Controversial breast cancer screening methods in elderly women
Dr Jacques Fracheboud - Erasmus Medical Center, Rotterdam, Netherlands
Breast cancer screening has always been a contentious issue in so many ways but you’ve been looking at one of the controversial areas – whether you screen women over 70. Can you tell me what you did because you’ve got a huge study in the Netherlands looking at this, what was it that you did?
In this study we compared the screening performance, mammography screening performance, between women from 50-69 and women from 70-75 because, in fact, our programme is the first national programme that’s started to invite women up to 75 years. The controversial issue was, and still is, that there is no trial evidence that screening, mammography screening, might be efficacious in this age group from 70-75.
Now, the data you’ve got is from 14 million screens so it should be quite strong evidence. What did you get out of this?
What we found in this study is indeed a better screening performance in older women but that is not astonishing because we expected that. Elderly women have more fatty breasts and that makes it easier to detect cancers. The risk of this is that negative side effects of mammography screening such as over-diagnosed cancers could be a consequence of screening in elderly women.
So you found overall, then, that screening is justified for the 70-75 age group did you?
Yes, we did and this is recently confirmed by IARC in the new Handbook of Cancer Prevention for Breast Cancer Screening that has to be published one of these days. They think that there is sufficient evidence for effectiveness of screening in women from 70-74 years.
What about screening for women between 49 and 69 years of age, how much did you confirm that that brings a benefit?
Not with this study but our department did several studies on the impact on breast cancer mortality and there we found a clearly related breast cancer mortality reduction, clearly related to the introduction of the mammographic screening programme.
That’s very good to know. You’ve therefore justified screening right up to the age of 75, what about beyond the age 75, what data do you have there?
We have no data but we would not recommend to screen beyond 75 years at the moment because the risk of negative side effects will become larger and the balance between harms and benefits will become less positive.
Over-diagnosis is an issue, what are the hazards of over-diagnosis? What do you come up against?
What we found is that 10%, approximately, in our programme of screening detected breast cancers might be over-diagnosed. But there’s a lot of debate on this issue because several studies found much larger proportions of over-diagnosed cancer. Also there were also studies that found a very, very limited proportion of over-diagnosed cancers. At the moment some reviews show that approximately 10-15% of screening detected breast cancers are over-diagnosed and that is a reasonable estimation.
With mammography screening one of the balances you have to make is between the cost of screening and the way that money could have been spent otherwise, perhaps on treatment. Do you have any information on that?
No specific information but, of course, this is a more political discussion so just what are your priorities. We think, in the Netherlands, that the programme costs annually approximately €65 million, that this is still justified.
You’re not having to economise on treatments which might also extend life.
No, that’s not threatening medical care so it’s completely outside of medical care. Of course the screening itself does not impact enough, you need what’s coming after the diagnostic, you need treatment and if the treatment is not optimal then it’s not sure if you should then screen. So, of course, it’s something that’s related to each other.
What, then, are the bottom line messages coming out of your study on the effectiveness of mammographic screening, particularly looking at older women?
We think that screening of women of 70-75 years has an impact on breast cancer mortality in terms of reduction of the breast cancer mortality. We think even that this effect is not marginal. But at the moment we do not yet have estimates of how large this effect is so this is still an issue of ongoing studies.
So the bottom line message to cancer doctors for implementing this right now is what, very briefly?
We would recommend screening women up to 75 years but of course you need a high quality programme and a clear design of how do we screen and how you can warrant also treatment of what’s coming after the screening.