This has happened to a friend and the oncologist sees them ever three months and doesn't want to rush him back to HT because his quality of life will change. I think the number is less important than the rate of change but it is certain that the rate of increase will be monitored and that is likely to guide decisions on further treatment.
These days that could well mean chemo as it's got very good results feom the Stampede trial. I think acknowledging that the cancer isn't cured (not totally sure if this is the case here but it is in my friend's case) is a huge leap. Good luck.
Love
Devonmaid