ASCO GU 2018: Impact of Tumor Size on Survival Outcome in mRCC Treated with Targeted Therapy

San Francisco, CA ( Dr. Wanling Xie and colleagues from the Dana-Farber Cancer Institute presented their findings assessing the impact of tumor size on survival in patients with mRCC treated with targeted therapy at today’s poster session at GU ASCO. It is generally accepted that patients with small renal masses (4 cm or less) are at low risk of disease recurrence after surgery. However, the impact of tumor size on survival in mRCC patients treated with targeted therapy (TKI) is unclear, forming the objective of this study.

For this study, two cohorts were identified from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC). Cohort 1 patients (n=1,903) had initial nephrectomy for M0 RCC and subsequently developed metastasis during follow-up. Cohort 2 patients (n=2,186) presented with de novo metastasis with or without cytoreductive nephrectomy. Cox regression was performed to assess the associations of primary tumor size (≤4 vs > 4cm) and overall survival (OS) on first line TKI, adjusted for histology, sarcomatoid features, tumor stage, number of metastasis, IMDC risk groups and age at TKI initiation.

Among the 4,089 patients included in the cohort, patient characteristics were generally balanced between tumor size groups (≤4 vs > 4cm), except for patients with ≤4cm tumors being more likely to have a solitary metastasis (29% vs 18%, p = 0.001) and less likely to have IMDC poor risk (32% vs 39%, p = 0.04) compared to patients from cohort 2. For patients from cohort 1, tumor size at initial nephrectomy did not impact OS after TKI initiation (p = 0.689). However, in patients presenting with de novo metastasis (cohort 2), small primary tumors were associated with improved OS after TKI initiation, but only in T1-2 tumors:

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In conclusion, the authors suggest that tumor size impacts survival outcome with targeted therapy in mRCC patients presenting with de novo metastasis and T1-2 disease. As such, these results may need to be taken into consideration when designing clinical trials.

Speaker: Wanling Xie, Dana-Farber Cancer Institute, Boston, MA

Co-Authors: Renzo DiNatale, A. Ari Hakimi, Frede Donskov, Camillo Porta, M. Neil Reaume, Naveen S. Basappa, Aaron Richard Hansen, Brian I. Rini, Benoit Beuselinck, Georg A Bjarnason, Sandy Srinivas, James Brugarolas, Sun Young Rha, Lori Wood, Aly-Khan A. Lalani, Dominick Bosse, Audrey Duquette, Daniel Yick Chin Heng, Toni K. Choueiri

Written by: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Twitter: @zklaassen_md, at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA