Older women diagnosed with breast cancer years after their last mammogram,
and those who never had a mammogram, have an increased risk of dying from their
cancer, a new study suggests.
Researchers analysed data from about 8 600 women in the United States who
were diagnosed with breast cancer.
The investigators found that 23% of women who had their last mammogram five
or more years before being diagnosed with breast cancer had advanced cancer,
compared with 20% of those who had a mammogram six months to a year before their
This is a statistically significant difference that could affect large
numbers of women, according to the researchers.
The study also found that a longer interval between a mammogram and breast
cancer diagnosis was associated with an increased risk of dying from breast
cancer among women aged 75 and older.
In this age group, those who were diagnosed five or more years after their
last mammogram or had never had a mammogram were three times more likely to die
from breast cancer than those who had a mammogram six months to a year before
These associations were not found in younger women, according to the study
scheduled for presentation at the annual meeting of the American Association for
Cancer Research (AACR), taking place in Washington, DC.
"I am not sure why we are seeing these results particularly for older women.
Tumours of younger women were more likely to be a little more unfavourable
overall," Dr Michael Simon, leader of the breast multidisciplinary team at the
Barbara Ann Karmanos Cancer Institute in Detroit, said in an AACR news
"It is possible that the differences in the relationship between screening
interval and [death] in older versus younger women may be related to the more
aggressive nature of the tumours in younger women, which might obliterate the
effects of more screening. Other reasons may include differences in cancer
treatment, information that was not available for this [group] of women," Simon
The study did not prove a cause-and effect relationship between gaps in
mammograms and worse breast cancer results. Because it was presented at a
medical meeting, data and conclusions should be viewed as preliminary until
published in a peer-reviewed journal.
The US National Cancer Institute has more about mammograms.