Anaplastic -a pathological description of cells, describing a loss of differentiation and more primitive appearance

Benign -tumors that are generally well differentiated and do not metastasize and invade surrounding normal tissue.  Benign tumors are often encapsulated and slow growing.  Although most benign tumors do little harm to the host, benign tumors of the brain (because of their location) are considered behaviorally malignant because of the adverse effect on the host.

Brachytherapy – radiation treatment of disease accomplished by inserting radioactive sources directly into the tumor site.

Carcinoma - a malignant tumor that starts in the surface layer (epithelium) of an organ or body part and may spread to other parts of the body

Carcinogens – substances that increase the risks of developing neoplasms (tumors)

Carcinogenesis – the generation of cancer from normal cells

 Cellular differentiation - the degree to which a cell resembles it’s cell of origin in morphology and function

Chemotherapeutic agents – chemotherapeutic agents that are classified by their action on the cell or their source and include alkylating agents, antimetabolites, antibiotics, hormonal agents, nitrosoureas, vinca alkaloids, and miscellaneous agents.

Combination chemotherapy - the selection of drugs that act on the cell during different phases of the cell cycle, increasing the killing potential.  In addition, drugs with known toxicities are used for maximum effectiveness, resulting in fewer side effects.

Critical structures - normal tissue whose radiation tolerance limits the deliverable dose.

Cytoxic - the ability to kill cancer cells.   Cytoxic drugs are used to destroy cells of the primary tumor and those that may be circulating throught the body.

Dosimetrist - radiation therapy practitioner responsible for production of the patients’ treatmentplan and any associated quality assurance components.

Electrons - negatively charged subatomic particles that can be accelerated by a variety of machines or are emitted from decaying isotopes and used for external beam treatment and brachytherapy

En bloc - a French term meaning “in one block.”  In surgical cancer care, it means “in one specimen.”

Epidemiology - the study of defining the distribution and determinants causing disease and injury in human populations.

Etiology - the study of the causes of disease

False positive or negative – screening tests may yield false-positive or false-negative readings.  A false positive reading indicates disease when in reality none is present.  A false –negative reading is the reverse; the test indicates no disease when in fact disease is present.

Gamma rays – electromagnetic radiation emitted from decaying isotopes and used for external beam treatment and brachytherapy. (High energy electromagnetic radiation of no mass and no charge emitted during nuclear decay

Grade – the grade of a tumor provides information about its biological aggressiveness and is based on the degree of cell differentiation.  For some tumors, such a high-grade astrocytoma, grade is the most important prognostic indicator.

Immunotherapy – therapy producing or increasing immunity.

Intraoperative – a boost technique in which a single dose of 10 to 20 Gy is delivered directly to the tumor bed with electrons or photons.  The tumor bed has been surgically exposed, allowing critical normal structures to be shielded or displaced out of the radiation beam.

Intrathecal - an injection that requires drugs to be instilled into the space containing cerebrospinal fluid.  Although most chemotherapy drugs can be administered by a the patient or nurse, intrathecal administration is only done by physician.

Malignant – tumors that are malignant often invade and destroy normal surrounding tissue and’, if left untreated, can cause the death of the host.

Metastasize – the process of tumors spreading to a site in the body distant from the primary site.

Multicentric - arising from many foci and having multiple originations.

Natural history – the normal progression of a tumor without treatment.

Necrosis - death or disintegration of a cell or tissue caused by disease or injury.

Neoplasm –  abnormal growth of tissue: a tumor or tissue containing an abnormal growth

Neoplasia –  the formation or existence of tumor

NED (no evidence of disease) at the time of patient follow up examination, there is no residual cancer noted.

Oncogenes – a gene that regulates the development and growth of cancerous tissues.

Palliation – noncurative treatment to relieve pain and suffering when the disease has reached the stage where the disease is no longer curable.

Pedrizone – drug that is used to help patients tolerate the chemotherapy drugs

Phase I, II, III studies – a series of studies performed to assess the risk, benefits, and effects of proposed treatment options.  A phase I study is the first step in testing a new treatment in humans, assessing the best way to give a new treatment and best dose.  The dose is usually increased a little at a time to find the highest dose that does not cause harmful side effects.  A phase II study test whether a new treatment has an n appropriate tumoricidal effect against certain cancers.  A phase III study compares the results of people taking a new treatment with the results of people taking the standard treatment to prove the safety and efficacy of a new treatment.

Photon – small packet of electromagnetic energy (e.g., radio waves, visible light, and x-rays and gamma rays)

Prognosis – the estimation of life expectancy.

Prophylaxis – a treatment to prevent something from happening

Prospective study – a study in which the theory of the cause of a condition or disease is tested by examing those who have a particular characteristic or trait.  The population to be examined is selected in the beginning of the study.

Radiation oncologist - the physician that reviews the medical findings with the patient a discusses treatment options and the benefits of radiation therapy as well as possible side effects.  The physician makes a treatment plan and sends the patient on for treatment planning and/or simulation.  During treatment, the radiation oncologist generally sees the patient once a week to ensure the treatment is progressing as expected.

Radiation therapist– the medical practitioner on the radiation oncology team who sees the patient daily and is responsible for treatment delivery and daily assessment of patient tolerance and treatment.

Radioprotectors – certain chemicals and drugs that diminish the response of cells to radiation.

Radiosensitizers – chemicals and drugs that help enhance the lethal effects of radiation.

Retrospective studies – a study of a group of individuals all having the same disease and common characteristics that might have caused the disease.

Sarcoma – a malignancy arising from other that epithelial tissues of the body

Simulation – a process carried out by the radiation therapist under the supervision of the radiation oncologist.  It is the mockup procedure of a patient treatment with radiographic documentation of the treatment portals.

Systemic treatment – cancer management treatment that encompasses the patient’s entire system, generally through venous means.  Chemotherapy affects not only cancerous cells but other also because of the systemic nature of its delivery.  Radiation therapy has a local and regional focus, meaning it only affects the locals it is aimed at.

Tumoricidal – a dose high enough to eradicate the tumor.