The effect of a treatment delay on outcome in metastatic renal cell carcinoma.

•No data are available if the delay of the medical therapy affects the outcome of patients with metastatic renal cancer (mRCC).•The data of 635 patients have been analyzed to test the effect of a treatment delay within 6 months.•mRCC patients with bone metastases and advanced disease at diagnosis have a significant probability to delay the beginning of a treatment.•A delay greater than 6 weeks from the initial diagnosis does not significantly affect outcomes and survival.