there are actually two kinds of side effects from radiation therapy -- early and late. early side effects such as nausea or fatigue are usually temporary. they develop during or right after treatment and last for several weeks after treatment ends but then improve. late side effects such as lung or heart problems may take years to develop and are often permanent when they do. the most common early side effects from radiation therapy are fatigue and skin problems. other early side effects such as hair loss and nausea are typically specific to the site being treated.
how soon might someone have side effects from radiation therapy?