The impact of tumor burden characteristics in patients with metastatic renal cell carcinoma treated with sunitinib

BACKGROUND:

An important goal of noncurative therapy for metastatic renal cell carcinoma (mRCC) is tumor burden (TB) control. However, to the authors' knowledge, the impact of TB characteristics on clinical outcome has not been studied in patients with mRCC who were treated with vascular endothelial growth factor‐targeted therapy.

METHODS:

Patients with clear cell mRCC who were treated with sunitinib between June 2004 and October 2007 were retrospectively identified. Computed tomography scans were re‐reviewed from baseline, at the time of maximal TB shrinkage (TS) while receiving sunitinib, and at the time of progressive disease (PD). Measurements were recorded as per Response Evaluation Criteria In Solid Tumors (RECIST).

RESULTS:

A total of 69 patients were identified. The majority (54%) were classified as being of favorable risk using Cleveland Clinic Foundation Tyrosine Kinase Inhibitor (CCF TKI) risk group criteria. All patients underwent prior nephrectomy and 77% received prior systemic therapy. There were a median of 8 metastatic deposits across all organs (range, 1‐27 deposits). The median TB at the initiation of therapy was 14.0 cm (range, 3.0 cm‐42.2 cm). On multivariable analysis, baseline characteristics of disease confined to above the diaphragm (P = .03) and a total TB <13 cm (P = .09) were found to be independent positive predictors of progression‐free survival. A+ baseline, total number of metastases <10 (P < .001) and TB above the diaphragm <6.5 cm (P = .05) were found to be independent positive predictors of overall survival (OS). Increased TS while receiving sunitinib was found to be significantly associated with OS (P < .001). At the time of PD, tumor location and pattern of disease progression were not found to be associated with survival as measured from the date of PD. However, total TB (P = .003) and total number of metastatic deposits (≤12 vs >12; P < .001) were found to be significant predictors of survival after PD.

CONCLUSIONS:

The results of the current study indicate that TB characteristics are associated with clinical outcome in patients with mRCC who are treated with sunitinib. Cancer 2011. © 2010 American Cancer Society.