ASCO GU 2018: Conditional Survival and Landmark Analysis for Patients with Small Renal Masses Undergoing Active Surveillance at a Tertiary Care Center
MD Anderson enrolled patients into a prospective AS registry between May 2005 and January 2016; they included patients with localized SRM ≤4cm, and followed them with serial radiologic imaging available in-house for re-review. During that time, they enrolled 272 patients. Mean initial tumor size was 1.74 ± 0.77 cm and mean tumor size closest to the 2-year mark was 1.97 ± 0.83 cm.
On conditional survival analysis (overall survival analysis), the likelihood of continued survival to 5 years improved after the 2-year landmark was reached. Patients with tumors < 3cm who survived the first 2-years on AS had a 0.84-0.85 chance of surviving to 5 years, and if they survived 3 years, the probability of surviving to 5 years improved to 0.91.
Multivariable Cox proportional hazards analysis of survival revealed eGFR, Charlson comorbidity index (CCI), and tumor size of 3-4cm were significantly predictive of OS both at baseline and at 2-year mark (all p < 0.05). Interestingly, patients with a tumor size 3-4 cm were at a greater risk of non-RCC death (HR > 3.5; p ≤ 0.001).
A linear mixed effects model revealed slow tumor growth (beta: 0.12; p < 0.001) for tumors < 3cm. Adjusted tumor size predictions disclosed parallel growth rates for SRM of < 2cm and 2-2.99cm with insignificant difference (p = 0.969).
This study provides insight into the overall survival of patients with SRM on AS who have already survived a certain period of time, but unfortunately does not dive into cancer-specific survival outcomes. The conditional survival probability of patients with SRM < 3cm on AS improved after the initial 2 years, suggesting a role for re-counseling for those who survive to the 2-year landmark. Patient factors (renal function and CCI) were significantly associated with survival at baseline and at the 2-year landmark.
Speaker: Firas Petros, MD
Co-Authors: Aradhana M. Venkatesan, Diana Kaya, Chaan S. Ng, Bryan M. Fellman, Jose A. Karam, Christopher G. Wood, Surena F. Matin
Institution(s): UT MD Anderson Cancer Center, Houston, TX
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA