Breast reduction after lumpectomy and radiation does carry a higher complication rate in general but it can be safely done if certain principles are followed. The surgery should be delayed until all of the acute inflammation and swelling from the radiation have subsided and the surgical technique should employ shorter, wider pedicles and minimal undermining of the breast flaps.
Radiation is the "gift that keeps on giving." You are at higher risk for wound healing issues and tissue necrosis after radiation and surgery.
I've done lots of breast reductions on people who have had lumpectomy and radiation. The bottom line answer is that, yes you can still have a reduction, but your risks will be somewhat higher for complication. The increased risk is dependent on several factors. The fact that you say your breast looks and feels normal now is a good sign that the radiation didn't do extensive damage, but that doesn't mean that your risks still won't be increased. When you consult with a surgeon, they should be able to tell you based on the exam how much risk they feel would be encountered by doing a reduction. The most common risks would be poor wound healing or hardening/scarring of the breast.
Hope this helps.
B Hermann MD
Unfortunately there is no way to predict how your breast tissues will respond to a breast reduction surgery after radiation. Given that the tissues are soft with no visible skin change wound healing complications could be less likely but are still not guaranteed. Using a wide pedicle with thick skin flaps would also be somewhat more protective. If you do have trouble healing postoperatively, hyperbaric oxygen treatments could be considered. You really need to have a detailed consultation with a surgeon certified by the American Board of Plastic Surgery to discuss your increased risks. Then you can make an informed decision and decide if the benefits outweigh the risks for you.
You could undergo surgery but with the understanding that you are more likely to experience wound breakdown and/or problematic scarring. A full discussion of the risks and potential benefits would need to be undertaken. There are no precautions that would need to be taken in terms of a medical regimen. The concerns would all be in terms of what would be encountered at operation and consequences thereafter. Best of luck to you and congratulations on being a survivor!