El cáncer colorrectal es un tumor importante desde el punto de vista epidemiológico con una alta incidencia en los países industrializados, suponiendo el 10-15% de todos los cánceres. Representaun excelente ejemplo por el manejo multidisciplinar (cirugía, radioterapia y quimioterapia) que requiere. El uso convencional de la escisión total de mesorecto en el tratamiento quirúrgico junto con la utilización de radioquimioterapia neoadyuvante/adyuvante ha conseguido disminuir la recaída local, aumentar la tasa de preservación de esfínter, mejorar la tolerancia a los tratamientos e incrementar la supervivencia. Sin embargo, la terapia integral con intención curativa no deja de ser un tratamiento agresivo, que puede conferir secuelas físicas y alteraciones clínicas funcionales en nuestros pacientes y empeorar así su calidad de vida. El presente estudio pretende identificar las variables dosimétricas de radioterapia administradas que puedan afectar negativamente en las alteraciones del esfínter anal, para poder limitarlas en futuros tratamientos. Conocer también si el uso de determinado agente quimioterápico oxaliplatino, pueda influir en las alteraciones anales y evaluar la calidad de vida que tienen los pacientes sometidos a estos tratamientos. En nuestra opinión, los resultados de este proyecto pueden ser de gran utilidad para los profesionales implicados y resultar beneficioso a nuestros pacientes, quienes realmente, son los verdaderos protagonistas.

Background The objective of the study is to determine the correlations among the variables of dose and the sphincter function (SF) in patients with locally advanced rectal cancer treated with preoperative capecitabine/radiotherapy followed by low anterior resection (LAR) + total mesorectal excision (TME). In the same sample, we analyzed the effects of adjuvant Oxaliplatin and the relationship between the sphincter function and overall quality of life. Methods We retrospectively reviewed 92 consecutive patients with LARC treated at our center with LAR from 2006 and more than 2 years free from disease. We recontoured the anal sphincters (AS) of patients with the help of the radiologist. SF was assessed with the Wexner scale (0–20 points, being punctuation inversely proportional to annal sphincter functionality). All questionnaires were filled out between January 2010 and December 2012. Dosimetric parameters that have been studied include V20, V30, V40, V50, mean dose (Dmean), minimum dose (Dmin), D90 (dose received by 90% of the sphincter) and D98. Statistical analysis the correlations among the variables of dose and SF were studied by the Spearman correlation coefficient. Differences in SF relating to maximum doses to the sphincter were assessed by the Mann–Whitney test. Results Mean Wexner score was 5.5 points higher in those patients with V20 =0 compared to those for which V20 = 0 (p = 0.008). In a multivariate regression model, results suggest that the effect of V20 on poor anal sphincter control is independent of the effect of distance, with an adjusted OR of 3.42. Wexner test median values did not change significantly between OXA-treated and untreatd patients with p value 0.450. Conclusions In order to improve the SF in rectal cancer treated with preoperative radiotherapy/capecitabine followed by conservative surgery, the maximum radiation dose to the AS should be limited, when possible, to <20 Gy.