"For example, MRI does not pick up microscopic calcifications, which are an indirect marker for breast cancer, so mammograms remain a very important tool."
Experts also say that the recommendation of MRI screening is not meant for those who are without any increased risk. One of the reasons is that the test still has a high error rate, which can lead to unnecessary biopsies.
"There is really no evidence that MRI improves cancer detection in the general population," said Schnall.
MRIs are also expensive, costing $2,000 or more. Mammograms, on the other hand, cost $100 to $150 on average.
While insurers generally follow government guidelines, the new ACS recommendations may prove influential in getting MRIs covered for high-risk patients.
While women at increased risk for breast cancer may benefit from the earlier initiation of screening, shorter screening intervals, or the addition of screening methods such as breast ultrasound or MRI, according to the ACS, the updated guidelines also state that there is insufficient evidence for other recommendations.
"The study and the new guidelines raise important questions for patients," said Dr. Marisa Weiss, president and founder of BreastCancer.org. "Patients need to be reassured that it is important to ask questions and that they need to talk to their doctors to see what is recommended for their individual case."
ACS officials also urge women to be careful about where they get their MRIs. Of particular concern are places that perform breast MRIs but lack the facilities to perform biopsies. Patients who require follow-up evaluation with a biopsy then may need to undergo a repeat of the entire imaging procedure at a different center.
Experts agree, however, that research and technology are slowly providing doctors with new tools to both diagnose and treat diseases and that this work needs to continue.
"Our work and that of the ACS complement each other and tell us that we are really ready to bring MRI into the clinical care of high-risk breast cancer patients," said Lehman.