How does colorectal cancer present? Symptoms, duration, and clues to location

Most colorectal cancers still present with symptoms because screening, although effective, is not yet widely practiced. A careful history and physical examination are still the usual methods for suspecting colorectal cancer and ordering appropriate investigation. Therefore, we studied the symptoms, duration, and clues to location of colorectal cancer.

We reviewed both hospital and office records for 204 consecutive patients with colorectal cancer, first diagnosed after symptoms, at one regional referral center from 1983-87. We abstracted data on demographic characteristics, presence and duration of 15 symptoms, and characteristics of the tumors.

The 194 patients included in the study were similar to those with colorectal cancer described elsewhere in terms of age, gender, and tumor location (58% distal to the splenic flexure), and stage (56% stage A or B). The most common symptoms were rectal bleeding (58%), abdominal pain (52%), and change in bowel habits (51%); the majority had anemia (57%) and occult bleeding (77%). The median duration of symptoms (from onset to diagnosis) was 14 wk (interquartile range 5-43). We found no association between overall duration of symptoms and the stage of the tumor. Patient age, gender, and proximal cancer location were also not associated with a longer duration of symptoms before diagnosis. We developed a rule for predicting a distal location of cancer using multiple logistic regression. Independent predictors were (odds ratio [95% CI]): Hb (1.34 for each g/dl [1.16-1.54]); rectal bleeding (3.45 [1.71-6.95]); constipation (3.16 [1.38-7.24]); and proximal symptoms (at least one of anorexia, nausea, vomiting, abdominal pain, or fatigue) (0.48 [0.20-1.02]). The rule had sensitivity of 93% and a specificity of 47%, with an area under the ROC curve of 0.79.

Until prevention of colorectal cancer is more common, we must continue to rely on clinical findings for detecting this cancer. Our results will remind physicians to keep colorectal cancer on the differential diagnosis of "chronic" gastrointestinal symptoms, and our decision rule may prompt earlier investigation with colonoscopy.