Salvage radiotherapy after cryotherapy in prostate cancer

Cryotherapy (CT) is increasingly used as a primary treatment for prostate cancer (PC), though guideline recommendations remain limited. This study evaluates toxicity, including the use of hypofractionation, as well as local and biochemical control, and survival outcomes in patients treated with salvage radiotherapy (sRT) after recurrence following CT.

We retrospectively analyzed 21 patients with recurrent PC after CT treated with sRT at our institution between 2013 and 2023. Toxicity was assessed with the RTOG scale, fractionation-related toxicity was compared with chi-square test. Biochemical recurrence was defined using Phoenix criteria. Survival and local control were analyzed with Kaplan-Meier method.

Median follow-up was 56 months (4.4-136.6). Median age at diagnosis was 73 years (55-80), and median interval from CT to sRT was 45.5 months (14.2-189.23). Median radiation dose was 73.14 Gy (70-78); 86% received hormonal therapy, and 52% underwent hypofractionation. Acute grade 2 genitourinary (GU) toxicity occurred in 23.8%. Chronic GU grade 2 and 3 toxicities were 28.6% and 9.5%, respectively. Gastrointestinal (GI) toxicity included one case (4.76%) of acute G2 and one case each of chronic G3 and G4. No difference between conventional fractionation and hypofractionation was found. Median overall survival (OS) after sRT was 108.45 months (22.44-194.46). Mean OS was 98 months with 90.4% local control.

sRT after CT can provide durable local and biochemical control in selected patients, but severe late toxicity may occur in a small proportion of cases. Hypofractionation was not associated with increased toxicity in this cohort and appears to be a feasible option.