In 1987, first lady Nancy Reagan had surgery for early-stage cancer in her left breast. The tumor was just 7 millimeters in diameter, the smallest size malignancy doctors were able to detect through mammography at that time.

Since then, mammography has become much more reliable for identifying early-stage breast cancers — thanks in large part to the move 15 years ago from film to digital mammography.

One recent study of 11.3 million breast cancer screenings in the U.K. found digital mammograms improved breast cancer detection by 14 percent. The biggest advances were seen in detecting early-stage invasive cancers.

However, false positives are an issue: X-ray mammography comes with a 50 to 60 percent chance of a false positive after 10 yearly mammograms.

According to one study from the U.K., “false positive mammography results and additional imaging are common, particularly for younger women and those with risk factors.”

Here’s what you can do to get the most from your mammography:

• Find a center with digital mammography equipment. The ongoing TMIST study is comparing 2D- and 3D-digital mammography; it's thought, but not yet proved, that 3D may be advantageous for women with dense breast tissue.

• Get screened. To avoid unnecessary procedures and false positives, the U.S. Preventive Services Task Force recommends that women 50 to 74, at average risk for breast cancer, get a mammogram every two years. Earlier screening is appropriate on a case by case basis.

If you're given a positive reading, follow up pronto. If you're the beneficiary of accurate early detection (stage 0 or 1), your chances for beating it are near 100 percent.