For reference, 6 years ago when I left medical school the average survival for metastatic melanoma patients was 6 months.

5 Year survival rate is one of the standard measures for the effectiveness of a medical treatment.

That's what always bugged me: after a 5-year survival, what is the typical probability of cancer ever returning? I.e. to what extent 5-year survival == "cure"?

Muy guess is that you have 52% of surviving another 5 years. But as the xkcd lanes comic linked explains you are never really cured.

If you want a display that imo really hits home for some reason, see xkcd "Lanes". The uncertainty that patients are going through in the years after a cancer diagnosis/treatment must be brutal.

https://www.xkcd.com/931/

Oh I'm aware. I'm over 2 years since my diagnosis.

Oh, I'm sorry. I wish you all the best!