Challenges in Managing Synchronous Advanced Prostate and Pancreatic Cancers: A Case Report

Prostate cancer (PCa) and pancreatic cancer (PC) are distinct malignancies with diverging epidemiological and prognostic profiles. PCa often mimics benign prostatic hyperplasia, while PC remains asymptomatic until advanced stages, complicating early detection. As cancer survivorship and screening improve, the incidence of synchronous multiple primary malignancies (MPMs) is rising, with emerging data suggesting a potential biological link between PCa and PC. Managing such cases requires a delicate balance of treatment sequencing and toxicity management. Reporting these rare encounters is vital for refining clinical strategies in complex oncologic presentations.

This report details the clinical course of a 76-year-old male diagnosed synchronously with high-grade ductal PCa and pancreatic adenocarcinoma. Staging via PSMA PET-CT incidentally identified a pancreatic tail mass with an unusually high SUVmax of 5.2. Despite initiating standard androgen deprivation therapy, the aggressive ductal variant exhibited a "PSA escape" following treatment interruption. As the pancreatic lesion progressed metastatically, the patient's refusal of conventional chemotherapy and a lack of genomic profiling prompted a salvage, "last-resort" combination of pembrolizumab and olaparib. While this strategy achieved temporary biochemical stabilization and slowed tumor growth, the patient eventually succumbed to metabolic dysregulation and multi-organ failure.

This case highlights the diagnostic challenges of MPM management, specifically rare PSMA-avidity in primary pancreatic tumors which can mimic metastatic spread. While empirical immunotherapy and PARP inhibitor combinations may offer temporary clinical benefit in resource-limited settings, they cannot substitute for biomarker-guided precision medicine. Success depends on strict therapeutic adherence and early multidisciplinary coordination.