(CNN) Despite what the American Cancer Society and other health organizations advise, many doctors still recommend routine mammograms to screen for breast cancer in younger and older women, a new paper suggests. Experts are divided on whether more screenings are beneficial.
The American Congress of Obstetricians and Gynecologists recommends annual mammograms starting at 40 for all women, whereas the US Preventive Services Task Force recommends biennial mammograms starting at 50 for all women.
In 2015, the American Cancer Society relaxed its guidelines to recommend that women with an average risk of breast cancer should wait until age 45 for regular mammogram screenings instead of 40.
In the new paper, many of the primary care physicians and gynecologists surveyed said they still recommended screening for women ages 40 to 44 last year. The paper was published in the journal JAMA Internal Medicine on Monday.
"All guidelines agree that discussions about mammography should begin at age 40. There is universal agreement on this age. Where the difference comes is the age at which screening should be recommended without the need for an informed decision," said Dr. Richard Wender, chief cancer control officer of the American Cancer Society, who was not involved in the new paper.
About 12% of women born in the United States will develop breast cancer at some time during their lives, according to the National Cancer Institute.
'Ultimately, there is no perfect answer'
The new paper involved data on 871 primary care physicians and gynecologists in the United States who self-reported their breast cancer screening practices in a mailed survey from May to September 2016.
The data came from the Breast Cancer Social Networks national survey, which included physicians who were randomly sampled from the American Medical Association's physician masterfile.
Overall, 81% of physicians who completed the survey recommended screening for women 40 to 44; 88% for women 45 to 49; and 67% for women 75 and older.
"Our results serve as a benchmark for breast cancer screening recommendations as guidelines continue to evolve," said Dr. Archana Radhakrishnan, a researcher at Johns Hopkins Medicine in Baltimore and lead author of the new paper.
"Despite changes to guidelines, doctors are continuing to recommend routine mammograms to both younger and older women," she said. "The recommendations varied depending on physician specialty -- gynecologists were the most likely to recommend screening."
Among the physicians in the paper who recommended screening, 62.9% recommended annual examinations for women 40 to 44; 66.7% for women 45 to 49; and 52.3% for women 75 and older.
"I trust the results of the paper. The response rate was high for a survey. The distribution of specialties was reasonable and clearly reported," Wender said.
Dr. Mitva Patel said that she not only recommends annual screenings for women 40 and older, but she also follows those guidelines herself.
"I am 42. I have had my annual mammogram at age 40, 41 and 42," said Patel, a breast radiologist at the Ohio State University Comprehensive Cancer Center, who was not involved in the paper.