Patients whose colorectal cancer (CRC) is detected during a screening colonoscopy are likely to survive longer than those who wait until they have symptoms before having the test, according to a study in the July issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).
The study, "Survival in patients with colorectal cancer diagnosed by screening colonoscopy," looked at 312 patients in 10 gastroenterology practices in Germany, all aged 55 or older, who were diagnosed with CRC in 2003-2005. Of those, 60 patients were diagnosed during a screening colonoscopy, meaning they had no symptoms and/or only a negative fecal occult blood test (FOBT). The other 252 patients had their cancers detected during a diagnostic colonoscopy, following a positive FOBT and/or symptoms including abdominal pain, iron deficiency anemia, weight loss, changes in bowel habits, or rectal bleeding.
None of the patients had had a previous colonoscopy, and all received endoscopic follow-up care. The patients were followed for as long as 10 years after diagnosis.
Patients whose cancer was detected during screening colonoscopy lived 20.2 months longer, on average, than those who had the test after noticing symptoms or having a positive FOBT (diagnostic colonoscopy). The latter group tended to have more advanced stage tumors; as expected, those whose cancer was in a more advanced stage had shorter survival times.
About 55 percent of the patients with diagnostic colonoscopy, and about 77 percent of the screening colonoscopy patients, survived beyond the time period of the study.
According to the lead author, Kilian Friedrich, MD, "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."
The researchers concluded that, although screening approaches differ between nations, this finding of increased survival among recipients of screening colonoscopy likely applies to other countries.