What Does Cancer Screening Tell Us?

Cancer is an especially frightening disease. To “catch it early” we have come to rely on screening tests such as a mammogram, PSA, and colonoscopy. Whether a physician recommends a test or we learn about it through advertisements, we have come to believe that early detection will significantly increase life expectancy. Yet, a recent article in the Journal of the American Medical Association states, “The high hopes that early diagnosis of cancer through screening extends life expectancy have become increasingly controversial.” (The Future of Cancer Screening—Guided Without Conflicts of Interest, Hans-Olav Adami, MD, PhD et al JAMA Internal Medicine August 28, 2023).


In plain language, the authors are casting some doubt on the association between early detection and outcome. They note, “After much enthusiasm for cancer screening in the 1970s to early 2000s, realization of uncertain benefits, growing concern about overdiagnosis, and recognition of the harms of false-positive screening tests and burdens of downstream diagnostic and therapeutic procedures have made cancer screening a polarized area in contemporary medicine.”


To further complicate issues surrounding screening, the authors raise potential conflicts of interest by those who manufacture the tests, those who perform them and those who provide treatments. The authors acknowledge, “It is difficult or indeed impossible to phase out screening programs, even when research has failed to document significant benefits.”


With this in mind, what is a patient to do about understanding the benefits or potential harms of cancer screening? The answer to this question is complicated. Patients are not experts in medical science or the politics of healthcare. Yet, it is in their best interest to ask about the purpose of the test and its reliability in establishing an accurate diagnosis.


As much as we’re grateful for advances in screening technologies, patients once again need to take responsibility for initiating conversations about the accuracy of these tests. This effort may feel like an added burden or uncomfortable but understanding the reliability of test results could lessen the possibility of receiving unnecessary procedures and treatments. For anyone being screened for cancer, that’s no small matter.