Sept. 15, 2014 -- Including women ages 70 and over in a national breast cancer screening program does not lead to a large decline in advanced cases, and it may have certain consequences, a Dutch study says.
In the Netherlands, the upper age limit for getting screened was extended from 69 to 75 in 1998. That allowed researchers from the Leiden University Medical Centre to look at the impact on diagnoses of late-stage cancers in this upper age group.
They tracked 25,414 new cases of breast cancer diagnosed among Dutch women in that age range from 1995 to 2011.
Spotting More Early Cases
The researchers found that new cases of early-stage breast cancer among 70- to 75-year-olds rose sharply after national screening was introduced, from 248.7 to 362.9 per 100,000 women.
Although there was a drop in the numbers of new cases of advanced breast cancer, the overall decrease was small, dropping from 58.6 before to 51.8 cases per 100,000 women, after the national screening program was introduced.
Among a smaller group of women aged 76 to 80, who were also included in the study for comparison, as they were not screened, new cases of early stage disease fell slightly, but the numbers of new cases of advanced breast cancer did not change significantly.
For every advanced stage cancer detected by screening among 70- to 75-year-olds, the researchers calculated that around 20 extra early-stage cancers were picked up, and therefore "over-diagnosed."
They say this over-diagnosis is important, because over-treatment can undermine quality of life, partly because older people are more vulnerable to the side effects of breast cancer treatment.
Current recommendations in the United States are that all women 50 and older get screened for breast cancer with mammograms, although recommendations vary on whether they should get the test every year or every 2 years. That depends on a woman’s risk of breast cancer and her wishes.
All women between the ages of 40 and 49 should talk to their doctor about when they should start getting mammograms. Some groups recommend starting yearly mammograms at age 40, while others think waiting is better.
Recommendations on when to stop getting screened also vary. While the American Cancer Society says to continue mammograms as long as the woman is healthy, the U.S. Preventive Services Task Force says there’s not enough proof to say what women 75 and older should do.
The authors of the new study, which is published on bmj.com, recommend that routine breast cancer screening among women 70 and over should not be done on a large scale until the results are in from a large trial by Cancer Research UK.
The results of this trial are not expected for years.
In the meantime, they say, "the harms and benefits of screening should be weighed on a personalised basis, taking remaining life expectancy, breast cancer risk, functional status, and patients’ preferences into account."
Commenting on the Dutch study in a statement, Caitlin Palframan, PhD, head of policy at Breakthrough Breast Cancer, says: "This study provides some useful insights, as women over 70 were not included in the original breast screening trials on which modern screening programs are based. It's very important we learn more about the benefits and risks for this particular age group before we decide whether to offer these women routine screening."