Therapeutic principles and options in radiation oncology

Radiation therapy is used increasingly as a definitive or adjunctive treatment for cancer. Definitive irradiation allows functional preservation of structures critical to function. Adjunctive irradiation following surgical resection of the primary lesion treats regional lymph nodes and/or sites of primary extension at high risk for microscopic involvement. Specialized techniques can be applied to deliver higher total doses of irradiation and minimize late normal tissue effects to adjacent normal tissues. Local-regional tumor control combined with functional preservation represents the specific goals of radiation therapy applied alone or in conjunction with surgical resection.