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Comment by scarecrowboat | Hacker News Reader

What if the followup procedure is invasive and expensive? It's possible that this procedure could be net negative in aggregate depending on the % of false positives and # of resulting needless followup procedures. Not to mention the emotional stress.

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Exactly! This reminds of the recent case of the AMA increasing the suggested age of regular mammograms. More testing means earlier detection of breast cancer. But a false positive means an invasive biopsy. These are the two sides that need to be balanced. The AMA decided that since the base rate of cancer is so low in women under 50, the posterior probability that you have cancer given a positive mammogram for the under 50 age group is considerably low. Therefore they decided that the increased costs (monetary and emotional) do not outweigh the benefits.

From https://www.ama-assn.org/sites/ama-assn.org/files/corp/media...

"Screening mammography reduces mortality from breast cancer, including in women younger than age 50 years. However, screening mammography carries harms such as false positive results that can lead to additional imaging and invasive biopsy procedures, and overdiagnosis that could lead to treatment in patients who may not benefit from it. The USPSTF considered the balance of benefits and harms using a commissioned targeted systematic evidence review of randomized clinical trials and a decision analysis that compared the expected health outcomes of starting and ending mammography at different ages and using annual and biennial screening strategies; it concluded (in part) that routine screening should begin at age 50 years and continue biennially until age 74 years."

>But a false positive means an invasive biopsy.

Nah, there's plenty of other things you'd try before the biopsy.

Don't do it, then. Try homeopathy or whatever thing feels good for you.

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