DCIS, the misunderstood breast cancer

Ductal Carcinoma In Situ, or DCIS, is the most common form of non-invasive breast cancer—and it remains the subject of debate and confusion, as reflected recent news coverage, here and here. In 2007, radiation oncologist and scientist Eileen Rakovitch, chair of the Breast Program at Odette Cancer Centre at Toronto’s Sunnybrook Hospital and head of a Health Services Research Program devoted to improving treatment and outcomes for women with DCIS, sat down with Maclean’s to shed light on this misunderstood diagnosis.

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Dr. Eileen Rakovitch is a breast cancer specialist and scientist with Sunnybrook Health Sciences Centre, University of Toronto. She is one of the country’s leading authorities on DCIS.

Q: Media coverage of Belinda Stronach’s diagnosis of DCIS raised awareness — and confusion — about the disease. What is DCIS?

A: DCIS stands for ductile carcinoma in situ; it is a disease of the breast where there are some cancer cells but they’re confined within the walls of the duct. The breast is comprised of ducts, and these cells have not spread outside the duct to other parts of the breast and they have not spread to the lymph nodes. That’s in distinction to invasive cancer. And because these cells have not yet developed the ability to spread, DCIS is highly curable.

Q: So because DCIS is contained, it, in itself, is not life-threatening?

A: No.

Q: Yet it’s defined as a cancer.

A: DCIS should be thought of as a non-invasive breast cancer; it has the potential to become an invasive cancer but it’s one step before.

Q: What are the odds of that happening?

A: That partly depends on the treatment and on certain risk factors, but we know that for women who have DCIS, their overall chance of dying of breast cancer is very low — less than two per cent at 10 years. About five to 10 per cent of women with DCIS may develop an invasive cancer.

Q: Do we know which women are at greater risk?

A: A higher grade DCIS may have a higher chance of developing a recurrence or an invasive cancer but that has not been consistently shown. The extent of diseases and the size of the DCIS is known as a risk factor for recurrence of DCIS.

Q: Is there discussion about whether DCIS should even be called cancer?

A: Yes. One of the challenges is to identify which women are at highest risk of getting an invasive breast cancer so we could recommend more aggressive treatments to those women, and we could say to the majority of women with DCIS, “Your chances of getting an invasive breast cancer are so low you just need a lumpectomy, you don’t need any other treatment.”

Q: Your own research reflects the confusion. One study you conducted found many women diagnosed with DCIS react as if they have invasive cancer.

A: Yes. We asked, “What do you think the likelihood is that you will die of breast cancer?” and almost a third of women thought they were very likely to die of breast cancer; the responses were similar to women who had invasive breast cancer. We asked about the psychological impact — difficulty sleeping, anxiety, depression — and the responses were exactly the same between women diagnosed with DCIS and women with early invasive breast cancer.

Q: Why is there so much confusion? 

A: It’s confusing because treatment for DCIS and treatment for invasive cancer are very similar. Both are treated with surgery. Most women with DCIS will have a very confined disease that can be completely excised with a lumpectomy, and they can have radiation treatment, keep their breast, and do very well. But sometimes the disease will involve the majority of the breast, so the best treatment for those women is a mastectomy. The point of breast-conserving treatment is to be left with a good cosmetic result, and if you’re going to remove 90 per cent of breast tissue you’re better off removing it all and having reconstruction.

Occasionally a woman will choose a mastectomy because it gives her peace of mind. They should have the right to choose that, but that doesn’t mean it’s better treatment and it shouldn’t make the other women who choose to keep their breast feel they’re compromising their own outcomes. They’re equivalent. A lumpectomy and radiation is equivalent to mastectomy — equivalent survival, equivalent outcome — but most women don’t choose to have a mastectomy if they don’t need to. But a few women will choose a mastectomy. And the reassuring point — counterpoint to that — for women who have to have a mastectomy is to say, “The chances of recurrence are very low, they’re about one per cent at 10 years in that breast. And you don’t need radiation. So similarities in treatment, and the fact that both are often called breast cancer, lead women with DCIS to believe they have invasive breast cancer. In my practice, I will spend more time with a woman with DCIS than the average woman with an early-stage invasive breast cancer because there is a whole element of educating the woman with DCIS. Whereas women are very well-informed about what early- stage breast cancer is. Women with DCIS need to understand that the goal of treatment for them is to help lower their chances of actually getting an invasive cancer. It’s a prevention treatment.

Q: What role does mammographic screening play in identifying DCIS?

A: Before mammographic screening was taken up in the early ‘80s, DCIS represented less than five per cent of all breast cancers. Now DCIS represents about 20 per cent of all newly diagnosed breast cancers. Most women who have mammographic screening are 50 and older and the average size of most mammographically detected DCIS is one centimetre. When DCIS is picked up in younger women not routinely undergoing screening, then it’s often because they’re presenting with symptoms — a lump or, less commonly, bleeding from the breast. Mammographic screening is very important and the fact that we are detecting more DCIS is a testament to that. On the other hand, many women will have DCIS and it will never develop into an invasive cancer, and there lies the potential to be over-treating women who would never have otherwise developed invasive cancer.

Q: The notion of over-treating a potential cancer will strike many as odd. What is over-treatment?

A: Over-treatment refers to the unnecessary use of treatments that may have significant side effects, so unnecessary use of mastectomy, or unnecessary use, potentially, of radiation. Also, because we know the risk of spreading to the lymph nodes is close to zero, women should not be having an axillary dissection of the lymph node under the arm because having that has some downsides — it can cause swelling of the arm, it limits mobility. And yet we’ve seen that women in Ontario continue to have it done. What we’ve also found is that about a third of women with DCIS still continue to receive a mastectomy, and it raises the question as to whether these women are receiving unnecessary mastectomies.

Q: Are you concerned that Belinda Stronach having a mastectomy will link the treatment of DCIS with mastectomy or lead women to think that’s the preferred treatment?

A: Without knowing the specifics of Belinda Stronach’s situation, mastectomies are recommended in cases where the DCIS is very extensive such that removing all of the disease would not leave them with a good cosmetic result. If extensive DCIS involving most of the breast is not completely removed, there’s a very high risk of recurrence even with radiation. I don’t know whether she chose it or it was recommended, but most women do not need to have it. There is no survival advantage to having a mastectomy if the disease is contained within one portion of the breast, if it can be removed with a lumpectomy, and if she has radiation treatment afterwards.

Q: If you had a DCIS patient with a small DCIS who wanted a mastectomy would you advise against it? 

A: I think the most important aspect for a woman and her physician is that the woman make an informed decision. All women with DCIS should have the opportunity to see both a surgeon and a radiation oncologist. Multidisciplinary care is very important for all aspects of cancer care but certainly for DCIS.

Q: Is there much debate over how DCIS is treated? 

A: There’s a lot of debate about whether women who’ve had a lumpectomy require radiation treatment.

Q: Why wouldn’t you have radiation?

A: Because radiation has a small chance of having side effects, and so because women with DCIS have a curable disease and excellent survival it is nice to avoid radiation treatment. There’s also the point of view that because DCIS is not an invasive cancer it should be treated with a wide local excision and then a radiation treatment should be avoided, particularly for women who may have a lower risk disease.

Q: Has all of the publicity surrounding Stronach affected your patients?

A: My patients have said two things. When it was quoted that women with DCIS should be reassured they don’t have invasive disease, then the women with invasive disease say, “Well, I should really worry, then.” And then there are the women with DCIS who said, “I didn’t choose a mastectomy, everyone told me it was fine to have a lumpectomy and radiation, that it’s equivalent.” So there are women who said, “Have I compromised my own survival because I didn’t have the mastectomy that Belinda had?”

Q: There’s talk routine mammographic screening should start at age 40. What is your opinion?

A: There may be a benefit in reducing breast cancer-related deaths if we start screening at 40, which they do in the States. And perhaps that’s a good thing, but it may also be the price of diagnosing even more women and younger women with DCIS. And so you’re creating more potential morbidity and over-treatment. Of course I’m not suggesting that we eliminate mammographic screening but we have to minimize the downside. We know that almost all women with DCIS will be just fine, so we need to better understand the disease so that we can tailor the treatments — be it mastectomy, radiation treatment, or even an extensive local excision — and avoid unnecessary treatments for those women who don’t need it.

Perhaps we can even change the name for those women who are deemed to be at such low risk that we no longer call it ductile carcinoma in situ, but we’re not there yet.

Q: Your current research is attempting to change that. 

A: Yes, we’re engaged in a population-based study of women diagnosed with DCIS in Ontario to identify predictors of recurrent invasive breast cancer. It’s unprecedented in terms of its scope and funded by the Canadian Breast Cancer Research Alliance and National Cancer Institute of Canada. We’ve just received a five-year renewal of a three-year grant for $1.3 million to continue our work.