Encyclopedia of Health and Medicine

376 Cancer
Antibiotic chemotherapy agents The anthracyclines
and the related DRUG bleomycin are antibiotics
that come from the FUNGUS Streptomyces
verticillus, which naturally occurs in soils primarily
in Japan though also can be cultivated. These
chemotherapy drugs work by forming free radicals
that disrupt the structure of cellular DNA. They
are particularly effective against leukemia, lymphoma,
and many types of CARCINOMA, notably
breast cancer. Bleomycin is similar to the anthracyclines,
derived also from the S. verticillus fungus,
but a different chemical composition and action in
cells. It is most effective in combination with other
chemotherapy agents for treating lymphoma and
TESTICULAR CANCER. The most significant SIDE EFFECT
of the anthracyclines is damage to the HEART, and
of bleomycin damage to the LUNGS, as a result of
free radical activity.
COMMON ANTIBIOTIC CHEMOTHERAPY AGENTS
bleomycin
dactinomycin
daunorubicin
doxorubicin
epirubicin
idarubicin
mitoxantrone
Camptothecins, etoposide, and vinca alkaloids
The camptothecins block the function of topoisomerase,
an enzyme cells need to synthesize DNA.
Their original source was the bark of the Camptotheca
acuminata tree native to China. Etoposide
has the same action but comes from the bark of
the mandrake tree. Vinca alkaloids derive from
the leaves of the Vinca rosea plant, a type of periwinkle.
The vinca alkaloids disrupt cell division.
Like the alkylating agents, the camptothecins,
etoposide, and vinca alkaloids are effective in
treating a broad spectrum of cancers from
leukemia and lymphoma to carcinomas and some
sarcomas.
COMMON CAMPTOTHECINS,
ETOPOSIDE, AND VINCA ALKALOIDS
etoposide
vincristine
vinblastine
vinorelbine
irinotecan
topotecan
Taxanes The taxanes come from the bark of
the Taxus brevifolia—the Pacific yew tree. They
work as chemotherapy agents by blocking the
ability of cells to form the structures necessary to
divide. They also appear to enhance a number of
immune functions and are particularly effective in
treating some types of metastatic breast cancer.
Currently there are two taxanes, each of which is
often more effective in combination with other
chemotherapy agents than alone. As well, each
taxane has specific side effects: docetaxel can
cause severe EDEMA (fluid retention) and paclitaxel
can cause MUSCLE pain. Both drugs can cause NEU-
ROPATHY (dysfunction of the nerves) and severe
depletion of neutrophils (NEUTROPENIA), white
BLOOD cells (leukocytes) important for fighting
INFECTION. Neutropenia raises the risk for infection.
docetaxel
paclitaxel
TAXANES
Platinum compounds Platinum compounds
disrupt cellular DNA function as well as the ability
of cells to synthesize DNA. These chemotherapy
agents are particularly effective in treating LUNG
CANCER, testicular cancer, and colorectal cancer.
They can cause kidney damage and neuropathy.
PLATINUM COMPOUNDS
carboplatin cisplatin oxaliplatin
Risks, Side Effects, and
Complications of Chemotherapy
Because chemotherapy is a systemic treatment, it
affects all cells in the body. Those most severely
affected are those that grow and divide rapidly.
Though cancer cells are at the head of that list,
some healthy cells in the body also grow and
divide rapidly. Among them are the cells of hair
follicles (which produce hair), blood, and gastrointestinal
tract, accounting for the most significant
side effects of chemotherapy: hair loss, ANEMIA,
increased susceptibility to infection, nausea, VOM-
ITING, and DIARRHEA. However, the extent to which
these side effects occur varies across the spectrum
of chemotherapy drugs, and many people receiving
chemotherapy do not experience them.
Medications and complementary remedies such
as GINGER may help with chemotherapy-related
nausea. ACUPUNCTURE also provides relief from
nausea and other discomforts. Antinausea medica-