Prostate cancer: High KI-67 does not predict hormone resistance

Objectives: To evaluateKi-67 expression in metastatic prostate tumors and correlate it with overall survival and progression-free survival data in patients submitted to central hormone blockade. Methods: Retrospective analysis of medical records and review of biological material of 45 patients with metastatic prostate cancer who were diagnosed and followed up at the São Paulo Medical School, Universidade Federal de São Paulo, São Paulo, Brazil, from 2000 to 2013. Results: Bone metastasis was present in 97% of the patients, and visceral metastases more frequently involved the lungs (42.8%) and bone marrow (28.6%). A high-volume disease involving four or more bone lesions, with at least one being extra-axial and/or visceral, was found in 66% of the patients. All participants who began cancer treatment were submitted to central hormone blockade, and the mean time for reaching prostate-specific antigen nadir was 13.6 months. Progression-free survival of 23.8 months and overall survival of 42.5 months were observed. The maximum Ki-67 median for the high tumor burden group was 6.67, and it was 8.24 (p=0.50) for the group with low disease volume. Evaluation of the relationship between maximum Ki-67 and progression-free survival showed a relative risk of 1.03 (95% CI: 0.979-1.094, p=0.23). No correlation was found between maximum Ki-67 and overall survival, with a relative risk of 1.03 (95% CI: 0.935-1.140). Conclusions: Cell division rate analysis, the simplest measure of change in cell growth associated with neoplastic transformation, did not correlate with prognosis of metastatic prostate cancer.