Cancer Glossary » Q

Q10 A substance found in most tissues in the body, and in many foods. It can also be made in the laboratory. It is used by the body to produce energy for cells, and as an antioxidant. It is being studied in the treatment of cancer and in the relief of side effects caused by some cancer treatments. Also called coenzyme Q10, CoQ10, vitamin Q10, and ubiquinone.

qi (chee) In traditional Chinese medicine, vital energy or life force that keeps a person’s spiritual, emotional, mental, and physical health in balance.

QS21 A substance from plants that is being studied together with vaccine therapy for its ability to improve the way the immune system responds to disease. It belongs to the family of drugs called saponin adjuvants.

quadrantectomy Surgical removal of the region of the breast (approximately one quarter) containing cancer.

quality of life The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual’s sense of well-being and ability to carry out various activities.