(HealthDay News) — The likelihood of having breast cancer with a poor prognosis is increased for cancer diagnosed after a screening mammography with negative results, according to a research letter published online May 3 in JAMA Oncology.
Anne Marie McCarthy, Ph.D., from Massachusetts General Hospital in Boston, and colleagues analyzed data for 306,028 women aged 40 years and older with no earlier diagnosis of breast cancer who underwent mammography screening between 2011 and 2014.
The researchers found that the likelihood of a poor prognosis was increased for cases of cancer diagnosed after screening mammography with negative results versus those diagnosed after mammography with positive results (43.8 versus 26.9 percent). Among all women with negative mammography results, the odds of receiving a cancer diagnosis were increased for women with dense versus non-dense breasts (odds ratio, 2.07). In women who received a cancer diagnosis after negative mammography results, younger age correlated to having cancer with a poor prognosis (patients aged 40 to 49 versus patients aged 70 to 89 years: odds ratio, 3.52). Breast density and family history were not significantly associated with poor prognosis.
“Cancers that are present but not detected by screening mammography may be more likely to be associated with a good prognosis and occur among older women, whereas cancers that develop between screening examinations may be more likely to be rapidly growing cancers associated with a poor prognosis and occur among younger women,” the authors write.