Prophylactic treatment reduces the severity of xerostomia following radiation therapy for oral cavity cancer.

Abstract

Hypothesis: The underlying mechanism of irradiation-induced injury to the salivary glands was an enigma for French radiobiologist Jean Bergonie, who first described the phenomenon in 1911. Bergonie was also the scientist who characterized as “radiosensitive” tissues that, like hematological stem cells, are composed of primitive, undifferentiated cells with a high mitotic rate; and yet he was aware that salivary cells, which are highly differentiated (especially serous acinar cells), and have a low mitotic rate, are particularly radiosensitive. The enigma has not been solved and xerostomia still causes much discomfort. Annually, irradiation-induced xerostomia affects between 30000 and 50000 individuals treated for head and neck cancer in the United States alone. Since irradiation-induced xerostomia was first described, much research has been devoted to understanding the mechanism of its development. This is due, in part, to its appeal as an enigma; additionally, there is no adequate therapy for its prevention or treatment. The delivery of therapeutic radiation was greatly improved during the last decade, mainly through 3-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy (IMRT). These technologies allow high rates of salivary gland preservation in head and neck–irradiated patients, but they are either unavailable or insufficient for too many of them. Irradiation damage occurs because of the location of the glands (symmetrical and extended), the extent of the tumors, and the high doses of radiation that are often indicated. Can one expect that, in the near future, prophylactic treatment will reduce the severity of xerostomia following radiation therapy for oral cavity cancer?