Any symptom similar to IBS can be a symptom for Carcinoid. If you are treated for IBS and get no better - you need your doctor to do some further testing. You need to research this disease and see if the symptoms you are experiencing are similar to these and if so you need to be YOUR OWN ADVOCATE and bring it to the attention of your doctor. A doctor can only diagnosis something if he actually tests for that "something".
A Good Gastroenterologist or Primary Care Provider should be willing to do the testing for you. Most NET Specialists will only see you if you have been confirmed to have the disease. A good Oncologist should also be a doctor that would be able find this disease.