Mammograms have long been the preferred method for early detection of breast cancer and strongly recommended by doctors for women in certain age groups. A new study published in the New England Journal of Medicine, however, questions the effectiveness of mammograms in women over 50 years of age.

The study, summarized in a CNN article, examined over 40,000 cases of women with breast cancer from Norway, which began a breast cancer screening program in 1996 in selected counties. The report reviewed data on breast cancer cases from 1996 to 2005 in counties that had a screening program and compared that data with counties that did not. The goal of the study was to see if screening had any impact on the mortality rates for breast cancer patients.

Comparing the two groups, the study found that the rate of death for the screening the group was reduced, but that screening alone accounted for only one-third of the reduction. Mortality rates in the non-screening group decreased 18 percent from the prior decade, presumably due to increased breast cancer awareness, better treatment, and improved diagnostic tools.

Early Detection and Misdiagnosis

Though breast cancer can strike any person at any time, the risk of being diagnosed with cancer increases with age. According to the National Cancer Institute (NCI), women over 50 have a 2.38 percent chance of being diagnosed, while women over 60 are most at risk with a 3.45 percent chance.

The NCI recommends that women over age 40 get a mammogram every one to two years. These mammograms — often referred to as screening mammograms — have long been advised as an effective way to detect and treat breast cancer early.

Screening mammograms, however, do not prevent misdiagnosis. Despite the advances in imaging technology, the NCI estimates that screening mammograms miss up to 20 percent of the breast cancers that are present at the screening. A 2006 study by the Susan G. Komen Foundation estimated that up to 90,000 people could be living with their cancer misdiagnosed.

Though giving a patient a clean bill of health when they have an early form of cancer is the most serious type of misdiagnosis, pathologists often diagnose cancer in patients when none is present. According to a report in The New York Times, nearly 17 percent of cases involving ductal carcinoma in situ, typically the first stage of breast cancer, are misdiagnosed. This can lead to overtreatment, unnecessary mastectomies and the fear and anxiety of living with cancer.

Another study published by Dutch researchers indicates that population-based mammography programs lead to earlier cancer diagnoses and save lives. Indeed, despite arguments against mammography programs, researchers believe they are key to avoiding delayed breast cancer diagnoses and misdiagnoses.

Critics of breast cancer screening programs argue that they subject many patients to unnecessary testing, overtreatment and worry, all for little effect: modern treatments for breast cancer are so effective that the chances of surviving it are as high as if the condition were detected early in a screening program. Dutch researchers discovered, however, that screening patients for breast cancer every two years reduced deaths significantly: when combined with adjuvant therapy – usually chemotherapy, hormonal therapy, radiation therapy, or drug therapy – screening programs reduced the incidence of death from breast cancer by 27.4 percent.

Thanks to modern treatment techniques, a diagnosis of breast cancer is no longer a death sentence. No matter the treatment, however, avoiding a delayed diagnosis is still key to ensuring a patient’s chances for a positive prognosis.