Mammography-detected breast cancer in 40-49 year-olds has better prognosis

Based on a study of nearly 2,000 breast cancer patients, researchers at the Swedish Cancer Institute in Seattle say that, in women between the ages of 40 and 49, breast cancers detected by mammography have a better prognosis. The study appears in the March issue of Radiology.

"In our study, women aged 40 to 49 whose breast cancer was detected by mammography were easier to treat and had less recurring disease and mortality, because their cancer was found at an earlier stage," said Judith A. Malmgren, Ph.D., president of HealthStat Consulting, Inc.

Dr. Malmgren and a team of researchers reviewed breast cancer patient data from a dedicated registry at the Swedish Cancer Institute's community cancer center. The researchers analyzed data on 1,977 breast cancer patients between the ages of 40 and 49 who were treated between 1990 and 2008. The researchers looked at method of diagnosis (detected by mammography, patient or physician), stage at diagnosis (0-IV, confirmed by biopsy), treatment, and annual follow-up information, including recurrence of disease.

"Our goal was to assess the differences between mammography and non-mammography detected breast cancer, to determine whether earlier detection confers a treatment and morbidity advantage because the disease is found at an earlier stage," Dr. Malmgren said.

The data analysis revealed a significant increase in the percentage of mammography-detected breast cancer over the 18-year period: from 28 percent in 1990 to 58 percent in 2008. Over the same period, patient- and physician-detected breast cancer declined from 73 percent of all cases in 1990 to 42 percent in 2008.

Breast cancer is the second most lethal cancer in women. (Lung cancer is the leading cancer killer in women.) The good news is that early detection and new treatments have improved survival rates. The 5-year survival rate for women diagnosed with cancer is 80%. About 88% of women diagnosed with breast cancer will survive at least 10 years. Unfortunately, women in lower social and economic groups still have significantly lower survival rates than women in higher groups.

Several factors are used to determine the risk for recurrence and the likelihood of successful treatment. They include:

Location of the tumor and how far it has spread
Whether the tumor is hormone receptor-positive or -negative
Tumor markers
Gene expression
Tumor size and shape
Rate of cell division

The good news is that women are living longer with breast cancer. Due to better treatment options, breast cancer mortality rates declined by about 25% since 1990. However, survivors must live with the uncertainties of possible recurrent cancer and some risk for complications from the treatment itself.