[A CASE OF CASTRATION-RESISTANT PROSTATE CANCER ASSOCIATED WITH HEREDITARY BREAST-OVARIAN CANCER SYNDROME SHOWING LONG-TERM RESPONSE TO A POLY-ADP RIBOSE POLYMERASE INHIBITOR].

The patient was a 69-year-old male. Eight years ago, he underwent radical prostatectomy for locally advanced prostate cancer at another hospital, and then underwent endocrine therapy due to biochemical recurrence. Five years later, progression to castration-resistant prostate cancer was confirmed, and abiraterone treatment was started. Macroscopic hematuria persisted, so he visited our department. Magnetic resonance imaging revealed a mass at the bladder neck. A tissue biopsy was performed, and prostate cancer was identified. The patient was diagnosed with local recurrence at the prostatectomy site. Salvage radiotherapy with a total dose of 70. 2 Gy was promptly administered. The recurrent lesion subsequently disappeared on imaging ; however, shortly thereafter, multiple liver metastases were detected on computed tomography. Treatment with docetaxel was initiated. The liver metastases promptly disappeared thereafter, and the prostate specific antigen (PSA) level decreased to 0.001 ng/ml. Since then, 17 courses were administered. Docetaxel was effective ; however, the patient's bone marrow function, indicated that the treatment was approaching its limit, and a gene panel test, Foundation One-CDx, was performed. Inactivating mutations in BRCA2 were identified. The diagnosis made was prostate cancer associated with hereditary breast and ovarian cancer syndrome. The patient was started on olaparib, a poly (ADP-ribose) polymerase inhibitor. To date, his PSA level has remained below 0.001 ng/ml. He has been taking the medication for more than 42 months without any side effects, and imaging studies have consistently shown a complete response.