The diagnostic value of a change in bowel habit for colorectal cancer within different age groups

Abstract

Background: Change in bowel habit as a sole alarm symptom for colorectal cancer is disputed.

Objective: We investigated the diagnostic value of change in bowel habit for colorectal cancer, particularly as a single symptom and within different age groups.

Methods: This retrospective cohort study examined colorectal cancer fast track referrals and outcomes across four Swedish hospitals (April 2016-May 2017). Entry criteria constituted one or more of three alarm features: anaemia, visible rectal bleeding, or change in bowel habit for more than 4 weeks in patients over 40 years of age. Patients were grouped as having only change in bowel habit, change in bowel habit plus anaemia/bleeding or anaemia/bleeding only.

Results: Of 628 patients, 22% were diagnosed with colorectal cancer. There were no cases of colorectal cancer in the only change in bowel habit group under 55 years, while this was 6% for 55-64 years, 8% for 65-74 years and 14% for 75 years and older. Among subjects under 55 years, 2% with anaemia/bleeding had colorectal cancer, this increased to 34% for 55 years and older (P < 0.0001). Change in bowel habit plus anaemia/bleeding gave a colorectal cancer prevalence of 16% in under 55 years and increased to 30% for 55 years and older (P = 0.07).

Conclusion: Change in bowel habit as the only alarm feature has a low diagnostic yield for colorectal cancer in patients under 55 years.

Keywords: Change in bowel habit; anaemia; colorectal cancer; visible rectal bleeding.

Figure 1.

Flowchart of the Swedish colorectal cancer (CRC) fast track pathway, with anaemia, visible rectal bleeding and change in bowel habit (CIBH) for over 4 weeks in patients aged over 40 years as the three entry criteria. High-risk patients are those with one or more of the following: have had CRC or are part of a surveillance programme for colorectal polyps, have had colitis for at least 20 years, have two first-degree relatives with CRC, have a relative who has been diagnosed with CRC or endometrial cancer when less than 50 years old. Not included in the flow chart or in this study are those patients who entered the pathway with only medical imaging, rigid sigmoidoscopy or digital rectal examination findings suggestive of CRC.

Figure 2.

Flowchart of patients referred to the Swedish fast track colorectal cancer pathway.

Figure 3.

Colorectal cancer (CRC) prevalence by each symptom group – all ages. The combination of anaemia, bleeding and change in bowel habit (CIBH) had the highest prevalence of CRC (46%). For single symptoms, CRC prevalence was highest for anaemia (34%), followed by visible rectal bleeding (20%) and lowest for CIBH (8%).

Figure 4.

Colorectal cancer (CRC) prevalence by symptom group and age category. There were no cases of CRC in the change in bowel habit (CIBH)-only group who were under 55 years, while this was 9.7% in those aged 55 years and older (P = 0.075). Moreover, while 2% of anaemia/bleeding subjects under 55 years were diagnosed with CRC, this increased to 33.5% for those aged 55 years and older (P < 0.0001). Finally, CIBH + anaemia/bleeding gave a CRC prevalence of 16% in those under 55 years, and increased to 30.1% for those aged 55 years and older (P = 0.07).

Figure 5.

Diagnostic outcomes in change in bowel habit (CIBH)-only patients without colorectal cancer (CRC) (all ages). In the CIBH-only patient group without CRC, diverticulosis (31%) and adenomatous polyps (25%) were the most prevalent pathologies, followed by haemorrhoids (10%) and unspecified colitis (8%). Microscopic colitis (3%) and angiodysplasia (2%) were less prevalent. Thirty-six per cent of these patients had no organic pathology to account for their symptoms.