M.R.I.s Can Better Detect Cancer in Women With Dense Breasts, Study Finds

M.R.I.s Can Better Detect Cancer in Women With Dense Breasts, Study Finds

A large study found that M.R.I.s detected tumors missed by mammograms, cutting interval cancers by half or more.


Just under half of women over the age of 40 have dense breasts, which means their breasts have more connective and fibrous tissue than usual, and relatively less fat.


Philippe Garo/Science Source

By Roni Caryn Rabin

  • Nov. 27, 2019

Many women who have mammograms get normal results that come with a caveat: They are told they have dense breast tissue, which can make their scans harder to read and could leave cancer undetected.

Sometimes those patients are advised to follow up by getting ultrasounds or magnetic resonance imaging (M.R.I.) scans, but for many, it is unclear what their next step should be.

Now, a new study provides strong evidence that supplemental M.R.I.s are more effective in finding tumors in these women than mammograms alone.

The study, of more than 40,000 women with extremely dense breasts in the Netherlands, found that those who had mammograms followed by M.R.I.s, had more tumors detected than with mammography alone. The research also found that those who had M.R.I.s were less likely to find a palpable cancerous lump in between routine screenings; by the time tumors are big enough to be felt, they tend to be more advanced.

The study, the first large randomized controlled trial of supplemental M.R