Stages of neuroendocrine tumors
Identifying the stage of disease is an important step in planning the appropriate treatment for neuroendocrine tumors. NETs may:
- Be contained in a particular area of the body (localized)
- Have spread to nearby tissues or lymph nodes (regional)
- Have spread throughout the body (metastatic)
More than 50 percent of NETs have already spread to other parts of the body by the time they are diagnosed. NETs metastasize most often to the liver, peritoneal cavity or bone.
Neuroendocrine tumors are staged according to the TNM staging system: tumor (T), node (N), metastasis (M). The World Health Organization (WHO) classifies neuroendocrine tumors according to the malignant potential of the tumor:
- Well-differentiated neuroendocrine tumors (grade 1 and 2)
- Poorly-differentiated neuroendocrine tumors (grade 3)