Top Highlights From the 2016 ASCO GU Cancers Symposium

January 29, 2016

Conference | ASCO Gastrointestinal Cancer Symposium

This slide show includes some of the top highlights from the 2016 ASCO Genitourinary Cancers Symposium, including studies on hypofractionation in low-risk prostate cancer, cabozantinib in advanced RCC, and more.

References:

1. Lee WR, Dignam JJ, Amin M, et al. NRG Oncology RTOG 0415: A randomized phase III non-inferiority study comparing two fractionation schedules in patients with low-risk prostate cancer. Presented at the 2016 Genitourinary Cancers Symposium. Abstract 1.

2. Dearnaley DP, Syndikus I, Mossop H, et al. Comparison of hypofractionated high-dose intensity-modulated radiotherapy schedules for prostate cancer: Results from the phase III randomized CHHiP trial (CRUK/06/016). Presented at the 2016 Genitourinary Cancers Symposium. Abstract 2.

3. Shipley WU, Pugh SL, Lukka HR, et al. NRG Oncology/RTOG 9601, a phase III trial in prostate cancer patients: Anti-androgen therapy (AAT) with bicalutamide during and after salvage radiation therapy (RT) following radical prostatectomy (RP) and an elevated PSA. Presented at the 2016 Genitourinary Cancers Symposium. Abstract 3.

4. Scher HI, Graf R, Louw J, et al. Single CTC characterization to identify phenotypic and genomic heterogeneity as a mechanism of resistance to AR signaling directed therapies (AR Tx) in mCRPC patients. Presented at the 2016 Genitourinary Cancers Symposium. Abstract 163.

5. Abel EJ, Zargar K, Margulis V, et al. Role of cytoreductive nephrectomy in renal cell cancer (RCC) with venous tumor thrombus. Presented at the 2016 Genitourinary Cancers Symposium. Abstract 496.

6. Motzer RJ, Sharma P, McDermott DF, et al. CheckMate 025 phase III trial: Outcomes by key baseline factors and prior therapy for nivolumab (NIVO) versus everolimus (EVE) in advanced renal cell carcinoma (RCC). Presented at the 2016 Genitourinary Cancers Symposium. Abstract 498.

7. Escudier BJ, Motzer RJ, Powles T, et al. Subgroup analyses of METEOR, a randomized phase 3 trial of cabozantinib versus everolimus in patients (pts) with advanced renal cell carcinoma (RCC). Presented at the 2016 Genitourinary Cancers Symposium. Abstract 499.

Hypofractionation for Low-Risk Prostate Cancer Noninferior to Conventional Fractionation:

A phase III trial that included 1,092 evaluable patients found that a hypofractionated radiotherapy regimen was noninferior to conventional fractionation (abstract 1). Half of the patients (n = 542) were randomized to receive conventional fractionation of 41 fractions of 1.8 Gy over 8.2 weeks, for a total dose of 73.8 Gy. The experimental group (n = 550) received 28 fractions of 2.5 Gy over 5.6 weeks, for a total dose of 70 Gy. After a median follow-up of 5.8 years, the disease-free survival rate at 5 years was 85% with conventional fractionation and 86% with hypofractionation, for a hazard ratio of 0.85 (95% CI, 0.64â1.14).[1] Photo Â© ASCO/Todd Buchanan 2016.

Three-Arm Prostate Cancer Trial Suggests Middle Ground for Hypofractionation RT:

A three-arm trial involving 3,216 mostly intermediate-risk prostate cancer patients found that a hypofractionation radiotherapy (RT) regimen of 60 Gy over 4 weeks was noninferior to conventional RT. Results were presented by David P. Dearnaley, MD, of the Institute of Cancer Research in the United Kingdom (abstract 2). The CHHiP trial randomized patients into one of three groups: conventional RT totaling 74 Gy (control); hypofractionated RT totaling 60 Gy; or hypofractionated RT totaling 57 Gy. The 5-year control rates were 88.3% with conventional RT, 90.6% with the 60-Gy regimen, and 85.9% in the 57-Gy group. Compared with the control, the 60-Gy group had a hazard ratio of 0.84 (

= .004), which met the prespecified criteria for noninferiority.[2] Photo Â© ASCO/Todd Buchanan 2016.

Adding Bicalutamide to Salvage Radiation Therapy Improved Survival in Prostate Cancer:

A phase III trial of anti-androgen therapy with bicalutamide during and after salvage radiation therapy in prostate cancer patients improved overall survival and reduced the incidence of metastatic disease and disease-specific mortality, according to data presented by William U. Shipley, MD, of the Massachusetts General Hospital Cancer Center in Boston (abstract 3). The trial involved 761 patients randomized to radiation therapy with either 150 mg bicalutamide daily (n = 384) for 24 months or placebo (n = 377). Median follow-up was 12.6 years. Overall survival at 10 years was 82% in the bicalutamide arm and 78% in the placebo arm for a hazard ratio of 0.75 (95% CI, 0.58â0.98). Incidence of metastatic prostate cancer at 12 years occurred less frequently in the bicalutamide arm than in the placebo arm (14% vs 23%;

Cell Diversity in Liquid Biopsy Could Indicate Poor Prostate Cancer Prognosis:

Patients who have a more heterogeneous set of detectable circulating tumor cells (CTCs) are more likely to develop resistance to anti-androgen therapy, according to the results of a study presented by Howard I. Scher, MD, a medical oncologist at the Memorial Sloan Kettering Cancer Center in New York (abstract 163). Among prostate cancer patients treated with either enzalutamide or abiraterone, patients with a high CTC heterogeneity score had a shorter progression-free survival (5 months vs 17 months;

= .00182) and overall survival (9 months vs not yet reached;

Some Metastatic RCC Patients With Venous Tumor Thrombus May Not Benefit From Cytoreductive Nephrectomy:

Metastatic renal cell carcinoma (RCC) patients with inferior vena caval (IVC) thrombosis above the diaphragm or patients classified as unfavorable using the University of Texas MD Anderson Cancer Center (MDACC) criteria may not derive benefit from cytoreductive nephrectomy in the presence of venous tumor thrombus, according to a study presented by Edwin Jason Abel, MD, of the University of Wisconsin School of Medicine and Public Health in Madison, Wisconsin (abstract 496). In a study of 293 patients, median overall survival in patients with IVC thrombus above the diaphragm was 6.8 months (95% CI, 2.2â19.1) compared with 18.9 months in patients with IVC thrombus below the diaphragm (95% CI, 6.7â44.5) and 18.8 months among patients with renal vein thrombus (95% CI, 8.1â37.8). Using MDACC criteria, overall survival was lower in unfavorable-risk patients compared with favorable-risk patients (8.2 vs 18.8 months;

Consistent Survival Benefit Seen With Nivolumab in RCC:

An analysis of the phase III CheckMate-025 trial showed that nivolumab as second-line therapy for patients with advanced renal cell carcinoma (RCC) produced a consistent objective response rate and survival rate across different subgroups, according to data presented by Robert J. Motzer, MD, of Memorial Sloan Kettering Cancer Center in New York (abstract 498). The CheckMate-025 trial randomized 811 metastatic RCC patients to second-line treatment with either nivolumab (n = 410) or everolimus (n = 411). The data showed that patients on nivolumab performed better across baseline factors such as Karnofsky performance status, Heng risk criteria, or number of prior therapies, regardless of prior treatment with sunitinib, pazopanib, or IL-2.[6] Photo Â© ASCO/Todd Buchanan 2016.

Cabozantinib Delays Progression in Advanced RCC:

Patients with advanced renal cell carcinoma (RCC) treated with cabozantinib had improved progression-free survival compared with those treated with everolimus, according to updated results of the phase III METEOR trial presented by Bernard J. Escudier, MD, of the Institut Gustave Roussy in Villejuif, France (abstract 499). The study randomized 658 patients 1:1 to either cabozantinib or everolimus. Using the Memorial Sloan Kettering Cancer Center risk assessment criteria, 43% of patients on study had favorable-risk disease, 41% had intermediate-risk disease, and 15% had poor-risk disease. Median progression-free survival was 7.4 months in the cabozantinib arm compared with 3.9 months in the everolimus arm.[7] Photo Â© ASCO/Todd Buchanan 2016.