TNM T3a renal cell carcinoma: adrenal gland involvement is not the same as renal fat invasion.

Purpose: Upper pole tumors with direct extension into the adrenal gland are currently staged as pT3a tumors in the 1997 TNM staging system. To determine whether the clinical behavior of pT3a adrenal tumors differs from that of tumors with perinephric fat invasion (also stage pT3a) a retrospective analysis was performed.

Materials And Methods: Of 1,087 patients who underwent nephrectomy 27 were identified with direct adrenal involvement and 187 were identified with perinephric fat or renal sinus involvement. Variables and outcomes analyzed in each group included the percent of patients with metastatic disease at presentation, lymph node involvement, Eastern Cooperative Oncology Group score, response to immunotherapy, and median and overall survival using Kaplan-Meier curves.

Results: Median survival for patients with pT3a disease and perinephric or renal sinus fat involvement was 36 months with a 36% 5-year cancer specific survival rate. In contrast, patients with adrenal gland invasion had significantly worse survival at a median of 12.5 months and a 0% 5-year cancer specific survival rate (p <0.001), which was similar to median survival of those with stage pT4 disease (11 months).

Conclusions: Upper pole tumors with direct extension into the adrenal gland predict significantly worse survival than similarly staged tumors with fat invasion and they have a prognosis similar to that of stage pT4 disease. While these data await external validation, consideration should be given to re-categorizing tumors with direct adrenal gland involvement as stage pT4 or in a subcategory such as pT4a.