As previously mentioned at Croakey, the latest Medical Journal of Australia has published a study examining the impact of the national bowel cancer screening program. It suggests that the program may be more likely to benefit the better off.
Professor Mark Harris, from the UNSW Centre for Primary Health Care and Equity, says there is enough evidence, from this and other studies, to suggest that efforts are needed to ensure lower SES groups participate in screening and are able to access related procedures.
“The findings of the study in the MJA are interesting but we need to keep three things in mind:
Firstly there is not necessarily evidence of a social gradient in colorectal cancer incidence (i.e. a sliding scale of incidence getting lower as income increases). There was, however, a social gradient in male bowel cancer mortality in 2000. The poorest 60% of the population had 1.2 to 1.3 times the colorectal cancer mortality of the richest 20% in men, but not women, aged 25-64 years (AIHW 1998-2000). This suggests that we may already have had a problem even before the National Bowel Cancer screening program.
The second consideration is that though the study shows that there may be a social gradient in screening – with a bigger proportion of cancers detected by screening in high SES groups (25/605= 4.1%) compared with lower SES groups (7/443=1.6%) – the numbers involved are small.
Thirdly, the pilot CRC screening study showed that there was also a social gradient in the proportion of patients who tested positive who then subsequently had a colonoscopy. Thus the pilot predicted that there may be a social gradient both in uptake of screening and subsequent colonoscopy of positive cases. This was not due to lower rates of presentation at GPs (as rates of presentation at GPs were higher in lower SES groups).
Thus on balance we can infer that there is a social gradient in screening (both FOBT and colonoscopy). This is all consistent with studies overseas that have shown that more educated and richer people respond to initiations to faecal occult blood testing (FOBT) screening (McCaffery K et al J Med Screen 2002; 9: 104-8).
We need to improve the uptake of screening in low SES groups
This may be done by improving the invitation. The current letter is formal and complex and is unlikely to motivate poorly educated patients. The content should be simpler and based on health promotion theory.
We should also involve GPs more actively, for example by sending mailed invitations from practices to encourage patients, especially males in poorer areas. Invitations should be tailored to encourage different groups of patients (Myers RE Prev Med 1990; 19: 502-14).
We need to address barriers to colonoscopy amongst positive patients
Significant socioeconomic barriers to colonoscopy clearly remain. Despite poorer patients being more likely to see their GP following screening, they are less likely to have a colonoscopy than richer patients.”