Dues Adjuvant Oxaliplatin Affect The Sphincter Function In Patients With Locally Advanced Rectal Cancer (Larc) Treated With Preoperative Chemoradiotherapy Followed By Low Anterior Resection (Lar) With Total Mesorectum Excision (Tme)?

e14585 Background: The objective of the study is to determine if the addition of oxaliplatin administered postoperatively influences on sphincter function in patients with locally advanced rectal cancer (LARC). Methods: We have reviewed 51 patients with LARC treated at our center with low anterior resection (LAR) and without colostomy from 2004 and free of local relapse at the time of the study. Anal sphincter function was assessed by Wexner´s incontinence score (0 to 20 points, being punctuation inversely proportional to sphincter function). Mean time from LAR to fecal function assessment was 58 months (25 to 96 months). All questionnaires were completed between January 2010 and December 2012. Patients’ characteristics such as age, stage, distant to the anal margin, radiotherapy dose to sphincter, and Wexner’s incontinence score, were summarized using descriptive statistics. Comparisons of these variables between the subgroups of patients who did or did not received oxaliplatin were carried out using the Mann-Withney test or the X2trend test. Multivariate linear regression models were fitted to assess the relationship between the use of oxaliplatin and incontinence, and to evaluate if the use of oxaliplatin modifies the effect of radiotherapy on incontinence. Results: The median incontinence score was seven points (0-20). About 40% of the patients (21/51) received oxaliplatin in the adjuvant CT. No difference was found in the median Wexner incontinence score between the groups according to the use of oxaliplatin (p=0.929). The other variables did not differ among the subgroups (age p=0.127; distance to the anal margin p=0.859; mean radiotherapy doses p=0.135) except for stage (p=0.028, being higher in the group with oxalipatin). Multivariate model results suggest that there is no relationship between the use of oxaliplatin and incontinence (p=0.974). Neither the data suggest that the oxaliplatin modify the effect of radiation, in relation to the incontinence degree (interaction term with mean dosesk, p=0.723). Conclusions: Our results show that, in these patients, adjuvant oxaliplatin does not affect negatively this function