Late radiation side-effects in three patients undergoing parotid irradiation for benign disease

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