The demographic characteristics and the baseline information of the prospective cohort were shown in Table 1, while the prevalence data were in Table S1. During a mean follow-up time of 8.0 yr, a total of 14,564 males were diagnosed with PCa, of which 959 (8.2%) died of PCa, 1,173 (8.1%) died due to other reasons and 12,193 (83.7%) survived till the latest follow-up in Jan 1st, 2022. Men who died of PCa were less likely to have a BPH diagnosis (15.7% vs. 19.6%, P=0.004) compared to men with the non-lethal disease. PCa patients without a BPH history would have a higher PCa-specific mortality rate (crude PCa-specific mortality rate in males without BPH was 8.49 per 1,000 men vs. 6.91 per 1,000 men in males with BPH, rate ratio, RR=1.28 ,95% confidence interval, 95%CI: 1.08-1.56, P=0.004). There was no difference in family history of PCa (P>0.9) between the two groups (Table 1, Table S2). Besides the increasing age, a higher score on the Charlson Comorbidity Index (indicating a greater burden of illness) was also associated with an increased lethal PCa risk in three different defined subgroups (P<0.001, Table S2).
A total of 21 SNPs were used to calculate BPH/PV PRS finally (Table S3). And the Odds ratios (ORs) per 1-SD increment in BPH-related PRS represented 1.75 (OR, 95%CI: 1.68–1.83) increased risk to have BPH (significance test P<0.001, empirical P<0.001). Due to mismatched allele codes, we only matched 130 out of 147 SNPs and 24 out of 47 SNPs reported in the PRACTICAL PRS[11, 25] and PHS [26](established lethal PCa-related PRS), respectively.
BPH/PV PRS was not only significantly associated with PCa-specific mortality (Hazard ratio, HR=0.92, 95%CI: 0.86-0.99, P=0.02) in PCa patients, but also associated with incident PCa death (HR=0.92, 95%CI: 0.85-0.99, P=0.03 or P=0.008) at a population level. The PRACTICAL PRS and the PHS performed similarly well in predicting lethal PCa to those previously reported, especially in the prevalence and incidence cohort (both P<0.05). However, they showed no significant relation with lethal PCa outcomes in PCa patients (P>0.05). The survival analysis in the entire PCa cohort revealed that men with lower BPH/PV PRS might have a significantly shorter survival time (Log-rank test P=0.004). Compared with those with top BPH/PV PRS (75-100th percentile, the highest risk of BPH), PCa patients with lowest BPH/PV PRS (0-25th percentile, the lowest risk of BPH) would have a 1.40-fold increased risk of PCa death during the follow-up (HR, 95%CI: 1.16-1.69, P=0.001, Table 3), as well as a relatively lower long-term survival probability at 83.7% (20-year survival probability, 95%CI: 80.4-87.1%, P for trend<0.001) and shorter survival time of 0.37 yr (RMST, 95%CI: 0.14-0.61, P=0.002).
The carrier rates of P/LP mutation in the UKB unselected PCa patients (data available in 5,899 PCa patients) for each of the ten genes were shown in Table 4, ranging from 0.02% for MLH1 to 1.64% for CHEK2 (Mutations listed in Table S4). BRCA2 and PALB2 were significantly associated with PCa death, with HR estimated at 3.91 (95%CI: 2.34-6.51, P<0.001) and 4.24 (95%CI: 1.34-13.34, P=0.01). Mutation status was not significantly associated with shorter survival time after PCa diagnosis except for mutations in BRCA2. BRCA2 carriers were 3.23 yr (RMST, 95%CI: 1.55-4.90, P<0.001) earlier to die from PCa. When investigating the interaction between mutation status and BPH/PV PRS, additional analyses were performed in subgroups of patients based on the carrier status (Figure 2). In non-carriers, a decreased BPH/PV PRS was significantly associated with an increased risk of PCa death (Log rank P=0.03, Figure 2.A). However, the trend was not observed among DNA damage repair (DDR) gene carriers (Log rank P=0.28, Figure 2.B). And no interaction effects between BPH/PV PRS and hereditary gene mutations were detected (Pinteraction for BRCA2/PALB2: 0.83; Pinteraction for DDR: 0.99).