I hope you don’t mind, one of the moderators asked us if we could post something on your thread.
It would be a good idea to speak to your hospital team or GP about this. I think they will want you to start radiotherapy as planned, but do check with them.
This subject is a bit complicated and so I have tried to give you some general information. People whose immune systems are weakened do need to take care if potentially exposed to chickenpox. This includes people with cancer who are having chemotherapy or radiotherapy that suppresses the immune system. Local radiotherapy treatment to the breast (which I assume you are having) does not usually have a major impact on the immune system. Radiotherapy treatment involving the bones (where blood cells are made in the bone marrow), or chemotherapy can have more of an effect on the body’s ability to fight infection.
Around 90% of adults raised in the UK are immune to varicella (the chickenpox virus). If you have had chickenpox before you are probably immune to it and so your risk of developing chickenpox is low. If you have not had chickenpox, there is a risk that your could get it if exposed to someone who is still contagious with chickenpox. You may have already read that adults can be quite unwell with chickenpox, so this is best avoided if possible.
In some situations, people whose immune system is suppressed can have a blood test to find out if they have developed the antibodies to varicella, and so are protected from chickenpox. But I don’t know if this would apply to your situation.
It is not possible to catch shingles from someone with chickenpox (but it is possible to catch chickenpox from someone with shingles). It might help to read information about chickenpox on the NHS Choices website here and here.
I hope you are able to speak to someone in your team soon as they are the best people to advise you.
