Prostate cancer radiation therapy with reduced planning target volume (PTV) margins.

Abstract

124 Background: Electromagnetic tracking of the prostate during radiation therapy for prostate cancer allows decreased PTV margins which may reduce dose to nearby tissues. Sandler, et al. reported a reduction in patient-reported acute morbidity with this strategy (Sandler HM, et al. Urology, 2010 May;75 (5):1004-8). We conducted a similar prospective study and compare our results with Sandler’s Assessing Impact of Margin Reduction (AIM) study and with a group treated with radiation therapy without reduced PTV margins from the Sanda, et al. PROST-QA cohort (Sanda MG, et al. NEJM, 2008 Mar 20;358 (12):1250-61). Methods: 25 patients with low-to-intermediate risk prostate cancer were treated on a prospective study with definitive intensity-modulated radiation therapy with 3 mm circumferential PTV margins and daily electromagnetic localization. An EPIC quality of life questionnaire was completed prior to treatment and at the last treatment. Using data from the referenced publications, we performed a two-tailed t-test to compare EPIC scores from our cohort with the AIM and PROST-QA cohorts treated with external beam radiation therapy alone. Results: Table lists mean pre- and post-treatment EPIC scores and the differences between them. Conclusions: Our patients fared similarly to the PROST-QA cohort, but had a significantly greater mean decrement in the urinary irritation and sexual domains in comparison to the AIM cohort. Clinical trial information: NCT01589939. [Table: see text]