(Purpose) To describe our initial experience in salvage cryoablation targeting recurrent lesions after definitive irradiation for prostate cancer. (Methods) Eligible patients for this treatment were those who developed biochemical failure after definitive radiotherapy for localized prostate cancer, but without distant metastasis, and with solid lesions identifiable on multiparametric magnetic resonance imaging (mpMRI). Histological proof of recurrence with mapping biopsy covering corresponding sites was obtained. Two to four cryoprobes were inserted transperineally into the prostate under general anesthesia with extensive lithotomy position. The rapid expansion of argon gas cryogen through a small opening within the cryoprobe cools itself to make an ice ball and the quick exchange to helium gas induces an active thawing phase. Entire procedure is monitored and guided with the use of transrectal ultrasonography. Postoperative follow-up included patient interview, digital rectal examination, prostate specific antigen (PSA) testing and quality of life (QOL) monitoring using IPSS and IIEF-5 at 1, 3, 6 and 12 months postoperatively. Changes of mpMRI findings with time, particularly at one month, were used to judge immediate treatment impact. (Results) Five patients underwent salvage cryoablation between October 2015 and September 2016. No grade 3/4 complications such as rectal fistula or urethral stenosis were experienced. Mean and maximal percent decline of PSA from baseline levels at 1, 3, 6 and 12 months following cryoablation were 72.2 and 94.7%, 79.4% and 93.9%, 78.2% and 92.1%, 79.6% and 90.9%, respectively. Posttreatment IPSS showed temporary worsening with average changes in score of 1.8, 1.5, 1.6, and 1.0 times over baseline levels, respectively. IPSS score returned to the baseline in one at six months and two at 12 months. Two of 5 patients were sexually active prior to therapy and thus evaluable. Both showed significant decline in IIEF score by 95% at 12 months. No patients showed any signs of recurrence. mpMRI at one month following cryoablation confirmed complete disappearance of visible lesions in all cases. (Conclusions) Salvage cryoablation for recurrent lesions of prostate cancer after definitive radiotherapy is feasible with minimal morbidity. Both oncological outcome and adverse events should be monitored carefully with longer follow up.
Keywords: Salvage cryoablation; definitive radiotherapy; prostate cancer.