Screening for cancers has resulted in earlier diagnoses and a decrease in mortality, new research from the National Cancer Registry Ireland (NCRI) has shown
The report, which examined trends in breast, cervical and colorectal cancer, details for the first time the positive impact of screening services.
Breast, cervical and colorectal cancer 1994-2019: National trends for cancers with population-based screening programmes in Ireland found that, for all three cancers, incidence rates fell significantly. Cervical cancer cases showed the biggest decreasing trend at 2.8 per cent per year since 2009 – one year after CervicalCheck was introduced – reversing an upward trajectory of cases experienced in Ireland from 1999 to 2009.
Rates of colorectal cancer have seen a downward trend of 2.5 per cent per year since the introduction of BowelScreen in 2012. In contrast, recent incidence trends for breast cancer have shown an annual increase of 1.7 per cent since 2014, but are more complex, with BreastCheck having begun nationally in 2007 after a lengthy regional rollout, and age eligibility for the service increasing from 50-64 to 50-69 years from 2015.
While, almost a third of cervical cancer cases and a quarter of female breast cancer cases diagnosed during 2017-2019 were detected as a result of screening, just six per cent of colorectal cancers were screen detected.
Cancers found through screening were, on average, detected at a substantially earlier stage than other cases diagnosed at the same ages. The impact of screening is more prominent when comparing cases between those within the age eligibility for the screening service, and those outside the age group. For example, the proportion of cervical cancer cases diagnosed at stage 1 or 2 is 88 per cent among women in the screening age group, compared to 52 per cent in the non-screening group.
In the case of colorectal cancer, of cases detected through screening, 64 per cent of all male diagnoses and 62 per cent of female diagnoses were stage 1 or 2. This contrasts with 37 per cent of male cases and 39 per cent of female cases being early-stage among those diagnosed outside of the 60-69 year age group that is eligible for BowelScreen.
The proportion of women diagnosed with stage 1 or 2 breast cancer is 93 per cent in women in the screened age group compared to 78 per cent in women under 50 and 75 per cent in women over 70 years of age.
Mortality rates have also substantially fallen. There has been a decreasing trend in mortality in cervical cancer patients of an average of 1.1 per cent per year over the 1994-2019 period. Colorectal cancer showed a decreasing mortality trend of 3.7 per cent per annum over the same period, while breast cancer had a falling mortality rate of approximately 1.8 per cent annually.
While improvements in treatment and care have no doubt contributed significantly to falling death rates, decreases in the age-groups targeted for screening have been more substantial than the overall decreases for all three cancers.
Director of the NCRI, Professor Deirdre Murray, said: “Internationally, there is clear evidence that programmatic cancer screening improves cancer outcomes and saves lives. This report demonstrates that the trends in Ireland are consistent with these international findings which is reassuring for service users, providers and policy makers.”
Ahead of World Cancer Research Day tomorrow, the ten-year established charity Breakthrough Cancer Research has announced an additional €2 million in research funding to find new treatments and early diagnosis for Ireland’s seven deadliest cancers – lung, pancreatic, oesophageal, ovarian, liver, stomach and brain. They will also now allocate 80% of their annual funding to these diseases, which cause almost half of cancer deaths in Ireland every year. Incidents are expected to double in the next 30 years.