The director of surgery at the Royal Brisbane and Women's Hospital has told a Brisbane trial, Jayant Patel's operation on a patient in 2004 should have been done as a last resort.

Patel, 63, has pleaded not guilty in the District Court in Brisbane to causing grievous bodily harm to Ian Vowles, 66.

Patel, the former director of surgery at the Bundaberg Hospital, removed Mr Vowles' colon and rectum in Bundaberg in October 2004 after finding a polyp and diagnosing familial cancer.

The court heard the polyp was found to be benign.

The court also heard Mr Vowles had had two previous cases of colon cancer.

Dr Barry O'Loughlin performed corrective surgery on Mr Vowles in June, 2005.

Ken Fleming QC for Patel put it to Dr O'Loughlin that Patel's management of the patient was appropriate and did not amount to gross negligence.

Dr O'Loughlin said he did not agree.

He said even a diagnosis of familial cancer would not change his opinion that the patient should have been managed with regular screening.

Dr O'Loughlin said the removal of Mr Vowles' colon and rectum would not prevent cancer forming in other parts of his body.

Dr O'Loughlin agreed with the Crown that Patel's actions were considerably lower than those of a competent surgeon.