Are We Really Making an Advance in the Treatment of Metastatic Renal Cell Carcinoma?

Unclassified renal cell carcinoma: an analysis of 85 cases

OBJECTIVES

To compare cancer-specific mortality in patients with unclassified renal cell carcinoma (URCC) vs clear cell RCC (CRCC) after nephrectomy, as URCC is a rare but very aggressive histological subtype.

PATIENTS AND METHODS

Eighty-five patients with URCC and 4322 with CRCC were identified within 6530 patients treated with either radical or partial nephrectomy at 18 institutions. Of 85 patients with URCC, 55 were matched with 166 of 4322 for grade, tumour size, and Tumour, Node and Metastasis stages. Kaplan-Meier and life-table analyses were used to address RCC-specific survival. Subsequently, multivariate Cox regression analyses were used to test for differences in RCC-specific survival in unmatched samples.

RESULTS

Of patients with URCC, 80% had Fuhrman grades III or IV, vs 37.8% for CRCC. Moreover, 36.5% of patients with URCC had pathologically confirmed nodal metastases, vs 8.6% with CRCC. Finally, 54.1% of patients with URCC had distant metastases at the time of nephrectomy, vs 16.8% with CRCC. Despite these differences in the overall analyses, after matching for tumour characteristics, the URCC-specific mortality rate was 1.6 times higher (P = 0.04) in matched analyses and 1.7 times higher (P = 0.001) in multivariate analyses.

CONCLUSIONS

These findings indicate that URCC presents with a higher stage and grade, and even after controlling for the stage and grade differences, predisposes patients to 1.6-1.7 times the mortality of CRCC.

Histologic subtype of metastatic renal cell carcinoma predicts response to combined immunochemotherapy with interleukin 2, interferon alpha and 5-fluorouracil

OBJECTIVES

Combined immunochemotherapy with interleukin 2 (IL-2), interferon alpha (IFN-alpha), 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.

METHODS

From 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.

RESULTS

For 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.

CONCLUSIONS

No objective response was seen in patients with pRCC. Hence, the use of immunotherapeutic agents must be questioned in this histologic subtype.