Radiotherapeutic Management of Synchronous Prostate and Rectal Cancers Using Proton Beam Therapy.

Treatment of synchronous prostate and rectal cancers is a rare yet challenging problem with compounded toxicities. We report a case of a 65-year-old man who underwent proton beam therapy (PBT) with concurrent capecitabine and hormonal therapy for his synchronously found prostate (intermediate-risk) and rectal (cT2, N2b, stage IIIB) cancers; he also received low anterior resection. Before PBT, the patient experienced hematochezia.