Does anyone had a tumor bigger than 9 cm? Or had a feet nerve complication from chemo?

Hi, my mom has lung cancer (small cells carcinoma), the tumor used to be 10,5 cm but after 7 chemos is now 9. The doctors say is not operable because is reaching the pleura and the only thing that can be done is radio, that she just started but they don't seen to be very hopefull and they are not really good in talking about what comes next. I don't really know if I am dealing with something that can be turned around of if it is not a possibility. Does anyone got better from a tumor that size?

She can't do chemo anymore because she had a complication and now her foot nerves are damaged and she can't walk without feeling pain. The doctos say there's nothing to do about that pain.

Also, we found out about the tumor because she started to feel severe pain on her torax. Then after the diagnostic, she started to take morphine and did not feel pain anymore. Now, a little before the chemo cicle got to a end the pain came back, stronger. She is taking more morphine but still strong. That begun before the ct that showed that the tumor got 1 cm smaller.

Anyone know what that pain might mean? The doctors don't know and are not looking for what could be and I would like to understand it so I can look for a way of making it better.