Ovarian Cancers

Women who have a family history of ovarian cancer are at an increased risk of developing ovarian cancer.

Women who have one first-degree relative (mother, daughter, or sister) with ovarian cancer are at an increased risk of developing ovarian cancer. This risk is higher in women who have one first-degree relative and one second-degree relative (grandmother or aunt) with ovarian cancer. This risk is even higher in women who have two or more first-degree relatives with ovarian cancer. Some ovarian cancers are caused by inherited gene mutations (changes).

Ovarian cancer is a disease produced by the rapid growth and division of cells within one or both ovaries—reproductive glands in which the ova, or eggs, and the female sex hormones are made. The ovaries contain cells that, under normal circumstances, reproduce to maintain tissue health. When growth control is lost and cells divide too much and too fast, a cellular mass is formed. If the tumour is confined to a few cell layers, for example, surface cells, and it does not invade surrounding tissues or organs, it is considered benign. If the tumour spreads to surrounding tissues or organs, it is considered malignant, or cancerous. When cancerous cells break away from the original tumour, travel through the blood or lymphatic vessels, and grow within other parts of the body, the process is known as metastasis

Many kinds of tumours can form in the ovaries. In fact, there are over 30 known histopathologic, or diseased tissue, types. Experts group ovarian cancers within three major categories, according to the type of cells from which they were formed.

 

  • Epithelial cancers, which are the most common ovarian cancers, arise from cells lining or covering the ovaries.
  • Germ cell cancers start from germ cells (cells that are destined to form eggs) within the ovaries.
  • Sex cord, stromal cell cancers, begin in the cells that hold the ovaries together and produce female hormones.

Incidence and Prevalence
Ovarian cancer is a disease that principally affects middle and upper-class women in industrialized nations. It is uncommon in underdeveloped countries, perhaps because of different dietary factors in these regions 

It is estimated that approximately 30,000 new cases of ovarian cancer will be diagnosed this year, with 15,000 women dying from this disease. Ovarian cancer most frequently appears in women who are older than 60 (about 50% of patients are over age 65), although it may occur in younger women who have a family history of the disease. Ovarian cancer is responsible for 5% of all cancer deaths among women.

There are marked differences in survival among patients with ovarian cancer, depending on factors such as age, cancer stage, and tissue type. Younger patients tend to fare better in all stages than do older patients, whereas race does not play a factor, as it does in other cancers. Survival rates are similar in black and white women.

Ovarian Anatomy
The ovaries are female reproductive organs that are akin to the testes in men. They produce the ova (eggs) that, when fertilized, will develop into a foetus; they also generate the female sex hormones oestrogen and progesterone. There are two ovaries, each of which is located within the pelvic region beside the uterus (womb).

Ovarian Structure
The ovaries are oval-shaped and are approximately 1 ˝ inches in length. They are pinkish-grey in colour and have an uneven surface. The ovaries are connected to the uterus by the fallopian tubes, or oviducts, which carry the eggs into the uterine cavity. Each ovary contains numerous Graafian follicles, egg-containing tubes that grow and develop between puberty, sexual maturation, and menopause, when the monthly menstrual cycle stops. When a woman is fertile, each month a Graafian follicle travels to the surface of the ovary, bursts, and releases an egg and its fluid contents into a fallopian tube.

The Graafian follicles are fixed in a network of supporting tissue (stroma) and blood vessels. They are covered by a clear, smooth, plasma-like membrane that develops from the peritoneum - lining of the abdominal cavity. Also within the ovaries are small numbers of corpus lutea - the remains of Graafian follicles that have released an egg and are in the process of being reabsorbed by ovarian tissue. Each month the corpus luteum (the scar tissue of a Graafian follicle) is responsible for the production of progesterone. Progesterone is the pregnancy hormone that readies the lining of the uterus for the arrival of a fertilized egg.

Ovarian Function
During the first half of a woman's menstrual cycle - about 2 weeks before ovulation, an egg is released. The hypothalamus in the brain sends a hormonal signal to the pituitary gland to release follicle-stimulating hormone (FSH) into the bloodstream. When the blood-borne FSH reaches the ovaries, it spurs the Graafian follicles to grow and produce oestrogen. Additional oestrogen is made by hormone-producing tissue within the stroma. One Graafian follicle in an ovary begins to outgrow the other follicles while the eostrogen level is increasing.

Meanwhile, once the oestrogen level has peaked, the pituitary gland stops the output of FSH and begins to release luteinizing hormone (LH). The LH causes the Graafian follicle to bubble out on the outside of the ovary, burst, and eject its egg into the fallopian tube. This process of ovulation occurs on or about the 14th day of the menstrual cycle. The ovulated egg travels through the fallopian tube for 5 to 7 days, after which it is released into the uterus.

Connective Tissue
The ovaries are held in place by bands of fibrous tissue known as ligaments. The ligament of the ovary is a rounded cord that extends from the upper uterus to the lower, inner region of the ovary. The fimbria ovarica are fringe-like tissues that attach the ovaries to the fallopian tubes. The round ligaments are two cords, 4 to 5 inches in length, that connect with layers of the broad ligament (ligament that attaches to each side of the pelvic wall to support the uterus) in front of and below the fallopian tubes.

Blood Vessels and Nerves
The ovarian arteries, which are offshoots of the abdominal aorta, furnish the ovaries and fallopian tubes with blood. They enter the ovary via an attached border, or hilus. The ovarian veins parallel the route of the arteries, forming a tangled network in the broad ligament known as the pampiniform plexus.

The nerves that supply the ovaries are branches of the inferior hypogastric nerve, the pelvic plexus (network), the ovarian plexus, and uterine nerves within the fallopian tubes.

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