Hi Mike,
Welcome to OCF and I am so sorry to read of your wife's cancer. I had surgery and radiation treatment in early 2020. My saliva and flavors have continued to return even today over 4 years later. So, try to show patience on that. Although my saliva is still well below what it was before, it is better than a couple years ago. I just kept trying different flavors every month or two. My wife will try something I am eating and be impressed I can handle that level of spice. She knows how sensitive spices were for me over these four years.
There are so many factors in a recurrence calculation. Your oncologist should be a best source on that but feel free to try to find another source if you want it. But, if you do, I would recommend they have access to all your data (the hospital has your exact radiation dosage, surgery details, etc. on file) and you can get a copy for another source to review.
Living after cancer has it's anxieties. I find I am best at reducing that anxiety when I practice gratefulness for every day and stay active both physically and emotionally. One of my favorite internet quick reads on this is "What it's Really Like To Receive a Cancer Diagnosis." on Cancer Pal website. Here is a link.
https://www.cancerpal.co.uk/post/what-it-s-really-like-to-receive-a-cancer-diagnosisAlso, here is one of the most content rich books on how to live a life to reduce cancer risk. Anticancer - A New Way of Life. It covers everything from food, to exercise, to stress, etc.
Hope this helps and please keep us up to date.
Best,
Nels