One out of every 17 bowel cancer assessments in Australia from July 2012 to June 2013 detected an advanced adenoma (precancerous lesion), and a bowel cancer was detected in one out of every 32 assessments.
The National Bowel Cancer Screening Program (NBCSP) aims to reduce the morbidity and mortality from bowel cancer by actively recruiting and screening the target population for early detection or prevention of the disease.
The NBCSP has been running since August 2006, and this report focuses on measures of program performance for people invited to screen from July 2012 to June 2013 (those turning 50, 55 or 65).
How many 2012-13 invitees participated in the NBCSP?
About 33.5% of the 964,000 people invited from July 2012 to June 2013 returned a completed bowel cancer screening kit for analysis. This overall participation rate was slightly lower than that of the previous monitoring report (Table 1), and small decreases were evident in all 3 target age groups.
How many positive screening results were there?
About 23,500 participants (7.5%) who returned a valid screening test had a positive screening result. These people were encouraged to follow up this result by visiting their primary health-care practitioner (PHCP) for referral to further investigative testing (colonoscopy).
Seventy per cent of those with a positive screening result were recorded as having a colonoscopy at the time of this report.
How many bowel cancers and adenomas were detected?
One participant in every 32 who underwent a colonoscopy to follow up a positive screening result was diagnosed with a confirmed (52 participants) or suspected (352 participants) cancer, while advanced adenomas were found in a further 728 participants (1 in 17 colonoscopies) assessed. Adenomas are benign growths that have the potential to become cancerous, and their removal is likely to lower the risk of future bowel cancers in these patients.
Were there differences between subgroups participating in the NBCSP?
As in previous years, women were more likely to screen than men; conversely, men had higher rates of screen-detected bowel cancers, and overall bowel cancer incidence and mortality.
Aboriginal and Torres Strait Islander participants, participants who lived in Regional and Remote regions, and participants who lived in areas of lower socioeconomic status, had higher rates of positive screening results, yet lower rates of follow-up colonoscopies than other participants.