Prognostic factors and analysis of S100a4 protein in resected pulmonary metastases from renal cell carcinoma.

Background: This study analyzes our experience with pulmonary resection for metastases from renal cell carcinoma. The goals were to search for factors influencing prognosis and to investigate the presence and the prognostic value of S100A4 protein in lung metastases and corresponding primary renal tumors.

Methods: Sixty-five patients underwent surgical resection for renal and pulmonary lesions between 1992 and 2007. S100A4 protein expression was immunohistochemically examined in the peritumoral infiltrate of 64 lesions (32 metastases and the 32 corresponding primary carcinomas).

Results: Overall 3-, 5-, and 10-year survival rates were 58, 46, and 25%, respectively. Univariate analysis revealed that surgical radicality (p = 0.0039) and stratification into groups according to the International Registry of Lung Metastases classification (p = 0.0137) were prognostic factors. Multivariate analysis confirmed that this classification was a significant prognostic factor (p = 0.01). All metastases and the corresponding primary carcinomas expressed S100A4 protein. Twenty-one metastases (66%) had weak expression and 11 (34%) had strong expression. Twelve (37.5%) primary lesions had weak expression and 20 (62.5%) had strong expression. The 5-year survival rate for patients with strong expression in primary carcinoma was 41%, significantly lower than that of patients with weak expression (78%; p = 0.05).

Conclusions: Pulmonary resection in metastatic renal cell carcinoma results in long-term survival. Complete resection and stratification into groups according to the International Registry of Lung Metastases classification were prognostic factors. Overexpression of S100A4 protein in primary tumors was correlated with a poor prognosis. If confirmed in larger studies this finding could be used to schedule adjuvant treatments in patients undergoing nephrectomy for renal cell carcinoma.