Abstract P011: Clonal hematopoiesis and risk of lethal prostate cancer: a prospective cohort study with long-term follow-up

Abstract Background: Clonal hematopoiesis (CH), the presence of acquired mutations in leukemia driver genes, promotes systemic inflammation and is common among aging men. Prostate cancer, a subset of which is lethal, also develops in aging men. We hypothesized that CH contributes to development of lethal prostate cancer. Methods: We conducted nested case-cohort studies for metastatic prostate cancer and prostate cancer-specific death (lethal prostate cancer) within the prospective Health Professionals Follow-up Study. First, we followed 1155 men free of prostate cancer and cardiovascular disease at blood draw (1993-1995) for development of lethal prostate cancer over up to 26 years. Second, we followed 532 men with incident non-metastatic prostate cancer for development of lethal prostate cancer. We sequenced blood DNA from 1488 participants for putative CH driver mutations in the 9 most common CH-defining genes with a custom targeted panel (VariantPlex, Invitae, Inc.) at ultra-high depth (mean, 18,000x), employing unique molecular identifiers for error correction. CH variant calling used a novel ensemble calling approach, ArCCH, validated with in-silico tumor dilutions and blinded technical replicates, which had high accuracy for variant allele frequencies (VAFs) as low as 0.1%. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) in proportional hazards regression with Prentice case-cohort weights. Results: In a random sample of 968 men initially free of prostate cancer and cardiovascular disease (median age at blood draw 60 years, interquartile range 52 to 67), 80% of men had CH at a variant allele frequency (VAF) of >0.1%, 15% had VAFs >2%, and 3% had VAFs >10%; 75% of men had variants in epigenetic modifier genes (DNMT3A, TET2, ASXL1), and 21% had variants in DNA repair genes (PPM1D, TP53, CHEK2). CH burden was strongly age-associated, with approximately one additional CH variant per decade of age at blood draw (mean difference 1.07 variants, 95% CI 0.93 to 1.21). Among men initially free from prostate cancer, after adjusting for age at blood draw, CH clones between 0.1% and 10% VAF were not related to lethal prostate cancer (206 events total; HR 0.93, 95% CI 0.49-1.76 for VAFs 2-10% vs. no variants detected at >0.1% VAF). Results for epigenetic modifiers and DNA repair genes were similar. While inconclusive, data were compatible with positive associations among younger men (< 65 years) or for VAFs >10%. Among men initially diagnosed with non-metastatic prostate cancer, results were similarly null for progression to lethal prostate cancer (164 events). Conclusions: This large prospective study with long-term follow-up suggests that low-level CH is unlikely a major contributor to and not well suited for early detection of lethal prostate cancer. Citation Format: Konrad H. Stopsack, Irenaeus C. Chan, Evelyn Schmidt, Alex Panchot, Samantha McNulty, Nicole A. Schreiber, Yiwen Zhang, Kathryn L. Penney, Michael F. Berger, Luis A. Diaz, Ross L. Levine, Kelly L. Bolton, Lorelei A. Mucci, Philip W. Kantoff. Clonal hematopoiesis and risk of lethal prostate cancer: a prospective cohort study with long-term follow-up. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P011.