PPP02 Presentation Time: 10:39 AM

In the Russian Federation the number of patients with prostate cancer in stage I-II has increased from 48.4% to 63.0% over the past 10 years (2012 - 2022). It is the second most common cancer in men after lung cancerin 2021 in Russia. One of the most common methods of treating localized prostate cancer is brachytherapy. In the Department of radiation and surgical treatment of urological diseases with the prostate cancer brachytherapy group of the A.F.Tsyb MRRC, HDR-BT as monotherapy has been performed since 2016 with the use of Ir-192.

Purpose

Compare the efficiency of modes of HDR-BT with the use of Ir-192 in the treatment of localized prostate cancer.

Materials and Methods

In the study the review is given to the results of treatment of patients with localized prostate cancer of low and intermediate risk progression groups who were treated at the A.F.Tsyb MRRC from April 2016 to December 2019. 276 patients were randomized to receive HDR-BT as either a single fraction of 19 Gy or as two fractions of 15 Gy two week apart. The number of patients in the 2 × 15 Gy group was 146, in the 1 × 19 group - 130. The characteristics of the patients are presented in Table 1. Brachytherapy was performed with the use of Ir-192 under spinal anesthesia. Follow-up included a TRUS of prostate, recording of toxicity, and measurement of serum PSA. Patients with biochemical failure (nadir + 2 ng/ml) or clinical suspicion of recurrence were investigated with multiparametric MRI of prostate, and PSMA-PET. Any radiographic suspicion of local recurrence was confirmed on biopsy.

Results

Biochemical relapse was documentedin32 patients: 5 patients in group 15 Gy х 2 and 27 patients in group 19 Gy. The dependence of the risk of relapse on the HDR-BT mode, estimated using the Mantel-Cox log-rank criterion, was statistically significant (p<0.001). The analysis performed using the Kaplan-Meyer method showed that the average time of recurrence among patients who received 2 fractions of HDR-BT was 88.25±1.77 months (95% CI: 84.78 - 91.72), among patients who received one fraction of HDR-BT - 67.45±1.98 (95% CI: 63.58 - 71.32). The median was not reached in both groups of patients.

Conclusions

In conclusion, HDR monotherapy delivered as two fraction of15 Gy have a high cancer control rate than as one fraction of 19 Gy. Single fraction monotherapy provides inferior results and is not used in our center now.