Screening programmes are contributing to reduced incidence and better patient outcomes for three common cancers, according to a report from the National Cancer Registry (NCR).
The latest report looks at trends for breast, cervical and colorectal cancer — which are all screened for nationally — between 1994 and 2019.
It finds favourable trends in incidence, the stage at which cancers are detected, survival rates and mortality “consistent with improvements in early detection and outcomes, with clear evidence for additional or more recent benefits of screening”.
Almost one-third of cervical cancer cases and one-quarter of female breast cancer cases diagnosed during 2017-2019 were detected as a result of screening. Just 6 per cent of colorectal cancers were screen-detected.
According to the report, the introduction of a population-based screening programme would be expected to reduce the incidence of cervical and colorectal cancers, but not breast cancer. The NCR says incidence trends in its report “are consistent with this”.
Cancer cases detected through the screening programmes were, on average, detected at a substantially earlier stage than other cases diagnosed at the same ages. Survival has improved for all three cancers, with the biggest improvements seen in the age groups targeted by the national screening programmes.
Death rates for all three cancers have fallen significantly. Decreases in the age groups targeted for screening were greater than the overall reductions for all three cancers.
General improvements
A fall in mortality rates, which started prior to the introduction of screening programmes, is attributed to general improvements in cancer care and treatment rather than being considered a consequence of screening alone.
“Internationally, there is clear evidence that programmatic cancer screening improves cancer outcomes and saves lives,” according to NCR director Prof Deirdre Murray. “This report demonstrates that the trends in Ireland are consistent with these international findings which are reassuring for service users, providers and policymakers.”
“With the publication of this report and the detailed analysis of the various screened populations we can now confidently say that a portion of that improvement is directly attributable to CervicalCheck, BowelScreen and BreastCheck,” said Fiona Murphy, director of the National Screening Service. “The public can be reassured that our screening programmes are effective.”
The report finds a significant increase in the proportion of stage IV cervical cancer tumours in women of screening age. “There are a number of possible explanations for this increase, the most likely of which is the occurrence of advanced disease in women who do not participate (or regularly participate) in cervical screening.”
In addition, screening is not effective for some subtypes of cervical cancer, such as adenocarcinomas.
