In lung cancer, like the type I have, EGFR refers to the Epidermal Growth Factor Receptor. In my case, I have a mutation of the EGFR gene, Exon 19. The Exon 19 designation indicates the specific protein molecule that has mutated. The mutation has caused the receptor cell to become cancerous, which means it's replicating way faster than intended.

Tagrisso is a targeted therapy that specifically targets these runaway receptor cells. The beautiful thing about this targeted therapy is that Tagrisso crosses the blood/brain barrier, unlike chemo. So Tagrisso protects our brains as well as the rest of our body.

I had my brain surgery to remove the metastatic lung cancer cyst in 2020. September 30 will be three years cancer-free, thanks to Tagrisso.

As sg points out, eGFR refers to something else in kidneys - a filtration rate, used to determine if the kidneys are functioning normally.