Association of percentage of tumour burden removed with debulking nephrectomy and progression-free survival in patients with metastatic renal cell carcinoma treated with vascular endothelial growth factor-targeted therapy

Abstract

Objective: To determine if the fractional percentage of tumour volume (FPTV) removed with debulking nephrectomy was associated with progression-free survival (PFS) after subsequent targeted therapy, as a debulking nephrectomy is the standard of care in metastatic renal cell carcinoma (mRCC), but there are few data.

Patients and methods: The Cleveland Clinic Taussig Cancer Institute Urologic Oncology database was retrospectively reviewed from 2005 to 2008 to identify patients with mRCC who had undergone debulking nephrectomy followed by vascular endothelial growth factor (VEGF)-targeted therapy, defined as sunitinib-, sorafenib- or bevacizumab-based therapy. FPTV was calculated as the largest diameter of the primary tumour divided by the total tumour burden (as per the Response Evaluation Criteria in Solid Tumors, RECIST) through investigator re-review of imaging. PFS was defined from the start date of systemic therapy to disease progression per RECIST criteria.

Results: Forty-six patients were identified (80% men, median age 61 years, all clear cell histology and 67% with an Eastern Cooperative Oncology Group performance status of 0). Patients received treatment with bevacizumab ± interleukin-2 (18), sunitinib (14), sorafenib (11) or sunitinib + bevacizumab (three). The median diameter of the primary tumour was 10.0 cm. The median (range) FPTV removed was 95 (80-99)%. In univariable analysis, the FPTV removed (P = 0.002) and normal haemoglobin level (P = 0.04) were associated with improved PFS. In multivariable analysis, the FPTV removed (P < 0.001), male gender (P = 0.001) and corrected calcium (P = 0.05) were independent predictors of PFS.

Conclusion: A greater percentage of tumour burden removed at debulking nephrectomy is significantly associated with improved PFS on subsequent VEGF-targeted systemic therapy.