Waiting to Have Colonoscopy Until Symptoms Arise Reduces Survival

Colonoscopy can catch tumors in a more treatable stage.

Patients who wait until they have colon cancer symptoms are less likely to survive the disease than those whose cancer is detected in a colonoscopy.

A study published recently in GIE: Gastrointestinal Endoscopy evaluated 312 patients aged 55 years or older diagnosed with colorectal cancer between 2003 and 2005. Of these patients, 60 were diagnosed during a screening colonoscopy and as such had no symptoms or a negative fecal occult blood test (FOBT).

The remaining 252 patients were diagnosed with cancer during a diagnostic colonoscopy after they had a positive FOBT or experienced symptoms such as abdominal pain, iron deficiency anemia, weight loss, bowel habit changes, or rectal bleeding. None of these patients previously underwent a colonoscopy, while all of the patients received follow-up endoscopic care.

Researchers followed the patients for up to 10 years following diagnosis. Patients with cancer detected during a colonoscopy lived an average of 20.2 months longer than patients who had the test after the onset of symptoms or a positive FOBT.

Patients who waited had more advanced stage tumors, which contributed to shorter survival times. Approximately 55% of patients who underwent a diagnostic colonoscopy and approximately 77% of patients who underwent a screening colonoscopy survived beyond the study duration.

"We know that screening colonoscopy can prevent cancer by detecting and removing precancerous polyps. Independent of that, this study shows that screening colonoscopy also can contribute to reduced mortality from colorectal cancer by catching tumors at earlier and more treatable stages,” lead author Kilian Friedrich, MD, said.