The debate over how to manage ductal carcinoma in situ (DCIS) has gained momentum following a recent study suggesting that surgery might not be necessary for women diagnosed with the condition.
Often described as "stage zero breast cancer" or "a very early form of breast cancer," DCIS is not actually cancer but rather a cluster of abnormal cells contained within the milk ducts.
Despite its non-cancerous status, the use of terms like “carcinoma” or “cancer” can cause considerable anxiety, prompting many women to choose aggressive treatments such as surgery and radiation—interventions that may not offer any clear benefit to their outcomes.
Mayo Clinic overview of DCIS
Last month, a new randomised trial, published in JAMA once again, challenged the necessity of surgery for DCIS.
Researchers tracked 995 women aged 40 and older with a new diagnosis of DCIS. Approximately half underwent surgery, while the remainder were monitored through active surveillance.
After two years, the incidence of invasive cancer was 5.9% in the surgery group compared with 4.2% in the surveillance group—a difference that was not statistically significant.
These findings suggest that, for many women, surgery may not be the life-saving intervention it has long been thought to be. Instead, active surveillance, where the disease is closely monitored, could be a safe and equally effective alternative.
Overdiagnosis
This raises the broader issue of overdiagnosis, a problem that has been exacerbated by widespread mammography screening.
Public health campaigns often champion mammograms with slogans like “early detection saves lives,” but this oversimplifies the complex reality of cancer screening.
Since the 1980s, fear-based messaging has been used to boost participation in these programs. A notable example is the American Cancer Society's advertisement warning women, “If you haven’t had a mammogram, you need more than your breasts examined.”
In reality, screening frequently detects cases of DCIS that might never progress to invasive cancer, and many harmless cancers that would never have caused any issues during a woman’s lifetime. This phenomenon of overdiagnosis leads to overtreatment.
Moreover, it does not reduce overall mortality. Randomised trials show that total cancer mortality and overall mortality remain unchanged.
DCIS now accounts for 20%–25% of all newly diagnosed breast abnormalities in the United States.
As a result, women are subjected to radical surgeries and other interventions that offer no survival benefit, yet carry risks of complications and cause considerable emotional distress. This phenomenon of overdiagnosis leads to overtreatment.
Peter Gøtzsche, a Danish physician and co-founder of the Cochrane Collaboration, has been a vocal critic of mammogram screening. He has long argued that overdiagnosis is a significant downside of widespread breast cancer screening programmes.
Gøtzsche, who literally wrote the book on mammography screening, has shown how screening often identifies abnormalities that would never become clinically significant. These findings cause unnecessary anxiety and lead to unnecessary treatment.
He contends that the benefits of mammography have been exaggerated, while its harms—including the overdiagnosis of conditions like DCIS—are routinely downplayed. Gøtzsche has even called for the discontinuation of breast screening programmes.
"It is long overdue,” Gøtzsche said. “Breast cancer screening programmes can no longer be justified. I think women should avoid getting mammograms and simply consult a doctor if they notice any irregularities in their breasts.”
Despite his blue-chip credentials, Gøtzsche has faced backlash for his views, even being branded a misogynist by László Tabár, a Swedish radiologist who claimed mammograms were “the best thing to happen to women in 3,000 years.”
“That’s nonsense,” Gøtzsche retorted. “There is a collective denial about mammogram screening and a misrepresentation of the facts.”
“Millions of women have been misled into attending breast screening without understanding how it could harm them. It’s a violation of the principles of informed consent and a breach of their human rights,” he added.
Gøtzsche is not alone in his critique.
Several years ago, I spoke with Dr Ranjana Srivastava, a Melbourne-based medical oncologist. She shared similar concerns about the potential harms of breast screening due to the overtreatment of DCIS.
“Do we rename DCIS as something else? Do we counsel women before they have a mammogram that a diagnosis of DCIS is not the same as invasive breast cancer?” Dr Srivastava asked, expressing unease over the risks of over-treating breast abnormalities.
“Too much medicine can actually cause harm, and angst and confusion,” she noted, advocating for the merits of restraint in treatment. “Sometimes, the hardest thing to do in medicine is to do nothing.”
While targeted detection can be invaluable for women with a strong family history or genetic predisposition to breast cancer, routinely screening all women over the age of 40 carries significant harms overall.
The findings of this latest study on low-risk DCIS provide further evidence for a more cautious approach to the treatment of breast abnormalities.
Perhaps it is also time to stop classifying DCIS as a “carcinoma” or “early cancer” enabling women to better understand that a watchful waiting approach may be a reasonable alternative to a mastectomy.
Maryanne Demasi PHD
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By elocal magazine