RESUMO
Introduction: There have been few reports of patients for whom a cancer gene panel test for solid tumors revealed the simultaneous presence of BRCA mutation and microsatellite instability (MSI)-high status. BRCA mutations have been reported in 13% of castration-resistant prostate cancer (CRPC) patients, and 3.1% of prostate cancer cases are MSI-high/mismatch repair deficient. Case Presentation: A 71-year-old man with a history of urinary retention was referred to our department for clinically suspected prostate cancer and a high prostate-specific antigen (PSA) level (141 ng/mL). MRI revealed features of prostate cancer invading the bladder, seminal vesicles, and rectum. A histopathological examination of a transperineal needle biopsy specimen obtained from the prostate revealed adenocarcinoma. Bone scintigraphy revealed multiple metastases. The patient was treated with abiraterone acetate combined with androgen deprivation therapy followed by local radiation. Rectal wall thickening and lymph node metastasis were also observed, and docetaxel was administered. A cancer gene panel test was positive results for BRCA2 mutation with a MSI-high. After six courses of docetaxel, lymph node enlargement was observed and olaparib was initiated. Two months later, the metastatic lesions showed enlargement and the PSA level increased. Subsequently, pembrolizumab was administered. At 2 to the patient months after the initiation of pembrolizumab administration, PSA levels decreased to <0.025 ng/mL and the rectal lesions and lymph node metastases disappeared. The patient was continuing to receive pembrolizumab without any apparent adverse events or exacerbations, 9 months after initiation. Conclusion: We herein report a case in which pembrolizumab treatment resulted in a complete response in a CRPC patient with both a BRCA2 mutation and an MSI-high status.
RESUMO
A 71-year-old man with a history of hoarseness and right upper extremity numbness was referred to our department for evaluation of an intrathoracic mass that was detected on chest radiography and a right kidney tumor observed on computed tomography (CT). Histopathological examination of percutaneous kidney biopsy and bronchoscopic lung biopsy specimens revealed renal clear cell carcinoma with multiple lung metastases. The patient showed a poor risk based on the International Metastatic renal cell carcinoma Database Consortium score, and nivolumab plus ipilimumab were initiated as first-line therapy. His symptoms gradually improved, following four courses of nivolumab plus ipilimumab treatment, and CT revealed shrinkage of all lesions. However, he developed diarrhea, rash, anemia, and elevated serum C-reactive protein levels (CRP) following this therapy. Diarrhea and rash were considered immune-related adverse events, and he was treated with oral prednisolone and topical corticosteroid. Nivolumab administration was discontinued because anemia worsened together with elevated serum CRP levels despite improvement in diarrhea. He subsequently developed constipation and abdominal bloating, following further treatment for 4 months. CT revealed intestinal tumor-induced intussusception, necessitating partial resection of the small intestinal tumor, which was histopathologically diagnosed as metastases. Both anemia and elevated CRP improved postoperatively. Currently, all metastatic lesions other than the resected intestine have continued to respond to treatment over 12 months after initiation of nivolumab plus ipilimumab therapy.