The natural history and outcomes of the patients with carcinosarcoma involving kidney and renal pelvis.

Background. The objective of this paper was to examine the epidemiology, natural history, and prognostic factors of carcinosarcoma of the kidney and renal pelvis (CSKP) using population-based registry. Patients and Methods. Forty-three patients with CSKP, diagnosed between January 1973 and December 2007, were identified from the national Surveillance, Epidemiology, and End Results (SEER) database and reviewed. Results. 79% of all patients with known SEER stage were classified as having regional or distant stage; almost all the patients with known histology grade had poorly or undifferentiated histology. The median cancer specific survival was 6 months (95% CI 4-9). The 1-year cancer-specific survival rate for entire cohort was 30.2%. There were no differences in terms of age at diagnosis, histological grade, tumor stage on presentation, and frequency of nephrectomy between carcinosarcoma of kidney (CSK) or renal pelvis (CSP). In multivariate analysis, age at diagnosis, tumor stage, and year of diagnosis were found to be significant predictors for cancer-specific survival. Conclusion. CSKP commonly presented as high-grade, advanced stage disease, and was associated with a poor prognosis regardless of location.