An analysis of breast cancer diagnosis data from nearly 6,000 women in Michigan suggests that mammography and self-breast exams remain important tools for detecting breast cancer, even among women aged 40 to 49 for whom routine mammography has been questioned by the U.S. Preventive Services Task Force (USPSTF).

Researchers found that women under the age of 50 who have breast cancer were more likely to be diagnosed based on a palpable mass (detectable by feel) rather than through mammography.

Those women diagnosed because of a palpable mass had a more advanced stage of cancer and were more likely to undergo mastectomy as opposed to breast conservation surgery.

Using a statewide breast cancer registry compiled from 14 institutions through the Michigan Breast Oncology Quality Initiative, Jamie Caughran, MD, Medical Director of the Comprehensive Breast Center at the Lacks Cancer Center in Grand Rapids, Michigan, and her research team examined data on breast cancer diagnosis and treatment gathered on 5,903 women between 2006 and 2009 to determine how the 2009 USPSTF breast cancer screening recommendations might affect future breast cancer detection, particularly in women age 40 to 49.

The study examined data on the method of detection, cancer stage, age at detection, treatment type and patient demographics.

In 2009, the USPSTF recommended that mammograms should only be conducted biennially after 50 years of age, and those women aged 40 to 49 should not be offered routine mammography but should discuss the risks and benefits with their physicians. The recommendations also discouraged teaching breast self-examinations, citing a high number of benign biopsies performed after a palpable breast mass is found.

The previous recommendations stated that women aged 40 to 49 should undergo routine mammography every year.

The new recommendations were controversial because in many cases they were in conflict with more established approaches, which included annual screening mammograms for women between ages 40 and 49, and encouraged regular self-exams.In their review, the investigators in this study found that overall, 65.5 percent of breast cancers were detected by mammography, 29.8 percent were detected by palpation and 4.7 percent by other methods.

The majority of women whose tumours were detected by mammography (3,869) were over 50 (81 percent). Of women whose tumours were found by palpation (1,759), 40 percent were under 50. In women under 50, cancers were detected by mammography in 48.3 percent of women compared to 46.1 percent detected by palpation.

Women with palpable tumours had more advanced cancers; 50 percent and 17 percent were diagnosed at stage II and III, respectively, compared to 18 percent and 4 percent found through mammography. As a result, the researchers found that patients whose tumours were detected through palpation were more likely to undergo mastectomy (46 percent) than those found by mammography (27 percent).

Women whose tumours were diagnosed by palpation were also more likely to undergo chemotherapy (22.7 percent) than those diagnosed by mammography (15.7 percent).

"While there has been ongoing debate about when and how breast cancer screening should occur, this study validates that women who undergo regular mammography screening present at earlier stages and often require less aggressive treatment than those who do not.

This is true for women older than 50 years, as well as women aged 40 to 49 years for whom routine mammography is questioned by the USPSTF," said Dr. Caughran. "In addition, women of all ages presented with palpable tumors, highlighting the use of self-breast exam as an important public health measure."

Source: ASCO