Wednesday, October 21, 2015

Some common sense on breast cancer screening

Yesterday, the American Cancer Society updated its guidelines on screening mammography for women at average risk, moving closer to the U.S. Preventive Services Task Force guidelines by recommending that most women start screening at age 45 (rather than 40) and be screened every other year (instead of annually) starting at age 55. The ACS also cast doubt on the effectiveness of the clinical breast examination in women who are already undergoing mammography screening. Although I don't agree with every aspect of the new guideline, it has the potential to make breast cancer screening more effective by preserving the benefits and reducing the harms.

A common critique I've heard about the ACS and USPSTF guidelines is that they will "confuse" women who have gotten used to the traditional routine of having annual mammograms starting at age 40. I don't disagree with this; incorporating new scientific evidence into medical practice is always confusing at first. But explaining the implications of new guidelines to individual patients is my job as a family physician - and it's your physician's job, too! I went on NPR's All Things Considered to offer my take on what the new guidelines mean for women. You can listen to the whole segment or read excerpts from the transcript below.

AUDIE CORNISH (HOST): So we heard in our report that the American Cancer Society still wants every woman to talk to her doctor to figure out what makes the most sense. How do you interpret all this?

LIN: What you've just said is probably the best way to describe it, that women should be talking to their doctors about mammography. It shouldn't be automatic. It shouldn't be reflexive. It shouldn't be like the experience of many of my friends who are in their early 40s and they show up at their doctor's and they get a slip and they say, "go get your mammogram." We instead should be raising the topic saying, look, we have this test. It could prevent you from either dying or having a serious illness from breast cancer. But it's not perfect. It has many harms as well, including false positives, diagnosis of a breast cancer that may not ultimately be true cancer but something that we might have to act on. So it's best viewed as an invitation to both patients and physicians to have that conversation if they haven't been having it before.

CORNISH: There have been several studies that have shown that doctors really don't talk all that much about the risks of cancer screenings. They don't give numbers for how many people actually do benefit from the screenings. Do you think these guidelines will change that?

LIN: I hope they do. Now in defense of those doctors, it is a challenging conversation. There are a lot of numbers. There's a lot of uncertainty about some of the numbers. I think that it can be helpful to present patients with either a handout or some sort of visual aid where you can show what the numbers really are for the benefits and the harms. And it's something that I've been doing, but I think a lot of doctors haven't been doing that and I'm hoping the new guidelines encourage them to because I think it's difficult to have this conversation without something to look at to visually illustrate those numbers.

CORNISH: If your doctor doesn't initiate this discussion, what kinds of questions should you ask? I mean, this kind of relies on women thinking of their own family history, race or whatever and somehow divining risk factors. What should patients be thinking about?

LIN: The guideline that the ACS released was a guideline for average risk women who are defined as not having one of the breast cancer genes or not having a family history where you have several family members with breast cancer or a single member at a young age. So the rest of women are kind of lumped into this average risk category. And certainly there are things that may not be accounted for in risk assessment tools that may be important to someone. So I think a patient should go to their doctor and say, look, this is how I feel about mammography. This is my experience with cancer, my family history. Perhaps they don't like having to go for repeated tests. You know, I'm worried about false positives. I think they should also ask their doctor, well, you know, what are downsides to this test? That's really the first question. Doctors always volunteer the upsides, but I think you have to ask specifically what are the downsides. And hopefully that will spark a conversation if your doctor seems otherwise inclined to gloss over it.

CORNISH: What do you say to women who today are are frustrated, maybe even angry or upset, women who have had annual mammograms for many years who've gone ahead with procedures that turned out to be unnecessary? Was that a waste?

LIN: Unfortunately in science this is kind of the way that things progress. We do the best we can with the information we have at a given time. The same thing sort of happened for prostate cancer screening in men. It used to be something that you started at age 50, you do it every year, and now organizations that say you don't do it at all, or if you do it, you have to be aware of the downsides. I understand it can be frustrating to patients. But the greater error is to cling to an old guideline and say, well, we're going to dig in our heels and keep starting at age 40 and doing it every year and ignore the new guideline, because that would be a worse mistake. We have to operate with the knowledge that we have. And I think the ACS has very comprehensively summarized what we know about mammography at the present time and their guidelines reflect that knowledge.