Safe period - The days in a woman's menstrual cycle when conception is least likely. Ovulation usually occurs midway through the cycle, about 15 days before onset of menstruation, and the fertile period is about 5 days before and 5 after ovulation. Providing periods are regular, it can be calculated when intercourse is unlikely to result in pregnancy but it is an unreliable method of contraception.
Saline solution - Saltwater; sometimes used in breast implants.
Satellite nodules - Small structures attached to the larger tumor.
Scatter damage - Damage caused to tissue by the diffusion of X rays when they strike an object.
Screening Mammogram - A two-view mammogram used to screen a woman for breast cancer when no known abnormality exists in the breasts.
Scrotum - The sac that contains the testicles and holds them outside the body to permit production and storage of sperm at a temperature lower than that of the abdomen.
Secondary sexual characteristics - The physical features that develop at puberty. In girls, the breasts and genitals increase in size and pubic hair grows. Boys grow pubic hair and facial hair, the voice breaks and the genitals become adult size.
Segmental Mastectomy ( Partial Mastectomy/Lumpectomy) - A surgical procedure in which only a portion of the breast is removed, including the cancer and the surrounding margin of healthy breast tissue.
Semen - The fluid that contains the sperm, which is ejaculated from the penis during sexual intercourse.
Sensitivity - The ability to react to a stimuli. The value of a diagnostic test; the procedure of clinical observation.
Sentinel node - The first lymph node draining a malignant tumor.
Sentinel node biopsy - A promising but unproven procedure in which only the first draining node or nodes are removed through a small incision instead of an entire axillary node dissection.
Seroma - A fluid mass caused by the localized accumulation of lymph fluid within a body part or area. This condition sometimes occurs after an operation. In breast surgery it may occur after an axillary dissection.
Sex-linked - Disorders conditions produced because the genes controlling certain characteristics are carried on the sex chromosomes, usually the X-chromosome. Some result from an abnormal number of chromosomes, e.g. Klinefelter's syndrome affecting only men, and Turner's syndrome affecting only women. Other disorders, such as haemophilia, are carried on the X-chromosome and these manifest themselves in men because although the genes are recessive, there is no other X-chromosome to mask the recessive type, as is the case with women.
Sexually transmitted diseases (STDs) or venereal diseases - Diseases transmitted by sexual intercourse. These include HIV/AIDS, syphilis, gonorrhoea, nonspecific urethritis, etc.
Side effects - Reactions to drugs or treatments that are usually temporary and reversible.
Silicone - A chemical polymer that is used to replace numerous body parts. Breast implant envelopes are made of silicone.
Silicone gel - Silicone produced in a semisolid, semi liquid state used as a filling in breast implants; similar in consistency to a normal breast.
Simple or total mastectomy - Removal of the breast only; the lymph nodes and pectoralis muscles are preserved.
Simulation - Radiation planning session designed to map out the radiation field.
Skin-sparing mastectomy - Removal of the breast with less skin removal and shorter incisions; only the nipple and areola are excised as well as the overlying skin in those areas. Only appropriate for individuals who have no tumor involvement of the skin area to be spared. Usually combined with immediate breast reconstruction.
Sloughing - The process in which the body rids itself of dead tissue. Frequently this happens when the tissue being used does not have an adequate blood supply.
Sperm - The mature male reproductive cell or gamete. It has a head with the haploid nucleus containing half the chromosome number and an acrosome (a structure that aids penetration of the egg). Behind the head comes a midpiece with energy-producing mitochondria, and then a long tail that propels it forward. A few millilitres of semen is ejaculated during sexual intercourse, containing many millions of sperm.
Spermatic - The term given to any vessel or structure associated with the testicle.
Spermatozoon (pl spermatozoa) - The scientific name for sperm.
Spermicide - A cream, foam, jelly, etc, that kills sperm and is used in conjunction with a diaphragm as a contraceptive.
S-phase fraction - Measurement of how fast a tumour is growing.
Spiculated - Appearing on mammography as small projections into surrounding tissues from a mass.
Sporadic - Occurring occasionally or in scattered intervals.
Staging - System for classifying cancer according to the size of the tumour, its stage of development, and the extent of its spread.
Staging system - The assessment of a cancer by size and quality.
State of the art - The best treatment available.
Statistical probability - The mathematically determined likelihood that some event (such as survival from breast cancer) will occur.
Stelate - Appearing on mammography as a star-shape because of the irregular growth of cells into surrounding tissue. May be associated with a malignancy or some benign conditions.
Stem cell - An immature blood cell that has the ability to generate new bone marrow.
Stereotacfic Needle Biopsy - Biopsy done while breast is compressed under mammography. A series of pictures locate the lesion, and a radiologist enters information into a computer. The computer calculates information and positions a needle to remove the lesion. A needle is inserted into the lump, and a piece of tissue is removed and sent to the lab for analysis. May be referred to as Mammotest or core needle biopsy.
Stereotactic (minimally invasive) biopsy - Newer closed-needle or minimally invasive biopsy method using three-dimensional computer imaging for removing suspicious areas seen on mammograms but not able to be felt for analysis by a pathologist.
Sterilization - A surgical operation to render someone incapable of producing children. Men usually undergo a vasectomy while in women it can be achieved by cutting and tying the Fallopian tubes or removing them. The latter operation is performed via an incision in the abdominal wall or through the vagina.
Stillbirth - The birth of any child that provides no evidence of life.
Subcutaneous mastectomy - Performed before cancer is detected, removes the breast tissue but leaves the outer skin, areola and nipple intact. (This is not suitable with a diagnosis of cancer.)
Subcutaneous tissue - The tissue under the skin.
Supraclavicular Nodes - The nodes located above the collarbone in the area of the neck.
Survival rate - The percentage of people who live a period of time after a surgical procedure or the diagnosis of a disease as opposed to the percentage of those who die.
Symmetric - Balanced. When one side matches the other. One of the chief goals of the patient and plastic surgeon for breast reconstruction.
Syphilis - An infectious, sexually transmitted disease caused by the bacterium Treponema pallidum. Treatment of syphilis is with penicillin early in the development of the disease.
Systemic - Involving the entire body.
Systemic control - The control of cancer throughout the body.
Systemic spread - The spread of cancer cells to the other organs via the bloodstream.
Systemic treatment - Treatment involving the whole body, usually with drugs.