Ductal carcinoma in situ (DCIS) is also called stage 0 breast cancer or pre-cancer. It means that malignant cancer cells have been found in the milk ducts but have not spread beyond them. It’s considered cancer and is something to take seriously, but the prognosis is typically good and it is treatable.

In fact, because of its early stage, there has actually been concern about over-diagnosis and over-treatment of DCIS in the medical community. Do some women with such early-stage cancer really need to get a double mastectomy or undergo radiation? Can some patients instead take a wait-and-see approach to see if the cancer becomes more aggressive?

It’s a risk many breast cancer patients are (rightfully) not willing to take. It’s difficult for many people to justify active surveillance instead of immediate treatment when it comes to a cancer diagnosis; there’s a lot of fear of the unknown.

A study of DCIS cases in the United Kingdom seems to support the idea that immediate treatment is the best route to go — but other experts are still skeptical.

The UK Study

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The study was published online in the British Medical Journal. Researchers from the University of Oxford in the UK analyzed the data of 35,024 women who were diagnosed with DCIS between 1988 and 2014.

They found that any diagnosis of DCIS (low, intermediate, or high grade) is linked to an increased risk of invasive breast cancer (IBC) and death. The risk of IBC after a DCIS diagnosis was over double that of national cancer incidence rates, with an incidence rate of 8.82 per 1000 per year. The risk of death was also more than double, with a death rate of 1.26 per 1,000 per year. This is 70% higher than the national rate.

Increased risk of invasive breast cancer started two years after the initial diagnosis of DCIS and continued for 20 years.

However, immediate treatment seemed to result in a lower risk of IBC. In particular, it was lower for women who had both breast-conserving surgery and radiation, women with ER+ cancer who underwent hormone therapy, and women who had larger surgical margins.

Experts Disagree

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Some experts in the medical community who were not associated with the study disagree with the findings, and have pointed out problems with the study’s conclusions.

Henry M. Kuerer, MD, is a professor of breast surgical oncology at the University of Texas MD Anderson Cancer Center in Houston. He says that improved treatment methods over the past 30 years overall have led to better outcomes, not immediate and radical treatment.

“The conclusion that mastectomy for patients — that is, more radical treatment — might lead to improvement is patently false,” he told Medscape Medical News.

The study analyzed DCIS patients as far back as the ’80s, and treatment and detection have both come a long way since then. Kuerer emphasized that health professionals are now able to isolate and treat small amounts of cancerous tissue using more advanced technology, and clear margins are seen in much greater detail.

The most notable addition to breast cancer treatment over the past couple decades has been endocrine therapy (commonly referred to as hormone therapy) — and that could be the driving factor in creating better outcomes for DCIS patients.

The Role Of Hormone Therapy

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Dr. Laura Esserman, MD, MBA, is the director of the Carol Franc Buck Breast Care Center at the University of California, San Francisco, and she is a strong proponent for managing most DCIS cases by active surveillance since 95% of DCIS is minimal risk.

“It is incumbent upon us to learn how to better manage DCIS across the spectrum of the types of DCIS. It is likely that some women may be very responsive to risk reduction with endocrine therapy alone and may never need surgery, while others may benefit from a surgical removal,” Esserman said.

In the UK study, patients who had the highest breast cancer mortality rates or were at the highest risk for getting invasive breast cancer were diagnosed between 1988 and 2000. This is before hormone therapy was used to treat DCIS.

“This in fact suggests that the biggest difference can be made with endocrine therapy,” Esserman said.

Next Steps

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Vered Stearns, MD, is a professor of oncology, the breast cancer research chair in oncology, and director of the Women’s Malignancies Disease Group at Johns Hopkins University School of Medicine and Johns Hopkins Kimmel Cancer Center in Baltimore, Maryland.

“Clinicians should continue to recommend optimal local treatment to women with DCIS and also discuss the role of endocrine therapy,” Stearns said. “I hope that there will not be a tendency to recommend or choose a mastectomy [after a diagnosis of DCIS].”

“Until we have strong biological markers to truly differentiate DCIS or invasive cancer with a high risk of recurrence, invasion, and metastases, I support the use of screening programs in carefully selected patients based on their age, comorbidities, and other characteristics,” she added. “Women should continue to have annual screening mammograms as long as they are in good health and have a reasonable life expectancy.”

There are currently several other trials looking at the best treatment options for women with DCIS. We look forward to seeing the results of those.