An analysis of breast cancer diagnosis data from nearly 6,000 women in Michigan suggested that mammography and self-breast exams remain important tools for detecting breast cancer, even among women ages 40 to 49 for whom routine mammography has been questioned by the U.S. Preventive Services Task Force (USPSTF), according to the abstract of a study presented at the annual Breast Cancer Symposium held in San Francisco, Sept. 8-10.
The researchers found that women under the age of 50 who have breast cancer were more likely to be diagnosed based on a palpable mass 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, Mich., and colleagues 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 ages 40 to 49. The study examined data on the method of detection, cancer stage, age at detection, treatment type and patient demographics.
In their review, the investigators 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 tumors were detected by mammography (3,869) were over age 50. Among the 1,759 women whose tumors were found by palpation, 40 percent were under age 50. In women under age 50, cancers were detected by mammography in 48.3 percent of women compared to 46.1 percent detected by palpation.
Women with palpable tumors 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 tumors were detected through palpation were more likely to undergo mastectomy (46 percent) than those found by mammography (27 percent). Women whose tumors 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,” Caughran said in a statement. “In addition, women of all ages presented with palpable tumors, highlighting the use of self-breast exam as an important public health measure.”
For more about screening mammography, read the September Health Imaging & IT cover story “USPSTF Guidelines Two Years Later: The Fallout Continues.”