Treatment efficacy of carrelizumab in metastatic castration-resistant prostate cancer, and the significance of circulating tumor DNA fraction

Purpose: To explore the efficacy of carrelizumab in the treatment of metastatic castration-resistant prostate cancer (mCRPC), and the significance of circulating tumor DNA (ctDNA) fraction in the process. Methods: 100 mCRPC patients who were treated in the Oncology Department of Harbin Medical University Cancer Hospital in a time frame of January 2018 to January 2019 were enrolled and assigned (1:1) into control and study groups and were given a regimen consisting of a combination of docetaxel and prednisone. Prognosis of patients with high and low ctDNA fractions relative to baseline ctDNA level, was compared. Results: The study group obtained considerably higher objective response rate (ORR) in relation to the control group (p < 0.05). Serum levels of prostate-specific antigen (PSA) and testosterone (TTE) were significantly lower in the study group versus control group. Better quality of life and bladder function were witnessed in the study group when compared to control group (p < 0.05). The proportion of patients with ctDNA fraction < 2 % in the study group significantly increased, but there was no significant change in ctDNA in the control group. The clinical prognosis of patients with low ctDNA fraction was significantly better than that of patients with high fraction (p < 0.05). Conclusion: Combined use of carrelizumab and docetaxel-prednisone regimen for mCRPC patients substantially improved clinical efficacy, quality of life, and long-term prognosis, while reducing ctDNA levels. Thus, the combination regimen has promise for the treatment of mCRPC patients.