Cancer Dictionary – O
observational study A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).
occult primary tumor (uh-KULT PRY-mayr-ee TOO-mer) Cancer in which the site of the primary (original) tumor cannot be found. Most metastases from occult primary tumors are found in the head and neck.
occult stage non-small cell lung cancer (uh-KULT … KAN-ser) Cancer cells are found in sputum (mucus coughed up from the lungs), but no tumor can be found in the lung by imaging or bronchoscopy, or the primary tumor is too small to be assessed.
occupational therapist A health professional trained to help people who are ill or disabled learn to manage their daily activities.
oncogene A gene that normally directs cell growth. If altered, an oncogene can promote or allow the uncontrolled growth of cancer. Alterations can be inherited or caused by an environmental exposure to carcinogens.
oncologist (on-KAH-loh-jist) A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.
oncology (on-KAH-loh-jee) The study of cancer.
oncology nurse (on-KAH-loh-jee…) A nurse who specializes in treating and caring for people who have cancer.
oncology pharmacy specialist (on-KAH-loh-jee FAR-muh-see SPEH-shuh-list) A person who works with an oncologist to prepare anticancer drugs.
Onconase A substance being studied in the treatment of cancer. It is a type of ribonuclease enzyme. Also called ranpirnase.
Oncophage (ON-koh-fayj) A vaccine made from a patient’s tumor cells that may help the body’s immune system find and kill cancer cells. This vaccine is being studied in the treatment of melanoma, kidney cancer, brain tumors, and other types of cancer. It belongs to the family of drugs called biological therapies. Also called gp96 heat shock protein-peptide complex vaccine or gp96 HSP-peptide complex.
opiate A drug used to treat pain. It contains opium or a substance made from opium (such as morphine).
opioid (OH-pee-OYD) A drug used to treat moderate to severe pain. Opioids are similar to opiates such as morphine and codeine, but they do not contain and are not made from opium.