Prognostic value of gain of chromosome 5q in localized renal cell carcinoma.

623 Background: While gain of chromosome 5q is a frequently seen cytogenetic abnormality noted to occur in patients with renal cell carcinoma (RCC), little is known about its prognostic significance. We investigated the association of gain of 5q with disease-free survival (DFS) in patients with localized (non-metastatic T1-2) RCC. Methods: All patients from UCLA with primary tumor stage T1-2 RCC who had tumor cytogenetic analysis on tumor specimen were included. Alterations in chromosome 5q was specifically reviewed in this study. Logistic regression analyses were used to assess association of gain of 5q with final histopathology, ISUP grading, and T-stage. Cox proportional hazard modeling and Kaplan-Meier analyses were used to assess the impact of gain of 5q on DFS. Recurrence was defined as any local recurrence or development of new metastasis. Results: A total of 676 patients were included in this study. Gain of 5q occurred in 108 (16%) patients and was more commonly seen in clear cell versus non-clear cell tumors (19% vs. 9%, p = .002). Gain of 5q was associated with low grade ISUP (1 or 2) of clear-cell RCC (p = 0.011). On survival analysis, there was a 67% decreased risk of RCC recurrence for patients with gain of 5q (HR = 0.33, p = 0.018). The 5- and 10-year risk of recurrence was 2% vs. 16% and 14% vs. 28% for patients with and without gain of 5q, respectively (p = 0.013). In multivariable Cox analysis, the gain of 5q was an independent prognostic factor (p = .026 with ISUP grade and p = .025 with T-stage). These findings were confirmed among clear-cell RCC subgroup. Conclusions: Gain of chromosome 5q is an independent prognostic factor associated with decreased risk of recurrence in patients with localized T1-2 renal cell carcinoma. Identifying patients with a gain of 5q will improve the stratification of the risk of recurrence, could allow to adapt the follow-up protocols and avoid adjuvant treatment.