Whether it is a mammogram, colonoscopy or a skin cancer screening – after a certain age, we are subject to various early cancer detection screenings. Yet many of us don’t know that these screening tests are also associated with risks. This is something what Dr. Sylvia Sänger from the University Medical Center Hamburg-Eppendorf discovered in a study.
In this interview with MEDICA.de, she talks about the reasons for this lack of knowledge, further study results and the point of different early detection methods.
Dr. Sänger, in your study about early cancer detection tests you discovered that 46 percent of patients don’t feel adequately informed by their physician about the advantages and risks of screening tests. Why is that?
Sylvia Sänger: Every physician is obligated to educate his patients on examination or treatment methods – this also applies to early detection. He should introduce all options to the patient and explain their benefits and risks. Only then is it possible to ponder the purpose of a screening test for the respective patient together. This approach however, is still not practiced by all physicians.
Among other reasons, this is due to historic development. Ever since the statutory early detection programs have been introduced in 1971, the notion was "detected early- danger averted". Today we know that this is not the norm.
What’s more, we only have a limited amount of data available to properly illustrate the benefits and risks of early cancer detection. We need randomized controlled trials for this where the healthy population is randomly assigned into two groups. In one of the groups, early detection screenings are conducted over many years and none with the other group. Subsequently, you compare how many people from both groups were saved from cancer death. These types of high-quality studies are not yet available to a sufficient degree.
How can this be counteracted?
Sänger: Not only do we need better studies, but also better informative literature for physicians and patients. I would like to illustrate this with the example of mammography education. Women after the age of 50 are asked to get this type of screening test. When it comes to benefits and risks, the fact sheet from 2003 only states that the benefits outweigh the possible risks. The pamphlet was revised in 2010 to also include the stats on so-called false-positive test results. This means that a tumor might be detected that actually isn’t there at all or a woman is given the all-clear even though she has cancer. This type of information was not mentioned this way before.
After a study by the Swiss Medical Board in 2014 found out that mammography as an early detection cancer screening should generally be reviewed again, the German Federal Joint Committee (German: Gemeinsamer Bundesausschuss, G-BA) commissioned the Institute for Quality and Efficiency in Healthcare (IQWiG) to rework the informative literature once again. Women are meant to be objectively informed about what we know from research so far. This should include statistics that are easy to understand.
What further insights were you able to gain from your study?
Sänger: Many people trust their doctor and rely on his/her recommendation. If the physician therefore recommends a screening test, the patient usually undergoes the exam – 84 percent of study participants confirmed this.
It is good and important for the physician to be the first contact in this type of situation. Yet both physicians and patients need a good database to decide together which exam makes sense on an individual basis. People are also required to change their way of thinking in this case. As a patient, I cannot just hand off my responsibility in the waiting room like a coat and expect the doctor to tell me what I should do. This is not how joint decision-making works.
What consequences does lack of knowledge have for the patient and for the health care industry overall?
Sänger: It can mean enormous psychological strain on patients. I am using the example of testing for hidden blood in a stool sample, which is recommended annually after the age of 50. We know from studies that out of 1,000 persons with positive test results, 100 have colon cancer, while 900 do not. That means, out of 1,000 people who tested positive, 900 get a false cancer alarm. The physician says, you have blood in your stool and it might be cancer. This needs to subsequently be checked with additional tests. During the next two to three days until the final results are available, the patients are under tremendous psychological strain.
Added to the psychological strain of patients is the economic impact on society. After all, subsequent exams need to be performed that were ultimately unnecessary in 900 out of 1,000 cases. It might potentially also lead to unneeded treatments that incur additional costs.
Does this mean cancer screening makes no sense?
Sänger: It absolutely makes sense especially when there is personal risk. If my mother has been diagnosed with breast cancer for instance, I would definitely want to get a mammogram and take advantage of this exam. However, the physician should still educate me on the risk factors. Early cancer detection tests make sense on an individual basis. Whether they make sense for the general population however, is something we as a society need to determine on a regular basis.
The Tuberculosis screening test can be a role model for this. I still remember from my childhood that my parents were routinely invited to so-called serial X-ray testing for some time. Healthy people were X-rayed to find those people, who might possibly be infected with TB. Even though only 18 out of 10,000 people in the seventies still had TB, society still adhered to serial X-ray testing for a long time until the random serial X-ray testing was legally discontinued in Germany in 1988. We also need to have this kind of courage to examine the relevance of a cancer-screening test today.