Note
Mom was put on hormone replacement therapy after menopause. Studies have shown lower risk of bones breaking, and lower risk of colorectal cancer. She later (in 2005) developed ER/PR- and HER2/neu-positive breast cancer, and studies have shown an increased risk of developing breast cancer for women who take the combination of hormones that she was prescribed. Her breast cancer was caught early by a mammogram, and all of it was removed in the biopsy surgery. However, her oncologist had her do radiation therapy and chemo as well. The radiation was aimed at the general area where the small lump had been, and that is where she now has lung cancer, on the left side.
I think the hormone therapy was probably excessive and causally linked to the breast cancer, and the radiation therapy was probably unneeded and causally linked to the lung cancer.
The lung cancer metastasized to the bone before they found it. Chemotherapy starts next week, unless one last test shows high PD-L1 (unlikely), in which case they can try targeted therapy against PD-L1.