Comparison of Oncological Outcomes of Salvage Cryotherapy After Radiation Therapy Compared to Primary Cryotherapy: 10 Year Experience at a Large Canadian Referral Center
Supervisor / Principle Investigator:
Dr. Michael Chetner
Dr. Ryan McLarty
Dr. Adam Kinnaird
Dr. Ambikaipakan Senthilselvan
Dr. Gerald Todd
MD Class of 2019
Introduction: Salvage cryotherapy is an accepted treatment of localized prostate cancer recurrence after radiation therapy with a durable biochemical recurrence-free survival achieved in approximately one-third of patients. However, there is little evidence analyzing the outcomes of salvage cryotherapy for recurrent prostate cancer following different primary therapy energy modalities.
Methods: We performed a retrospective analysis of patients who received salvage cryotherapy between 2007–2017, at a large tertiary referral center, after primary radiation or primary whole gland cryotherapy. The primary outcome was rates of biochemical recurrence-free survival, defined as per the Phoenix criteria (PSA nadir + 2.0 ng/ml). Secondary outcomes included time to biochemical failure, and need of any further oncological treatment.
Results: 58 out of 391 patients who received cryotherapy were identified as having received salvage cryotherapy (after primary cryotherapy, n=21; after radiation therapy, n=37) during the study period. Median follow-up time was 57 months. Biochemical recurrence occurred in 21 (57%) patients in the previous radiation therapy group and in 17 (81%) patients in the previous cryotherapy group. Median time to biochemical recurrence was 18 months in the previous radiation therapy group and 13 months in the previous cryotherapy group. 14 (38%) patients in the radiation therapy group and 13 (62%) patients in the cryotherapy group required further oncologic treatment. The biochemical free survival rate for primary radiation therapy patients was 71% at two years compared to 23% at two years for patients who underwent primary cryotherapy.
Conclusion: These results suggest that salvage cryotherapy may offer more durable oncological control to patients after radiation compared to primary cryotherapy with a lower overall rate of biochemical recurrence and a longer duration without recurrence.