Although mammograms remain the gold standard for detecting breast cancer, the screening procedure may not be the most effective tool to detect a second breast cancer occurrence in women with a history of the condition, according to a study published in the Journal of the American Medical Association and reported by HealthDay News.

For the study, researchers evaluated 12 years of data from almost 60,000 mammogram screenings. Of those mammograms, 19,078 were of women with early stage breast cancer. In addition, scientists looked at an equal number of mammograms from 55,315 women who never had breast cancer. (Researchers matched participants for age, breast density and risk factor of the disease.)

Findings showed that false positives and interval cancers (cancers found between screenings) were higher in women with a history of breast cancer and that mammogram screenings missed tumors 11 percent more often in survivors. Also, women with a history of breast cancer were more likely to be called back for additional tests (18 percent compared to 8.3 percent of women with no cancer history).

But these test shortcomings shouldn’t stop women with a history of breast cancer from getting their annual screening mammogram, said Diana Miglioretti, senior investigator at Group Health Research Institute in Seattle and a coauthor of the new research.

“But [the women] also need to remain vigilant because they are at increased risk of cancers not detected on mammography that show up between mammograms,” Miglioretti advised.

So what’s the good news? Of the undetected cancerous tumors missed by cancer survivors’ screening mammograms, most of them are early stage, Miglioretti said. That’s why women must continue getting screened after their breast cancer treatment, and why they must report any symptoms to their doctor immediately.

Click here to learn more about how to lower your breast cancer risk.