Don't get a whole-body PET-CT or a “tumor marker package” when you have no symptoms

Cost

A whole-body PET-CT costs about 7000 to 10000 CNY per scan and also exposes you to ionizing radiation. A tumor marker package costs a few hundred CNY. The real cost comes afterward: finding one “abnormality” that turns out to be a false alarm (called a false positive), and then the follow-up tests, tissue sampling and surgery, where the money and the suffering add up.

What you get

The USPSTF, the U.S. body that grades preventive measures, gave a grade of D, meaning it recommends against, to screening women with no symptoms for ovarian cancer using CA-125 and ultrasound. The basis was the PLCO trial. The share who died of ovarian cancer was 0.34% in the screening group and 0.29% in the usual-care group. RR 1.18 (95% CI 0.82–1.71). Screening did no good. The share who had surgery they did not need because of a wrong result (a false positive) ranged from 0.2% to 3.25% across trials, and among these people up to 15% had serious surgical complications. Another study gave whole-body CT screening to 1,192 people with no symptoms. Of them, 86% had at least one “abnormality” found, and 37% were advised to have further tests. The original says “most findings were described as benign.” It looks like a good deal because “check the whole body at once, catch it early, treat it early” fits intuition so well

Notes

The tumor marker part is backed by randomized controlled trials. The whole-body CT and PET-CT part has only follow-up records of what happened to people who had it, with no comparison groups, so the evidence is a notch weaker, roughly grade B. The few screenings that really do have evidence, such as colorectal, cervical and breast cancer, and low-dose chest CT for high-risk people, are a different matter; see §1. A PET-CT in someone who already has symptoms or has already been diagnosed with cancer is medical care, not screening, and is a separate case

Evidence grade

A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.

Sources

1. US Preventive Services Task Force (2018). Screening for Ovarian Cancer: US Preventive Services Task Force Recommendation Statement. JAMA（同一份建议另有 USPSTF 官方页）. https://doi.org/10.1001/jama.2017.21926、https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/ovarian-cancer-screening
2. Furtado CD et al. (2005). Whole-body CT screening: spectrum of findings and recommendations in 1192 patients. Radiology. https://doi.org/10.1148/radiol.2372041741

Translated from the Chinese original. Original book, section 6, tip 7. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer