Mammogram Risks for Age 70+ Outweigh Benefits
Researchers from Leiden University Medical Centre in The Netherlands report that their study suggests that breast cancer screening programs for older women results in a large proportion of women being over-treated, and at risk from the harmful effects of such treatment, because these women were more likely to die from other causes than from any tumors detected in the early stages of growth. The team presented the findings the European Breast Cancer Conference in Glascow UK.
A release from the conference quotes Dr Gerrit-Jan Liefers MD, PhD as saying: “For a screening program to be effective, one would expect that the incidence of early stage breast cancer would increase while the incidence of advanced stage cancer would decrease because any cancer would have been detected at an earlier stage. However, when we investigated the effect of extending the screening program in The Netherlands from age 69 to 75, we found that it had not led to a decrease in the rate of advanced breast cancers detected, while the numbers of early stage tumors strongly increased. This implies that the effect of screening in elderly women is limited and leads to a large proportion of over-diagnosis.”
The Netherlands breast cancer screening program was extended in 1998 to include women up to the age of 75. Dr. Liefers and his colleagues looked at results from The Netherlands Cancer Registry for 25,414 women aged between 70-75 who were diagnosed with breast cancer between 1995 and 2011.
They found that after the extension of the upper age limit, the incidence of early stage breast cancer (stages 0, I and II) increased significantly from 260 cases per 100,000 women in 1995 to up to 382 cases per 100,000 women in 2011. Meanwhile, the number of advanced stage breast cancers (stages III and IV) did not change significantly. In 1995 there were 59 cases detected per 100,000 women compared to 53 per 100,000 in 2011.
“In these more elderly women, other, competing causes of death are of major importance. Although surgery that is confined to removing just a small tumor (loco-regional treatment) is generally considered to be low risk, we have previously demonstrated that the proportion of patients who develop postoperative complications strongly increases with age and increasing numbers of other diseases or conditions that they may have. Furthermore, older patients are at risk from the adverse side effects of adjuvant treatments such as hormone therapy or chemotherapy. Therefore, screening could result in over-treatment and consequently in decreased quality of life and ability to function in older breast cancer patients, without lowering the incidence of advanced stage breast cancer or deaths from the disease,” Dr. Liefers said. “In upcoming decades, an increasing proportion of breast cancer patients will be elderly and, therefore, the additional costs of treating over-diagnosed tumours could result in a tremendous increase in health expenditure, while no actual health benefits are being obtained. Since breast cancer treatment in older patients is mostly not evidence-based due to poor inclusion of older patients in clinical trials, we propose that studies investigating breast cancer treatment are much more important than breast cancer screening in this population and should be prioritized.