ABSTRACT
OBJECTIVE: We retrospectively evaluated the efficacy of combining the SpaceOAR (SOAR) hydrogel with prostate brachytherapy, using colonoscopy findings to assess for radiation proctitis. METHODS: Among 731 patients undergoing iodine-125 low-dose-rate prostate brachytherapy (LDR-BT), SOAR was utilized in 394 patients (53.9%). Colonoscopy was performed for 97 patients (13.3%) to assess the presence, location, condition, and treatment of radiation proctitis. We also investigated treatment factors associated with the occurrence of radiation proctitis. RESULTS: Radiation proctitis was observed in 57 patients (7.8%) and 17 (2.3%) were treated with argon plasma coagulation (APC). The incidence of radiation proctitis was 12.2% in the non-SOAR and 4.1% in the SOAR group (p < 0.001). In the non-SOAR group, the incidence of radiation proctitis was 6.6% for LDR-BT monotherapy and increased to 22.0% when combined with external beam radiation therapy (EBRT) (p = 0.001). However, in the SOAR group, these rates significantly decreased to 3.3% and 5.7% for monotherapy and combination therapy, respectively (p = 0.035, p < 0.001). With SOAR, inflammation was observed directly above the DL in most patients (87.5%), and only one patient (6.3%) required APC. The absence of SOAR (p < 0.001, HR = 0.29) and the concurrent use of EBRT (p = 0.018, HR = 2.87) were identified as significant risk factors for the occurrence of radiation proctitis. CONCLUSION: The use of SOAR significantly reduced the incidence of radiation proctitis in patients undergoing LDR-BT monotherapy and combined EBRT. Inflammation primarily occurred directly above the DL; further examination is necessary to clarify its cause.
ABSTRACT
Perineal recurrence after brachytherapy is an exceedingly rare complication. Moreover, ductal adenocarcinoma is a rare histological variant of prostate cancer. Herein, we describe a case of perineal recurrence from ductal adenocarcinoma of prostate after low-dose-rate brachytherapy (LDR-BT) in a 65-year-old male patient. The patient had localized prostate cancer, for which he received LDR-BT; however, he experienced perineal recurrence 2 years after receiving LDR-BT. Surgical excision was attempted, but we were unable to remove the whole tumor, owing to invasion to surrounding tissue. Pathological examination of resected tumor showed ductal adenocarcinoma of the prostate. External beam radiation therapy and high-dose-rate brachytherapy (HDR-BT) were performed for residual tumor. Mild mediastinal lymph node swelling was observed during clinical course of the disease. Hence, androgen deprivation therapy was administered with abiraterone after radiation therapy, and prostate-specific antigen level decreased to undetectable level. Biochemical failure after transperineal brachytherapy for prostate cancer should be considered as a perineal recurrence.
ABSTRACT
OBJECTIVES: The aim of the present study was to report on our early experience with hydrogel spacer (SpaceOAR) placement in combination with iodine-125 low-dose-rate brachytherapy for prostate cancer. METHODS: From April 2018, SpaceOAR hydrogel spacer was placed in 100 consecutive patients undergoing iodine-125 low-dose-rate brachytherapy. Complications and the status of the placement were evaluated. Deformation of the prostate by the spacer was examined measuring prostate diameters and evaluating the change from preoperative status. The position of the prostate was similarly examined by evaluating the change in distance between the pubic symphysis and the prostate. Post-plan dosimetric data were compared with 200 patients treated without a spacer. RESULTS: No complications were found during either the intraoperative or perioperative periods. The mean displacement distance of 11.64 mm was created, the mean value before spacer placement was 0.28 mm (P < 0.0001). The change of the prostate diameters showed a positive increase in all directions, with no significant negative change in any one direction. Regarding the change in distance between pubic symphysis and the prostate, no significant shortening trend was observed between the two groups (P = 0.14). Whereas the dosimetric parameters showed means of 0.001 and 0.026 cc for RV150 and RV100 in the spacer group, they were 0.025 and 0.318 cc, respectively, in the non-spacer group, showing a significant decrease in both parameters (P < 0.001). CONCLUSIONS: Prostate deformation secondary to hydrogel placement might adversely affect dosimetric parameters in patients undergoing low-dose-rate brachytherapy. However, a significant reduction in the rectal dose can be adopted without adversely affecting the other parameters related to treatment outcome.
