Overall Survival after Partial Versus Radical Nephrectomy for a Small Renal Mass: Systematic Review of Observational Studies.

Introduction: In EORTC trial 30904 of partial versus radical nephrectomy overall survival was significantly better in the radical nephrectomy arm. However, many observational studies reported better survival after partial than radical nephrectomy. We present an updated systematic review of observational studies of overall survival after partial versus radical nephrectomy with assessment of quality of evidence.

Methods: The literature search was performed until December 31, 2013, and all studies reporting overall survival after partial vs radical nephrectomy were included in the initial review. Further inclusion criteria for complete review were malignant tumors 7 cm or smaller, or benign tumors of any size, and survival analysis performed with adjustment for confounding variables. Studies not meeting these criteria were excluded from full review because of selection bias in favor of patients treated with partial nephrectomy who were younger and with less advanced tumors.

Results: A total of 34 studies were included in the initial review and 13 were included in the full review. The 13 studies were based on the SEER database (6) or on institutional cohorts (7). In 8 of the 13 studies the estimated hazard ratios were significantly below 1, indicating better overall survival after partial nephrectomy, while in the remaining 5 studies estimated HR was not significantly different from 1. Median HR was 0.80 (interquartile range 0.57 to 0.96, absolute range 0.40 to 1.10).

Conclusions: In most observational studies overall survival was better after partial than after radical nephrectomy. However, because residual confounding could be present despite adjustment for measured covariates, another randomized trial of partial vs radical nephrectomy may be needed to confirm or refute the findings of EORTC 30904.