Histologic Subtype of Metastatic Renal Cell Carcinoma Predicts Response to Combined Immunochemotherapy with Interleukin 2, Interferon α and 5-Fluorouracil

ObjectivesCombined immunochemotherapy with interleukin 2 (IL-2), interferon α (IFN-α), and 5-fluorouracil (5-FU) is an established first-line therapy for metastatic renal cell carcinoma (RCC). However, data on histologic parameters predictive of clinical benefit are rare. In this study, we evaluated the response to immunochemotherapy in the main histologic subtypes of renal cell carcinoma and performed a subgroup analysis of inoperable patients.MethodsFrom 164 patients treated with one or two cycles of combined immunochemotherapy, radical nephrectomy had revealed 22 cases of papillary RCC (pRCC; 13.4%) and 131 cases of clear cell RCC (ccRCC; 79.9%). In the remaining 11 (6.7%) their disease was inoperable. The overall response rates were evaluated according to World Health Organization criteria.ResultsFor ccRCC and inoperable disease, responses of 34.4% and 27.3% after one cycle and 28.8% and 16.7% after two cycles, respectively, were noted. In contrast, no patient with pRCC showed any response after two cycles of combined immunochemotherapy.ConclusionsNo objective response was seen in patients with pRCC. Hence, the use of immunotherapeutic agents must be questioned in this histologic subtype.