Signs of disease could potentially have been missed in up to 1500 patients undergoing bowel cancer and upper GI screenings by a doctor in a Queensland public hospital, authorities say.

Concerns about the 1500 colonoscopy and endoscopy procedures were first raised in September 2018 after a bowel lesion was detected in a patient who had previously been cleared by the doctor.

About 450 patients who underwent the procedures at Redland Hospital, near Brisbane, between 2012 and 2018 had already had a repeat procedure, of whom 14 patients were found to have early interval cancer, missed cancer or unexpected significant pathology, according to Metro South Health, which manages the hospital.

“While there’s no suggestion that any direct harm was caused at the time of the original procedure, it appears this doctor may have missed early clinical signs of disease during some of these endoscopies and colonoscopies,” Metro South Health said earlier this month.