Background:

Diethylstilbestrol (DES) at low doses is effective in metastatic castration resistant prostate cancer (mCRPC), understudied in the context of currently available treatments. We describe the efficacy and tolerability of low doses of DES for patients with heavily pretreated mCRPC.

Material and methods:

Single center retrospective cohort of patients with mCRPC treated with low dose DES between 2005 and 2020.

Results:

Thirty-four patients were evaluated, with a median age of 74 years (range 56-94), and a median of 3 previous treatment lines (range 1-7). 64.7% had received chemotherapy. A biochemical response was achieved in 10/32 patients (31.3%). Median progression free survival was 3.7 months. Median overall survival (OS) was 9.7 months. The most common adverse events were fatigue, gynecomastia, and nausea. Two deaths occurred due to arterial thrombosis.

Conclusions:

Low dose DES remains active in highly pretreated patients, with median PFS comparable to other available treatments. Patient selection is important for treatment safety.