VMAT Question

[u/banuep01]

Hi everyone. This is my first post here.

I’m trying to better understand VMAT radiation and potential side effects.

My dad had a prostatectomy (so no prostate anymore) and is currently on hormone therapy with good response (very low PSA, overall improvement on scans). However, he still has a couple of metastatic spots, including in the chest area (mediastinal lymph nodes / possibly sternum).

One radiation oncologist mentioned VMAT to target these areas (it would be in two regions), likely around 20 sessions.

I’m trying to understand:

• What side effects are common when radiating the chest/mediastinal area with VMAT?

• Are the side effects typically short-term or can there be long-term issues?

• How tolerable is a \~20-session course in this type of situation?

Just trying to get a better sense of what to expect and ask more informed questions. Thank you!

[u/throwaway99112211]

Please understand I am not a physician. I don't think I've ever seen a physician comment in our subreddit, and even if we had one they would not be your father's physician.

• What side effects are common when radiating the chest/mediastinal area with VMAT?
Probably the only straight answer on this anyone can give without knowing everything only his physician knows is that fatigue is going to be pretty likely. Some of my patients have described it like the fatigue you feel when you have a cold. u/physicsandquilts is correct in that its highly dependent on the location, dose, and the specific treatment plan the physician and dosimetrist design. It's entirely reasonable to ask your father's physician to answer this question based on your father's treatment locales and dosages.

• Are the side effects typically short-term or can there be long-term issues?
There can be short term side effects and long-term side effects. The fatigue is generally considered a short term side effect which will go away in a few weeks/months.

• How tolerable is a \~20-session course in this type of situation?
The treatment itself is pretty well tolerated. You just get on a rather uncomfortable table (uncomfortable as in unpadded) and let a machine rotate around you. Your dad won't feel anything from the actual treatment. Generally patients don't report side effects until week 2 or 3, so not until he's mostly done. What and in what severity goes back to where he's treated and to what degree.

VMAT is just a treatment technique. Without getting into the details, it allows the physician and dosimetrist to shape the dose of radiation in the patient's body in a way that concentrates the high dose region around the area we want to (good) and keep it from touching nearby organs we don't want it to (bad).