Application of metastatic biopsy based on “When, Who, Why, Where, How (4W1H)” principle in diagnosis and treatment of metastatic castration-resistance prostate cancer

BACKGROUND: To determine the feasibility of secondary biopsy of metastatic castration-resistance prostate cancer based on the “4W1H—When, Who, Why, Where, How” principle and analyze the factors that affect tumor detection. Its application will further direct the patients for individualized precision therapy. METHODS: A total of 55 patients were collected for secondary biopsy (27 prostate biopsies and 55 metastases biopsies). The parameters of biopsy location, computed tomography attenuation coefficient, lesion size, core number, laboratory tests, and the use of bone protection were evaluated. Histopathological data and the pathogenesis and etiology classification were used to guide precision treatment. RESULTS: Fifteen/27 patients had a positive prostate biopsy, and 47/55 had positive metastasis biopsy. Bone metastasis biopsy was positive in 21/29 of cases. Also, parenchymal organs and lymph node biopsies were positive. In the prostate rebiopsy, significant differences were observed between total prostate volume (P=0.028), prostate-specific antigen (PSA) density (P=0.047), PSA velocity (P=0.036), and positive biopsy results. In the bone metastasis biopsy, we divided the patients into biopsy-positive and -negative groups. The computed tomography attenuation coefficient, PSA, alkaline phosphatase, and hemoglobin were related to tumor positive detection. However, the lesion size, core number, bone-sparing agents and previous treatments did not affect tumor detection. CONCLUSIONS: In metastatic castration-resistant prostate cancer (mCRPC) patients, the “4W1H” principle was applied in the second biopsy. The biopsy site, image, and laboratory variables affected the positive of tumor tissue. Further pathological analysis of tumor tissue is essential to guide the precision medicine of mCRPC etiological classification.