Typically, no – we avoid using radiation therapy during pregnancy, including IG-SRT, out of an abundance of caution for the developing fetus. While IG-SRT’s radiation is very localized and wouldn’t directly expose the uterus in, say, a facial treatment, the principle in medicine is to minimize any radiation to a fetus because they are more sensitive to its effects. If a skin cancer were diagnosed during pregnancy, usually the recommended treatment would be surgery, since local anesthesia and surgery can be done safely during pregnancy (particularly in the second trimester) and that avoids any radiation exposure issues. If surgery were not an option for some reason and the cancer was growing, a conversation with both a radiation oncologist and obstetrician would be needed – but this is a rare scenario. In general, dermatologists would plan to treat a pregnant patient’s skin cancer with something like excision and then consider any needed follow-up therapies after delivery. The risk from IG-SRT to a fetus might be extremely low (especially if treating a distant area like the scalp, with shielding on abdomen), but we err on the side of safety. If you are or could be pregnant, it’s very important to inform the doctor before starting treatment. We would then discuss timing – often skin cancers are slow enough that one could defer radiation until after giving birth if needed. Each situation is individual, but as a blanket rule: we do not perform elective radiation treatment on pregnant patients. So if you’re pregnant, IG-SRT would usually be postponed and alternative measures taken in the interim. It’s one of the few instances where the otherwise safe profile of IG-SRT intersects with a contraindication, purely because any unnecessary radiation during pregnancy is avoided. After pregnancy (and breastfeeding period, just for completeness – though radiation to skin doesn’t affect breast milk or anything), IG-SRT could be resumed.
In summary, pregnancy is a contraindication to IG-SRT unless under extraordinary circumstances. We’d find another way to manage the skin cancer temporarily or definitively without radiation in that scenario.
