Late Radiation Side-Effects in Three Patients Undergoing Parotid Irradiation for Benign Disease

Abstract

We report three patients in whom standard radiation therapy was given and serious late radiation damage was seen.The first patient suffered recurrent parotiditis and a parotid fistula. He was treated initially with 20Gy in ten fractions via a 300kV field. Further irradiation was required 1 year later and 40Gy was given in 2Gy fractions by an oblique anterior and posterior wedged photon pair. Ten years later he developed localized temporal bone necrosis. The second patient, with pleomorphic salivary adenoma, developed localized temporal bone necrosis 6 years after 60Gy had been given using standard fractionation and technique. The third patient received 55Gy in 25 fractions for a pleomorphic salivary adenoma and after 3 years developed temporal bone necrosis. Sixteen years later the same patient developed cerebellar and brainstem necrosis.All patients developed chronic persistent infection during or shortly after the radiation therapy, which increased local tissue sensitivity to late radiation damage. As a result, severe bone, cerebellar and brainstem necrosis was observed at doses that are normally considered safe. We therefore strongly recommend that any infection in a proposed irradiated area should be treated aggressively, with surgical debridement if necessary, before radiotherapy is administered, or that infection developing during or after irradiation is treated promptly.