Breast Cancer Screening Tied to Overdiagnosis
A new report suggests that when a breast cancer screening program was rolled out in Norway, up to 10 women were diagnosed and treated for cancer unnecessarily for every breast cancer death that was prevented.
That’s because when doctors screen for cancer in women who don’t have symptoms, it’s impossible for them to tell whether a tumor picked up by mammography will grow quickly into advanced cancer or will only progress slowly or not at all, said lead author Dr. Mette Kalager.
And although women are well-versed in the benefits of mammography, they aren’t always warned about the possible harms of so-called overdiagnosis and overtreatment, according to Kalager, a breast cancer surgeon and a visiting scientist at the Harvard School of Public Health in Boston.
“You have to really consider the benefit and the harm against each other, and really think through: what is my risk of dying from breast cancer, and what is my risk of being overdiagnosed?” she said.
The problem with treating tumors that would never cause any symptoms or cut women’s lives short is that women only experience harms with no health benefit, Kalager added.
“These women undergo treatment, that is surgery, radiotherapy, chemotherapy or hormone treatment for breast cancer, that they don’t really need,” she told Reuters Health.
“It’s not only the distress of being a cancer patient, but really the harms of treatment.”
Radiation therapy itself is linked to a slightly increased risk of cancer and chemotherapy comes with a range of side effects, from nausea and fatigue to a higher risk of infections.
“For years I think we’ve exaggerated the benefits (of mammography) and we’ve sort of downplayed or minimized the harms,” said Dr. H. Gilbert Welch, who studies cancer screening at the Dartmouth Institute for Health Policy & Clinical Practice in Lebanon, New Hampshire.
“The issue is no longer whether overdiagnosis occurs, it’s how often,” said Welch, the author of Overdiagnosed: Making People Sick in the Pursuit of Health, who wasn’t part of the new study team.