A–B

adenocarcinoma A type of cancer that arises
from the endothelial cells of glandular structures.
Adenocarcinoma is the most common type of can-
cer 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 (noncancer-
ous) tumor, an adenoma. Over time, GENEmuta-
tions in the cells of the adenoma may cause the
tumor to transition to an adenocarcinoma. Adeno-
carcinomas can involve numerous organs and tis-
sues.
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 (non-
cancerous) 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 muta-
tions become increasingly prevalent among the
cells, resulting in DYSPLASIAand 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 child-

hood cancer, to be curative. Treatments for many

types of BONE CANCER, BRAINcancer, Hodgkin’s LY M-

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 FAILUREthat 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 dam-

age the HEART, manifesting in adulthood as CAR-

DIOMYOPATHYor heart failure. Radiation to the head

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