Circulating Tumor DNA Analysis on Metastatic Prostate Cancer with Disease Progression

SIMPLE SUMMARY: In our study, we found genetic mutations in the DNA of cancer cells obtained from the blood of many patients with metastatic prostate cancer. These changes were more common in patients whose cancer was progressing and aggressive in nature, often unresponsive to conventional treatment strategies. Additionally, these genetic mutation findings were more sensitive than the conventional method of checking the prostate-specific antigen (PSA) level in the blood for detecting prostate cancer progression. This means a simple blood test could help us track genetic mutations, detect aggressive cancer subtypes, determine the progression of the disease, and manage advanced prostate cancer more effectively. ABSTRACT: The positivity rate of circulating tumor DNA (ctDNA) next-generation sequencing (NGS) varies among patients with metastatic prostate cancer (mPC), complicating its incorporation into regular practice. This retrospective study analyzed the ctDNA sequencing results of 100 mPC patients from May 2021 to March 2023 to identify the factors associated with positive ctDNA. Three custom gene panels were used for sequencing. Overall, 63% of the patients exhibited tier I/II somatic alterations, while 12% had pathogenic/likely pathogenic germline alterations. The key genes that were altered included AR, TP53, RB1, PTEN, and APC. Mutations in BRCA1/2, either germline or somatic, were observed in 21% of the patients. Among the metastatic castration-resistant prostate cancer (mCRPC) patients, the ctDNA-positive samples generally showed higher median prostate-specific antigen (PSA) levels and were more likely to be at the radiographic and clinical progressive disease stages, although they were not significantly associated with PSA progression. Our results suggest that ctDNA analysis could detect meaningful genetic changes in mPC patients, especially during disease progression.