Re-irradiation of head and neck tumors. Benefits and toxicities.

Most patients with head and neck cancer that recurs after irradiation should be treated with curative surgery. In patients whose tumors are nonresectable, or if surgery would cause unacceptable morbidity, a trial of curative re-irradiation may be considered. Taking into account the overall poor prognosis of these patients and the high rate of late tissue toxicity, especially soft tissue necrosis, fistula formation, and potential nerve damage, patients should be carefully selected. Several sites, notably the larynx and nasopharynx, can be re-irradiated with a relatively high rate of locoregional tumor control. In other sites, several criteria may be used to select patients for curative re-irradiation: limited tumor size, a relatively long period since previous irradiation (a suitable, though arbitrary, minimal time period may be 1 year), good performance status, and lack of evidence of skin or soft tissue damage (skin fibrosis, atrophy or telangiectasis) by the previous irradiation course. Even when these selection criteria are used, the prognosis is poor, and long-term survival rates are low even if locoregional tumor control is achieved. Innovative strategies and techniques, including aggressive combined chemoradiation, hyperfractionation, and limiting the extent of irradiated tissues by using conformal irradiation, may improve locoregional control rates. It should be emphasized, however, that the only chance for achieving locoregional control and cure is through the delivery of a full dose of radiation, similar to the dose required for primary tumors. The delivery of a low radiation dose, commonly practiced to avoid complications, is expected to achieve palliation only.