HISTOLOGIC CHARACTERISTICS OF RESIDUAL RENAL-CELL CARCINOMA FOLLOWINGINTERFERON-ALPHA-BASED THERAPY - CORRELATION WITH CLINICAL-PARAMETERS

To compare the histologic characteristics of residual renal cell carci noma (RCC) following an interferon-alpha (IFN-alpha)-based therapy wit h clinical parameters, we examined 12 metastatic and 6 primary kidney tumors resected from 18 patients with advanced RCC. The histologic par ameters including tumor necrosis, nuclear grade, inflammatory response and hemosiderin deposition were assessed. The immunophenotypes of tum orinfiltrating lymphocytes (TILs) were also characterized. The tumors of the 12 patients who had partial clinical response (responders) show ed more tumor necrosis than the tumors of the 6 non-responders (patien ts with minor response or stable disease) (p = 0.0061). A tendency of longer overall survival was observed in the group with tumor necrosis compared to the group without necrosis. Predominance of T-cell TIL was demonstrated in all 9 responders compared to 3 non-responders (p = 0. 053). Our findings suggest that tumor necrosis and a high percentage o f T-cell TILs in residual RCC may be associated with favorable clinica l response following IFN-alpha-based therapy.