My dad has recently been in the same position and I can fully sympathise with your anxiety regarding spread. Sadly my dads has but on the positive side, not a lot and it’s still treatable. You just have to focus on the positives, this horrible disease is very much treatable these days and the treatments have come on leaps and bounds. I’m a healthcare professional and thankfully due to contacts in my hospital, I pushed for all my dads imaging/biopsies and clinic appointments to happen quite rapidly, now we are just awaiting more biopsy results to come back so that the oncologist can decide on targeted treatment. This has been the longest wait and it’s been awful, I feel sorry for people who have to wait weeks for all the investigations and clinics. We have been very fortunate. 
just stay positive as much as you can, positivity breeds positivity