Methods of Classifying Cancers
Source: Cancer Terminology: The Language of Cancer page at "The Genetics of Cancer resource center". June 11, 2001. © 2001 by PRR, Inc. Eugene Pergament, MD, PhD, Northwestern University Medical School, Chicago, and Morry Fiddler, PhD, School for New Learning, DePaul University, Chicago. This appears to be a dead link. Heavily edited for length by B.Rick.
Classifying by Type of Tissue
- Carcinoma: a neoplasm ("new growth") occurring in the epithelial cells that line organs and cover the surface of the body (~ 90% of all cancers fit into this category)
- Sarcoma: a solid tumor occurring in connective tissue, muscle, and bone (~ 2% of all cancers)
- Leukemia or lymphoma: a neoplasm occurring in the circulatory (leukemia) or lymphatic (lymphoma) systems (~ 8% of all cancers)
Classifying by Type of Cell Transformed
- Adenomatous cells —ductal or glandular cells
- Squamous cells —flat cells
- Myeloid —blood cell
- Lymphoid —lymphocytes or macrophages
Classifying by Site of Origin, Tissue or Cell Type, and/or Founder's Name
- Breast —breast carcinoma of ductal, medullary, papillary, etc, cells
- Bone —osteosarcoma, Ewing's sarcoma
- Eye —retinoblastoma
- Lip, tongue, mouth, nasal cavity —squamous cell carcinoma
- Lymphocytes —acute lymphocytic leukemia, chronic lymphocytic leukemia, Hodgkin's lymphoma
- Prostate —adenocarcinoma
- Ovary —adenocarcinoma, choriocarcinoma, teratoma, Brenner tumor
Cancers are Classified as Benign or Malignant:
- are generally slow growing and enclosed in a fibrous capsule
- are generally considered innocuous, although their location can make surgical removal risky.
- are not considered cancerous (that is, they are not malignant)
- are given names that usually end in "oma" (although a melanoma is a malignant skin cancer)
- proliferate rapidly, invading neighboring tissues
- can metastasize, or spread, to other sites of the body
- are named using the conventions of tissue, cell type, and origin
- A tumor of the bone is an osteoma if benign and an osteosarcoma if malignant;
- a tumor of nerve cells may be a ganglioneuroma if benign and a neuroblastoma if malignant;
- a tumor of melanocytes are nevi if benign but a melanoma if malignant.
Classifying by Tumor Progression
The three variable TNM clinical staging system is used to describe the severity and extent of neoplasm progression.
- Tumor: size and appearance of the tumor. (TIS("in place"), T1, T2, and T3).
- Node: extent of lymph-node involvement. Metastasis is more likely with higher N numbers (N0, N1, N2, and N3).
- Metastasis: extent of metastases. M0 (metastases absent) or M1 (metastases present).