Press release from the Cancer Registry of Norway, May 30, 2013.
A new study from the Cancer Registry of Norway shows that the nationwide Norwegian mammographic screening programme reduces breast cancer mortality by 43 % among attendees compared to non-attendees. This is a much larger effect than expected. The results are based on a large epidemiological study using data from about 700 000 Norwegian women aged 50-69.
The study, published in Cancer, May 29, 2013, was performed by researchers at the Cancer Registry of Norway. These are the first results from the screening programme in Norway using individual level data to study the effects of the mammographic screening programme on breast cancer mortality. The researchers analysed breast cancer mortality among almost 700 000 women aged 50 – 69 who were invited to the programme during the period 1996 – 2009. The study compared mortality among attendees and non-attendees.
Breast cancer mortality nearly reduced by half among attendees
The study shows that breast cancer mortality was 43 % lower among those who attended the programme, compared to the non-attendees.
The mortality reduction is larger than what has been found in previous studies from Norway, but the results are consistent with results from recent international publications, says first author and senior researcher at the Cancer Registry of Norway, Dr Solveig Hofvind.
- It is important to be aware of the long follow-up time required from the start-up of a screening programme until effects can be observed. This is one of the reasons why our findings are stronger than previous studies. The use of individual level data in this study is another reason why the results in this study are more reliable than previous studies, Dr. Hofvind explains.
All women in Norway aged 50 – 69 are invited every other year to the Norwegian Breast Cancer Screening Programme, and about 75 % choose to participate. A rough estimate shows that a 43 % reduction in breast cancer mortality among attendees in the program corresponds to a reduction of more than 100 breast cancer deaths per year in a country with about 2.5 million female inhabitants. This study shows that the effect of attending the screening programme is indisputable, says Dr Hofvind.
- These results will be important in the governmental evaluation of the Norwegian screening programme, says Dr. Giske Ursin, Director of the Cancer Registry of Norway and co-author of the study. In Dr. Ursin’s opinion, these new results ought to motivate women to attend the programme.