[Effect of change to flutamide for prostate cancer patient who developed breast pain during bicalutamide treatment (BIP-F study)].

In Japan, prostate cancer is treated with non-steroidal anti-androgen (flutamide and bicalutamide). Development of breast pain during bicalutamide treatment, in prostate cancer patients reduces their quality of life (QOL) and treatment compliance. We studied the safety and effectiveness of switching from bicalutamide to flutamide in 13 prostate cancer patients who developed breast pain during bicalutamide treatment. We estimated the change in breast pain using a face scale and the Expanded Prostate Cancer Index Composite (EPIC) and EPIC-hormone domain (HD) score. The switch to flutamide relieved breast pain in nine patients, had no effect in one patient, and increased breast pain in two patients. One patient dropped out. Furthermore, summary score and hormone function were improved with a significant difference in the EPIC-HD score. Switching to flutamide in prostate cancer patients who develop breast pain during bicalutamide is safe and effective.