Hypothesis / aims of study
Anatomical and physiological alteration after colorectal cancer (CRC) resection causes bowel dysfunction in cancer survivors (1). Anterior Resection Syndrome (ARS) describes the storage and evacuation symptoms often seen following resection and oncological treatment (2). Previous retrospective studies have found over 40% of patients report severe ARS (3). The primary objective of this prospective cohort study was to examine the prevalence of ARS using the Low Anterior Resection Syndrome score (LARS), a validated tool, in cancer survivors who had undergone sphincter-preserving anterior resection for CRC. The secondary objectives were to: (i) explore the risk factors for ARS; and, (ii) screen for bladder and sexual dysfunction symptoms.
Study design, materials and methods
This is a prospective observational study evaluating the prevalence of anterior resection syndrome after CRC resection and treatment. All consecutive patients who were diagnosed with CRC and attended follow-up appointments in hospital outpatient clinics from 2019 were identified. The Low Anterior Resection Syndrome Score (LARS) and the bowel bladder sexual function questionnaire were administered as part of standard care during the consultation. Surgical and medical history were obtained from the medical record. Patients who had undergone sphincter-preserving anterior resection for sigmoid or rectal cancer, and had bowel continuity restored, with or without previous temporary ostomy, for a minimum of 6 months were eligible. Patients were excluded if they had: (i) permanent ostomy or dyfunctioning stoma awaiting reversal; (ii) evidence of cancer recurrence; (iii) difficulty comprehending questionnaires due to lack of language or cognitive impairment; (iv) other co-morbidities that may affect bowel function such as inflammatory bowel disease, neurological disorders, radiotherapy treatment for previous prostate or gynaecological cancers; and, (v) revision of surgery due to local recurrence. Eligible participants were asked to complete the questionnaires at their follow-up appointments. The questionnaires used in the study include: 1) Low Anterior Resection Syndrome Score (LARS), a validated 5-item questionnaire (total score 42). The total score is categorised as No LARS (0-20), Minor LARS (21-29) and Major LARS (30-42). 2) Participants also completed a self-designed questionnaire for screening of bowel, bladder and sexual function which consisted of 4 dichotomous questions. Other collected data included: demographic information, cancer characteristics, surgery and oncological treatment details. All consecutive CRC patients who attended the clinics were captured for data collection between March 2019 and December 2020. LARS score differences between sub-categorical groups were evaluated with Independent sample t tests. Chi-squared test was used to assess the association between categorical variables, with binary logistic regression used where associated risk factors were combined into clinical patterns.
Results
Overall, 63 patients were eligible, one was excluded due to local recurrence during study: 66% (n=41) were male. The mean age was 64 (30-83 year). Thirty-five patients (56.5%) had sigmoid cancer and 27 (43.5%) had rectal cancer. Stage of disease: 56.5% stage I, 19.4% stage II, 59.7% stage III and 3.2% stage IV. Surgical techniques used were: High (58.1%), Low (19.4%) and Ultralow (22.6%) anterior resection. In total, 19 patients (30.6%) had a temporary stoma, with mean duration of dyfunctioning stoma before reversal of 7.8 months (2-17 months). Long course neoadjuvant chemoradiotherapy was given to 11.3%, short course neoadjuvant radiotherapy to 1.6% and postoperative adjuvant chemotherapy to 59.7% of the study cohort. The mean length of time of bowel function assessment after re-establishment of bowel continuity (after initial bowel reconstruction surgery without stoma or after stoma was reversed) was 19.65 months (4-58 months).
In terms of bowel dysfunction, 71% were categorised in No LARS group (n=44), 12.9% in Minor LARS group (n=8) and 16.1% in Major LARS group (n=10). Amongst the patients who scored 0-20 (No LARS), 61.4% had an anastomotic height >11cm; of those who scored 30-42 (Major LARS), 60% had anastomotic height 0-5.9cm. The mean difference in LARS score between an anastomotic height 0-5.9cm and >11cm was 15.5 (95%CI 8.6, 22.39, p<0.0001) (Fig. 1). Of the proposed potential risk factors for LARS, anastomotic height (RR 4.79, p=0.002), prior stoma (RR 5.69, p= 0.014) and radiotherapy (RR 6.71, p= 0.019) had the strongest association with ARS on logistic regression. When combining these three associated risk factors into clinical patterns, the risk of ARS in patients with high anastomotic height (>11cm), without prior stoma or radiotherapy was 0.148 (95%CI 0.038,0.585) p=0.003. By contrast patients with a low anastomotic height (0-5.9cm), temporary stoma in the original surgical procedure, and who received neoadjuvant radiotherapy had a risk of ARS of 9.462 (95%CI 1.70, 52.71) p=0.004 (Fig.2).
New onset of bladder symptoms was reported in 30.6% and new sexual dysfunction symptoms in 21% of the study population respectively.
Interpretation of results
Our prospective study found 29% of patients continued to suffer from bowel dysfunction, as measured by LARS score, after re-establishment of bowel continuity. The severity of ARS increased with substantial involvement of rectum together with associated factors of anastomotic height, temporary stoma and radiotherapy. Patients who had an anterior resection with low anastomotic height; a temporary stoma; and who received radiotherapy were at highest risk of having ARS. New onset of bladder and sexual dysfunction symptoms also developed in a substantial proportion of our study cohort after anterior resection.