Presentation Authors: Caitlin Shepherd*, Harry Clarke, Charleston, SC
Introduction: Transperineal injection of a degradable hydrogel, (SpaceOAR,Augmenix, Bedford, MA) is FDA approved for expanding the space between the prostate and rectum during radiation therapy (RT) to reduce rectal dose. We previously described the use of this agent in treating patients undergoing salvage cryoablation (SC) for recurrent prostate cancer (CaP). We now report patient outcomes after one year of use of this novel modality at our institution.
Methods: We analyzed results of patients who underwent SC of the prostate with concomitant injection of SpaceOAR from July 2017 to July 2018.. Postoperative outcomes at 2-weeks 3, 6, 9 and 12 months are reported using the Clavien-Dindo Classification along with PSA values for patients with available data.
Results: 16 patients underwent cryoablation of the prostate with the injection of SpaceOAR; 15 SC and 1 primary cryoablation. Mean age was 69 years; initial clinical stratification was low (5/16), intermediate CaP (2/16), high risk (1/16) and 8 patients with unknown pathology at time of cryotherapy. Previous treatment for those undergoing salvage cryoablation consisted of radiation alone (7/16), radiation plus androgen deprivation therapy (4/16), external beam, brachytherapy and androgen deprivation therapy (2/16), radiation followed by salvage cryotherapy (1/16), proton beam therapy (1/16). A mean prostate volume of 20.3g was recorded. At initial post-operative follow up, a third of patients reported a grade 1 complication including scrotal swelling, perineal pain or dysuria (5/15) with one patient reporting a grade 2 complication (inpatient admission for UTI at an outside facility). At 3 months postop, two patients continued to have grade 1 complications (perineal pain) and one patient that had previously undergone SC presented with a grade 3 complication (rectoprostatic fistula). No further complications were noted. No grade 4-5 complications have been noted. The patient with the rectorprostatic fistula required further surgical intervention for repair. PSA nadired to undetectable as defined as PSA < 0.1ng/dl in 40% of patients with at least 3 month follow up with PSA data (4/10).
Conclusions: Use of SpaceOAR with SC is associated with minor complications with only one reported grade 3 complication in our series. PSA was undetectable in large portion of patients after SC likely due to ability to aggressively freeze the prostate gland safely with use of this hydrogel spacer. Further studies evaluating the long term oncologic and functional outcomes of this new technique are needed.