Adjuvant treatment for resected renal cell carcinoma: are all strategies equally negative? Potential implications for trial design with targeted agents.

BACKGROUND: Although data from ongoing trials with targeted agents are awaited, we used a meta-analytical approach to explore whether cytokines (CK), vaccines (VAX), or other therapies may differentially influence patients' outcomes.
MATERIALS AND METHODS: The objective was to determine whether significant interactions exist according to treatment (CK vs. VAX vs. other), in the context of a literature-based meta-analysis. Fourteen trials (3380 patients) were identified, with 10 randomized clinical trials (RCTs) (2257 patients) providing data for the primary outcome--5-year relapse-free survival (RFS). The primary selected end point was 5-year RFS; secondary end points were 5- and 2-year overall survival (OS) and 2-year RFS. Event-based relative risk (RR) ratios with 95% confidence intervals (CI) were extracted and cumulated according to a random-effect model from articles/presentations. Testing for heterogeneity was performed as well.
RESULTS: Although not statistically significant, an effect in favor of a qualitative interaction according to treatment was found for 5-year RFS, with a likely detrimental effect in CK (P = .42) in contrast to that found in VAX subpopulation (P = .76). For the secondary end points, a similar effect in favor of a quantitative significant interaction according to treatment was found for 5-year OS, regardless of the approach adopted, with a different magnitude of treatment effect. In addition, a borderline significant (P = .05) detrimental effect in terms of 2-year OS against the use of adjuvant treatment was determined in the CK subpopulation (RR, 1.24; 95% CI, 0.99, 1.54).
CONCLUSION: The effect in favor of a qualitative interaction according to the adopted strategy is intriguing and suggests potential implications for trial design with targeted agents.