By Roy Benaroch, M.D., Emory University Affiliated Hospitals
There are some important questions about cancer screening. Does it work? Is it always successful in finding the cancer it is supposed to find? Are these screenings 100% accurate? The truth is that cancer screening is a complicated process and is not as simple as it seems. It is believed that the perfect screening tests will be able to detect all major cancers.
Ben Stiller’s Fight Against Prostate Cancer
Ben Stiller, a brilliant actor, comedian, and filmmaker, was diagnosed with prostate cancer in October 2016 at the age of 48. In an essay in the Huffington Post titled “The Prostate Cancer Test That Saved My Life”, Stiller talks about a blood test for a protein called Prostate Specific Antigen, usually abbreviated to PSA. In his essay, Stiller wrote that taking the PSA test led to the detection of his cancer when it was still at an early stage. Doctors were able to perform the required surgery and remove the cancer.
However, there is more to Ben Stiller’s story than the successful removal of prostate cancer. Stiller had no family history nor the symptoms of this type of cancer. He was not a high-risk patient. Stiller took the PSA test at the recommendation of his doctor. The test results revealed he had prostate cancer that was at a treatable stage, and it was successfully removed, which saved his life. He pointed out that the PSA test went against the guidelines of the US Preventive Services Task Force. According to Stiller, if his doctor had followed the guidelines, Stiller would never have been tested at all and would have been in the dark about the cancer until it was too late to treat it successfully.
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Effectiveness of Cancer Screening
When Ben Stiller had his cancer screening, he was 48 years old and had not reached the recommended age for regular PSA screening as per the US Preventive Service Guidelines. According to a CNN report at the time, the American Cancer Society had debated whether cancer screening should be recommended at the age of 50. It is not a firm recommendation and according to the chief medical officer of the American Cancer Society, Ben Stiller’s case is based on one positive experience. Numerous men had negative experiences of PSA testing that didn’t make the news. He also stated, “They sometimes miss cancer that needs to be found, and they find cancer that doesn’t need to be found.”
Cancer screening is a complicated process and the media has not been able to explain it in a way that provides a positive outlook toward this process. In Ben Stiller’s case, the screening found a cancer in its early stage and allowed it to be treated, with high chances of success. Any medical test, including cancer screening, is not perfect. There are no tests that can guarantee 100% accurate results. In a scenario where perfect screening tests are carried out, it would be impossible to miss out on any important cancers. However, the PSA tests fail to identify all prostate cancers, even the dangerous and the large ones. The old view of cancer was simple—once an organ developed cancer, it would eventually spread and kill the patient. This viewpoint is still common and is seen in many media stories such as that of Ben Stiller. These stories imply that all cancers must be identified and treated. This viewpoint was quite common and accurate until the 1950s and 60s. However, the ability to identify cancers early has changed the understanding of what cancer is all about.
This is a transcript from the video series The Skeptic’s Guide to Health, Medicine, and the Media. Watch it now, on Wondrium.
Dr. H. Gilbert Welch’s Conceptualization of Cancer
In his book Less Medicine, More Health, Dr. H. Gilbert Welch compared cancer to a barnyard filled with three different animals—birds, rabbits, and turtles. According to Dr. Welch, the goal of early cancer detection would be to fence that barnyard in and not let the animals escape. But one cannot fence in a bird. In Dr. Welch’s book, birds represent the most aggressive cancers, the ones that have spread widely before its detection. Thus, cancer screening is ineffective for some kinds of aggressive cancers. Rabbits represent the kinds of cancers that have high chances of being detected in cancer screening. If these cancers are detected in screening, they can be treated before it is too late. Finally, there are the turtles. These are slow-growing cancers and are medically termed ‘indolent’. In such cases, the cells, technically, have the properties of cancer, but they will not spread for many years and will not cause any harm. Unfortunately, most of the cancer screening methods are better at finding turtles than finding rabbits. To complicate things further, one cannot predict what kind of cancer will be detected in the screening. According to Dr. Welch, the best screening is not the one that finds the most cancer, but the one that finds the right cancer. In this context, the right cancer is neither a bird nor a turtle. Not a bird, an aggressive cancer that has spread so far that it cannot be treated; and not a turtle, a cancer that’s unlikely to ever make anyone sick.
It is seen that with PSA screening, most of the identified prostate cancers are turtles. According to the data from the Cochrane review from 2013, prostate cancer screening with PSA testing in men aged 50 or older does not save lives overall and does not prevent deaths from prostate cancer. The results can, however, differ depending on factors such as a family history of prostate cancer, or other health conditions that changed their risk factor. But for average men of average risk, cancer screening with a PSA test is of questionable value. It is not only ineffective but can be harmful as well. It is seen that out of 1,000 who are screened, 160 of them end up getting a biopsy, and sometimes learn that they don’t have cancer after all. The treatment is painful, and expensive, and leaves many men impotent or incontinent.
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Common Questions About Cancer Screening
The media hasn’t been able to explain cancer screening in a way that provides a positive outlook toward the process.
Cancer screenings are complicated and not perfect. They do not guarantee 100% accurate results.
According to the old view, once an organ developed cancer, it would eventually spread and kill the patient.
In his book Less Medicine, More Health, Dr. H. Gilbert Welch compared cancer to three animals—birds, rabbits, and turtles.
According to Dr. Welch, the best cancer screening is not the one that finds the most cancer, but the one that finds the right cancer.
