Probability of downsizing primary tumors of renal cell carcinoma by targeted therapies is related to size at presentation

Abstract

Objective: To evaluate the probability of downsizing primary renal tumors by targeted therapy in correlation to size.

Methods: A literature search was conducted and our own data were pooled with data of retrospective series and prospective trials in which patients were treated with tyrosine kinase inhibitors (TKIs) and in which tumor sizes before and after treatment were reported. Included were 89 primary clear cell renal tumors, including 34 from our institutes. The longest diameter of the primary tumors before and after treatment was obtained. Primary tumor size at presentation was divided in 4 categories: <5 cm (n=10), 5 to 7 cm (n=21), 7 to 10 cm (n=31), and >10 cm (n=27). Pearson correlation and t test were used for statistical analysis.

Results: The TKI was sorafenib in 21 tumors and sunitinib in the remaining 68. Smaller tumor size was related to more effective downsizing (P=0.01). Median downsizing was 32% (-46% to 11%) in the first group (<5 cm) and 11% (-55% to 16%) in the second group (5-7 cm); however, 8 of 21 (38%) in this group reduced to a range of 2.3 to 4.7 cm in which ablative techniques are feasible and nephron-sparing surgery may benefit from the reduced size. Median downsizing was 18% (-39% to 2%) in tumors of 7 to 10 cm and 10% (-31% to 0%) in those>10 cm.

Conclusion: The smaller the primary tumor, the greater the likelihood and the more effective the downsizing. A potential benefit of neoadjuvant treatment to downsize the primary tumor for ablative techniques or nephron-sparing surgery may exist, particularly in tumors sized 5 to 7 cm.