Hi @Kats162.
This is such a sneak lurking shit of a disease. Mine came back after 10 years NED though, thankfully, it appeared to be confined to my armpit (where it had set up camp with great authority)
My situation is not comparable to yours, local recurrence is not the same as metastatic disease. Thing is, even though my life was pretty good, I wasn't surprised. I felt like I had spent 10 years waiting for the news it was still after me. I know it is still there. It was still there last time I thought I was free. I find that quite challenging because all I can do is wait until the next time.
The cancer was likely to always have been present, just hanging around in the background. Mongrelling stuff that it is. Now you know where it is, you can have a red hot go at keeping it in its box. That's probably pretty trite advice, but this shit can drive you mad, which will make a bigger impact on your life in the short term than the disease is likely to.
Good luck with the treatment next week. It's tough walking back in those doors when you know what is on the other side. You are stronger than you think, and you will find your own way through this. Mxx