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Comment by phkahler | Hacker News Reader

>> Increased use of screening programmes has contributed to this phenomenon to a certain extent, although a genuine increase in the incidence of early-onset forms of several cancer types also seems to have emerged.

How do they separate these two. Early testing is becoming more common so you expect to see more cancer simply due to looking for it.

Doc: Early screening has increased the 5-year survival rate for various cancers.

Patient: Of course it has, but will I live any longer?

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Early-stage cancer survivorship rates are much higher, and early detection catches cancers at an earlier stage. Studies have been done that show the benefit of early screening, separate from the bias.

Do those studies account for the (emotional and monetary) cost of false positives from those early detection?

I don't think monetary cost was accounted for, and I assume by emotional cost you don't mean the hits to someone's health due to emotions (which are accounted for). It's really hard to get diagnosed with a cancer, but early detection is very helpful for improving outcomes.

In the US (in particular), there is a lot more monetary cost to someone's late-stage cancer treatment, and then eventual death, than there is to early-stage cancer treatment, so I would assume that early screening tests are monetarily net beneficial based on the reduction in cancer deaths.

The only cancer routinely screened for in people under 50 is cervical cancer. Even then, the test detects precancerous lesions mainly. As such, ascertainment bias is not a major methodological concern.

Ok. Overall, though, there aren't a lot of cancer screenings otherwise either. You might get a colonoscopy, but you probably aren't checking for bone cancer either.

But you would probably get an MRI of your brain if you were having headaches. An ultrasound to check for gallstones, a CT scan to see if that's your appendix that is hurting. And we are getting way more scans than we used to. A lot of tumors are found as a result of modern imaging technology. More are found by self-examination: We know to watch moles and to do breast or testicular exams at home, for example.

When we find precancerous stuff, we can often keep an eye on it and/or do something about it, hopefully before it gets out of hand.

Colon cancer guidelines have changed screenings to 45.

Yes, but that’s recent and after most of the data in the article was collected.

Lots of cancers are screened in younger people outside of routine: melanoma, colon cancer, breast cancer, etc. are all things that doctors will test for if a person has certain signs (like a suspicious mole or rectal polyps).

That isn’t screening though, which by definition occurs in people without symptoms or signs. It is true that better access to healthcare or higher health literacy or more scans being done for other reasons will increase the early detection rate of cancers in younger people. But this almost certainly doesn’t explain the increasing incidence as the article talks about.

You should be able to see the 'real' increase from death rates, assuming the cause of death is correctly identified as cancer pre or post mortem.

This is the reason most medical studies look at all cause mortality. Cause of death reporting is prone to all kinds of medical judgement and human error that cause reporting specific causes of death to be problematic.

Cancer death rates are going down [1], which to me means we are probably better at treating cancer but also probably finding it more often even when not life threatening and might have gone on unnoticed in an earlier time.

Also we are getting better at treating other diseases and living longer, leading to being more likely to get cancer since if you live long enough you will almost certainly get some form of it.

1. https://www.cdc.gov/cancer/dcpc/research/update-on-cancer-de...

It's slow progress, but we can dream of a day where getting a cancer diagnosis is not a death sentence, but rather something like HIV. Not really curable, but with the right treatment, you can live a fairly normal life. You die with cancer, but not of cancer.

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