Can tyrosine kinase inhibitors be discontinued in patients with metastatic renal cell carcinoma and a complete response to treatment? A multicentre, retrospective analysis.

Discontinuation of treatment with tyrosine kinase inhibitors (TKIs) and readministration in case of recurrence could improve quality of life (QoL) and reduce treatment costs for patients with metastatic renal cell carcinoma (mRCC) in which a complete remission (CR) is achieved by medical treatment alone or with additional resection of residual metastases. To evaluate whether TKIs can be discontinued in these selected patients with mRCC. A retrospective analysis of medical records and imaging studies was performed on all patients with mRCC treated with TKIs (n=266) in five institutions. Patients with a CR under TKI treatment alone or with additional metastasectomy of residual disease following a partial response (PR), in which TKIs were discontinued, were included in the analysis. Outcome criteria analysed were time to recurrence of previous metastases, occurrence of new metastases, symptomatic progression, improvement of adverse events, and response to reexposure to TKIs. Sunitinib 50mg/day for 4 wk on and 2 wk off, sorafenib 800mg/day. Response according to Response Evaluation Criteria in Solid Tumours (RECIST). We identified 12 cases: 5 CRs with sunitinib, 1 CR with sorafenib, and 6 surgical CRs with sunitinib followed by residual metastasectomy. Side-effects subsided in all patients off treatment. At a median follow-up of 8.5 mo (range: 4-25) from TKI discontinuation, 7 of 12 patients remained without recurrence and 5 had recurrent disease, with new metastases in 3 cases. Median time to progression was 6 mo (range: 3-8). Readministration of TKI was effective in all cases. The study is limited by small numbers and retrospective design. Discontinuation of TKI in patients with mRCC and CR carries the risk of progression with new metastases and potential complications. Further investigation in a larger cohort of patients is warranted before such an approach can be regarded as safe.