#1075
Prevalence of BRCA Gene Mutations in Metastatic Prostate Cancer
L. Tran1
1University of Medicine and Pharmacy at Ho Chi Minh city, Urology, Ho Chi Minh, Vietnam
Introduction:
Prostate cancer is the second most common cancer among men worldwide and ranks fifth in Vietnam. The majority of patients are diagnosed at a metastatic stage in Vietnam. Treatment requires a long-term strategy, particularly in patients with homologous recombination repair (HRR) gene mutations, among which BRCA mutations have shown high responsiveness to Poly ADP-Ribose Polymerase (PARP) inhibitors. Our study aims to determine the prevalence of BRCA gene mutations in patients with metastatic prostate cancer treated at Cho Ray Hospital, Binh Dan Hospital, Military 175 Hospital and Thong Nhat Hospital at Ho Chi Minh city, Vietnam.
Material and methods:
All cases of metastatic prostate cancer diagnosed, treated, and tested for homologous recombination repair (HRR) gene mutations at Cho Ray Hospital, Binh Dan Hospital, Military Hospital 175, and Thong Nhat Hospital were included. The study period was from October 2022 to June 2024. Collected variables included age, serum PSA level at diagnosis, ISUP histological grade at diagnosis, mutation prevalence, mutation detection rate by specimen type and disease stage, and time to progression to castration-resistant metastatic stage.
Results:
The study included 75 cases. The mean age was 68.1 ± 8.8 years (range: 49–85). At diagnosis, 86.7% were in the metastatic stage and 13.3% were non-metastatic. Serum PSA levels were >20 ng/mL in 87.8% of patients at diagnosis. Most patients had an ISUP grade of 3–5 (94.2%). The proportion receiving third-line treatment was 18.4%. The mutation rates were 0% for BRCA1, 12% for BRCA2, and 5.3% for other HRR genes. Mutation detection rates were 9.5% in tissue samples and 8.3% in blood samples. Among those with detectable mutations, 33.3% were in the hormone-sensitive metastatic stage and 66.7% in the castration-resistant metastatic stage. The median time to progression from metastatic hormone-sensitive prostate cancer to metastatic castration-resistant prostate cancer was 14.9 ± 8.4 months in the BRCA-mutated group and 33.2 ± 26.1 months in the non-BRCA-mutated group