I get two regular surveys:

- one every 3 months because I'm a participant in the international IRONMAN study (called TruNTH here in Canada)

- one from the Ontario health ministry called "Your Symptoms Matter", which tracks symptoms like pain, mobility, energy level, continence, emotional state, etc. It comes before every quarterly oncology appointment, and helps my medical team spot changes over time

I'd be concerned about anything that just appeared in your inbox out of the blue. You can call your cancer centre or oncologist's office to see if it's legit and appropriate.