Welcome back and I am sorry that things are difficult right now.
If you have been diagnosed with cancer, it is more important now to stop drinking then ever before. Your body needs to be as strong as possible to handle the treatments, surgeries, and stress that comes with cancer. Mentally, you need to be clear, focused, and aware to make the correct decisions for yourself with doctors, and to really arm yourself with all the knowledge you need to make decisions and to tackle this disease.
I know getting news like that is a huge trigger for drinking, but please do WHATEVER it takes to reach recovery. Do you have a support system you can lean on right now? Have you thought about attending meetings or an outpatient rehab program? Counseling would be a huge asset right now, at least for me it is.
Please be honest with your doctors about EVERYTHING. This is not the time to tell half truths or withhold information from your doctors. They need to be completely informed in order to help you the best way possible.
I am so sorry you are going through this, I know this isn't easy but right now it truly can be life or death, and I know even if it is difficult that you choose life.
HUGS
Keep posting, keep reaching out, and never...ever give up on yourself. YOU ARE WORTH IT.