As treatment for breast cancer becomes more refined, more personalized for each patient, one kind of breast cancer continues to be misunderstood and often mistreated – ductal carcinoma in situ, or DCIS.
DCIS is diagnosed when abnormal cells are found inside a milk duct in the breast. According to the Mayo Clinic, it’s considered the earliest form of breast cancer, and is noninvasive. That means it hasn’t spread beyond the milk duct.
DCIS often is found during a mammogram, and because more women are having mammograms more often, diagnoses of DCIS have increased dramatically in recent years. As we’ve often noted, mammograms often represent overscreening, which can subject women to unnecessary and potentially risky additional tests. DCIS is a good example of potential overtreatment from these screenings.
“[S]ince the introduction of screening mammography,” wrote Dr. Robert McNutt, a contributing editor to TheHealthCareBlog.com, “nearly 1 in 5 women with cancer are diagnosed with this type. DCIS is not an invasive type of cancer and a woman diagnosed with DCIS will have a low recurrence rate of either local or distantly spread cancer (only 1-2% in a life time). Hence, life expectancy with DCIS is nearly normal.”
So depending on the patient, sometimes the best treatment is “watchful waiting,” which means doctors monitor the patient without invasive procedures if something is seen on a screening test that might or might not become dangerous. Sometimes, though, DCIS requires surgery and radiation to prevent it from spreading.
According to the Mayo Clinic, surgery might be appropriate if:
- You have a large area of DCIS.
- More than one area is affected by DCIS.
- Biopsy shows abnormal cells at or near the margins of the tissue specimen.
- You’re not a candidate for radiation therapy.
- You prefer to have a mastectomy rather than a lumpectomy (which spares the breast but removes significant tissue).
McNutt explained the two main surgical options for treating DCIS that have been studied. Unilateral mastectomy (one breast is removed) is the most studied option. But a more conservative treatment, removing only the area of the cancer rather than the entire breast, followed by radiation therapy, might be the best option for many patients even though it hasn’t been studied directly in comparison with mastectomy for DCIS.
But in the last six months, McNutt wrote, “I have been asked by 3 women diagnosed with DCIS if they should have bilateral mastectomy [both breasts are removed]. Some women had seen up to 3 cancer surgeons and 3 cosmetic surgeons and had been advised by all that bilateral mastectomy was a reasonable option for treatment.”
McNutt is a vigorous, thoughtful advocate for rethinking this scenario. In answer to the question, “I have DCIS, should I have a bilateral mastectomy?” he says that the benefit of such a radical procedure is, well, NONE.
He relies on science for his reason: “No women with DCIS have been included in a randomized controlled trial.”
One study McNutt referred to found that out of 600 women at one institution, 42 in 100 undergoing bilateral mastectomy had complications; only 29 in 100 who had unilateral mastectomy had complications. Serious complications of bilateral mastectomy occurred for 14 in 100, but only in 4 of 100 with the unilateral procedure.
“There is no trade-off between benefit and harm,” McNutt wrote. So, because “there is no benefit, only harm is possible. Informed medical-decision-making requires a trade-off between added benefit and added harm. This is not the case for DCIS and bilateral mastectomy.”
Bilateral mastectomy for DCIS has never been studied, McNutt said, and it has been limited to women with high-risk cancers, including those with genetic abnormalities like the BRCA 1 and 2 genes that prompted Angelina Jolie to opt for this radical approach.
But even in those situations, he says, good science is lacking. There are no “gold-standard” randomized trials, so what’s left is evidence based only observational studies. “Observational studies,” as McNutt explained, “are not experiments. In these study designs, some women choose to undergo the procedure while others do not, and we are unclear why. It may be that women who chose to have a bilateral mastectomy are different types of women than those who do not. … a woman’s personal characteristics may obscure our ability to assess the independent effects of treatments examined only in observational studies.”
No one should make such a treatment decision with such significant consequences with only observational studies as a guide. “[O]nly information from randomized experiments should be used for making your medical decisions,” McNutt said, noting that more people are harmed than helped when they act on treatments proposed only from observational studies.
“[I]f you have DCIS,” he concluded, “a recommendation by a physician for bilateral mastectomy is based on conjecture. Despite the lack of evidence for benefit, bilateral mastectomy for early stage cancer is on the rise. In 1998 2% of women in California underwent bilateral mastectomy; in 2011, 12% did. While some women have stated that removing both breasts reduces their worry of breast cancer in the future, this statement cannot be made based on evidence. We don’t know if women will be better off with bilateral mastectomy so we don’t know if you can/should worry less or not.”
For more information, see our blogs, “Malpractice in Overdiagnosis of Breast Cancer” and “Women Still Misunderstand Risks of Breast Screening.”