Cancer cells divide and multiply much faster than most normal
cells — and that's typically how they do their harm.
Uncontrolled cell growth can lead to masses of cancer cells
called tumors, or to a situation where healthy cells are crowded
out and can no longer do their jobs efficiently. Chemotherapy
(or "chemo") and radiation, the two most common types of cancer
treatment, work by destroying these fast-growing cells. But
other types of fast-growing healthy cells (such as blood and
hair cells) also can be damaged along with cancer cells, causing
adverse reactions, or side effects. Side effects can range from
fatigue and flu-like symptoms to hair loss and blood clotting
problems. Because it's hard for doctors to predict how a child's
body will react, all kids who undergo treatment for cancer are
very closely monitored. Doctors weigh the amount and severity of
side effects against the benefits of treatments. Fortunately,
most side effects are temporary — as the body's normal cells
recover, these problems gradua