treatment options appear slim. Different oncolo-
gists may view the same person’s situation differ-
ently based on their level of experience and
knowledge of specific cancers or treatments.
Oncologists who practice through medical centers
affiliated with research facilities, such as are com-
mon at large universities that have medical
schools, often know of the newest drugs and ther-
apies under evaluation in current or upcoming
clinical trials.
There is an abundance of information about
cancer available on the Internet and in publica-
tions; sorting through it all to determine what is
reliable and what is potentially useful for an indi-
vidual is confusing and often overwhelming.
Because there are no controls over the content of
Web sites in particular, a large amount of informa-
tion is, unfortunately, inaccurate or potentially
harmful; with the emotional factors that surround
a cancer diagnosis, it is important to make treat-
ment decisions based on sound principles. Many
cancer treatment centers have staff and resources
to help people put such information into contexts
that are relevant for their personal situations. The
American Cancer Society (www.cancer.org) and
the US National Institutes of Health’s (NIH’s)
National Cancer Institute (www.cancer.gov) pro-
vide numerous resources to help people sort
through treatment claims and methods.
See also ALTERNATIVE AND COMPLEMENTARY REME-
DIES FOR CANCER; BLOOD STEM CELLS; CANCER PREVEN-
TION; COPING WITH CANCER; DIAGNOSING CANCER; END
OF LIFE CONCERNS; QUALITY OF LIFE; STEM CELL; SURGERY
BENEFIT AND RISK ASSESSMENT.
cancer vaccines Preventive therapies to keep
cancer from developing in people who do not
have it or to keep cancer from growing or recur-
ring in people who have it. Most cancer vaccines
remain in clinical trials. Two approved by the US
Food and Drug Administration (FDA) are those
for HEPATITIS B VIRUS(HBV), the virus primarily
responsible for LIVER CANCER, and for some types of
HUMAN PAPILLOMAVIRUS (HPV), the virus primarily
responsible for CERVICAL CANCER. Preventing the
viral infection nearly eliminates the risk for devel-
oping the cancer.
The HBV vaccine is among the recommended
childhood vaccines in the United States, given as a
series of three shots in infancy. Adults may also
receive the HBV vaccine. Health experts recom-
mend routine HPV vaccination for girls between
ages 11 and 12, and for all young women to age- The HPV vaccine is a series of three injections
given over 6 months. The vaccine protects against
infection with HPV types 6 and 11, which cause
genital warts, and types 16 and 18, which can
cause cervical cancer. Both vaccines are effective
indefinitely. However, the HPV vaccine is not
effective in women who already have HPV infec-
tion.
Therapeutic cancer vaccines target an individ-
ual’s cancer specifically, using antigens from the
cancer cells to stimulate an IMMUNE RESPONSE
against those cells. The laboratory makes a vaccine
using cancer cells from the person. These cells
contain the antigens for which the vaccine will
stimulate the IMMUNE SYSTEMto produce antibod-
ies. Therapeutic vaccines showing promise in clini-
cal trials target PROSTATE CANCER, some types of
BREAST CANCER, some types of LYMPHOMA, and some
types of LUNG CANCER.
See also ANTIBODY; ANTIGEN; CANCER TREATMENT
OPTIONS AND DECISIONS.
CA-125 Cancer ANTIGEN125, a protein often ele-
vated in the BLOODcirculation when certain can-
cers are growing in the body. The cells of the
OVARIES, UTERUS, and FALLOPIAN TUBESproduce CA-
125; consequently CA-125 levels rise in OVARIAN
CANCER, ENDOMETRIAL CANCER(cancer of the uterus),
and CERVICAL CANCER. The most pronounced eleva-
tion occurs with ovarian cancer. However, numer-
ous factors other than cancer can produce
elevated CA-125 levels, including benign OVARIAN
CYSTand UTERINE FIBROIDS. Though an elevated CA-
125 level may be one of numerous diagnostic fac-
tors the doctor considers when evaluating the
possibility of a cancer diagnosis, this tumor marker
by itself is not a reliable indicator of cancer. A
blood test measures CA-125.
See also CARCINOEMBRYONIC ANTIGEN (CEA);
GENETIC TESTING; ONCOGENES; PROSTATE SPECIFIC ANTI-
GEN(PSA); TUMOR MARKERS.carcinoembryonic antigen (CEA) A protein
present in the BLOODcirculation with certain types
of cancer. In this regard, CEA serves as a tumorcarcinoembryonic antigen (CEA) 373