This study demonstrated that the Spanish version of the ICIQ-B is appropriate for clinical use among colorectal cancer patients as our results suggested adequate values compared to a criterion and good internal consistency. Regarding its construct validity, the questionnaire showed a factorial structure slightly different to the original analysis 13. These small differences might be explained by the characteristics of our sample which was not composed of only incontinent individuals but of people before and after receiving aggressive cancer treatments. Despite the parallel analysis, from the exploratory factor analysis, suggesting the instrument to be unidimensional in this sample, we decided to maintain the original three-factors structure considering our more heterogenous sample and the possibility to use this instrument among populations with anal incontinence.
Another indicator for construct validity used in this study, the hypothesis testing, was partially fulfilled. We confirmed two of the three previous hypotheses: (1) rectal cancer patients showed worse bowel function compared to colon cancer patients, and (2) bowel function prior to surgery was worse compared to post-surgery. However, our third hypothesis was not confirmed as there was no difference between men and women regarding bowel domains.
As expected, rectal cancer patients had worse bowel function compared to colon cancer patients. Rectal cancer and its treatments affect anorectal function more than colon cancer. After colon cancer surgeries, diarrhea is common and more liquid stools increase the risk of incontinence 2. After sphincter preserving surgeries for rectal cancer, bowel disfunctions are very common presenting with incontinence, urgency and increased evacuatory frequency 5,20. Preoperative chemoradiotherapy also increases the risk of showing bowel dysfunctions after rectal cancer surgery 10.
Before cancer surgery, our participants showed worse bowel control and quality of life compared to those participants assessed post treatments. Similarly, another study with 30 colorectal cancer patients from Australia, using the ICIQ-B, showed that the percentage of participants with bowel symptoms decreased from 60% preoperatively to 44% 6 months after surgery 21. The previous study also highlights that at six months after surgery, patients had significantly less abdominal pain but more fecal incontinence compared to their preoperative status 21. The difference regarding fecal incontinence comparing to our study might be attributed to our assessment after surgery that was not standardized and was quite longer (Mean = 32.3 months after cancer surgery) compared to the previous study.
Bowel symptoms were present both before and after treatments, the most prevalent were liquid stool incontinence (43.4%), gas incontinence (60.4%), and urgency to defecate (52.8%). Sometimes colorectal cancer survivors are not aware of these bowel habit changes. A qualitative study demonstrated that patients would like to have received information, previous to their colorectal cancer treatments, regarding possible changes in bowel habit and impact on diet 22. After treatments, colorectal cancer survivors experience survivorship as an individual, life-changing process, with uncertainties and need to deal with bowel dysfunction and ostomy 23.
Contrary to what was expected, men and women from this study had similar scores for bowel function and quality of life. Usually, women report more pelvic floor symptoms as hormonal and obstetric variables play an important role 24. Among healthy participants, anal squeeze pressure and duration are higher in men than women 25. At least one year after colorectal cancer surgery, being female is a risk factor for presenting worse bowel dysfunction 7. The incidence of major LARS was bigger among women (18%) compared to men (9%) 26. In addition, the epidemiology of chronic constipation shows a female predominance, women have more severe constipation symptoms, specifically incomplete evacuation and painful defecation, and perform poorly than men in the balloon expulsion test 27.
In the criterion validity analysis, we found a fair correlation between items of the ICIQ-B and the EORTC QLQ CR29, which is acceptable. However, a study with rectal cancer patients after sphincter preserving surgery found that neither the EORTC C-30 nor the CR-38 are sensitive instruments in delineating differences in bowel function 28. It is very common to use quality-of-life questionnaires to assess bowel function but using more specific questionnaires such as the ICIQ-B is probably more appropriate. Future studies should compare the ICIQ-B with other scores for bowel symptoms such as Wexner, Fecal Incontinence Quality of Life Scale (FIQL), and LARS score.
Internal consistency was very high for the total set of question items (α = 0.909) and good for the domains of bowel pattern (α = 0.710), bowel control (α = 0.879), and quality of life (α = 0.817). These values were similar to the English original version 13. Likewise, the identified tendency to a floor effect might be explained as this questionnaire was originally developed to assess the bowel function among anal incontinent individuals.
The LARS terminology is broadly used and, sometimes, studies also use this terminology and the LARS score indiscriminately for other types of surgeries, such as those for colon cancer 6. We suggest that the better terminology to use is bowel dysfunctions, anorectal symptoms, or anorectal dysfunctions. For such purposes, the ICIQ-B is a comprehensive instrument that considers the complete framework of bowel function that might be useful for diagnosing dysfunctions, as well as planning and confirming the effectiveness of treatments.
The limitations of this study were mainly related to not including only incontinent patients, which was justified by the need to measure bowel function as a broader concept both before and after colorectal cancer treatments. Data collection took much longer than planned due to the Covid-19 pandemics. As a strength, this is one of the first studies to report data on bowel function of Latin-American colorectal cancer patients.