For metastatic NSCLC patients who are started on first-line platinum doublet chemotherapy and are subsequently found to have an EGFR exon 19 or 21 driver mutation, do you switch to an EGFR TKI immediately once the mutation is detected or do you wait until progression on chemotherapy?

It depends on the response and toxicity of the chemo. If patient is in first 2 cycles and responding without out much toxicity I complete 4 cycles and then switch more or less as maintenance. If patient is not responding or having unacceptable toxicity, I switch right away. I have two patients on er...