Encyclopedia of Health and Medicine

A–B
adenocarcinoma A type of cancer that arises
from the endothelial cells of glandular structures.
Adenocarcinoma is the most common type of cancer
to occur in the PROSTATE GLAND (PROSTATE CAN-
CER), gastrointestinal tract (ESOPHAGEAL CANCER,
STOMACH CANCER, PANCREATIC CANCER, LIVER CANCER,
COLORECTAL CANCER), and endocrine glands (TESTIC-
ULAR CANCER, OVARIAN CANCER, THYROID CANCER).
Adenocarcinoma begins as a benign (noncancerous)
tumor, an adenoma. Over time, GENE mutations
in the cells of the adenoma may cause the
tumor to transition to an adenocarcinoma. Adenocarcinomas
can involve numerous organs and tissues.
See also BLASTOMA; CARCINOMA; ENDOCRINE GLAND;
FAMILIAL ADENOMATOUS POLYPOSIS (FAP); HEREDITARY
NONPOLYPOSIS COLORECTAL CANCER (HNPCC); INTESTINAL
POLYP; LEUKEMIA; MUTATION; SARCOMA.
adenoma-to-carcinoma transition The changes
that take place in an ADENOMA, a benign (noncancerous)
tumor, as it transforms into an ADENO-
CARCINOMA, a malignant (cancerous) tumor. The
transition to cancer can occur with any adenoma
though is most common with adenomas of the
colon (intestinal polyps, also called adenomatous
polyps). Only a small percentage of adenomas
become cancerous. The sequence of events that
transform an adenoma to an adenocarcinoma
begins with multiple mutations in the genes that
regulate cell division and APOPTOSIS (planned cell
death). Over a series of cell divisions the mutations
become increasingly prevalent among the
cells, resulting in DYSPLASIA and ultimately cancer.
Because of the risk for an adenoma to become
adenocarcinoma, doctors often surgically remove
adenomas when feasible.
See also CANCER PREVENTION; COLORECTAL CANCER;
FAMILIAL ADENOMATOUS POLYPOSIS (FAP); GENE; HEREDI-
TARY NONPOLYPOSIS COLORECTAL CANCER (HNPCC);
INTESTINAL POLYP; MUTATION.
adult survivors of childhood cancer The current
generation of adults is the first to grow up in the
era of successful treatment for many childhood
cancers. Nearly 300,000 American adults who are
now in their 20s, 30s, and 40s enjoy CANCER-free,
healthy lives. Doctors consider treatments for
most types of LEUKEMIA, the most common childhood
cancer, to be curative. Treatments for many
types of BONE CANCER, BRAIN cancer, Hodgkin’s LYM-
PHOMA, and kidney cancer (WILMS’S TUMOR) are
also curative. Some health concerns may linger or
occur, however, as a result of the cancer itself or
the therapies used to treat the cancer.
Complications of Cancer Treatment
Complications of cancer treatment are the most
significant cause of later health concerns for adults
who had cancer as children. Some therapies for
cancer that were the standard of care 20 or 30
years ago presented significant health risks that
survivors are now beginning to experience. For
example, doctors now know the CHEMOTHERAPY
drugs, notably anthracyclines such as doxorubicin,
can cause HEART FAILURE that tends to show up 10
to 30 years after treatment. Chemotherapy drugs
affect all rapidly dividing cells in the body and can
have a significant effect on healthy cells notably in
the endocrine system, affecting THYROID GLAND
function, growth, PUBERTY, and FERTILITY. Radiation
to the chest, such as to treat lymphoma, can damage
the HEART, manifesting in adulthood as CAR-
DIOMYOPATHY or heart failure. Radiation to the head
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