Waiting times for colonoscopy and colorectal cancer diagnosis

To evaluate whether prolonged waiting times for colonoscopy in public hospitals could result in delayed diagnosis of colorectal carcinoma.

Analysis of all outpatient colonoscopies performed at a Western Australian tertiary teaching hospital, 1 November 2003 - 31 October 2005. Colonoscopy data, corresponding pathological findings, category of urgency at referral for colonoscopy, and waiting time for colonoscopy were obtained. Patients were coded as having cancer if it was diagnosed by colonoscopy or if colonoscopy identified a lesion subsequently diagnosed as cancer.

Colorectal carcinoma detected by outpatient colonoscopy and length of waiting time to colonoscopy.

1632 outpatient colonoscopies were recorded. Category I patients received a colonoscopy within the recommended 30 days from referral. Median waiting times for Category II and Category III patients exceeded recommendations (observed, 113 days and 258 days; recommended, within 90 days and 180 days, respectively), although the number of cancers detected was low (2.4% and 0.6% of referrals, respectively in each category). Early- and late-stage cancers had similar median waiting times from referral to diagnosis. Age over 65 years and the blood-loss indications - a positive faecal occult blood test or iron deficiency/anaemia - were predictors of an increased risk of carcinoma at colonoscopy.

Waiting time for colonoscopy was not associated with an increase in the proportion of late-stage cancers diagnosed. Age over 65 years and evidence of blood loss increased the likelihood of a cancer diagnosis.