Stage 3 lung cancer

a surprise discovery of a 6cm mass in my mediastinum on chest xray in August with PET and biopsy following, I have had my first oncology appointment today.   I have been told I have an adenosquamous carcinoma in a paratracheal lymph node which makes this cancer a stage 3a. The original lung cancer would appear to have vanished.

I have been told that without treatment, I have 6 months. With treatment there is a 60% chance of cure. Not suitable for surgery due to location and due to start chemo (carboplatin and paclitaxel) and radio in 2 weeks which will last for 6 weeks with a year of immunotherapy to follow.

I felt quite positive after the appointment but tonight it has hit me, I feel so lonely and tearful and I'm considering declining treatment. This is not a journey I wanted to take part in and I'm not sure I can do it.