Carcinoma Of The Breast (Breast Cancer)
by Wong Lai Teng
Currently, there are more than 180,000 new cases of breast
cancer every year in the United States and 46,000 deaths, and it
has been estimated that one of every eight American women living
to age 95 years will develop breast carcinoma. Until 1983,
breast cancer was the leading cause of cancer deaths among
females; despite an increase in the incidence of breast
carcinoma, it is now second to lung cancer because of the larger
increase in the number of women developing lung cancer.
carcinoma is rare before 25 years of age and uncommon before 30
years; the incidence increases sharply after 40 years, with a
mean and median age of 60 years. Statistically, the risk of
breast cancer is increased in nulliparous women (nuns have a
high incidence), in women who have early menarche and the late
menopause, and in those who have their first pregnancy after age
30. Breast feeding appears to have protective effect for the
Evidence linking oral contraceptives to breast cancer is
scant; a few studies suggest a very slightly increased incidence
in women who use oral contraceptives.
A familial history
(limited to first-degree relatives, i.e. mother, sister,
daughter) of breast carcinoma increases the risk fivefold. The
first-degree relatives of woman who develops bilateral breast
cancer before menopause are at greatly increased risk. The
increased risks resulting from atypical hyperplasia and family
history are additive.
The etiology of breast carcinoma is
unknown but is probably multifactorial. Genetic factors are
suggested by the strong familial tendency. There is no
inheritance pattern, suggested that the familial incidence is
due either to the action of multiple genes or to similar
environmental factors acting on members of the same family.
Mutation of the BRCA-1 and BRCA-2 is believed to cause breast
cancer. Hormones are also widely believed to play a role in the
etiology of breast cancer. Estrogen has been the most
extensively studied hormone because of the epidemiological
evidence that prolonged estrogen exposure (early menarche, late
menopause, nulliparity, and delayed pregnancy) increases the
risk of breast cancer. Viruses are also suspected of causing
breast cancer (e.g., the Bittner milk factor is a virus that
causes breast carcinoma in mice).
Carcinoma of the male breast
is extremely rare. It presents with a painless breast mass.
Histological features are identical to those of infiltrating
ductal carcinomas in the female. In spite of the small bulk of
the breast in men, the diagnosis of male breast carcinoma is
usually delayed; 50 % of patients have axillary lymph node
metastases at the time of diagnosis. As a result, male breast
cancer has a worse overall prognosis than female breast cancer.
Nulliparous-a woman who has never borne a viable child.
Hyperplasia-abnormal increase in the number of normal cells in
normal arrangement in an organ or tissue, which increases in