Robert-
My original diagnosis was Metastatic Adenocarcinoma lung primary and I was Stage 3b at the time. I was told that the staging is based on where all the cancer is found. I had a spot on my lung detected from a CT at a physical. When a biopsy was scheduled via navigational bronchoscopy one of my lymph nodes on the opposite side was found to have issues and was biopsied. Tumor is stage 1, stage 2 is detection nearby but still contained on the same side in the same organ. Stage 3 was outside that organ but within close proximity like a lymph node. 3b since the lymph node was on the opposite side. I became stage 4 when the cancer had spread to the fluid in the pleural effusion. At least that is how I remember the staging being explained to me. I was also told that staging is the way the physician determines the approach for treatment. From what I have read my initial treatment was textbook for my diagnosis. Chemo and radiation. Once complete it was typical to go to immunoyherapy for “maintenance” or prevention treatment. Unforunately, the immunotherapy did not work as expected for me. You are correct, not every drug works for every individual. That is why it is critical to seek as much expert advise as you can get.
Looking back, knowing what I know now, I would demand biomarker testing before any initial treatment. Of course hind sight is always 20/20. Who knows what would have happened since Tagrisso wasn’t approved by the FDA until I had already had a couple of months of treatment.