Study of anorectal physiology pre and pos neoadjuvant therapy for rectal cancer by anorectal manometry and Jorge-Wexner score

Abstract

– Background – The treatment of distal rectal cancer may be accompanied by evacuation disorders of multifactorial etiology. Neoadjuvant chemoradiotherapy (NCRT) is part of the standard treatment for patients with locally advanced extraperitoneal rectal cancer. The assessment of anorectal function after long-term NCRT in patients with cancer of the extraperitoneal rectum has been poorly evaluated. Objective – The aim of the present study was to evaluate the effects of NCRT on anorectal function and continence in patients with extraperitoneal rectal cancer. Methods – Rectal adenocarcinoma patients undergoing neoadjuvant therapy were submitted to functional evaluation by anorectal manometry and the degree of fecal incontinence using the Jorge-Wexner score, before and eight weeks after NCRT. The manometric parameters evaluated were mean resting anal pressure (ARp), maximum voluntary contraction anal pressure (MaxSp) and average voluntary contraction anal pressure (ASp). All patients underwent the same NCRT protocol based on the application of fluoropyrimidine (5-FU) at a dosage of 350 mg/m2 associated with folic acid at a dosage of 20 mg/ m2, intravenously, in the first and last week of treatment, concomitantly with conformational radiotherapy with a total dose of 50.4Gy, divided into 28 daily fractions of 1.8Gy. For statistical analysis of the quantitative variables with normal distribution, the mean, standard deviation, median and interquartile range were calculated. For comparison of two related samples (before and eight weeks after NCRT), Wilcoxon’s non-parametric test was used. Results – Forty-eight patients with rectal cancer were included in the study, with a mean age of 62.8 (39–81) years, 36 (75%) of whom were male. The use of NCRT was associated with a decrease in the values of ARp (55.0 mmHg vs 39.1 mmHg, P<0.05) and ASp (161.9 mmHg vs 141.9 mmHg, P<0.05) without changing MaxSp values (185,5 mmHg vs 173 mmHg, P=0.05). There was no worsening of the incontinence score eight weeks after the use of NCRT (3.0 vs 3.3; P>0.05). Conclusion – NCRT was associated with a reduction in the values of ARp and the ASp. There was no change in MaxSp, as well as in the degree of fecal continence by the Jorge-Wexner score.