Cancer Terminology

Radiation therapy
This is the exposure of tissues to a radioactive source. Brachytherapy implies radiation delivered over a short distance (usually given as implantable beads or as a radionuclide that is injected and seeks a specific target in the body). Teletherapy describes radiation given over a distance, from a machine under which the patient is positioned. The two main types of teletherapy are orthovoltage (high energy x-rays) and megavoltage (from a Cobalt radioactive source or from a linear accelerator). Megavoltage is most commonly used in both veterinary and human medicine.

Cancer
Cancer is the common term used to describe a neoplastic process in the body.

Neoplasia
Abnormal new growth of tissue, unresponsive to normal stimuli and regulatory signal

Hyperplasia
Increase in the number of normal cells resulting from stimulation, and resulting in an increase in the size of the tissue affected.

Dysplasia
Proliferation of tissue that is typically regarded as premalignant

Malignant
This term means that a tumor has the ability to metastasize (spread) throughout the body

Metastasis/metastasize
When a tumor leaves its original site and successfully grows in another site in the body, this new lesion is called a metastasis.

Chemotherapy
This term technically simply means treatment with drugs but has become synonymous with cancer chemotherapy in our culture. Chemotherapy drugs are commonly used to damage DNA in order to exploit cells that are rapidly dividing such as cancer cells. This property explains some of the side effects we see such as low white blood cell and platelet counts, and stomach upset, as there are populations of rapidly dividing normal cells in these tissues.