Yeah it would still be considered breast cancer because that’s where the cancer cells first developed. The cancer that has metastasized and spread to other locations are still genetically more similar to the original site than their new site and require being treated as such. So if her breast cancer metastasized to her lungs, breast cancer treatment methods would work best, lung cancer treatment wouldn’t be as good. You would have all the complications of lung cancer though. If it had metastasized to her lungs it could be referred to as secondary lung cancer, or lung metastasis. The term metastasis meaning that it came from elsewhere. But it is still breast cancer. Breast cancer cells don’t have to remain in the breasts, once they’re in the surrounding tissues and muscles, they’re there. The body doesn’t ever get rid of cancer fully, no matter how much treatment. Once it’s in the body it’s in the body, it might be sitting in the nearby skin or muscle tissues doing nothing, but it’s still there. It’s for that reason that we no longer tend to use the term cancer free, because you are never fully free of it. Instead we refer to it as in remission, which is when you no longer have the signs and symptoms of cancer. But it can always come back. Hope that helps clarify.
