Hi,
I filed my taxes with '0' entered after I got the professional advise from my CPA. Even though I didn't get the physician’s certificate showing a reasonable expectation of death within 24 months my CPA suggested to move on with '0' entered because you had a cancer and you should be continued to be monitored for the rest of your life. Just in case it will trigger the audit, I would try to keep all medical records.
Hopefully it helps and I hope the best with your health.
