Mammography Particularly Useful in Detecting Slow-Growing, Non-Aggressive Tumors

Breast cancer has a lower rate of recurrence when detected through screening mammography rather than other approaches, because screening mammography is especially likely to find slow-growing, non-aggressive tumors, a Yale study shows.

“The results suggest that many of the breast cancers found by mammography screening have excellent prognosis, not just because of early detection, but also because many of the cancers are relatively benign, requiring minimal therapy,” said Alvan R. Feinstein, M.D., of the Department of Internal Medicine at Yale School of Medicine and an author of the study published this month in the Archives of Internal Medicine.

The investigators reviewed the medical records of 233 patients who received their first breast cancer treatment in 1988. That was one of the first years in which mammography was both widely used for screening and had high technological quality in detecting very small tumors. The follow-up period for the patients extended for almost seven years.

The mammography screen-detected group represented 97, or 42 percent, of the 233 patients. On follow-up it was found that 95 percent of the mammography screen-detected group survived the breast cancer or had no recurrence, compared with 79 percent of patients whose tumors were detected by other approaches.

“This superiority resulted partly because 93 percent of the breast cancers detected with mammography screening were in the very early, good prognosis stages,” said Feinstein. “Of the 31 patients with early stage carcinoma, all of whom had disease-free survival, 77 percent were found by mammography screening.”

The other authors of the study were Sandra Y. Moody-Ayers, M.D., formerly a Robert Wood Johnson Clinical Scholar at Yale and currently assistant professor of medicine at the University of North Carolina, and Carolyn K. Wells, a lecturer in the Department of Internal Medicine at Yale School of Medicine.