In April, I was diagnosed with bilateral localized Stage1a ER+PR+HER2- breast cancer. My treatment plan includes partial mastectomy (completed in May), radiation (currently underway), and hormone therapy (commencing in August). I have a big dive trip planned in November, and my medical oncologist said I should be just fine to dive then, noting that we could adjust my hormone therapy medications as needed if I were having any adverse side effects. My radiation oncologist said that my skin should be fully healed by November, thus immersion in salt water should be OK. However, a different radiation oncologist oversaw a couple of my treatments this week, and I asked him about diving as well. He noted that I should wait 3-6 months after radiation to dive (thus the November trip should be fine), but he said something concerning. He said he'd heard of a patient who experienced lung problems on her first dive trip following radiation. The trip was very close to the end of her radiation, so his concern was that perhaps her lungs had experienced damage from the radiation and hadn't healed in time. He didn't have any other details, but of course it has me concerned. For breast cancer survivors, are there contraindications with possible long-term lung damage from radiation and diving? I'm trying to gather as much information as I can at this point, so that I can fully understand if diving will be a safe activity for me to pursue. I am also calling DAN to get their take on this. Thanks so much for any factual information that anyone could provide!