Neuroendocrine Tumors

Diagnosis

Diagnosis of neuroendocrine tumors usually begins with a physical exam. A healthcare professional may check for signs of cancer, including swollen lymph nodes or indications that the tumor is producing excess hormones. A review of symptoms and medical history is also part of the evaluation.

Tests to look for excess hormones

Some neuroendocrine tumors produce extra hormones. Blood or urine tests may be performed to detect elevated hormone levels, helping identify hormone-related symptoms.

Imaging tests

Imaging tests provide pictures of the inside of the body, showing the tumor’s location, size, and whether it has spread. Common imaging tests include:

• Ultrasound

• Computerized tomography (CT) scan

• Magnetic resonance imaging (MRI) scan

• Positron emission tomography (PET) scan with a tracer, sometimes called a somatostatin receptor (SSTR) PET scan or dotatate PET scan

Biopsy

A biopsy removes a small sample of tissue for laboratory testing to confirm the presence of cancer cells. The method depends on tumor location:

• Bronchoscopy for lung tumors

• Colonoscopy for tumors in the colon or rectum

• Surgery if other methods are not feasible

Examining the cancer cells

Lab professionals assess the tumor cells to determine differentiation:

• Well-differentiated tumors resemble normal cells, grow slowly, and are less aggressive. These are sometimes called carcinoid tumors.

• Poorly differentiated tumors look different from normal cells, grow quickly, and are more aggressive. These are called neuroendocrine carcinomas (NECs).

Differentiation helps the healthcare team predict behavior, prognosis, and guide treatment decisions.

Measuring how fast the cancer cells are growing

The tumor’s grade indicates how quickly the cells are growing. Lab tests measure the mitotic rate (dividing cells) and Ki-67 score (actively growing cells). Grades range from 1 to 3:

• Grade 1: Low grade, slow-growing tumors

• Grade 2: Intermediate grade, faster growth than grade 1 but slower than grade 3

• Grade 3: High grade, fast-growing tumors