hi there - sorry to hear about your tumour, and hope your gk goes smoothly.
without wanting to be unecessarily gloomy but wanting to give you as much info as possible - although many people do go directly back to work - it is highly variable how our bodies respond.
i happened not to be at work when i had my radiosurgery, and would not have been up to returning for at least a couple of weeks. i was acutely wobbly, needing to hold on to walk, very tired needing to lie down after minor exertion, and even if i had not told anyone they would have been able to see something had happened as one side of my face was swollen from the pins and my eyebrows were paralysed! i also had a lot of headache for some weeks. i did not appreciate how affected i might be so it was a bit of a shock to find myself so incapacitated. those symptoms settled largely by 2 weeks when i went on a cottage holiday but i was still quite fatigued at that point and spent a lot of time reading while my family explored.
i subsequently developed tumour swelling and lots of symptoms came along with that - but that is something most people do escape.
best wishes,
vikki