Most writing about prevention starts at the front end: the test, the scan, the blood value, the reassuring or worrying number. As a surgeon, I see prevention from the other end — the point where the consequences of those early decisions arrive in the clinic and, sometimes, on the operating table. That vantage point is not an argument for or against screening. It is a reason to look closely at what happens after the result.
The view from downstream
Screening programmes, check-ups and private scans sit at the beginning of a long chain. A nodule, a cyst or a polyp found there does not stay on a report; it becomes a referral, a second scan, a consultation — and occasionally an operation. Surgeons stand near the end of that chain. We meet the findings after they have already acquired weight: after someone has been told there is “something”, after the worry has had time to grow.
When the operation is the harm
Medicine has a name for one part of the problem: overdiagnosis, the detection of a “disease” that would never have caused symptoms or death. Welch and Black, summarising randomised trials, estimated that about 25% of mammographically detected breast cancers, about 50% of lung cancers found by chest X-ray or sputum testing, and about 60% of PSA-detected prostate cancers were overdiagnosed. The authors of the 2019 update of the Bosniak classification for kidney cysts wrote that cystic kidney cancer is likely overdiagnosed and overtreated, and that many benign or indolent masses have been removed without clear benefit.
For a surgeon, the consequence is concrete. Even routine operations carry risk: after gallbladder removal, for example, the European guideline puts the rate of major bile duct injury at 0.2–0.4%. When the finding was going to cause trouble, that risk is part of a reasonable trade. When the finding was harmless, any complication is pure harm — there was no benefit to set against it.
The path to such an operation is rarely one big decision. More often it is a cascade of small, individually sensible steps. In a US survey of internists, 99.4% had seen cascades of care after incidental findings, and 86.7% reported cascades that had harmed patients, mostly through anxiety, treatment burden and cost; 15.6% reported physical harm. I describe how to recognise harmless findings in the liver, kidney and adrenal glands in a separate article.
And yet: the patients who came too late
It would be easy, and wrong, to conclude that less testing is always better. Surgeons also see the other side: tumours that are found only when they cause symptoms, at a stage when the operation is larger, the chances poorer, or surgery no longer possible. For some screening tests, randomised trials show fewer deaths from the targeted cancer; our articles on colorectal cancer screening and lung cancer screening in heavy smokers discuss that evidence.
Both observations point to the same conclusion. The real question is not screening versus no screening. It is which test, in whom, and — above all — what we do with the result.
The value of not operating
Some of the most important decisions in surgery are decisions not to operate. Silent gallstones are a textbook case: German and European guidelines advise against removing the gallbladder when stones cause no symptoms, because complications are rare and the operation has its own risks (see our article on silent gallstones). Choosing to watch is not doing nothing. It is an active medical decision that needs explanation, a plan for what would change it, and the confidence to defend it to a patient who came expecting an operation.
Deciding together
Because the balance between benefit and harm is often close, the decision belongs to the patient as much as to the doctor. Shared decision-making is more than a slogan: a 2024 Cochrane review of 209 studies with 107,698 participants found that decision aids improve knowledge and the accuracy of risk perception (high-certainty evidence), reduce decisional conflict, and probably increase choices that match people's informed values.
Questions to ask before treating a screening finding
- What would most likely happen if we did nothing and watched?
- Does a guideline recommend treatment or follow-up for this finding — or neither?
- What are the risks of the procedure, in absolute numbers?
- What would make us change course later?
Bottom line
Prevention is judged by its consequences, not by its findings. Early detection saves lives where trials show it; elsewhere, incidental findings can lead to interventions whose only effect is harm. Ask what happens next before agreeing to any test, and decide on treatment together.
References
- Welch HG, Black WC. Overdiagnosis in cancer. J Natl Cancer Inst. 2010;102(9):605–613. doi:10.1093/jnci/djq099
- Silverman SG, Pedrosa I, Ellis JH, Hindman NM, Schieda N, Smith AD, et al. Bosniak classification of cystic renal masses, version 2019: an update proposal and needs assessment. Radiology. 2019;292(2):475–488. doi:10.1148/radiol.2019182646
- European Association for the Study of the Liver (EASL). EASL Clinical Practice Guidelines on the prevention, diagnosis and treatment of gallstones. J Hepatol. 2016;65(1):146–181. doi:10.1016/j.jhep.2016.03.005
- Ganguli I, Simpkin AL, Lupo C, et al. Cascades of care after incidental findings in a US national survey of physicians. JAMA Netw Open. 2019;2(10):e1913325. doi:10.1001/jamanetworkopen.2019.13325
- Stacey D, Lewis KB, Smith M, Carley M, Volk R, Douglas EE, et al. Decision aids for people facing health treatment or screening decisions. Cochrane Database Syst Rev. 2024;1:CD001431. doi:10.1002/14651858.CD001431.pub6
This article is general information and not individual medical advice. Decisions about tests and treatment belong in a conversation with your own physician.