Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
These symptoms usually call for prompt contact with the treating team, but they are not automatically emergencies.
Seek urgent or emergency care for severe breathing difficulty, fainting, confusion, sudden major blood-pressure symptoms, vomiting with inability to keep fluids down, heavy gastrointestinal bleeding, or intense abdominal pain with swelling and inability to pass stool or gas.
Follow-up is individualized according to the tumor’s site, grade, stage, treatment, and pattern of growth.
Routine follow-up may include symptom review, physical examinations, CT or MRI scans, and selected hormone or tumor-marker tests.
The same imaging method is often used over time so that changes can be compared accurately.
The article also says
Patients should report new or steadily worsening flushing, diarrhea, abdominal pain, wheezing, weight loss, swelling, or reduced ability to exercise.
Long-term care may also include heart monitoring for carcinoid syndrome, nutrition support, management of treatment effects, and genetic counseling when an inherited condition is possible.
Keeping copies of the pathology report, operative notes, imaging reports, and treatment history can help when care involves several specialists.
Every sign above is quoted from the sofidex article on Carcinoid apudoma. If you are not sure, err upward — it is always reasonable to be checked.