An alarming number of younger women are being diagnosed with breast cancer, a new study warns. And many of the cases are invasive, meaning the cancer has spread beyond the breast.Researchers reviewed data from seven outpatient facilities in the New York region over an 11-year period.They identified nearly 18-hundred breast cancers in about 13-hundred women ages 18 to 49. The majority were detected on diagnostic evaluation; the others with screening.Year after year, women under 50 made up one out of every four cancers found, according to the results.More than 80% of the cancers were found to be invasive. And many of them were aggressive types.One study author says, “This research shows that a significant proportion of cancers are diagnosed in women under 40, a group for whom there are no screening guidelines at this time.”She says, “We can’t rely only on age alone to decide who should be screened,”and recommends clinicians and patients pay closer attention to risk factors, including changes in the breasts, family history, genetic mutations and racial and ethnic background. SOURCE: These findings were presented at the annual meeting of the Radiological Society of North America..Sign up for our weekly HealthDay newsletter