Natural history of metastatic renal cell carcinoma in patients who underwent consultation for allogeneic hematopoietic stem cell transplantation.

We characterized the natural history of metastatic renal cell carcinoma (RCC) and identified prognostic factors among patients who did or did not undergo allogeneic hematopoietic stem cell transplantation (HSCT). A total of 99 patients (23 who underwent HSCT and 76 who did not) were included in the study. Overall survival rates were comparable between the HSCT and no-HSCT groups (excluding patients with poor performance status or brain metastasis from the latter group) at a median 17.4 months of follow-up (P=.92). In univariate analyses, Fuhrman's nuclear grade 4 (P=.05), high serum calcium (P=.002), or low hemoglobin levels (P=.02), 3 or more metastatic sites (P=.02), and <12 months from diagnosis to initial recurrence (P=.04) were identified as poor prognostic factors. In multivariate analyses, 3 or more metastatic sites (P=.005) and low hemoglobin levels (P=.02) were poor prognostic factors. In the HSCT group, median survival times from consultation and from transplant were 25 and 19 months for those with 0 prognostic factors (n=7) and 11 and 7 months for those with 1 or more prognostic factors (n=16). In conclusion, previous concerns that HSCT would negatively affect long-term outcome of patients with metastatic RCC were not confirmed. Patients with any of these poor prognostic factors should not consider HSCT for metastatic RCC. The role of allogeneic HSCT for patients with no prognostic factors should be explored in clinical trials for patients with targeted therapy-resistant metastatic RCC.