Post-colonoscopy upper gastrointestinal malignancies in positive immunochemical fecal occult blood test patients: An Australian data linkage study

Abstract

In immunochemical fecal occult blood test (iFOBT) positive subjects, colonoscopy screening can detect colorectal cancers and advanced adenomas, yet most iFOBT-positive subjects find no relevant lower gastrointestinal lesions. Limited data are available on upper gastrointestinal (UGI) cancer risk in iFOBT-positive patients. This study investigated the incidence of UGI malignancies diagnosed within 3 years post-colonoscopy after a positive iFOBT. Retrospective analysis of iFOBT-positive patients aged 50-75 years who underwent a colonoscopy at a single institution. All patients with a diagnosis of UGI cancer within 3 years post-colonoscopy were identified by linking with the Queensland Cancer Register. This was used to compare to the geographical population aged 50-74 years based on the Australian Bureau of Statistics and Queensland Cancer Council data. From 1748 eligible participants, 0.23% (95% confidence interval [CI] 0.06-0.58) were diagnosed with UGI cancer within 3 years post-colonoscopy. This indicates an esophageal cancers rate of 114.42 per 100 000 (95% CI 100.56-298.28) and gastric cancer rate of 57.21 per 100 000 (95% CI 55.76-261.12). Of the patients with a UGI cancer, 75% would have had an unexplained iFOBT. Annual incidence for the same geographic region, ages, and period for the combined esophageal and gastric cancer was 36.08 per 100 000 (95% CI 32.87-39.52). Among individuals with a positive iFOBT in a bowel cancer screening program, the rates of gastric and esophageal cancers were 2.7 and 7.5 times higher than the general population. Adding gastroscopy to a colonoscopy for iFOBT-positive patients in cancer surveillance programs may be justifiable.