Locally recurrent prostate cancer with RB1/TP53 alterations successfully treated by salvage focal brachytherapy: a case report.

Retinoblastoma transcriptional corepressor 1 (RB1) and tumor protein p53 (TP53) are well-known tumor suppressor genes; their alterations are associated with poor prognosis in human malignancies and quite rare in locally recurrent cases. The patient was a 58-year-old man who was diagnosed with cT1cN0M0 prostate cancer with Gleason score of 3+3=6 and underwent brachytherapy as the initial treatment. Local recurrence was detected in the left lobe of the prostate 154 months later and whole-exome sequencing that was performed at the request of the patient revealed RB1 loss-of-heterozygosity and TP53 p.I162Rfs*27 mutations. He underwent salvage focal brachytherapy with ¹²⁵I seeds and serum prostate-specific antigen levels has been stabilized without any genitourinary or gastrointestinal toxicity.