Diagnosing and treating neuroendocrine tumors (NETs) is complicated by the extreme variation in tumor behavior and tumor subtypes. Some patients are completely asymptomatic and diagnosed incidentally. Others have had symptoms for many years but remain undiagnosed because this malignancy is not considered. NETs are mostly diagnosed in the GI tract or lungs, but tumors of hormone-producing cells can occur almost anywhere. Also, the location of the tumor can lead to misdiagnosis based on the body part, i.e., pancreatic or lung cancer instead of a NET.

NETs have a reputation as slow-growing tumors, or “not cancer” due to the use of older terminology “carcinoid” (or cancer-like), but there are high-grade variations, such as the poorly differentiated neuroendocrine carcinomas (NECs), which are very aggressive and often recur. On the other hand, patients with indolent disease may get over-treated with aggressive therapy. Complicating the situation further is the lack of education about NETs in healthcare because it is classified as a rare disease.