Hello jaybe4 and thanks for posting,

Firstly, I think if these pains in your upper abdomen and lower back are persisting you should mention them to your GP, they may well have nothing to do with the lung cancer - pains in these areas are common and can have a number of causes - but it is always a good idea to get checked things like this out. Hopefully your GP will be able to give you some peace of mind.

I am not quite sure what the category 1(b) refers to, it could be the tumour size or the overall cancer stage (which is a combination of tumour size, lymph node status and whether the cancer has spread), but either way the number 1 infers an early stage cancer which is good. 

I wouldn't have thought that the KRAS mutation means your cancer is much more likely to come back - I have read that the presence of a KRAS mutation doesn't appear to have much of an effect on overall survival in people with early stage non small cell lung cancer (NSCLC). An adenocarcinoma is a type of NSCLC. 

Perhaps if you ever had a lung cancer specialist nurse you could ask them too. 

Give us a call if you want to have a talk. Our number is Freephone 0808 800 4040 and we are around from 9-5 weekdays.

Best wishes, 

Julia