When is first line treatment finished?

[Shelley (MLC)]

Hi everyone. I am trying to stay on top of everything with my mom, despite living 3000 miles away. She has completed the first of 4-6 cycles of her first line chemo. They are planning to do a CT after the 4th cycle. What will they be looking for in order to stop chemo (temporarily) at that time? Does it need to be at least a 50% shrinkage of the masses? If I remember correctly, if they are happy with the results, they will stop chemo and do monthly Chest xrays until they see a change for the worse. I believe the Oncologist also told us that studies have shown that there is not much difference in the outcome of people that receive 4 cycles vs 6 cycles of chemo. If they don't see a 50% shrinkage (or whatever they are looking for, will they continue with the final 2 cycles of the first line treatment, or does she immediately start her 2nd line? Thanks for your help with this! Shelley