On Monday, the U.S. Preventive Services Task Force (USPSTF) released its guidelines for screening for breast cancer. A similar set of guidelines that the body had released in 2009 had led to a lot of controversy as it went against the grain of popular - and even some expert - opinion at that time.

The new guidelines state that women that are at an average level of risk for breast cancer should have their screenings begin at the age of 50. They should have screenings at intervals of two years until they are 74. For women aged 75 and over, the guidelines say that, currently, there isn't enough scientific evidence that screenings benefit women in that group, and so more research is needed.

Most controversially, the guidelines say that the decision on screening for women between 40 and 49 should be made in consultation with their doctors, as the benefits of such screening are lower when compared with women in other age groups, according to Reuters.

There are other bodies that provide guidelines in respect of when women should consider starting screenings for cancer. A network of important cancer centers, called the National Comprehensive Cancer Network, recommends that women should start such screenings from the time that they are 40. These screenings are then to take place every year, according to The Columbus Dispatch.

In contrast, the American Cancer Society, which released its guidelines in October, recommends that women start screening when they turn 45. However, they maintain that the screenings are to be annual.

The Chief Medical Officer of the American Cancer Society, Dr. Otis Brawley, said: "We often talk about women in their 40s, but rarely talk about the number of lives that everybody agrees could be saved for women in their 50s, 60s and 70s who just don't get the screening test. A third of women 50 to 75 are not getting breast cancer screening," according to CBS News.

The new set of guidelines are not likely to have any immediate impact on the coverage that most health insurers provide for annual or biannual mammograms for women starting from the age of 40.

The President of the National Breast Cancer Coalition, Fran Visco, said, "The task force's recommendations are based on sound science ... not on decades of marketing mammography screening," according to The Columbus Dispatch.