When you have a hammer, every cancer cell looks like a nail
We know that we may be over-treating some breast cancer patients. But why?
I wrote the other day that there's some possibility that screening mammograms lead to overtreatment of breast cancer. I wouldn’t describe it as a broad consensus among researchers, but it’s fairly well established. And it’s another way in which science does not always drive treatment.
The specific kind of cancer that I have offers the best example of what overtreatment might look like. I have ductal carcinoma in situ (DCIS), which is also referred to as Stage 0 cancer. Some people call it pre-cancer because it consists of cancer cells contained in the milk ducts that haven’t yet become invasive. DCIS is very slow-growing, and scientists believe that about half of DCIS cases will later become invasive cancer.
DCIS is essentially treated the same way that Stage 1 cancer is treated. Curative mastectomies, lumpectomies, radiation, and hormone suppression therapy are the treatments for both Stage 0 and Stage 1 cancers. (Chemotherapy typically isn’t, at least for DCIS.)
But why is something that isn't invasive—and that may not ever become invasive— being treated like an invasive cancer? It’s due in large part to the advent of screening mammograms, which has made DCIS diagnoses exponentially more common than they were in the 1970s. DCIS is rarely physically palpable, and it was therefore not diagnosed very often or it was found in cases where patients also had other tumors.Today, about 20% of new diagnoses are DCIS diagnoses. Screening mammograms show asymptomatic DCIS. (We can probably conclude that asymptomatic DCIS has probably been fairly common for a while.)
But if you don’t treat it like an invasive cancer, what do you do? Rather than immediately starting cancer treatment, one might choose a strategy that's known as active surveillance. You would get regular MRIs and mammograms, usually one or the other every six months, and you would do monthly self-breast exams. Again, DCIS is extremely slow growing. You would probably catch it before it could advance very far. It also might not develop into invasive cancer. The chances are about fifty-fifty.
But doctors can’t predict which DCIS cases will turn into invasive cancers and which won’t, so the protocol is to treat it like Stage 1 cancer. That makes sense. But because of that protocol, we may never actually know what DCIS does when it is left alone. There's no such thing as what scientists call a “natural history” of DCIS. The “natural history” of an illness is whatever happens to the body and its systems if a disease is left untreated. Active surveillance is only rarely a treatment choice, and persuading patients to pursue it is very, very difficult. In the past few years, some clinical trials have tried to study it; one is the PROSPECT-1 trial. But they have trouble getting people to enroll. Given the choice, women with DCIS say “No, I don't want to be in this clinical trial; you're not going to treat this now; I'm not comfortable with that.”
Again, this is easy to understand! But we essentially know that half of women with DCIS, which about 25,000 women annually, are being over-treated. And the fact that we don't know which cases might progress means that we're going to keep over-treating 25,000 women a year.
As I was saying about screening mammograms, I think there are lots of reasons that someone would, in fact, just get immediate treatment. But in the absence of the risk factors that we were talking about last time—Ashkenazi heritage, genetic mutation, first-degree family history, part of a marginalized group routinely under-treated in medicine—I think it’s worth at least considering active surveillance. You could change your mind at any time—at six months, at twelve, whatever. But, understandably, that makes most people too nervous. There’s too much anxiety and suspense in going for tests every six months.
But I suspect that some people who might choose it are not being given the information or the tools they need to feel comfortable with active surveillance. Specifically, if I were an oncologist, I might say to a patient that a program of active surveillance is going to include more frequent scans and additional imaging tests, and it also includes a course of cognitive behavioral therapy. CBT is a very common intervention for anxiety and it’s backed up by lots of clinical research; it’s worth asking whether including CBT as part of oncology care would lead to some different decisions. I don't think that that's ever going to happen. But it is something that I think about a lot.
For the first three or so months after my diagnosis, I spent some time wondering about whether I should have talked to my doctors about active surveillance. I have some risk factors—my mom and half-sister had breast cancer, but I don’t know much about their diagnoses, and my dad’s family is Ashkenazi. I subsequently found out that I do have a genetic mutation for breast cancer, even though it didn’t show up on a test six years ago, when I had my first baseline mammogram. But, uh, when I was tested again this winter by a different lab, we discovered that Lab A had missed it. It's not, as is sometimes the case with genetic testing, that they got more information that would have produced a different result if they’d known it at the time. My genetic counselor conferred with Lab A again, and they discovered that because of the way the test was processed (or something), they had missed it. That sort of diminished my anxieties that I was being over-treated.
Still, when I consider what I would tell my friends with DCIS diagnosis, I think I would talk to them about active surveillance. You could buy yourself a little time, especially if you were not in a place to make decisions about cancer treatment or if going through cancer treatment would be disruptive in a really damaging and consequently way. But also, and this might be the biggest thing, you would have more time to breastfeed your kids and to have a better sex life than you probably will after you have cancer treatment. Those seem pretty huge!
This is one of the paradoxes of breast cancer treatment. The anxiety that seems to accompany a cancer diagnosis becomes a deciding factor in the course of treatment, and it can supersede more conservative treatment routes. Of course, if you have DCIS you should do the thing that feels right to you. I just think it’s worth considering what your other choices are— that it's useful to have considered before you're in a chair with an oncologist and they say, “You have DCIS and this is what we would like to do.”