HealthDay News — More than two-thirds of breast cancer deaths occur in unscreened women or those with an interval of two years or more between mammograms, study findings indicate.
Women who had not undergone screening with mammogram accounted for 71% of breast cancer deaths during an 18-year period, Blake Cady, MD, of Massachusetts General Hospital in Boston, and colleagues reported in Cancer.
Median patient age was 49 years, compared with 72 for women who died of other causes, supporting the initiation of mammogram screening before the age of 50.
“Even with effective adjuvant therapies, the best method for women to avoid death from breast cancer is to participate in regular mammography screening,” the researchers wrote. “Regular screening increases the likelihood of detecting nonpalpable cancers, and annual screening further increases the likelihood relative to biennial screening.”
Although studies show detecting breast cancer early reduces the risk for fatal breast cancer, the optimal age for initiating mammograms, as well as intervals between screens, has been debated.
Current United States Preventive Services Task Force (USPSTF) recommendations state routine screening with mammography should begin at age 50 and be optional for younger women, and favor biennial over annual mammograms for average-risk women.
However, organizations including the American Cancer Society and the American College of Radiology continue to push for annual screening and the emphasize the importance of catching breast cancer early.
To better understand the survival benefit of mammography among women who have been screened, Cady and colleagues analyzed data from 7,301 patients with newly diagnosed breast cancer from 1991 to 1999. Patients were followed through 2007.
Demographics, mammography use, surgical and pathology reports, recurrence and death dates were evaluated. Medical records were used to characterize mammograms as screening or diagnostic based on absence or presence of breast signs or symptoms.
A total of 1,705 documented deaths from breast cancer (609 deaths) or other causes (905 deaths) occurred during the study period.
Screen-detected tumors accounted for 118 breast cancer deaths, 111 of which involved tumors that were detected after two screening mammograms that occurred no more than two years apart. “Interval cancers,” or tumors that occurred in women with at least one negative mammogram performed no more than two years previously, accounted for 60 deaths.
Comparatively, 395 breast cancer deaths involved unscreened women, and 36 occurred in “off-program” women — those with a history of mammography, but who had not been screened for more than two years.
Half of all breast cancer deaths occurred in women younger than 50 years and 69% before the age of 60, the researchers found. Consequently, 83% of all non-breast cancer related deaths occurred in women older than 60 years.
“To maximize mortality reduction and life-years gained, initiation of regular screening before age 50 years should be encouraged,” the researchers concluded.