A new report out Monday threatens to reignite the fierce debate over when women should get mammograms.
It shows that many women diagnosed with breast cancer before age 50 who died had not ever been screened -- and the authors suggest that guidelines should be changed to encourage earlier, regular mammograms for all women. But other experts called the study flawed and said it would confuse women more than they already are.
Mammogram screening has been a sticky subject for years and there was an uproar when the US Preventive Services Task Force (USPSTF) said in 2009 that most women should not start getting regular mammograms until they are 50.
Screening women earlier, the group said, doesn't save enough lives to justify the expense, worry and needless procedures that women go through when they get a false-positive result: a suspicious-looking mammogram that turns out not to be a tumor.
And many experts say that the types of tumors that kill younger women are fast-growing and are not usually caught by mammograms.
For the latest report, a research team at Harvard Medical School looked at the cases of 7,301 women diagnosed with breast cancer between 1990 and 1999, checking their medical records until 2007. Of those, 609 died of breast cancer. Among those who died, 65 percent had never had a mammogram.
They concluded that this shows that earlier screening could have saved lives.
"Most deaths from breast cancer occur in unscreened women. To maximize mortality reduction and life-years gained, initiation of regular screening before age 50 years should be encouraged," Dr. Daniel Kopans of Massachusetts General Hospital and colleagues wrote in their paper published in the journal Cancer.
But other experts questioned the analysis. Just because someone got cancer and hadn't been screened doesn't necessarily mean that a mammogram would have caught the tumor in time to save the patient's life, according to the National Cancer Institute.
"Finding cancer early does not always reduce a woman's chance of dying from breast cancer," the NCI says on its website.
"Even though mammograms can detect malignant tumors that cannot be felt, treating a small tumor does not always mean that the woman will not die from the cancer. A fast-growing or aggressive cancer may have already spread to other parts of the body before it is detected."
It is one of the reasons that actress Angelina Jolie had her breasts removed when she found out she had genetic mutations that gave her an 80 percent chance of developing breast cancer. Many women with his genetic risks of breast cancer worry that a mammogram won't catch the tumors in time.
"My worry here is that people will assume from the article that if you find a cancer through screening, you're going to save that person's life," said Dr. Laura Esserman, head of the breast cancer center at the University of California, San Francisco.
"In fact, what they show is exactly the problem that we face. We know that younger women are more likely to develop the killer cancers," Esserman added. "Screening works best for more slow-growing cancers."
Doctors worry about sending mixed messages to women. Screening the right women can save lives, and there are fears that women may just give up and skip screening altogether if they fear it won't do them any good. And women with a high risk of breast cancer -- for example, those with a family history of the disease -- do need to start screening early.
"All of us in the field are trying to figure out better treatments, better screening and better prevention," Esserman said.
Studies have found that women really do worry when they get a questionable finding on a mammogram and need to have follow-up.
And a 2012 study found that women were in fact being diagnosed with breast cancers that never would have killed them. Researchers found that as many as a third of cancers detected through routine mammograms may not be life-threatening. They said 1 million women may have been overdiagnosed, which means they were needlessly treated, not to mention emotionally distressed.
A study earlier this year showed that women over 50 don't even need a mammogram every year - every other year is fine.
That's what the USPSTF recommends. But other groups -- and the U.S. government itself -- have rebelled against this. "Our policies remain unchanged," Health and Human Services Secretary Kathleen Sebelius said in 2009. "Indeed, I would be very surprised if any private insurance company changed its mammography-coverage decisions as a result of this action."
The American Cancer Society, which publishes Cancer, recommends that women get a mammogram every year starting at age 40. So does the NCI. The 2010 health care law requires insurers to pay for mammograms without charging patients any fees, such as a copay. Medicare will pay for its patients to have a mammogram every year.
Most recommendations say women should talk with their doctors about screening -- when they want to start and how often they would like to have the scans.