Interestingly, this is a matter of debate right now: see "Forget lung, breast or prostate cancer: why tumour naming needs to change: The conventional way of classifying metastatic cancers according to their organ of origin is denying people access to drugs that could help them" https://www.nature.com/articles/d41586-024-00216-3

A number of companies have sprung up that'll try to a tumor sample to a variety of treatments in order to figure out whether treatments from other tumor sites may work better.

My own tumors originated in my tongue; now I don't have a tongue any more (https://jakeseliger.com/2023/09/09/life-swallowing-tasting-a...) and the tumors reside in my neck and lungs. A lot of oncologists who specialize in head and neck cancers also work in lung, since there seems to be a lot of overlap between the two.

I don't know this for sure, but I think DNA profiling is changing how oncologists, and people more generally, view cancers, or at least many cancers. Decades ago, it wasn't feasible to take molecular snapshots of cancers. Now it's still not quite standard, though it should be, via companies like CARIS: https://www.carislifesciences.com/