Glossary of Cancer Related Terms O - R


OCN (Oncology certified nurse)

A registered nurse who has met the requirements and successfully completed a certification examination in oncology.


A doctor who specializes in oncology.


The study and treatment of cancer. Doctors who specialize in oncology are called oncologists.

Oncology clinical nurse specialist

A registered nurse with a master's degree who specializes in the education and treatment of cancer patients.


Palliative treatment

Treatment aimed at the relief of pain and symptoms of disease but not intended to cure the disease.

Pap (Papanicolaou) smear

A test to detect cancer of the cervix.


Removing fluid from the abdomen using local anesthesia and needle and syringe.

Pathological fracture

A break in a bone usually caused by cancer or some disease condition.


The study of disease by the examination of tissues and body fluids under the microscope. A doctor who specializes in pathology is called a pathologist.


Tiny areas of bleeding under the skin, usually caused by a low platelet count.


A painful inflammation of the veins.


Extreme sensitivity to the sun, leaving the patient prone to sunburns. This can be a side effect of some cancer drugs and radiation.


An inert substance often used in clinical trials for comparison.

Platelet (Plt)

Cells in the blood that are responsible for clotting.

Platelet count

The number of platelets in a blood sample.


A growth of tissue protruding into a body cavity, such as a nasal or rectal polyp. Polyps may be benign or malignant.

Port - Implanted

A catheter connected to a quarter-sized disc that is surgically placed just below the skin in the chest or abdomen. The tube is inserted into a large vein or artery directly into the bloodstream. Fluids, drugs, or blood products can be infused, and blood can be drawn through a needle that is stuck into the disc. Examples: Port-o-cath, Infusaport, Lifeport.

Port - Peritoneal

A catheter connected to a quarter-sized disc that is surgically placed in the abdomen. The catheter is inserted to deliver chemotherapy to the peritoneum (abdominal cavity).

Primary tumor

The original cancer site. For example, breast cancer that has spread to the bone is still called breast cancer.


One of the female hormones produced by the ovaries.

Progesterone-receptor assay

A test that determines if breast cancer is stimulated by the hormone progesterone.


The projected outcome of a disease; the life expectancy.

PSA (Prostate-specific antigen)

A marker used to determine prostate disease; it may be benign or malignant.


Artificial replacement of a missing body part.


A treatment plan.


Radiation therapy

X-ray treatment that damages or kills cancer cells.


A doctor who specializes in the use of x-rays to diagnose and treat disease.


The reappearance of a disease after a period of remission.

Red blood cells (Erythrocytes)

Cells in the blood that deliver oxygen to tissues and take carbon dioxide from them.

Red blood count (RBC)

The number of red blood cells seen in a blood sample.


The shrinkage of cancer growth.


The reappearance of a disease after its apparent cessation.


Complete or partial disappearance of the signs and symptoms of disease.

Risk factor

Anything that increases a person's chances of developing cancer, for example, smoking and lung cancer.

Source: National Institutes of Health and National Cancer Institute No implicit or explicit endorsement of any company is implied.