Management of locally advanced synchronous colorectal and prostate cancers: A case report.

INTRODUCTION: Synchronous colorectal and prostate malignancies are uncommon, with standard treatment guidelines not yet established. Chemoradiation therapy is involved in both colorectal and prostate cancers. However, differing dosage regimens and effects of irradiation field on anatomical planes for surgery makes management of the synchronous cancers challenging. We report the first case of synchronous prostate and rectal cancer being treated with a combination of treatment modalities with a unique addition of high dose rate prostate brachytherapy boost. PATIENT CONCERNS: The patient, a 69-year-old Chinese gentleman, presented with per-rectal bleeding with alternating bowel habits and a hemoglobin drop. He also had a history of urinary urge incontinence. DIAGNOSIS: Following diagnostic workup, he was diagnosed with synchronous rectal adenocarcinoma (T3N1M0) and prostate malignancy (T2bN0M0). INTERVENTIONS: The management consisted of neoadjuvant androgen deprivation therapy (ADT) and pelvic chemoradiation, followed by high dose rate prostate brachytherapy boost and subsequently anterior resection. OUTCOMES: Following therapy, the patient has no evidence of local recurrence or distant metastasis. CONCLUSION: We suggest a new feasible treatment strategy for the management of synchronous colorectal and prostate cancers.