Diagnosis of Carcinoid Tumors

Classification and Staging of Carcinoid Tumors

Classification of gastrointestinal carcinoid tumors is based on where the tumor originates and includes three categories:

  • Foregut - lung, thymus gland, pancreas, stomach, and duodenum
  • Midgut - small intestines, appendix, and cecum
  • Hindgut - colon (large intestine) and rectum

Staging of a tumor is a term used to indicate the presence and/or extent of the proliferation of tumor cells and how far they have spread. Low numbered stages indicate localized tumor with no activity outside the original tumor and high stages indicate metastatic spread to distant organs.

There are variations of approaches to staging carcinoid tumors. Some physicians stage carcinoid tumors as they would any other cancer of that particular organ while others divide the stages into 3 generalized categories of disease:

  • Localized - indicates that the tumor has not spread beyond the organ of origin
  • Regional - indicates the tumor has spread beyond the walls of the organ into nearly tissue (e.g. fat, muscle) and/or lymph nodes
  • Distant - indicates that the tumor has spread to other organs in the body

Since carcinoid tumor of the lung is rare, some physicians follow the same system of describing tumor growth and spread as that used for non-small cell lung cancer. The system is also known as the AJCC (American Joint Committee on Cancer) system and consists of:

  • T = Tumor Size - describes the size of the tumor and indicates if it has spread to nearby organs. The staging values range from T1 (tumor smaller than 3 cm. with no metastasis present) to T4 (tumor has spread extensively in the chest cavity or in other parts of the lung).

  • N = Nodal Involvement - describes the degree to which tumor activity has spread to the lymph nodes. Values range from N0 (lymph nodes are not affected) to N3 indicating that the tumor has spread either to the lymph nodes in the collar bone or to nodes around the second lung.

  • M = Metastases - describes the extent of the spreading of tumor to distant site. The range includes M0 (no spread to distant sites) and M1 (distant metastases are present).