You will need to share more of your histopath report. If there was need for IVC removal, there is a good chance that it was an advanced tumor, so you need to follow up for atlwasr 5 years after surgery. PET scanning at every 6 months is not required though. You can also get a contrast CT of chest and abdomen

Hi, Even after apparently complete surgical resection, however, local or distant relapse occurs in nearly 80% of cases. Documented cases exist of AC recurrence more than 10 years after presumed curative surgery. Recurrent or relapsing AC is usually a bad situation. Although symptoms of hormonal excess can often be medically managed in this setting, cure is virtually unknown. Consult Oncosurgeon....