Anatomical Structure-Based Deformable Image Registration in Locally Advanced Cervical Cancer for Radiotherapy including Adjuvant High-Dose-Rate Brachytherapy Implants

histology (n5 6 uterine papillary serous, 2 clear cell). The median CTV for patients not receiving prior irradiation was 23.7cc (range: 18.0-60.3) with a median D90 of 75.1Gy (range: 61.3-81.2); the median D2cc for the bladder, rectum, and sigmoid was 61.4Gy (range: 51.2 -72.2), 57.2Gy (range: 52.9-71.6), and 53.8Gy (range: 46.4-71.5), respectively. At a median followup of 15 months (range: 2-61), 24 patients with isolated vaginal and 7 with synchronous regional-nodal and vaginal recurrence completed salvage HDRB with a crude clinical complete response (CR) rate of 94% (n 5 29 of 31). The median time to failure was 6 months (range: 0-51); sites of failure were vagina (n51), lung (n52), para-aortic lymph nodes (n52), inguinal lymph nodes (n51) intra-peritoneal (n51), and brain (n51). Actuarial 2-year local control, distant control (DF), and overall survival (OS) was 97%, 67%, and 64%, respectively. Initial FIGO stage I vs II-IV (p!0.001, p50.021) and FIGO grade 1-2 vs 3 (p50.047, p50.025) were significant predictors of DF and OS; non-endometriod histology predicted for DF (p50.007) with a trend towards inferior OS (p50.151). No patient experienced $ grade 3 acute toxicity; however 6% (n52) had $ grade 3 toxicity (1 grade 4 vaginal necrosis resolved with hyperbaric oxygen, and 1 grade 3 gastrointestinal obstruction), with a 2-year actuarial incidence of $ grade 3 vaginal toxicity 8%, bladder toxicity 0%, rectal toxicity 0%, and small bowel toxicity 6%. Conclusions: Salvage 3D based HDRB shows promising tumor control and acceptable morbidity. The primary mode of failure is distant which is a function of histology, FIGO stage, and FIGO grade; these patients should be considered for more aggressive local or systemic salvage options.