July 15, 2015
2 min read

Colorectal cancer more survivable when detected by screening vs. diagnostic colonoscopy

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Patients with colorectal cancer diagnosed during screening colonoscopy survived longer than those whose cancer was confirmed during diagnostic colonoscopy, according to recent study data.

“Screening colonoscopy improves long-term survival in patients diagnosed with colorectal cancer (CRC),” Kilian Friedrich, MD, from the department of gastroenterology at University Hospital of Heidelberg in Germany, told Healio Gastroenterology. “This survival benefit is a result of CRC-diagnosis at an earlier stage when the tumor is accessible to more curable therapies. Therefore, patients undergoing screening colonoscopy profit from this measure in two ways: A) Polyps can be found and resected. This significantly decreases the risk to develop CRC. B) Even if a patient is diagnosed with CRC during screening colonoscopy, CRC is detected at an earlier stage with higher chances of a curable tumor therapy.”

Kilian Friedrich

Aiming to determine whether survival rates differed between patients whose CRC was diagnosed during screening vs. diagnostic colonoscopy, Friedrich and colleagues performed a retrospective observational study of CRC patients diagnosed at 10 private practices from 2003 to 2005 and followed until 2013. Screening colonoscopy was defined as the absence of symptoms indicative of CRC and negative results from any fecal occult blood tests performed.

A total of 60 patients were diagnosed during screening colonoscopy and 252 during diagnostic colonoscopy. Age at diagnosis and sex distribution were similar between groups. Mean follow-up was 81 ± 40.1 months.

Stage I and II CRC was detected more frequently in the screening colonoscopy group (81.6%) compared with the diagnostic colonoscopy group (59.9%; P < .002). Overall, 44.8% of the diagnostic colonoscopy group died during follow-up compared with 23.3% of the screening colonoscopy group (P = .02). Kaplan-Meier analysis showed reduced survival with diagnostic colonoscopy (mean 86.9 ± 3 months; 95% CI, 81-92.8) compared with screening colonoscopy (mean 107.1 ± 4.9 months; 95% CI, 97.4-116.9). Analysis excluding deaths unrelated to CRC (cardiovascular events, non-CRC malignancy, pulmonary emphysema, end-stage liver disease and septic pulmonary infection) still showed reduced survival with diagnostic colonoscopy (mean 89.4 ± 3 months; 95% CI, 83.5-95.4) compared with screening colonoscopy (mean 109.6 ± 4.7 months; 95% CI, 100.2-119).

“In this long-term observational study, we showed that patients with CRC detected by screening colonoscopy have better survival than occurs in patients with CRC detected during colonoscopy performed for diagnostic indications,” the researchers wrote. “This effect in screening colonoscopy occurs independent of polypectomy.

“Although CRC-screening methods differ between nations, our main finding of prolonged survival in cancers diagnosed at screening colonoscopy likely applies to screening colonoscopy in other countries,” they added. – by Adam Leitenberger

Disclosure: The researchers report no relevant financial disclosures.