It sounds like you are hang up on the fact that everyone "might have cancer", thus technically everyone "might have cancer"?

It depends on the context of the sentence. It is unlikely that they just sent out a one line email saying "you might have cancer" and nothing more.

If the context of the letter makes it clear that they are raising awareness about the possibility of people having cancer (such as for example listing symptoms to look out for, or general population statistics) that cannot be done "wrongly". (It might be still unduly alarming, distasteful, factually incorrect or unethical for a host of other reasons.)

If the context is that they are telling you that they have run tests on your recent lab samples, and those tests are positive for the presence of cancer. That is an entirely different animal. That can be done "wrongly" if for example they have not done lab tests or the lab tests do not indicate that you have a higher probability of having cancer.

"You might have cancer" is an example of a sentence whose meaning can't easily be analysed in terms of "truth conditions" (https://en.wikipedia.org/wiki/Truth_condition). When used appropriately, the speaker has information which they believe the listener does not already have and which, in the opinion of the speaker, should cause the listener to increase their estimate of the probabiliy of them having cancer ... or something like that. So the appropriateness of the statement depends rather crucially on the context and on prior knowledge. That's why sentences with the word "might" tend to become infuriatingly meaningless when quoted out of context by journalists.

80% of men over 80 have prostate cancer. It is virtually an inevitability that if you live long enough, some cancers will develop. The questions which are more pertinent are: at what stage is your cancer, where is it located, is it metastasizing, and how progressive is it.

This test goes beyond "do you have cancer" by probabilistically identifying the presence, location, and progression of cancers. The results are shared with your doctor, who analyzes the results, gives them to you, and sets up your diagnostic and treatment plan.

Galleri does not talk directly to patients. This email was more like "your results say you need to follow up with your doctor" so the result was 400 people potentially having an extra doctor visit where they did not have any cancer results to discuss. Hardly malpractice.

I was told on the phone I had vitiligo cause the doc mixed up my results with those of another patient. Devastated upon getting the news, so much relief when I went to visit him to discuss treatment and he told me the mistake.

You might have cancer.

Just as an example of how you might wrongly tell someone they might have cancer