WHAT IS DUCTAL CARCINOMA IN SITU (DCIS)?

Professor Sunil Lakhani is the Chair of the Breast Cancer Trials Board of Directors. He is a clinical diagnostic pathologist and also heads up a research team at the University of Queensland, comprising scientists and clinicians ensuring a translational focus to the program. We spoke with him about ductal carcinoma in situ and how it relates to breast cancer.

“So, DCIS stands for ‘ductal carcinoma in situ’ and the reason why it is called ‘in situ’ is because we are talking about a disease process, a cancer that is still confined within the ductal and lobular structure of the breast. So, in other words, it’s inside the tube-like structure in which the cells are normally present, which are benign and then eventually turn into cancer, but they’re still confined to the ductal lobular tree.”

“In order for the disease to be invasive, and therefore, how it differentiates from invasive cancer is that the cells have to break out of the tube-like structure and invade the surrounding stroma that contains those ducts. And so, in that sense, it is a cancer, but it is not a cancer that is broken out of its structure in which it is arising.”

“And therefore, doesn’t really have a propensity to spread to different parts of the body. So, it’s a good prognostic cancer. Because it is not invasive and therefore doesn’t have access to blood vessels and so on, in order to spread to the other parts of the body.”

“So, in the old days, you know, 50-100 years ago, DCIS would have been diagnosed because patients presented with a mass in the breast or pain or some other symptom. But these days almost all DCIS is diagnosed because of the mammographic screening program. Some types of DCIS have a propensity to get calcification within it because of the cells dying.”

“And when the cells die, that necrotic tissue often gets calcium deposited into it. And so, on the mammographic screening, the radiologist might pick up types of calcifications, which make them suspicious that it is present inside the ducts, and therefore that patient may have DCIS. So, most DCIS these days is actually picked up because of mammographic screening programs.”

What are some key pathological characteristics of DCIS and how might these impact its management and treatment?

“So, as I said the DCIS is basically a carcinoma in situ, meaning that the cancer cells are present inside the duct. And so, at biopsy, when somebody is suspicious that a patient has DCIS, that biopsy shows us that there are these atypical cells inside the duct.”

“And then we use features relating to how bad it looks to decide whether it is benign or malignant. And once we have decided that it is DCIS, we classify it according to the growth pattern in which we see those cells. But more importantly we grade them or type them by the nuclear characteristics, into low grade, intermediate grade, or high grade.”

“Now, these are not absolute categories. They are a continuum. But we try and separate these types of DCIS into those that we think might be less aggressive versus more aggressive through grading them into low, intermediate, and high. And all DCIS is managed mostly by surgical treatment, so you excise it.”

“And if you have a conservation operation, in other words, not a mastectomy, the patient will often have radiotherapy to try and reduce the risk of recurrence. The high-grade ones are more likely to recur than the low-grade ones. But overall, the treatment strategies are similar in that surgery is the mainstay, followed by radiation.”

“Pretty much all DCIS will have surgical treatment. The radiation is given if the operation is limited. In other words, it’s not a mastectomy. So, if it’s a conservation operation, for example a wide local excision, then radiation is usually given in order to reduce the risk of recurrence coming back into the breast.”

“The recurrence is also dictated by how wide the margins are during the surgical excision. But generally, the patient will receive radiotherapy to reduce recurrence.”

For women who have been diagnosed with DCIS, what important information should they know about the management of their condition?

“So, when they have a diagnosis of DCIS, they will go and see the surgeon, and then following the surgical treatment, they’ll also see a radiation oncologist. And so, they’ll get information relating to what type of DCIS it was and what kind of surgical procedures have taken place and, therefore the likelihood of recurrence depending on what grade it is.”

“But actually, most patients with DCIS will do well, and certainly there’s a very low risk of dying from the disease. Unless it recurs in the future, you know, with some other disease.”

How can knowledge about DCIS empower women in their healthcare decisions and discussions with their medical team?

“Well, I mean once you have a diagnosis of DCIS, obviously you’ve therefore had the disease and knowing that you’ve had the disease is important so that you can have regular screening where you will hopefully identify if any recurrence takes place. But the important thing is not to be over-anxious about it because it hasn’t broken out and become invasive and therefore it’s manageable and it’s highly unlikely that a very big harm will come to women with a diagnosis of DCIS.”

“So, they shouldn’t be scared of it and there’s certainly possibilities in terms of the screening program that will help to make sure that if there is a recurrence, it will be picked up sooner rather than later.”