of Severe Type B Lactic Acidosis Following First Dose of Nivolumab in a VHL-Mutated Metastatic Renal Cell Carcinoma

We report a case of severe type B lactic acidosis (LA) in a 51-year-old male, 12 days after he received his first dose of nivolumab for metastatic Von Hippel Lindau (VHL)-mutated, clear cell renal cell carcinoma. Throughout his hospital course, infection, hypoperfusion, and tissue necrosis were not identified. We propose that his LA may have resulted from either inherent tumor glycolysis or immune activation and enhanced metabolism. The patient’s course was complicated by acute renal failure, and his LA rose progressively, eventually necessitating daily hemodialysis (HD). After receiving five consecutive days of HD, the patient started everolimus daily with the intent of reducing glycolytic metabolism. Subsequently, the rate of lactic acid production slowed, and HD was no longer required after two doses of everolimus. To our knowledge, this is the first reported case of type B LA following nivolumab administration, and the use of everolimus to treat type B LA in a patient with renal cancer.

Evaluation of treatment response and resistance in metastatic renal cell cancer (mRCC) using integrated 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography/magnetic resonance imaging (PET/MRI); The REMAP study

BACKGROUND

Tyrosine kinase inhibitors are the first line standard of care for treatment of metastatic renal cell carcinoma (RCC). Accurate response assessment in the setting of antiangiogenic therapies remains suboptimal as standard size-related response criteria do not necessarily accurately reflect clinical benefit, as they may be less pronounced or occur later in therapy than devascularisation. The challenge for imaging is providing timely assessment of disease status allowing therapies to be tailored to ensure ongoing clinical benefit. We propose that combined assessment of morphological, physiological and metabolic imaging parameters using 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) will better reflect disease behaviour, improving assessment of response/non-response/relapse.

METHODS/DESIGN

The REMAP study is a single-centre prospective observational study. Eligible patients with metastatic renal cell carcinoma, planned for systemic therapy, with at least 2 lesions will undergo an integrated 18F-FDG PET and MRI whole body imaging with diffusion weighted and contrast-enhanced multiphasic as well as standard anatomical MRI sequences at baseline, 12 weeks and 24 weeks of systemic therapy allowing 18F-FDG standardised uptake value (SUV), apparent diffusion co-efficient (ADC) and normalised signal intensity (SI) parameters to be obtained. Standard of care contrast-enhanced computed tomography CT scans will be performed at equivalent time-points. CT response categorisation will be performed using RECIST 1.1 and alternative (modified)Choi and MASS criteria. The reference standard for disease status will be by consensus panel taking into account clinical, biochemical and conventional imaging parameters. Intra- and inter-tumoural heterogeneity in vascular, diffusion and metabolic response/non-response will be assessed by image texture analysis. Imaging will also inform the development of computational methods for automated disease status categorisation.

DISCUSSION

The REMAP study will demonstrate the ability of integrated 18F-FDG PET-MRI to provide a more personalised approach to therapy. We suggest that 18F-FDG PET/MRI will provide superior sensitivity and specificity in early response/non-response categorisation when compared to standard CT (using RECIST 1.1 and alternative (modified)Choi or MASS criteria) thus facilitating more timely and better informed treatment decisions.

TRIAL REGISTRATION

The trial is approved by the Southeast London Research Ethics Committee reference 16/LO/1499 and registered on the NIHR clinical research network portfolio ISRCTN12114913 .

Prognostic Value of Pretreatment Metabolic Tumor Volume and Total Lesion Glycolysis Using 18F-FDG PET/CT in Patients With Metastatic Renal Cell Carcinoma Treated With Anti-Vascular Endothelial Growth Factor-Targeted Agents

PURPOSE

The aim of this study was to evaluate the prognostic value of pretreatment metabolic tumor volume (MTV) and total lesion glycolysis (TLG) using F-FDG PET/CT in patients with metastatic renal cell carcinoma (RCC) after treatment with anti-vascular endothelial growth factor-targeted agents.

METHODS

Fifty-six patients with metastatic RCC who underwent F-FDG PET/CT for staging and recurrence evaluation were retrospectively enrolled. SUVmax, MTV, and TLG were measured using F-FDG PET/CT in all patients. The highest SUV in all the metastatic RCC lesions of each patient was defined as SUVmax. Metabolic tumor volume was defined as the total tumor volume greater than 40% of SUVmax. Total lesion glycolysis was calculated as (MTV) · (SUVmean). The prognostic significance of PET/CT parameters and clinical factors for progression-free survival (PFS) and overall survival (OS) were evaluated by univariate and multivariate analyses, along with other clinical factors.

RESULTS

The most common organ for metastases was lung (35 patients). In the univariate analysis, hypercalcemia, time from diagnosis to treatment, SUVmax, MTV, and TLG were significant prognostic factors affecting PFS (P < 0.05), and Karnofsky score, hypercalcemia, time from diagnosis to treatment, SUVmax, MTV, and TLG were significant prognostic factors affecting OS (P < 0.05). In the multivariate analysis, hypercalcemia, MTV, and TLG were independent prognostic factors affecting PFS (P < 0.05), and hypercalcemia, time from diagnosis to treatment, MTV, and TLG were independent prognostic factors affecting OS (P < 0.05). In subgroup analyses, the high MTV or TLG groups showed poor prognosis for PFS and OS in patients with intermediate or poor risk.

CONCLUSIONS

Metabolic tumor volume and TLG are independent prognostic factors for predicting PFS and OS in patients with metastatic RCC. Furthermore, MTV and TLG could provide additional prognostic information in patients with clinically high-risk metastatic RCC treated with anti-vascular endothelial growth factor-targeted therapies.

The Role of PET Scanning in the Evaluation of Patients With Kidney Disease

Patients with underlying kidney disease are often required to undergo imaging for a variety of purposes including diagnosis and prognosis. A test that is being increasingly used with for this group of patients is the positron emission test (PET) scan. In addition, combining the nuclear medicine technique (PET) with computed tomography scan allows additional imaging advantages over either alone. These imaging modalities are commonly used for a number of extrarenal indications (ie, cancer, coronary artery disease, central nervous system disease, infectious diseases, and others). They have also been used for diagnosis of acute tubulointerstitial nephritis, evaluation and management of retroperitoneal fibrosis, identifying infection within kidney and liver cysts, and distinguishing complex kidney cysts from kidney cancer in patients with underlying CKD. We will review PET scan utility in patients with kidney disease.

One-month assessment of renal cell carcinoma treated by everolimus using FDG PET/CT predicts progression-free and overall survival

PURPOSE

We evaluated ¹⁸F-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) results as outcome predictors for patients with metastatic renal cell carcinoma (RCC) treated by everolimus (EVL), an inhibitor of mammalian target of rapamycin.

METHODS

We retrospectively reviewed 30 patients who were treated with EVL for metastatic RCC between May 2010 and March 2015, by evaluating their FDG PET/CT result before and 1 month after starting EVL treatment. We examined the relationships between each patient's maximum standardized uptake value (max SUVmax) assessed by FDG PET/CT on progression-free survival (PFS) and overall survival (OS).

RESULTS

Median PFS for all 30 patients was 3.77 months (range 0.72-24.56 months) and median OS after EVL treatment of all 30 patients was 11.67 months (range 1.0-62.98 months). Enrolled patients were divided into two groups by max SUVmax prior to EVL (median = 7.6) and at 1 month after EVL treatment (median = 5.7). PFS were significantly shorter in higher max SUVmax prior to EVL (<7.6, PFS 7.8 vs 3.5 months, log-rank P = 0.017) and at 1 month after EVL (<5.7, PFS 10.6 vs 2.7 months, log-rank P = 0.002) than lower max SUVmax. OS were also significantly shorter in higher max SUVmax prior to EVL (<7.6, OS 18.1 vs 7.5 months, log-rank P = 0.010) and at 1 month after EVL (<5.7, OS 17.2 vs 7.5 months, log-rank P = 0.009) than lower max SUVmax. Multivariate Cox hazard regression analysis indicated that max SUVmax at 1 month after EVL is an independent predictor of both PFS and OS in patients treated with EVL although univariate regression analysis showed max SUVmax before EVL is a possible predictor.

CONCLUSIONS

Max SUVmax assessed by FDG PET/CT prior to EVL and at 1 month after EVL treatment can accurately predict PFS and can guide decisions on whether to continue or change treatments for patients with EVL-treated RCC who suffer from adverse events.

Pretreatment metabolic parameters measured by 18F-FDG-PET to predict the outcome of first-line chemotherapy in extensive-stage small-cell lung cancer

OBJECTIVE

Patients' pretreatment metabolic burden, as measured by radiotracer fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT), has been shown to predict treatment outcome in various malignancies. However, its predictive role in extensive-stage small cell lung cancer (SCLC) has not been definitively determined. This retrospective study investigated the viability of using common pretreatment metabolic parameters, obtained through F-FDG-PET/CT, to predict outcomes of first-line chemotherapy in extensive-stage SCLC.

PARTICIPANTS AND METHODS

The study population comprised 154 consecutive patients with extensive-stage SCLC who underwent a pretreatment F-FDG-PET/CT scan and received standard first-line chemotherapy between January 2011 and December 2015.

RESULTS

Ten (6.5%) and 66 (42.9%) patients achieved a complete or a partial response, respectively (considered an objective response); 35 (22.7%) and 43 (27.9%) experienced stable or progressive disease. The metabolic tumor volume (MTV) was a significant factor for predicting an objective response. For predicting disease control (objective response or stable disease), MTV and total lesion glycolysis (TLG) were nonindependent factors.

CONCLUSION

Greater MTV and TLG could indicate a poorer response to first-line chemotherapy for patients with extensive-stage SCLC, but the predictive efficiency was not high enough for routine reliance. For patients who are not suitable to receive first-line chemotherapy, MTV and TLG may help guide clinical decisions.

Applications of PET/MR Imaging in Urogynecologic and Genitourinary Cancers

Positron emission tomograph (PET)-magnetic resonance (MR) is a new modality combining PET and MR. In gynecologic cancers it can be used for staging of cervical and endometrial cancer, planning of radiation therapy in cervical cancer, assessing response to chemotherapy in ovarian cancer, and detection of recurrence in most gynecologic cancers. It is being explored for prostate cancer and other genitourinary cancers, but is still in experimental stages.

89Zr-Bevacizumab PET: Potential Early Indicator of Everolimus Efficacy in Patients with Metastatic Renal Cell Carcinoma

Currently, biomarkers that predict the efficacy of everolimus in metastatic renal cell carcinoma (mRCC) patients are lacking. Everolimus inhibits vascular endothelial growth factor A (VEGF-A) expression. We performed PET scans on mRCC patients with ⁸⁹Zr-bevacizumab, a VEGF-A-binding antibody tracer. The aims were to determine a change in tumor tracer uptake after the start of everolimus and to explore whether ⁸⁹Zr-bevacizumab PET can identify patients with early disease progression. Methods:⁸⁹Zr-bevacizumab PET was done before and 2 and 6 wk after the start of everolimus, 10 mg/d, in mRCC patients. Routine CT scans were performed at baseline and every 3 mo thereafter. Tumor tracer uptake was quantified using SUV_max The endpoints were a change in tumor tracer uptake and treatment response on CT after 3 mo. Results: Thirteen patients participated. The median SUV_max of 94 tumor lesions was 7.3 (range, 1.6-59.5). Between patients, median tumor SUV_max varied up to 8-fold. After 2 wk, median SUV_max was 6.3 (1.7-62.3), corresponding to a mean decrease of 9.1% (P < 0.0001). Three patients discontinued everolimus early. At 6 wk, a mean decrease in SUV_max of 23.4% compared with baseline was found in 70 evaluable lesions of 10 patients, with a median SUV_max of 5.4 (1.1-49.4, P < 0.0001). All 10 patients who continued treatment had stable disease at 3 mo. Conclusion: Everolimus decreases ⁸⁹Zr-bevacizumab tumor uptake. Further studies are warranted to evaluate the predictive value of ⁸⁹Zr-bevacizumab PET for everolimus antitumor efficacy.

18F-FDG PET/CT in the Staging and Management of Breast Cancer: Value in Disease Outcome and Planning Therapy

In hormone receptor-positive locally advanced breast cancer, endocrine therapy becomes an integral part of the therapeutic strategy. There are now significant numbers of available hormonal directed compounds, including selective aromatase and mTOR inhibitors, which allow an important therapeutic advance in these patients. Sequential F-FDG PET/CT studies provided essential information regarding response to different treatments, including targeted therapies, and adverse therapeutic effects that helped to better define the right moment to implement each therapeutic approach.

The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations

Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-d-glucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. Published clinical observations were discordant regarding the role of FDG PET/CT in diagnosing and staging RCC, and FDG PET/CT is not recommended for this purpose based on current national and international guidelines. However, quantitative FDG PET/CT imaging may facilitate the prediction of the degree of tumor differentiation and allows for prognosis of the disease. FDG PET/CT has potency as an imaging biomarker to provide useful information about patient’s survival. FDG PET/CT can be effectively used for postoperative surveillance and restaging with high sensitivity, specificity, and accuracy, as early diagnosis of recurrent/metastatic disease can drastically affect therapeutic decision and alter outcome of patients. FDG uptake is helpful for differentiating benign or bland emboli from tumor thrombosis in RCC patients. FDG PET/CT also has higher sensitivity and accuracy when compared with bone scan to detect RCC metastasis to the bone. FDG PET/CT can play a strong clinical role in the management of recurrent and metastatic RCC. In monitoring the efficacy of new target therapy such as tyrosine kinase inhibitors (TKIs) treatment for advanced RCC, FDG PET/CT has been increasingly used to assess the therapeutic efficacy, and change in FDG uptake is a strong indicator of biological response to TKI.

Update on advances in molecular PET in urological oncology

Integrated positron emission tomography/computed tomography (PET/CT) with 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) has emerged as a powerful tool for the combined metabolic and anatomic evaluation of many cancers. In urological oncology, however, the use of (18)F-FDG has been limited by a generally low tumor uptake, and physiological excretion of FDG through the urinary system. (18)F-FDG PET/CT is useful when applied to specific indications in selected patients with urological malignancy. New radiotracers and positron emission tomography/magnetic resonance imaging (PET/MRI) are expected to further improve the performance of PET in uro-oncology.

Prognostic Value of Quantitative Metabolic Metrics on Baseline Pre-Sunitinib FDG PET/CT in Advanced Renal Cell Carcinoma

Purpose

The objective of this study was to prospectively evaluate various quantitative metrics on FDG PET/CT for monitoring sunitinib therapy and predicting prognosis in patients with metastatic renal cell cancer (mRCC).

Methods

Seventeen patients (mean age: 59.0 ± 11.6) prospectively underwent a baseline FDG PET/CT and interim PET/CT after 2 cycles (12 weeks) of sunitinib therapy. We measured the highest maximum standardized uptake value (SUVmax) of all identified lesions (highest SUVmax), sum of SUVmax with maximum six lesions (sum of SUVmax), total lesion glycolysis (TLG) and metabolic tumor volume (MTV) from baseline PET/CT and interim PET/CT, and the % decrease in highest SUVmax of lesion (%Δ highest SUVmax), the % decrease in sum of SUVmax, the % decrease in TLG (%ΔTLG) and the % decrease in MTV (%ΔMTV) between baseline and interim PET/CT, and the imaging results were validated by clinical follow-up at 12 months after completion of therapy for progression free survival (PFS).

Results

At 12 month follow-up, 6/17 (35.3%) patients achieved PFS, while 11/17 (64.7%) patients were deemed to have progression of disease or recurrence within the previous 12 months. At baseline, PET/CT demonstrated metabolically active cancer in all cases. Using baseline PET/CT alone, all of the quantitative imaging metrics were predictive of PFS. Using interim PET/CT, the %Δ highest SUVmax, %Δ sum of SUVmax, and %ΔTLG were also predictive of PFS. Otherwise, interim PET/CT showed no significant difference between the two survival groups regardless of the quantitative metric utilized including MTV and TLG.

Conclusions

Quantitative metabolic measurements on baseline PET/CT appears to be predictive of PFS at 12 months post-therapy in patients scheduled to undergo sunitinib therapy for mRCC. Change between baseline and interim PET/CT also appeared to have prognostic value but otherwise interim PET/CT after 12 weeks of sunitinib did not appear to be predictive of PFS.

The Actual Role of LDH as Tumor Marker, Biochemical and Clinical Aspects

Lactate dehydrogenase (LDH) among many biochemical parameters represents a very valuable enzyme in patients with cancer with possibility for easy routine measurement in many clinical laboratories. Previous studies where mostly based on investigated LDH in serum of patients with cancer with aims to estimate their clinical significance. The new directions in investigation of LDH where based on the principle that tumor cells release intracellular enzymes trough damaged cell membrane, that is mostly consequence in intracellular mitochondrial machinery alteration, and apoptosis deregulation. This consideration can be used not only in-vitro assays, but also in respect to clinical characteristics of tumor patients. Based on new techniques of molecular biology it is shown that intracellular characteristics of LDH enzyme are very sensitive indicators of the cellular metabolic state, aerobic or anaerobic direction of glycolysis, activation status and malignant transformation. Using different molecular analyses it is very useful to analyzed intracellular LDH activity in different cell line and tumor tissues obtained from patients, not only to understanding complexity in cancer biochemistry but also in early clinical diagnosis. Based on understandings of the LDH altered metabolism, new therapy option is created with aims to blocking certain metabolic pathways and stop tumors growth.

Comparison of 11C-4DST and 18F-FDG PET/CT imaging for advanced renal cell carcinoma: preliminary study

PURPOSE

4'-[Methyl-(11)C]-thiothymidine (4DST) has been developed as an in vivo cell proliferation marker based on its DNA incorporation mechanism. This study evaluated the potential of 4DST PET/CT for imaging cellular proliferation in advanced clear cell renal cell carcinoma (RCC), compared with FDG PET/CT. Both 4DST and FDG uptake were compared with biological findings based on surgical pathology.

METHODS

Five patients (3 men and 2 women; mean (±SD) age 64.8 ± 11.0 years) with a single RCC (mean diameter: 9.3 ± 3.2 cm) were examined by PET/CT using 4DST and FDG. The dynamic emission scan of 4DST for RCC over 35 min followed by a static emission scan of the body for 4DST and FDG. Then we compared the maximum standardized uptake value (SUVmax) of 20 areas of RCC on both 4DST and FDG images with (1) the Ki-67 index of cellular proliferation (2) Fuhrman grade system for nuclear grade (G) in RCC and (3) pathological phosphorylated grade of mammalian target of rapamycin (pmTOR).

RESULTS

All patient cases showed clear uptake of FDG and 4DST in RCC tumors, with mean 4DST SUVmax of 7.3 ± 2.2 (range 4.3-9.4) and mean FDG SUVmax of 6.0 ± 2.8 (range 3.4-10.4). The correlation coefficient between SUVmax and Ki-67 index was higher with 4DST (r = 0.61) than with FDG (r = 0.43). Tumor 4DST uptake (G0: 1.4, G2: 2.6, G2 5.6, G4: 5.7) and tumor FDG uptake (G0: 1.8, G2: 2.9, G2 3.7, G4: 4.1) were both related to Fuhrman grade system. The 4DST uptake increased as the pmTOR grade increases (G0: 3.1, G1: 4.8, G2: 4.7, G3: 6.2); in contrast FDG uptake was unrelated to pmTOR grade (G0: 2.8, G2: 4.0, G2 3.3, G4: 3.6).

CONCLUSION

A higher correlation with the proliferation of RCC was observed for 4DST than for FDG. The 4DST uptake exhibits the possibility to predict pmTOR grade, indicating that 4DST has potential for the evaluation of therapeutic effect with mTOR inhibitor in patients with RCC.

Pharmacodynamic Biomarker Development for PI3K Pathway Therapeutics

The phosphatidylinositol 3-kinase (PI3K) signaling pathway is integral to many essential cell processes, including cell growth, differentiation, proliferation, motility, and metabolism. Somatic mutations and genetic amplifications that result in activation of the pathway are frequently detected in cancer. This has led to the development of rationally designed therapeutics targeting key members of the pathway. Critical to the successful development of these drugs are pharmacodynamic biomarkers that aim to define the degree of target and pathway inhibition. In this review, we discuss the pharmacodynamic biomarkers that have been utilized in early-phase clinical trials of PI3K pathway inhibitors. We focus on the challenges related to development and interpretation of these assays, their optimal integration with pharmacokinetic and predictive biomarkers, and future strategies to ensure successful development of PI3K pathway inhibitors within a personalized medicine paradigm for cancer.

FDG PET/CT as a prognostic biomarker in the era of molecular-targeting therapies: max SUVmax predicts survival of patients with advanced renal cell carcinoma

BACKGROUND

Various molecular-targeting therapies have become available for the treatment of advanced renal cell carcinoma (RCC). Accurate prognostication is desirable for choosing the appropriate treatment for individual patients. (18)F-2-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) is a non-invasive tool for evaluating glucose accumulation, which can be an index of biological characteristics of cancer. We prospectively evaluated FDG PET/CT as a prognostic indicator in patients with advanced RCC.

METHODS

A total of 101 patients slated for different systematic therapies for advanced RCC were enrolled between 2008 and 2014. A total of 61 patients had recurrent RCC (58 metastatic and 3 regional) and 40 patients had stage IV RCC (36 metastatic and 4 locoregional). Sixteen patients had not undergone nephrectomy. Pre-treatment FDG PET/CT was performed, and the max SUVmax (the highest SUV measurement in each patient) was recorded. The max SUVmax was compared with different clinical risk factors as prognostic indicators. The median observation period was 18 months (range 1-70 months).

RESULTS

The max SUVmax of the 101 subjects ranged from undetectable to 23.0 (median 6.9). Patients with high max SUVmax had a poor prognosis. Multivariate analysis with standard risk factors revealed that max SUVmax was an independent predictor of survival (p < 0.001; hazard ratio 1.265; 95% confidence interval 1.159-1.380). A cutoff of 8.8 for max SUVmax advocated in our previous report was highly significant (p < 0.0001). When we subclassified the max SUVmax values, the median overall survival of subjects with max SUVmax < 7.0 was 41.9 months. That of subjects with max SUVmax between 7.0 and 12.0 was 20.6 months. That of subjects with max SUVmax ≥ 12.0 was 4.2 months. The differences were statistically significant.

CONCLUSIONS

Pretreatment max SUVmax assessed by FDG PET/CT is a useful prognostic marker for patients with advanced RCC, providing helpful information for clinical decision making.

Alternate Metabolic Programs Define Regional Variation of Relevant Biological Features in Renal Cell Carcinoma Progression

PURPOSE

Clear cell renal cell carcinoma (ccRCC) has recently been redefined as a highly heterogeneous disease. In addition to genetic heterogeneity, the tumor displays risk variability for developing metastatic disease, therefore underscoring the urgent need for tissue-based prognostic strategies applicable to the clinical setting. We have recently employed the novel PET/magnetic resonance (MR) image modality to enrich our understanding of how tumor heterogeneity can relate to gene expression and tumor biology to assist in defining individualized treatment plans.

EXPERIMENTAL DESIGN

ccRCC patients underwent PET/MR imaging, and these images subsequently used to identify areas of varied intensity for sampling. Samples from 8 patients were subjected to histologic, immunohistochemical, and microarray analysis.

RESULTS

Tumor subsamples displayed a range of heterogeneity for common features of hypoxia-inducible factor expression and microvessel density, as well as for features closely linked to metabolic processes, such as GLUT1 and FBP1. In addition, gene signatures linked with disease risk (ccA and ccB) also demonstrated variable heterogeneity, with most tumors displaying a dominant panel of features across the sampled regions. Intriguingly, the ccA- and ccB-classified samples corresponded with metabolic features and functional imaging levels. These correlations further linked a variety of metabolic pathways (i.e., the pentose phosphate and mTOR pathways) with the more aggressive, and glucose avid ccB subtype.

CONCLUSIONS

Higher tumor dependency on exogenous glucose accompanies the development of features associated with the poor risk ccB subgroup. Linking these panels of features may provide the opportunity to create functional maps to enable enhanced visualization of the heterogeneous biologic processes of an individual's disease. Clin Cancer Res; 22(12); 2950-9. ©2016 AACR.

PET/Computed Tomography in Renal, Bladder, and Testicular Cancer

Imaging plays an important role in the clinical management of cancer patients. Hybrid imaging with PET/computed tomography (CT) is having a broad impact in oncology, and in recent years PET/CT is beginning to have an impact in urooncology. In both bladder and renal cancers, there is a need to study the efficacy of other tracers than F-18 fluorodeoxyglucose (FDG), particularly tracers with limited renal excretion. Thus, new tracers are being introduced. This review focuses on the clinical role of FDG and other PET agents in renal, bladder, and testicular cancers.

An update on current management of advanced renal cell cancer, biomarkers, and future directions

In the past decade, metastatic renal cell carcinoma (mRCC) treatment underwent significant advancement that resulted in an unprecedented improvement in the prognosis of this disease. This review will provide an updated review of currently approved treatment options, namely antiangiogenic and immunotherapy, as well as treatment guideline recommended by the National Comprehensive Cancer Network (NCCN). We will summarize studies ongoing in determining prognostic and predictive biomarkers in maximizing therapeutic benefit in the treatment of this disease. Lastly, we will discuss promising agents in clinical testing.

Lesion-based analysis of (18)F-FDG uptake and (111)In-Pentetreotide uptake by neuroendocrine tumors

PURPOSE

To characterize the heterogeneity of metastatic neuroendocrine tumor (NET) lesions, we compared the [(18)F]-fluorodeoxyglucose (FDG) uptake and the (111)In-pentetreotide (SRS) uptake for somatostatin receptor scintigraphy using the CT-based fusion imaging techniques of PET/CT and SPECT/CT.

METHODS

Fifteen consecutive patients with NET lesions were examined using both FDG-PET/CT and SRS SPECT/CT prospectively. A total of 45 metastatic NET lesions were evaluated for FDG uptake according to the standardized uptake value (SUV) and for SRS uptake according to the tumor-to-muscle count ratio (T/M ratio); these values were then compared according to the grade of NET (G), also compared to the tumor volume.

RESULTS

Both the SRS uptake and FDG uptake showed no significant correlation to the tumor volume, and suggested no significant artifacts in these data. The T/M ratio for the SRS uptake ranged from 192.7 to 1.9 and exhibited very wide range of distribution. The SUV for the FDG uptake ranged from 13.8 to 0.77 and exhibited narrow range of distribution. The uptake of the two tracers in individual lesions showed an inverse correlation. The G1 + 2 lesions had a higher SRS uptake than the G3 lesions, but the difference was not significant because of the large variation (40.65 ± 48.03, n = 39 vs. 8.66 ± 13.13, n = 6). However, the G1 + 2 lesions had a significantly lower FDG uptake than the G3 lesions (3.52 ± 1.84, n = 39 vs. 10.82 ± 4.50, n = 6). The tracer uptakes varied largely not only in an inter-subject manner, but also in an intra-subject manner.

CONCLUSION

An inverse correlation between SRS uptake and FDG uptake in the metastatic NET lesions observed in this study may be consistent with the opposing ideas of differentiation and proliferation in oncology. The large variations in SRS and FDG uptake by metastatic NET lesions suggest the biological heterogeneity of advanced NET. These results support the idea that combination therapy targeting both receptor-positive cells and proliferating cells may be beneficial from a functional imaging perspective.