As recently as this week the 2009 US Preventative Services Task Force Breast Cancer Screening Guidelines are back in the headlines.
As a cancer survivor with no known family history of breast or related cancers and whose cancer was first detected on a baseline mammogram at the age of 35, issues related to the value of screening and young women are very close to my heart. By all rights, my cancer might not have been found for another five years, and based on the current guidelines, perhaps it would not have even been found yet. So this is something that matters a great deal to me personally.
Before we look at the guidelines, the process by which they were developed, and the controversy that surrounds them, I need to be clear about something. As a breast cancer advocate I often speak about evidence-based decision making. By that I mean that our goal is to put our emotions in perspective. As a survivor, I know how truly difficult that is. And as a survivor, I can choose to allow my emotions to dictate as much of my decision-making as I wish. But a focus on evidence-based decisions helps me know when I am thinking rationally and when I am responding emotionally. There is sometimes a sense that evidence-based decision making is “harsh” and doesn’t account for a person’s fears. I respectfully disagree; it asks each of us to weigh the science in a balanced and fair manner, and then see how our emotional landscape informs a course of action. As such, what I address in this particular piece is the science, and only then how each of us utilizes science in our own lives is up to us.
The gist of the USPSTF Guidelines, as presented in 2009 include:
- Before the age of 50, the decisions about screening mammograms should be made between a doctor and patient, taking into account the patient’s medical history & risk factors, as well as the known risks of the screening.
- Biennial screening between the ages of 50-74.
- There remains insufficient evidence about the risks and benefits of screening after age 75.
In formulating the 2009 guidelines, the USPSTF reviewed a total of nine independent, randomized trials on mammography, only one of which held strong data on women in their 40s (known as the Age Trial). Of these, not all of the studies were well-designed and not all of the outcomes were statistically significant, each being weighted accordingly when the team evaluated the studies and drew their conclusions.
So, why the uproar?
Leave it to the media to complicate matters. In just one example, after the 2009 Guidelines were released the LA Times wrote: “Oncologists were nearly uniform in their disparagement of the guidelines, fearing the loss of a valuable cancer-prevention tool. Women in their 40s account for at least a quarter of breast cancer diagnoses.”
The thing is, mammograms don’t PREVENT cancer. They detect it….
In fact, while mammograms are a wonderful tool, there remain important risks associated with them. The National Cancer Institute outlines them as follows:
- Finding cancer is not curing cancer. The goal of a mammogram is to identify a malignancy early; before it can be felt on a clinical breast examination. But a small tumor is not necessarily a treatable one. Aggressive cancers, for example, may have already matastized (spread) through the body.
- Risks of false-positives. When a radiologist detects something on an image it needs to be followed up with additional testing – diagnostic mammograms, ultrasounds, biopsies. Along with the risks from these test, and the associated costs, they can invoke long-term anxiety. Moreover, the likelihood of false positives are higher among young women, women with a family history of breast cancer, and women taking estrogen.
- Risk of false-negatives. When mammography results appear normal yet fail to detect an existing cancer, it is a false-negative. False-negatives delay treatment and create a false sense of security. The NCI states that screening mammograms miss up to 20 percent of breast cancers that are present at the time of screening. This is especially true of denser (i.e. younger) breasts.
- Risk of over-diagnosis and overtreatment. We know that some cancers do not need to be treated – that they will never spread and therefore not become life threatening. Mammograms also find pre-cancers that may or may not ever become cancer. In either case, since we are unable to distinguish between those that will become life-threatening and those which will not, they demand treatment and in some cases that will be overtreatment.
- Radiation exposure. While the radiation exposure in a mammogram is low, radiation is cumulative. This risk needs to be considered when discussing the value of screening mammography and the age what which testing should begin, especially during a woman’s reproductive years.
My peers often ask me whether I’m upset about the USPSTF changes, especially by those who have a family history of breast cancer and are concerned that they will not be aggressively monitored. To begin, I assure them that this is not about them. Doctors will weigh a family history, especially a diagnosis of a first-degree relative, in their decisions to order screening. Doctors will hopefully weigh the anxiety that a family experience creates as well. But I also remind them that mammography is simply not as effective as we need it to be for the under-50 set. When breast tissue loses its density (anyone else sagging out there???), it is actually a bonus on mammogram – otherwise dark tissue becomes an almost white fat tissue on the film, allow a mass to stand out in contrast. Simply put, we must find better tools! But until we do, we must continue to weigh the cost-benefit of mammography.
Among the critiques of the change is that they were politically motivated, appearing as they did on the heels of 2009 Congressional health care reform bill. The truth is that the timetable for the USPSTF review was likely set long before the issues related to healthcare reform did. Moreover, if we are going to make healthcare accessible for all Americans, it is incumbent upon us to deal with cost-benefit issues, and that necessitates making hard choices. No one wants anyone’s cancer missed! And the adage that the early cancer is caught, the more treatable it typically is. I know how unpopular it is to say it, and how some will interpert this, but until something changes somewhere in our current system, the cost of health care will only continue to escalate.
Part of the challenge is that we respond emotionally. Cancer is scary. We hear 1 in 8 women will be diagnosed in her lifetime” and we seem to forget that means 12.5% of women. Yes, breast cancer seems ubiquitous, and I would be the very last person to suggest that we should not take this disease seriously. However, there is a “fear factor” that is not backed up by science. Moreover, we sometimes fail to distinguish between relative and absolute risk when we look at the effectiveness of mammography. Consider that the chance of a woman dying from breast cancer is about 1%. If you take the average 50 year old woman with and without screening mammography, you improve her chance of not dying by age 65 from 99.12% to 99.29%. How many false-positives, false-negatives, anxiety attacks, and unnecessary procedures justify a 0.07% improvement?
I wonder if, ultimately, we don’t wish for a set of guidelines that tell us what to do. Were it only that simple…. We have to remember that the guidelines are just that, recommendations based on a comprehensive review of the science. They lead us back to the heart of health care – a doctor-patient relationship. As patients it is upon us to share our histories, get informed, check our sources, ask questions and make decisions. We lean on our doctors as experts (which they must be, and not all are) to know the science, account for our individuality, explain our options, answer our questions and guide our decisions, including helping us separate good science from bad, and evidence-based decisions from emotion. It is a process of shared decision-making. Are we ready to take responsibly for that, or is it easier to blame the USPSTF?