Despite having a high rate of bowel cancer, Otago has the lowest rate of publicly funded colonoscopies in the country and the numbers being declined colonoscopy have been increasing.
Information in the Southern Cancer Network's audit of 33 patient referrals to Dunedin Hospital's colonoscopy service shows that Otago had 37.73 colonoscopies per 10,000 people, compared with 76.89 nationally in the last financial year.
• Records found to be inconsistent
Two smaller boards, West Coast and Southland, have the highest numbers of colonoscopies per 10,000 - above 120.
Nelson-Marlborough is the closest to Otago's rate, with about 60 procedures per 10,000 people.
Canterbury's rate is above 80.
Colorectal cancer incidence rates for the years 2001-04 show Southland had the highest rate, followed closely by Otago, South Canterbury and the West Coast.
As well as its low rate of colonoscopies, the Otago board's rate for the number performed per colorectal cancer diagnoses was less than half the national average (10.8) at 5.1.
During the five years in which the 33 patients in the audit were referred, the service carried out about 2800 colonoscopies.
The report shows that in the period January-June last year, almost a third of colonoscopy referrals (31%) were being declined, compared with 14% in July-December 2004.
No analysis has been made of the reasons for referrals to be declined but the report says Ministry of Health information from other boards indicated most never, or rarely, declined colonoscopies.
"The increasing percentage decline rate within the ODHB requires further inquiry," the report said.
Only one other unspecified board had similar numbers of self-reported declined referrals.
Over the five-year period in Otago, these ranged from 132 to 285 a year.
The review team noted a review using a random sample of patients accessing colonoscopy services and comparative data looking at other boards with varying rates of colonoscopies would provide a more balanced view of usual practice at the board and in relation to other boards.
Some of the work being undertaken by the Southern Cancer Network's bowel cancer mapping project could provide some information.
This project is gathering information to identify gaps in the diagnosis, treatment, follow-up and surveillance of colorectal cancer in both public and private South Island services.
