Calcification Small deposits of calcium seen as dots on a mammogram.

cancer A general term for abnormal cell growth and its uncontrolled spread. Cancer cells maygrow into a lump called a malignant tumour . They may invade and damage surroundingtissue. Some may also break away from the original (primary) cancer and travel in the bloodor lymphatic system to other parts of the body, where they form secondary tumours (metastases). The five main types of cancer are carcinomas, sarcomas, myelomas,lymphomas and leukaemia . Cancers at different sites in the body are discussed individually.

carcinogen [car-cin-o-gen] (adj. carcinogenic) Any substance that can cause cancer. 

cardiovascular system [car-di-o vas-cu-lar sys-tem] Consists of the heart and a network of blood vessels. The cardiovascular system is responsible for circulating the blood around thebody, which carries nutrients and oxygen to the tissues and removes waste products. Alsocalled the circulatory system.

CAT scan see CT scan

catheter [cath-e-ter] A hollow, flexible tube through which fluids can be passed into the bodyor drained from it. Sometimes used for specialised tests. A urinary catheter is sometimesused for a time after surgery to drain urine from the bladder.

Cautery Destroying tissue by burning.

cell Cells are the basic building block of the body. They are microscopic in size. They contain cytoplasm and a nucleus enclosed within the cell membrane. The human body consists of millions of cells of many different types, each type specialised to perform a particular function. Skin cells, for example, are flattish and arranged in sheets; nerve cells are long and slender: see differentiated cells.

cell division The process by which cells divide in two to reproduce and replace themselves.

central nervous system (CNS) The brain and spinal cord.

cervical [cer-vi-cal] Of either the neck or the cervix .

cervical smear [cer-vi-cal smear] see Pap test .

cervix [cer-vix] The narrow passage that connects the uterus with the vagina. Sometimes called the neck of the womb .

chemotherapy [che-mo ther-a-py]The use of particular drugs (cytotoxic drugs ) to kill cancer cells or slow down their growth (control cancer). Chemotherapy can also be used to relieve symptoms. The drugs used also affect normal cells and can cause undesirable side effects ,so the dosage must be carefully controlled. Most side-effects can be controlled or prevented, and most are temporary.

Chronic Describing an illness that continues over a long time, with slow changes.

chronic lymphoid leukaemia (CLL) [chron-ic lym-phoid leu-kae-mia] CLL is a type of leukaemia that usually occurs in older people; it is rare in people under the age of 35. People with CLL have too many immature lymphocytes in their blood . Also called chronic lymphatic leukaemia or chronic lymphocytic leukaemia.

circulatory system The vessels and organs that enable blood to flow around the body.

clinical trial Clinical trials test new cancer treatments or may compare existing treatments to determine the best way of improving health outcomes. The research is called a trial because it is uncertain whether a new treatment is better than existing ones.

colitis [col-i-tis] Inflammation of the colon and rectum . The symptoms are usually diarrhoea and pain in the lower abdomen. In ulcerative colitis, ulcers also form in the area.

colon [co-lon] The colon is the part of the bowel between the end of the small intestine and the rectum .

colorectal cancer [co-lo rec-tal can-cer] see bowel cancer .

colostomy [col-os-to-my] A surgical operation in which the colon is cut and brought to the surface of the abdomen to form an artificial opening (stoma) which allows the bowel to pass faeces for collection into a removable colostomy bag secured over the stoma.

colposcopy [col-pos-co-py]/colposcope [col-po-scope] The use of a colposcope to examine the vagina and cervix : see endoscope.

compatible The term used to describe the people donating and receiving a tissue transplant or blood transfusion . If the two are compatible, their tissues and blood are very alike, which means that the recipient's body is less likely to reject the transplant by forming antibodies against it: see tissue typing .

congenital [con-gen-i-tal] Existing from birth. Congenital diseases or deformities may have been contracted in the womb or may have been passed on genetically by either or both parents. They are usually recognised at birth, but some congenital conditions, though present at birth, may not be recognised for some time.

core needle biopsy The core biopsy removes a sliver of tissue for pathology examination.

cross-matching see blood typing .

CT scan [C-T scan] Computerised tomography scan (formerly CAT scan) is a technique for constructing pictures from cross-sections of the body by x-raying the part of the body to be examined from many different angles. Radio-opaque dyes are usually injected or swallowed first to enable the body structures to show up clearly under x-ray. The x-ray information, which is fed directly into a computer, is used to build up detailed cross-section pictures of the body.

cure A cure in cancer means that there is no evidence of cancer being present and a person's illness has gone completely. The length of time for cancer to be considered cured varies, but at least five years remission is a minimum.

cutaneous [cu-ta-ne-ous] Of the skin .

cyst An abnormal sac or closed cavity in the body. A cyst may be small or large, and may contain liquid or semi-solid material. There are many different types of cyst, arising in different parts of the body, with different causes.

cystectomy [cyst-ec-to-my] Surgical removal of the bladder .

Cystoscope An instrument that allows the doctor to see inside the bladder. It also allows removal of tissue samples or small tumours. Cystoscopy is the name for this procedure.

cystitis [cyst-i-tis] Inflammation of the bladder .

cytotoxic drugs [cy-to tox-ic] Drugs or medicines that damage or destroy cells. Cytoxic drugs are used in chemotherapy, used to treat cancer.