I. Ríos

Can we shorten the overall treatment time in postoperative brachytherapy of endometrial carcinoma? Comparison of two brachytherapy schedules

PURPOSE To analyze vaginal-cuff relapses (VCR) and toxicity of two brachytherapy (BT) schedules in postoperative endometrial carcinoma and to correlate vaginal toxicity with vaginal-surface-EQD2Gy3 dose (VS-EQD2Gy3). METHODS/MATERIALS 319 patients (p) I-IIIC-Figo-stage were treated with 2 BT schedules. One schedule included 166p (Group-1) to whom 3 fractions (Fr) of 4-6Gy per week (w) of BT were administered after external beam radiotherapy (EBI) (125p) and 6Fr/2w of 4-6Gy in exclusive-BT (41p). The second schedule included 153p (Group-2) with BT administered daily with 2Fr/w of 5-6Gy after EBI (94p) and 5-6Gy/4Fr/w in exclusive-BT (59p). Doses were prescribed at 5mm from the vaginal surface. Toxicity was evaluated using RTOG scores for the rectum and bladder and objective LENT-SOMA scores for the vagina. STATISTICS Chi-square, Fisher and Students-t tests. RESULTS Mean follow-up (months): Group-1: 66.55 (7.73-115.40), Group-2: 41.49 (3.13-87.90). VCR: Group-1: 3p (1.88%); Group-2: 2p (1.3%). No differences were found between the two schedules comparing rectal (p=0.170), bladder (p=0.125) and vagina (p=0.680) late toxicities and comparing vagina EBI+BTp vs. exclusive-BTp (p=0.667). Significant differences in VS-EQD23Gy were observed considering EBI+BT (Groups 1+2) vs. exclusive-BT (Groups 1+2) (p<0.0001); nevertheless, no association was found between VS-EQD23Gy and vaginal complications. CONCLUSIONS No differences were found between the two schedules. No association was found between vaginal toxicity and VS-EQD23Gy. Consequently, treatment with the least number of fractions is preferable.

Problems and solutions in IGRT for cervical cancer

The contribution of Image-guided Radiotherapy (IGRT) to modern radiotherapy is undeniable, being the way to bring into daily practice the dosimetric benefits of Intensity-Modulated Radiotherapy (IMRT). Organ and target motion is constant and unpredictable at the pelvis, thus posing a challenge to the safe execution of IMRT. There are potential benefits of IMRT in the radical treatment of cervical cancer patients, both in terms of dose escalation and decrease of toxicity. But it is essential to find IGRT solutions to control the aspects that can lead to geographic miss targeting or organs at risk (OAR) overdose. This review seeks to describe the problems and possible solutions in the clinical implementation of IMRT/IGRT protocols to treat intact cervical cancer patients.

PO-1024: Long-term results of daily HDR brachytherapy in the postoperative setting of endometrial carcinoma

Purpose/Objective: To analyse the outcome of Carcinoma Cervix patients treated with CT based planning for both External beam treatment and Brachytherapy, with the objective of understanding the benefits afforded by image based optimised Brachytherapy. Materials and Methods: Data of 60 patients from among 509 radically treated Cervix cancer patients treated with CT based treatment plans, between January 2011 to December 2012 were analysed for outcome. In view of extreme number of patients and limited resources, treating every patient with conformal RT is far from reality at our centre. Hence after the instillation of CT simulator at our centre, conventional pelvic EBRT portals were planned on CT images, making field adjustments ensuring target coverage, on the basis of soft tissue imaging information. Subsequently on similar lines CT imaging was used for Brachytherapy planning and isodose shaping to cover the cervix and uterus while keeping the normal organ doses within normal limits was attempted. CT optimization in Brachytherapy was to reduce OAR doses if found excessive with standard planning and Point A dose prescription. Subsequently dose volume optimization was attempted. But where the central disease was of small volume the point A dose was still kept at the standard prescription range if the OAR doses were acceptable. Results: At a median follow up of 22 months (5-36mo), 9 patients in the CT planned group documented relapse. 4 patients had distant relapse and 5 had pelvic recurrence. Of the pelvic recurrences one patient recurred outside the initial treatment field (lower vaginal) and one patient documented progressive disease while on EBRT. The 3 other patients with true in-field recurrence had very advanced disease at presentation with bladder infiltration on imaging. Proper Brachytherapy application was not possible in 2 of these patients due to poor anatomy. There were no documented grade 2, 3 bladder toxicity. 6 patients had grade 2 rectal toxicity. During the same period there were 32 relapses and 16 isolated infield failures among the 258 CT planned patients treated with conventional 2D Brachytherapy. Also there were 22 grade 2 rectal toxicities in the patients treated with 2D brachytherapy. Conclusions: CT imaging information could be used for EBRT and Brachytherapy planning with excellent clinical outcome in a setting with large patient numbers and limited resources. Technology adaptation to suit our conditions is important for improving outcome of cervix cancer patients in the developing world.