Neoadjuvant sunitinib for surgically complex advanced renal cell cancer of doubtful resectability: initial experience with downsizing to reconsider cytoreductive surgery

To evaluate neoadjuvant sunitinib in patients with synchronous metastatic renal cell cancer (mRCC) to downsize surgically complex tumours and reconsider cytoreductive surgery. Retrospective analysis of ten consecutive mRCC patients treated with sunitinib in an expanded access program who presented with surgically complex primary tumours or bulky locoregional metastases. Surgery-limiting tumour sites (SLTSs) were defined as primary or retroperitoneal lesions with direct invasion of adjacent organs or encasement of vital structures on imaging. Patients received sunitinib 50 mg/day for 4 weeks on and 2 weeks off to be followed by cytoreductive surgery after downsizing and individual reassessment. Response was measured according to Response Evaluation Criteria in Solid Tumours (RECIST). Six out of ten SLTSs revealed a reduction of tumour size with a median of 14% according to RECIST. None of the ten SLTSs had a partial response (PR), whilst at distant metastatic sites one complete remission and two PRs occurred. Downsizing of SLTSs appeared most prominent in the first 2-4 months, which resulted in reconsidering cytoreductive nephrectomy in three patients. These three tumours invaded the liver on imaging and were reduced by 11, 18 and 20%. In this patient group with mRCC and surgically complex primary tumours or locoregional metastases, downsizing of SLTSs by neoadjuvant sunitinib was limited. Cytoreductive surgery was reconsidered in three patients. Given the overall reduction in tumour burden by sunitinib alone, further investigation to define the role of cytoreductive surgery is warranted.