Body Mass Index and Doses at Organs at Risk Evaluated by CT in a Mediterranean Postoperative Vaginal Cuff Brachytherapy (VCB) Cancer Population

Abstract

PORTEC-2 trial suggested that isolated brachytherapy (BT) is equivalent when compared to external beam radiotherapy for intermediate-high risk patients. Moreover, BTwas associated to less gastro-intestinal toxicity. Our aim was to analyze local failure (LF) and toxicity of BT for intermediate risk stage I endometrial cancer in a series of patients treated in a single institution. We also conduct a toxicity analysis. Materials/Methods: One hundred and twenty four patients treated between 2009 and 2013 were retrospectively analyzed. The intermediatehigh risk group (IHR) was defined by PORTEC-2 eligibility criteria. Seven patients were excluded because they were retrospectively considered high risk (n Z 6) or low risk (n Z 1). BT was delivered with cylinder (94%) or ovoids (6%). The total dose was 24Gy (4 x 6Gy), prescribed 5mm in depth. The ICRU38 bladder point dose was calculated. LF and survival were done by Kaplan-Meier and Log-rank test was used for subgroup analysis. Student t test compared de mean doses between the groups with and without urinary toxicity. The toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE v4.0). Results: After a median follow up of 26 months, there were 2 vaginal failures (both at 18 month of follow-up) and 2 deaths not related to endometrial cancer. In a subgroup analysis, IHR did not increase the risk of LF, when compared to intermediate-low risk (p Z 0.869). The 3-years LF rate was 2.7%. Two patients (1.6%) developed grade 1 gastro-intestinal toxicity and 10 patients (8%) developed grades 1-2 urinary toxicity. The mean bladder point dose was 46.9% (11.25Gy) for the asymptomatic group and 49.8% (11.95Gy) for the symptomatic group (p Z 0.69). Three patients with urinary toxicities had urinary infection that required oral antibiotics, probably due the bladder catheterization. Conclusions: BT alone is an efficient adjuvant treatment for intermediate risk (high or low) stage I endometrial cancer. The 3-years local control, cancer specific and overall survivals were 97.3%, 100% and 97.1%, respectively. The favorable toxicity profile of the treatment (less than 10% G1-2 acute reactions), could not be previewed by the ICRU38 bladder evaluation point. Moreover, bladder catheterization may be responsible for 30% of the urinary toxicity, questioning the value of the ICRU 38 bladder point in this scenario. Author Disclosure: L. Sapienza: None. B.C. Almeida: None. A. Aiza: None. M.J. Chen: None. R.C. Fogaroli: None. A.C. Pellizzon: None. G. Baiocchi: None.