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April 22 - Mammograms Benefit Women Into Their 70s

New research from The Netherlands suggests that mammograms benefit women up to the age of 75 by cutting deaths. The researchers claim this is the first study to show demonstrate this information because until the late 1990s, few women over the age of 70 were undergoing mammogram screening.

The study is the work of Jacques Fracheboud, MD, a senior researcher at the Erasmus Medical Center in Rotterdam, and colleagues, who recently presented their findings at the Sixth European Breast Cancer Conference in Berlin.

In many countries, breast screening programs stop at the age of 70. However, in 1998, The Netherlands extended the cut off age to 75. Fracheboud and his colleagues examined data on mammograms performed since the age limit was extended. This included over 860,000 women aged 70 to 75 living in The Netherlands. They found the following:

* 7.37 million screening exams took place between 1998 and 2006.

* Of these, 862,655 were for women aged 70 to 75.

* 81.2% of women aged 50 to 69 and 71.9% aged 70 to 75 took part in the screening program.

* The participation rate for the older women increased significantly during this period, rising from 62.5% in 1998 to 77.6% in 2006.

* 12.8 per 1,000 of the 50- to 69-year-old women screened were referred for further diagnosis and in these, breast cancer was detected in 4.5 per 1,000, leading to a positive predictive value (percent of abnormal mammograms later confirmed as cancer) of 36%.

* 16.4 per 1,000 of the 70- to 75-year-old women screened were referred for further diagnosis and in these, the breast cancer detection was 7.8 per 1,000, giving a positive predictive value of 47%.

* From 2003, five years after screening was extended, deaths due to breast cancer among women aged 75 to 79 declinded steadily.

* By 2006, the breast cancer death rate among 75- to 79-year-old women was 29.5% lower than the average for 1986-1997 (a period during which breast cancer deaths among this age group had remained stable).

* The breast cancer death rate for women aged 75 to 79 dropped from 166 per 100,000 during 1986-1997 to 177 per 100,000 in 2006.

The investigators analysed mortality for the 75 to 79 age span because it takes several years for the effects of screening to come through.

"That means that women aged 70 to 75 at the time that screening was extended to this age group have become five years older, and the reduction in breast cancer mortality shows that the screening has started to have a statistically significant effect," Fracheboud said during a press meeting.

Fracheboud also explained that the difference in positive predictive value between the younger and the older group showed that it was "easier to find breast cancer in older women due to their breast tissue being less dense.

"But it is not necessarily an argument for continuing screening beyond 75 because many tumours found at this stage are slow growing and may never reach the stage of causing a problem," he added.

The study suggests that screening for women aged 70 to 75 has a strong effect on breast cancer death rates, said Fracheboud, and "that it is effective and appropriate up to 75 years".

The cost per mammogram is the same for this age group as for younger women, said Fracheboud. When the plans were being discussed to extend the age limit, it was feared the cost of mammogram screening for older women would be greater because fewer would take it up and screening might take longer because of lower mobility for example. However, the figures show this is not the case, and that participation among older women even went up.

The investigators concluded that 75 is "an appropriate upper age limit and saves lives without causing substantial harm by subjecting older women to over-diagnosis and over-treatment".

Source: Catherine Paddock, PhD, Medical News Today

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