In patients with renal cell carcinoma (RCC) with low tumor burden or slow growing disease, active surveillance is a common strategy. However, there are few available data on the use of active surveillance versus immediate treatment for the management of patients with metastatic RCC (mRCC). Igal Kushnir, MD, and colleagues in Canada conducted an analysis designed to examine the outcomes and safety of active surveillance compared with immediate systemic treatment for patients with mRCC.
Results were reported during a poster session at the ASCO 2019 Annual Meeting. The poster was titled Active Surveillance in Metastatic Renal Cell Carcinoma (mRCC): Results from the Canadian Kidney Center Information System (CKCis).
Utilizing data from the CKCis, the researchers identified patients with mRCC between January 2, 2011, and December 31, 2016. A strategy of active surveillance was defined as: (1) start of systemic therapy ≥6 months after diagnosis of mRCC; or (2) never receiving systemic therapy for mRCC with an overall survival of ≥1 year (overall survival ≥1 year was a surrogate to exclude patients not started on treatment due to poor prognosis).
Immediate systemic treatment was defined as starting systemic treatment ≤6 months following diagnosis of mRCC. The analysis compared overall survival and time until first-line treatment failure between the two cohorts.
Of the patients identified during the study period, 863 met the criteria for active surveillance (cohort A). Of those, 370 started systemic treatment ≥6 months following their initial diagnosis (cohort A1); 493 never received systemic treatment and were alive for ≥1 year (cohort A2). Cohort B included 848 patients who received immediate systemic treatment.
Median age for cohort A was 65.1 years compared with 62.2 years for cohort B (P<.0001). There were no statistically significant differences in sex distribution between the two cohorts. Patients in cohort A had fewer sites of metastatic disease compared with cohort B (P<.0001) and 23% of patients in cohort A had metastasectomy compared with 5% in cohort B (P=.0001).
Five-year overall survival probability was significantly greater for cohort A than for cohort B (70.2% vs 32.1%; P<.0001). Following adjustment for International Metastatic RCC Database Consortium risk criteria and age, both overall survival (hazard ratio [HR], 0.46; 95% confidence interval [CI], 0.38-0.56; P<.0001) and time to treatment failure (HR, 0.79; 95% CI, 0.69-0.92; P=.0021) were greater in cohort A1 compared with cohort B. Median time on active surveillance in cohort A1 was 14.2 months.
“Based on the largest analysis of active surveillance in mRCC to date, our data suggest that a subset of patients may be safely observed without immediate initiation of systemic therapy. Prospective validation is required in the contemporary immunotherapy era,” the researchers said.
Source: Kushnir I, Basappa N, Ghosh S, et al. Active surveillance in metastatic renal cell carcinoma (mRCC): Results from the Canadian Kidney Cancer information system (CKCis). Abstract of a poster presented at the American Society of Clinical Oncology 2019 Annual Meeting, June 3, 2019, Chicago, Illinois.