@caz591 i had radiotherapy first (continuing phesgo till I started Kadcyla/during radio) then 2 week break after radio before starting Kadcyla. Everywhere seems to be different… There is a very small risk of lung issues with both radiotherapy and Kadcyla so my cancer centre prefer to do one at a time to reduce the risk of any issues. I do think it is a very small risk though, as plenty places seem happy to do both at the same time.