External Beam Radiation Therapy Versus Image Guided High-Dose-Rate Endorectal Brachytherapy in the Management of Rectal Cancer: A Retrospective Study

Abstract

brachytherapy is an effective treatment for anal cancer and is often used in Europe as exclusive or boost treatment. The purpose of this study was to retrospectively assess the clinical outcome of patients undergoing brachytherapy as sole treatment or in combination with external beam radiation therapy and to search clinical predictive factors of toxicity and efficacy. Materials/Methods: From June 2000 to June 2010, 89 patients with anal canal carcinoma were treated in the 3 institutions of the GOCO (Occitan Catalan Oncologic Group) (39 patients in Montpellier, 31 in Toulouse and 19 in Barcelona). Data was retrospectively collected. Survival analyses were performed with the Kaplan-Meier method. The log rank test was used to find predictive factors of efficacy ant toxicity. Results: Brachytherapy was given as a boost in 94% of the patients. Tumor staging reported was T1 Z 19 patients (21%), T2 Z 63 patients (71%), T3 Z 5 patients (6%), and T4 Z 2 patients (2%). Tumor size was less than 3 cm in 52% of the patients. Lymph node status was N0 in 74 patients (83%), N1 in 10 patients (11%) and N2 in 5 patients (6%). Concomitant chemotherapy was associated with external beam radiation therapy in 51% of the cases. Pulsed dose rate brachytherapy was used in 73% of the cases (low dose rate in 27%). The median brachytherapy dose was 20 Gy. The median total radiation therapy dose was 64.6 Gy. 95.5% of patients had a complete clinical response at 3 months. Acute grade 3 or 4 toxicity occurred in 25% of the patients and was significantly correlated with the use of concomitant chemotherapy (p Z 0.003). The median follow-up was 4.6 years. Late grade 3 or 4 toxicity was observed in 9% of the patients but no clinical factor was correlated. The overall survival was 96, 91and 78%, respectively, at 3, 5 and 7 years. Local relapse free survival (LRFS) was 90, 84 and 80%, respectively, at 3, 5 and 7 years. LRFS was significantly correlated with the use of concomitant chemotherapy (p Z 0.016), especially in tumors less than 3 cm in size (1 local relapse with concomitant chemotherapy Vs 7 local relapse without, p Z 0.043). Conclusions: Interstitial brachytherapy is an effective and safe treatment which permits to deliver high dose to the tumor while limiting the risk of induced toxicity. Concomitant chemotherapy during the first part of external radiation therapy induces more acute toxicity but is an important factor for local control, even in tumors less than 3 cm, and despite the high dose of radiation delivered. Author Disclosure: O. Riou: None. F. Castan: None. F. Picaud: None. C. Llacer Moscardo: None. C. Gutierrez: None. J. Dubois: None. M. Cambray: None. D. Azria: None. F. Ferrer: None. M. Delannes: None.