Cancer Screening Controversies
Tuesday, October 18, 2011 at 9:56PM
Jeff Belkora in decision-making, patient participation

UPDATE - just got off the air and will add a postcript below.

I have just been invited to speak on KQED Forum, a San Francisco-based radio talk show, regarding cancer screening controversies.

The show will air Wed Oct 19, 2011, at 9 am PST and can be heard at 88.5 FM in San Francisco, or online at, or by podcast a day later at

I'm going to assemble a few resources that I can point listeners to and update this post. Email me if you have anything you want me to share with the public.

My key message about cancer screening or indeed any health-related action, is that all medical interventions have potential risks as well as benefits. It makes sense for individuals to learn what these are. In addition to consulting physicians, there are now educational resources called decision aids that take on specific topics. These decision aids can be print, audio-visual, or web-based materials. What distinguishes a decision aid from other health education materials is that they are organized entirely around a frequently encountered dilemma. Producers of good decision aids are not trying to persuade anyone to do anything in particular; rather they try to present a fair and balanced view of the pros and cons, including both quantitative evidence as well as qualitative stories or testimonials from patients who have experienced treatments and outcomes.

Producers of decision aids include a non-profit, the Foundation for Informed Medical Decision Making, which produces web, audio-visual and print decision aids with its commercial partner, a company called Health Dialog. Disclosure: I am the recipient of both research and implementation grants from the Foundation for Informed Medical Decision Making. Another producer is the non-profit organization Healthwise, which supplies many websites and medical centers with web or print patient education materials. Other sources of good information on medical decisions include the National Cancer Institute and the Mayo Clinic. There's a comprehensive index of decision aids at

Decision aid producers recognize that cancer screening programs create harms as well as benefits. Therefore, these producers have created decision aids targeted at some of the most frequent decisions: breast, prostate, colon cancer. I'll provide some links below. 

So why is there controversy? What could possibly be wrong with people weighing the risks and benefits of screening and making an informed decision with their doctor? I'm the wrong person to ask: I'm personally and professionally committed to informed and involved decisions. I am comfortable, overall, with the ethic of individual patient autonomy and self-determination. Occasionally ethical conflicts arise pitting the welfare of many against the freedom of the few, but these are rare and I don't see them in screening. The controversy may arise because we are still transitioning from paternalism to participation in health care decisions. As William Gibson said, "The future is already here, it's just unevenly distributed." 

Part of this transition is that there are many entrenched viewpoints and interests at stake. Outside of the health effects of screening on individuals and populations, there are people whose wealth or power or status grow with the use of screening technologies and processes. Conversely, some will benefit if screening technologies and processes decline in popularity. This is true in all industries, and health care is no exception. Some people are trying to drive revenue (for example, producers of drugs, devices, procedures and fees), while others are trying to contain costs (employers, insurance companies, government payers.) The patient is a passenger in a car with two drivers, one with a foot on the accelerator, the other with a foot on the brake. This is a dangerous ride. In that situation, the patient's best hope is to find a good doctor and take control of the car together.

OK on to some links:

1. Gary Schwitzer is a journalist who critiques media coverage of controversies, including screening. He has a great blog post at Scroll down to read his third point about cancer screening. A screening program is different from testing someone who is high risk or has symptoms. Testing can have very high benefits with very low risks or harms. Screening is when you go fishing in the general population in the hopes of preventing deaths at relatively low cost in financial or human terms. In actual fact, most screening programs prevent very few deaths at high human and financial cost.

2. Prostate cancer. A company called Health Dialog (see above) normally reaches patients through contracts with insurers, who pay to offer decision aids as a benefit to their members. However, the general public can access Health Dialog's decision aid on prostate cancer screening at Again, Health Dialog works with the non-profit Foundation for Informed Medical Decision Making to assure that the content is fair and balanced. Only medical editors with no financial or other conflicts of interest are allowed to shape the content.

3. Breast cancer - age 40. Regarding screening for breast cancer at age 40, my colleagues at the University of Sydney have produced a decision aid for that dilemma:

4. Breast cancer - age 50. A prominent health services researcher, Gil Welch of Dartmouth, has drafted a simple balance sheet that summarizes the benefits and risks of breast cancer screening for women in their 50s, I'm reproducing it here from his article in the British Medical Journal at

For every 1000 women undergoing annual mammography for 10 years in their 50s:

1 woman will avoid dying from breast cancer 2-10 women will be overdiagnosed and treated needlessly

10-15 women will be told they have breast cancer earlier than they would otherwise have been told, but this will not affect their prognosis

100-500 women will have at least one “false alarm” (about half of these women will undergo a biopsy)


5. Breast cancer - all ages. There is a more detailed presentation, broken down by age groups, in a Canadian decision aid for breast cancer screning:

6. Colon cancer. This screening is considered highly effective. I was a little shocked to review some numbers recently and learn how small the absolute benefit is, or to put it another way, how many people must be screened to detect one colon cancer (thousands!). The National Cancer Institute has helpful resources on screening. They are not exactly decision aids, because they are not structured in such a way as to synthesize the absolute data. But they provide good summaries. The one on colon cancer screening is at


Other than websites, I encourage people to review some informative books on the topics of cancer screening and risk reduction:

Gil Welch - Should I Be Tested for Cancer? Maybe Not and Here's Why. 

Gerd Gigerenzer - Calculated Risks. How to Know When Numbers Deceive You. 


We had a few callers on the show that with cancers diagnosed through screening. Their understandable reaction is that screening saved their lives. The hard truth is that we don't know what would have happened, whether symptoms would have developed, whether treatments at that point would have been effective. What we do know is that out of 100,000 people screened, we would expect a few lives saved. People have an understandable reaction that "if ANYONE is saved, it's worth it." If you feel that way, I understand, but then all of us should be parking a mile away from our office each day and walking that extra distance to work, because we would save about an equivalent number of lives, at no real harm (look both ways when you cross the street), and with the added benefit of feeling good from exercise. These are not mutually exclusive of course, you can do both. But the point is that we do make decisions that cost people lives - such as commuting to work from further away, in order to save on housing expenses. Lengthening your commute kills people. So if you feel your life was saved by screening, please evangelize people driving less as much as you evangelize screening.

I come away feeling that, in urging caution about screening, I am cast in the role of someone who wants to deny people access to potentially life-saving therapy. Not at all. My professional mission is for people to make informed decisions. If the benefits of screening sound like they are worth the harms, you should advocate for your access to the programs. The key point is self-determination. And the screening slogan should be, not so much, "Screening saves lives" but more accurately, "Screening saves a few lives per 1,000 people screened, and can lead to varying degrees of harm for dozens or hundreds of others. Whether it makes sense for you will depend on your priorities and perspectives. Review a decision aid and talk to your physician about it."

My wish is that people advocate harder for their access to decision aids. The public has long been too satisfied with the news media digesting and (mis)interpreting scientific studies. Ask your hospital or clinic or insurer to obtain decision aids for you if they don't already. Then make a list of questions and consult one or more doctors and record their answers so you don't forget them. These strategies are proven to improve patient understanding, question-asking, and information recall.


I have now heard from some colleagues who wish to convey their messages on this topic.

Hope Rugo, Director of the Breast Oncology Clinical Trials Program at the UCSF Breast Care Center, writes, "I think it is important for women to know that the reason for the controversy is that rapidly growing tumors that have the highest risk are least likely to be found on screening exams.  So in my mind, what we should learn from that is that: 1.  Screening mammograms are still useful, it is just not clear that you need to get them yearly when you are under the age of 50 as the breasts are very dense and lesions are less visible, as the benefit is low.  2.  Abnormal exam findings should always be thoroughly evaluated.  3.  The less frequent screening may not be the right advice for those with a family history or personal high risk (prior DCIS, calcs, etc)."

On the topic of bi-annual versus annual screening, Laura Esserman, Director of the UCSF Breast Care Center, writes: "Data is pretty clear. There is no demonstrated data that screening every year is better than every 2 years. There is an increased risk of being called back and having an unnecessary biopsy (Annals of internal medicine last week)- by almost 50% if you screen every year. The risk of missing advanced cancers is not statistically significant, and the magnitude of any difference negligible (2-3%). Same benefits, less risks. Screen every 2 years. And it fits biology that fast growing tumors present between screenings- even when annual." I will add from years of working with Laura, her highest priority is always that patients arrive at an informed decision with their doctors based on their personal priorities and unique biology.

From the Palo Alto Medical Foundation, Dr. Edmund Tai writes: "Family history is often overlooked and is tedious to do. We need to enlist patient to help with their own care by providing a more detailed history. THere is a free website run by the NCI called "My Family Health Portrait" that has a nifty software to allow a patient to enter their FH.  It can be tedious if there is a large family but it is a free tool developed by the surgeon general and is actually a good idea.  As I am involved in clinical cancer genetics FH is fundamental in identifying patients who are at the highest risk.  It is estimated that >30% of all cancer patients have some family hisotory of cancer and 2-5% (depends on cancer type) have very high risk hereditary transmission.  We have only developed an indepth understanding of breast, ovary, and colorectal cancer but more are forthcoming.  The reason is that there are only a few genes that have high penetrance and high specificity.  The majority probably are affected by multiple genes with low specificity and we hope newer technology would allow us to pick those up."




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