Hi Lilly- WOW, you've certainly done a good job researching your cancer. It can be pretty confusing, eh? Personally, I have never heard of STAS so I did my own research. Do you know how many things have STAS as their acronym?

I found this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354155/

I also found this study done pretty recently 2020. It has a more positive consideration for future surgery and results:
https://bmccancer.biomedcentral.com/articles/10.1186/s12885-020-07200-w
It's my feeling that a comprehensive conversation should take place concerning possible treatments at this stage, having DNA testing to see what anomalies there are and your next tests. If your present doctor doubts the existence of a particular finding and you don't feel this way I would get a second opinion!

At this point that may already have happened?