(P141) Rectal Spacer Injection in Postprostatectomy Patients Undergoing High-Dose Salvage External Beam Radiation

Jekwon Yeh, MD, Kenneth Tokita, MD, Jeffrey Chien, John Ravera, MD; Cancer Center of Irvine

OBJECTIVE/PURPOSE: There is now increasing literature to support the use of a rectal spacer to decrease rectal side effects during radiation therapy (RT) for patients with intact prostate cancer. There have been no reports on its usage in patients who are undergoing salvage RT after a prostatectomy. This study aims to report on the gastrointestinal toxicity of patients who have had a prostatectomy and received high-dose (>72 Gy) salvage RT with the rectal spacer.

MATERIALS AND METHODS: From January 2010 to October 2013, a total of 32 patients had the rectal spacer placed via transperineal injection posterior to the residual Denonvillier’s fascia under ultrasound guidance. All patients were treated to a minimum of 72 Gy to the prostatic fossa with intensity-modulated RT (IMRT) with daily cone-beam computed tomography (CT) to ensure treatment accuracy. All patients had at least 6 months of follow-up. Radiation Therapy Oncology Group (RTOG) scoring for gastrointestinal morbidity was assessed at the end of treatment and 6 months afterward.

RESULTS: At the end of treatment, 23 patients (72%) had no change in rectal symptoms. Nine patients (28%) developed grade 1 gastrointestinal (GI) toxicity. No patients developed grade ≥ 2 GI toxicity. At 6 months after treatment, 29 patients (91%) were back to their baseline GI function, with only 3 patients (9%) with residual grade 1 GI toxicity. No patients developed grade ≥ 2 GI toxicity.

CONCLUSIONS: Our study shows that rectal spacer placement in patients who have had a prostatectomy is feasible. Despite the high dose of salvage RT, GI toxicity rate was low, and no patient developed grade ≥ 2 GI toxicity with the rectal spacer.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org