ASCO 2017: Prognostic role of circulating tumor cells in metastatic renal cell carcinoma

Chicago, IL ( Circulating tumor cells (CTCs) can be isolated in peripheral blood of cancer patients and have been demonstrated to have a prognostic role in several metastatic tumors such as breast, colorectal and prostate cancer. However, there is lack of data available regarding its role in Renal Cell Carcinoma (RCC).

Dr. Basso presented a multicenter prospective observational trial aiming to assess the association between CTC counts and progression free survival (PFS) of RCC pts treated with an antiangiogenic tyrosine-kinase inhibitors (TKI) as a first-line regimen for metastatic disease. Overall survival (OS) and response rate were secondary objectives. Both basal and sequential counts were provided by Cellsearch system at 4 distinct time points: day 0 of treatment, +1 months, +3 months, at progression or 12 months in the absence of progression.

Among 15 Italian oncology units, 246 pts were enrolled, and 195 were eligible for the study. Out of these 195 patients, 72% were males with a median age of 69 years (range, 40 to 91), and 86% had a previous partial/radical nephrectomy. TKI treatment included sunitinib (77 %), pazopanib (21%) or sorafenib (2%). According to Heng criteria there were 24.6% good, 62.6% intermediate and 24.6% poor prognosis pts. After a median follow-up of 31.5 months, median progression free survival (PFS) was 13.6 months (23% censored), 49.2% of pts were still alive with an overall survival (OS) rate at 24 months of 59.9%. At baseline, 91 pts had 1 or more CTCs, (median 2, range 1 to 263). Pts with at least 1 CTC had a significantly shorter PFS compared to negative pts (8.8 vs 16.6 months, p = 0.03), HR = 1.41 (95%CI 1.02-1.9). Thirty pts had > = 3 CTCs, with a median PFS of 5.8 vs 15 months in the remaining pts (p = 0.002), HR = 1.99 (CI 1.28-3.03). Percentage of pts with > = 3 CTCs increased from 6.6% of good, 18.4% intermediate and 38.9% poor Heng score pts (p = 0.042). Pts with > = 3 CTCs had a shorter estimated OS of 13.8 months vs 52.8 months (p = 0.003), HR = 1.99 (CI 1.17-3.2). No significant correlation could be found between CTC positivity and response rate.

In summary, in this robust multicenter prospective cohort of first-line metastatic RCC pts, the presence of 3 or more CTCs predicted a significantly shorter PFS and OS. Further research is required to ascertain the true role of CTCs in these patients.

Presented By: Umberto Basso, Department of Clinical and Experimental Oncology, Istituto Oncologico Veneto IOV - IRCCS, Padova, Italy

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre
Twitter: @GoldbergHanan

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 – Chicago, Illinois, USA