Sorry to hear about your Dad's diagnosis. It sounds as if you feel a little overwhelmed and it's certainly not unusual to feel that all the information is a bit confusing.
We do have lots of information on our website about lung cancer with a specific page explaining some of the staging systems used by medical proessionals to describe types and sizes of lung cancer. The numbers and letters you mention refer to the TNM staging system which I've linked for you here.
I wonder if you might find it helpful to have a chat with one of our team of nurses who may be able to talk through things with you and help you understand. They are available Monday to Friday 9am to 5pm on 0808 800 4040 (free to call from a UK landline).
