The controversy over when to start screening mammograms and how often to get them in average risk women has been around since the early 1990s.

The American College of Radiology, United States Preventive Services Task Force and American Cancer Society all agree that screening every year starting at 40 will save the most lives. And yet, all three organizations have different recommendations for patients about mammograms.

The American College of Radiology, along with the National Comprehensive Cancer Network, American Congress of Obstetricians and Gynecologists, and American College of Surgeons recommend screening every year starting at age 40. The Cancer Society recommends considering a mammogram between ages 40 to 44 then definitely getting one every year between ages 45 to 54, followed by continued screening every one to two years.

The Task Force draft for 2015 recommends starting at age 50 and getting a mammogram every other year.

How can all these prestigious organizations, which are full of smart people, look at the same data and come to different conclusions?

The issue boils down to one important question: Should patients decide or should organizations decide for them?

While all agree that starting at age 40 and getting a mammogram every year saves the most lives, the reason why they disagree about when to start has to do with the relative value that each group places on the potential risks and costs associated with screening mammography.

These include the money and time spent on the exam, the anxiety it may cause and the possible additional tests that the mammogram may generate when cancer is not present.

Different patients often value each of the risks and benefits from a mammogram differently.

Some are more anxious than others. Some have greater concerns about the expense of the exams. And some have a more pressing need to know the results.

The Task Force and the Cancer Society have tried to weigh the life-saving benefit of mammograms against the risks and choose what is best for all patients.

Unfortunately, the Task Force recommendations are tied to insurance coverage through the Affordable Care Act.

For women between the ages of 40 to 49 years old the Task Force has assigned mammography a grade C.

A grade C does not require insurance coverage. While the words of the Task Force suggest the freedom of choice, their actions may require patients to pay the full cost of a mammogram from their own pocket. Those with limited incomes may have no choice at all.

The Cancer Society, Cancer Network and others recognize that women at average risk for breast cancer have different values and support continued insurance coverage for patients to get a mammogram and exercise their right to choose for themselves.

The opportunity should be offered every year beginning at age 40 because — as the College of Radiology, Cancer Society and Task Force agree — that is the schedule that saves the most lives.

Peter R. Eby, MD, FSBI, is section head of Breast Imaging in the Department of Radiology at Virginia Mason. He practices at Virginia Mason Federal Way Medical Center.