salivary gland cancer [sa-li-va-ry] A cancer of one of the salivary glands, most commonly the parotid glands (see parotid tumour). It usually appears as a slow-growing lump in the cheek.

screening Examining and/or testing a large number of people who have no symptoms of a particular disease, to identify anyone who may have that disease. This enables the disease to be treated at an early stage, when cure is more likely. Examples include Pap tests to detect precancerous changes of the cervix , and mammography, to screen women for early breast cancers.

secondary tumour see metastasis.

seminoma [se-mi-no-ma] A cancer of the testes. It occurs in an older age group than teratomas (the other main testicular cancer), and is treated by surgical removal of the testis (orchidectomy ). If it has spread to other parts of the body, chemotherapy or radiotherapy may be used: see testicular cancer.

serum [se-rum] The clear liquid portion of blood that is left if the blood cells, platelets and clotting substances (including fibrinogen) are removed. If the clotting substances are not removed, the clear fluid is called plasma.

serum alkaline phosphatase (SAP) [se-rum al-ka-line phos-pha-tase] see prostate-specific antigen .

side effects Many drugs (medicines) or treatments may affect the patient in ways other than and in addition to those intended. These are side-effects. Some side-effects are not a problem, but some are unpleasant, for example, chemotherapy may cause hair loss, radiotherapy and chemotherapy may cause nausea.

sigmoidoscopy [sig-moid os-co-py] Examination of the rectum and first 20-25 cm of the colon using a sigmoidoscope, a long flexible tube with a light at the end that is inserted gently through the anus : see endoscope, fibre optics.

sinus [si-nus] An air cavity within a bone.

skin The outer covering of the body. It consists of two layers: the outer layer (epidermis ) consists largely of cells containing keratin, which resists heat, cold and many chemicals. The epidermis protects the body from injury and invasion by parasites. The inner layer (dermis) contains the roots of hairs, glands that make sweat and oil, blood and lymphatic vessels, and nerves. The skin's colour comes from the brown pigment called melanin, which is made in cells called melanocytes in the lower part of the dermis. The melanocytes manufacture melanin when they are exposed to sunlight.

skin cancer The most common form of cancer in Australia. It affects all age groups from adolescence upwards. Skin cancer rates in Australia are higher than anywhere else in the world. There are three main types: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. All start in different parts of the outer layer of skin. Skin cancer is caused by the ultraviolet rays in sunlight.

small cell carcinoma A type of lung cancer that is strongly associated with cigarette smoking. About one-quarter of all lung cancers are small cell carcinomas. It causes few symptoms in the early stages, and spreads quickly. Also called oat cell carcinoma.

small intestine The part of the gastrointestinal tract between the stomach and the colon . Also called the small bowel.

smear test see Pap test .

solar keratosis [so-lar ker-a-to-sis] (pl. keratoses) A flat, slightly red, scaling area that may appear on skin that is exposed to sunlight, especially the face, hands and forearms. A solar keratosis is not a skin cancer, but people with solar keratoses often develop skin cancers as well. A few keratoses develop into skin cancers (see precancerous condition). About 40-55 per cent of Australians over the age of forty have one or more solar keratoses.

speech pathologist A health professional who diagnoses and treats people who have problems in communicating, either in being understood themselves and/or in understanding others. They also help people who have difficulty with swallowing. In the context of cancer, speech pathologists are most likely to work with those who have been treated for cancer of the larynx, throat, mouth, or brain. Also called speech therapist .

spleen An organ in the upper part of the abdomen on the left side, below and behind the stomach. The spleen produces lymphocytes, filters blood, stores blood and destroys cells that are ageing. It can mount an immune response to infections in the blood system.

splenectomy [sple-nec-to-my] Surgical removal of the spleen. This is sometimes done in the treatment of leukaemia, particularly chronic myeloid leukaemia, or in lymphomas when the spleen becomes enlarged and destroys too many normal blood cells . It is also the treatment for cancer of the spleen. Once the spleen is removed, other parts of the body take over its functions.

sputum cytology test [spu-tum cy-tol-o-gy test] A test that looks at sputum (phlegm), which contains cells from the lungs and air passages, that has been coughed up from the lungs. The test involves studying these cells under the microscope.

squamous cell carcinoma [squa-mous cell car-ci-no-ma] A type of cancer that is common in skin and can also be found in the mucous membrane lining areas within the body such as the mouth, vagina, etc. It forms in the squamous (scaly) epithelium, the outer layer of both skin and mucous membranes. As a skin cancer, it occurs on areas of the body most often exposed to the sun, that is, the head, neck, hands and forearms. It starts as scaly red areas that grow rapidly, over months. They bleed easily and may form ulcers or sores that do not heal. It is a less common skin cancer than basal cell carcinoma, but is more serious, grows faster and may spread to other parts of the body.

stable disease see remission .

staging For most cancers, the treatment used will depend on how far the cancer has spread, that is, the stage the disease has reached. It is important to assess this accurately. This assessment is called staging and is done by using various investigations such as x-rays, scans and biopsies.

stem cell A type of 'parent' cell from which all the different types of mature blood cells evolve. Most stem cells are found in bone marrow, with small numbers also found in blood. When doctors take bone marrow to use in a transplant, it is the stem cells they want. When stem cells are added to a patient's bloodstream, they will migrate to the interior of certain bones and start to produce cells that eventually become mature red blood cells, white blood cells or platelets : see bone marrow transplantation.

sterile In the non-reproductive sense, it means free of bacteria and refers particularly to medical equipment, dressings, etc.

stoma [sto-ma] An artificial opening in the body that has been created surgically, for example, where the colon or ileum is connected to a wall of the abdomen to form an opening through which wastes (faeces/urine) are passed, or the trachea is brought to an artificial opening in the neck, through which the patient then breathes: see colostomy, laryngectomy, tracheostomy.

stomach Part of the alimentary tract (gut); a sac-like structure just below the diaphragm (at about waist level). When food is swallowed, it passes first to the stomach, where the gastric juices start to digest it. After about one hour, the partly digested food moves on to the small intestine.

stomach cancer One of the ten most common cancers, more common in men and with increasing age. The symptoms are often vague and may also be caused by many other conditions. Treatment in the early stages is usually by surgery.

stomal therapist [sto-mal ther-a-pist] A health professional trained to help patients care for a colostomy or ileostomy. Also called enterostomy therapist.

stomatitis [sto-ma ti-tis] When the mucous membrane lining the mouth becomes inflamed and ulcers form. Stomatitis is a common side-effect of some chemotherapy drugs. Also called mucositis .

subcutaneous mastectomy [sub-cu-ta-ne-ous mas-tec-to-my] Surgical removal of breast tissue from beneath the skin , in which the skin and nipple remain in place: see mastectomy.

survival rate The percentage of people diagnosed with a particular disease who are still alive after a given length of time, say five years, which is a common measure of success in cancer treatment.

suture [su-ture] 1. n. A stitch used to close a wound or surgical cut. 2. v. To stitch closed a wound or cut.

syringe driver A small, portable pump that is used in palliative care to deliver pain relief and other drugs (often a mixture of two or three drugs). The whole pump will fit neatly in a small bag, and it holds enough drugs for one day.

systemic treatment [sys-tem-ic] Treatment that is directed at the body as a whole, rather than at individual parts or organs .