Colorectal cancer and polyps in patients aged 40 years and over who consult a GP with rectal bleeding

BACKGROUND: Rectal bleeding is common in the community and in general practice,but few studies have examined the causes of rectal bleedingin patients presenting to general practitioners. OBJECTIVE: To determine the frequency of neoplastic conditions in patientswith rectal bleeding presenting in general practice and to explainthe associations between presenting symptoms and final diagnoses. METHODS: We conducted two studies, the first in 1989, the second in 1991,in which we invited Danish general practitioners to register3–4 patients aged 40 and over presenting with rectal bleeding. RESULTS: In Study 1 among 208 patients aged 40 and over and presentingwith a first episode of rectal bleeding, colorectal cancer andpolyps were present in 15.4 and 7.7%, respectively. In Study2 among 209 patients aged 40 and over and presenting with overtrectal bleeding, 156 reported a first bleeding episode or achange in their usual bleeding pattern, and in this group colorectalcancer and polyps were diagnosed in 14.1 and 11.5%, respectively.In the group with unchanged bleeding the cancer polyp prevalencewas 6.7% (P < 0.05). The patients in both studies were followedthrough a yearly letter to the GP for at least 32 and 22 months,respectively. CONCLUSIONS: A joint analysis of the two study populations showed that onlyage and change in bowel habit contributed to differentiatingthe cancer from the non-cancer patients. Keywords. Colorectal cancer, polyps, rectal bleeding.