Encyclopedia of Health and Medicine

380 Cancer
and preserved foods appear to increase the risk for
cancer overall and particularly for cancers of the
gastrointestinal tract.
The extent to which nutrients can inhibit
tumor growth remains an area of intensive study
in CANCER PREVENTION research. Though foods and
nutrients are not the sole factors that prevent or
cause cancer, they clearly play significant roles in
immune function.
See also CANCER RISK FACTORS; DIET AND HEALTH;
EXERCISE AND HEALTH; LIFESTYLE AND CANCER;
LYCOPENE.
dysplasia Abnormal changes that are occurring
in cells. In dysplasia, rapidly dividing cells form
tissue that has an anomalous structure. This structure
has the potential of transitioning to cancer.
Dysplasia is an early stage of development for all
cancers but not all dysplasia becomes cancer.
Because there is no way to know which direction
dysplasia will go, doctors closely monitor and
often surgically remove or otherwise treat dysplasia.
ROUTINE MEDICAL EXAMINATION or health screening
commonly detects dysplasia, which seldom
produces symptoms. Frequently identified dysplasias
include cervical dysplasia, which affects a
woman’s CERVIX, and oral dysplasia, which affects
the mucous membranes in the MOUTH.
Doctors classify dysplasia according to the extent
of disruption within the tissue. The earliest stage of
dysplasia is hyperplasia, in which cells are growing
more rapidly than normal but the structural
integrity of the tissue remains normal. In mild dysplasia,
the excessive cell growth produces erratic
and abnormal tissue structure. In severe dysplasia,
also called cancer in situ, cell growth and tissue
structure are significantly abnormal but the irregularity
remains confined to a single site. The risk for
cancer in situ to evolve into a full cancer is high.
Treatment for dysplasia depends on the severity
and location of the dysplasia as well as other
health factors—such as smoking, which increases
risk for all types of cancer—or a condition such as
INFECTION with HUMAN PAPILLOMAVIRUS (HPV), which
increases risk for cervical cancer. Mild dysplasia
may revert to normal growth; often the doctor
will recommend diligent observation with examination
every three to six months to monitor cell
activity at the site. Electrocautery (burning),
cryotherapy (freezing), laser ablation, and surgical
excision are among methods for eradicating dysplasia.
Dysplasia may recur, depending on its
cause, though in most circumstances does not
return after treatment.
See also CELL STRUCTURE AND FUNCTION; LASER SUR-
GERY; PAP TEST.