Salvage prostate HDR brachytherapy combined with interstitial hyperthermia for local recurrence after radiation therapy failure

Abstract

The aim of the present retrospective study is to evaluate toxicity and early clinical outcomes of interstitial hyperthermia (IHT) combined with high-dose rate (HDR) brachytherapy as a salvage treatment in patients with biopsy-confirmed local recurrence of prostate cancer after previous external beam radiotherapy. Between September 2008 and March 2013, 25patients with local recurrence of previously irradiated prostate cancer were treated. The main eligibility criteria for salvage prostate HDR brachytherapy combined with interstitial hyperthermia were biopsy confirmed local recurrence and absence of nodal and distant metastases. All patients were treated with a dose of 30Gy in 3fractions at 21-day intervals. We performed 62hyperthermia procedures out of 75planned (83 %). The aim of the hyperthermia treatment was to heat the prostate to 41-43 °C for 60min. Toxicity for the organs of the genitourinary system and rectum was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE, v. 4.03). Determination of subsequent biochemical failure was based on the Phoenix definition (nadir + 2ng/ml). The median age was 71years (range 62-83years), the median initial PSA level was 16.3ng/ml (range 6.37-64ng/ml), and the median salvage PSA level was 2.8ng/ml (1.044-25.346ng/ml). The median follow-up was 13 months (range 4-48months). The combination of HDR brachytherapy and IHT was well tolerated. The most frequent complications were nocturia, weak urine stream, urinary frequency, hematuria, and urgency. Grade2 rectal hemorrhage was observed in 1patient. No grade 3 or higher complications were observed. The 2-year Kaplan-Meier estimate of biochemical control after salvage treatment was 74 %. The PSA in 20patients decreased below the presalvage level, while 11patients achieved a PSA nadir < 0.5ng/ml. All patients are still alive. Of the 7patients who experienced biochemical failure, bone metastases were found in 2patients. IHT in combination with salvage HDR brachytherapy is a well tolerated and effective treatment.