Retrospective investigation of demographic, epidemiological and clinical characteristics of patients diagnosed with metastatic castration-resistant prostate cancer

Objective: Prostate cancer is on of the important malignancies with its increasing incidence in Turkey and in the world. It is the second most common malignancy after lung cancer in men worldwide and the fifth leading cause of cancer death, due to cancer. Prostate cancer stages are of local (organ-confined) disease, locally advanced disease, metastatic hormone-sensitive disease, and metastatic castration-resistant disease. Although androgen deprivation therapy forms the basis of the treatment, castration-resistant prostate cancer (CRPC) develops in the majority of patients treated with androgen deprivation therapy. Abiraterone Acetate, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T and Lu-177 used in metastatic CRPC are the treatment regimens currently in clinical use. In this study, it is aimed to retrospectively evaluate the efficacy of hormone therapy, docetaxel, abiraterone acetate and enzalutamide treatments in metastatic castration-resistant patients. Material and Methods: 59 patients who were diagnosed and treated with metastatic castration-resistant prostate cancer in Duzce University Research and Application Hospital Medical Oncology Outpatient Clinic between January 2014 and March 2022 were included in this study. In the terms of overall survıval and progression-free survivval, patient data end electronic records in Duzce University Research and Application Hospital were evaluated retrospectively to determine the efficacy of hormonal therapy, docetaxel, abiraterone acetate and enzalutamide treatment in mCRPC patients. Data was collected from oncology files; demographic characteristics of patients, pathology at the time of diagnosis, prostate specific antigen (PSA) value, gleason score, first-line treatment agents, initiation time of first-line docetaxel chemotherapy and the number of cures received, agents used for second-line treatment, PSA values while under treatment with these agents, Data on radiological imaging, third line chemotherapeutic drugs givent to patients with progression during the second choice treatment, PSA values while under treatment with third line chemotherapeutic agents, and radiological imaging data were collected. Statistical analysis of the collected data was done with IBM SPSS 26.0 (SPSS Inc., Chicago, IL, USA) package program, p<0.05 was considered sufficient for statistical significance. Results: 17% of patients <65 years, 83% ≥ 65 years of age, median age at diagnosis was 72,22±7,63 years, median PSA value at diagnosis was 100 ng/ml (24 ng/ml-149 ng/ml), the median Gleason value at the time of diagnosis was 8 (7 - 9). Gleason score was >7 in 91% of the patients and mostly gleason 9(38%) pattern was detected. In terms of spreading, bone metastasis with ratio of (69%) was most frequent in patients. In the first-line treatment, 16(27%) patients received LHRH, 32 (55%) patients received LHRH + docetaxel, 9 (16%) patients received LHRH + abiraterone, 2 (3%) patients received LHRH + enzalutamide. The median radiological PFS for first-line therapy was 11,2 ± 0,927 months, and the median PSA PFS was 11,7 ± 1,414 months. In the second line treatment, 7(18%) of the patients received LHRH + docetaxel, 20(52%) LHRH + abiraterone, 11(30%) LHRH + enzalutamide treatment. The median radiological PFS in second-line treatment was 4,6±1,01 months. In the third line treatment, 8(71%) of the patients received LHRH + docetaxel, 2(18%) LHRH + abiraterone, 1 (9%) LHRH + enzalutamide treatment. The median radiological PFS of the patients was 3,48(2,11-6,36) months. The median overall survival of the patients was 26,5 ± 2,4 months. In first-line therapy, OS durations were 18,6 months for LHRH patients, 23,26 months for LHRH + docetaxel, 9,08 months for LHRH + abiraterone, and 8,25 months for LHRH + enzalutamide. Conclusion: In our study, it was observed that the gleson value in metastatic prostate cancer may correlate with the aggressiveness of the disease. When OS and PFS were evaluated according to treatment modalities, no statistically significant difference was found between OS and PSF of the treatment modalities in the first, second and third lines. However, it was determined that docetaxel treatment contributed more to OS and PSF in the first and third line treatments compared to other treatments, and the overall survival time was prolonged as the number of docetaxel cures increased. It was observed that treatment with abiroterone contributed more to PSF in patients who had previously been treated with docetaxel, and provided a shorter survival benefit than docetaxel in first-line therapy, but the number of patients was insufficient. The effect of enzalutamide treatment on overall survival in primary and secondary care was the lowest, but a clear interpretation could not be made due to the low number of patients. Although it is a partial advantage that our study consists of patients who are followed up in a single center, whose treatment approaches have not changed, and who have certain reference values for laboratory data, we think that the small number of patients and the numerical difference between the treatment groups may be a disadvantage. Larger studies are needed to obtain different clinical results. Keywords: prostate, cancer, LHRH, docetaxel, abiraterone acetate, enzalutamide