It's worse then that unfortunately. Even when invasive tests are positive, and we think we caught a cancer early, we know from population statistics that the reality is that often nothing would have happened. So we don't even truly know how to tell a cancer that will kill you from one won't. And we don't really know what it is that we don't know.
This is more true for some cancers then other though. Prostate, breast, and maybe melanoma are the worst in this regard. This is why prostate and breast cancer screening programmes are controversial, although the needle is swinging towards them being more useful as surgeries and treatments get better. Some other cancers like pancreatic cancer will always kill you eventually, so it's always good to catch them. It's a nuanced problem.
This whole issue is called "overdiagnosis", and personally I used to be obsessed with it. Being aware of it mostly caused a lot of hand wringing and grief, it's just easier to believe that every cancer you catch is a good thing. However, one of the broader issues is that we will never know what we don't know if we don't look. So there exists another perspective that all the suffering caused by overdiagnosis will eventually pay off in the long term. This is the "collect all the data for science/AI" perspective, and I've personally tentatively adopted it myself, although perhaps that's just because it's nicer to believe that you do some good even when you do harm. I think it's more likely that [novel cancer therapies](https://www.nature.com/articles/s41586-026-10738-7) will solve the "harm" part of treatment before we solve overdiagnosis.
The reality is that important breakthroughs are often entirely unrelated to the data for you are collecting, and even worse that possibly helpful data is locked away due to regulation and never used. This is kinda why I've come to make some kind of peace with private clinics scamming people with whole body MRIs, as I'm sure they're secretly selling the data which might lead to some good. However, they would probably do even more good if they didn't exist so they didn't jack up the prices for MRI machines by inflating demand. The marketing they do is the most morally reprehensible part of the whole deal, as it's usually just lying and creating health anxiety for profit. The fact that midjourney here is marketing themselves in this direction is giving me some serious Theranos vibes. Quick and cheap MRI equivalents would be really useful in the clinic, and it would have to spend a few decades there to prove it is useful before moving on to the "spa" stage. That they are trying to market a render of an idea directly to the wellness crowd firmly puts this in the "scam" folder for me. The fact that midjourney is mostly irrelevant now also fits well with this, making it likely that this is either a marketing stunt or a desperate pivot to get funded. Hopefully there are not that many suckers who will put their VC money down on this loosing bet.