Split course interstitial brachytherapy with a source shift: the results of a new technique for salvage irradiation in recurrent inoperable cervical lymphadenopathy greater than or equal to 4 cm diameter in 23 patients.

Between June 1981 and December 1986, 23 patients with prior irradiation of the neck for epithelial ENT tumors underwent salvage irradiation for isolated recurrent inoperable cervical lymphadenopathy greater than or equal to 4 cm. The initial irradiation had delivered 45-80 Gy to the cervical lymph nodes. Split course interstitial brachytherapy was used with a source shift in an attempt to decrease treatment complications. The first and second course of the split course implants delivered 35 Gy and 30 Gy at a 1 month interval. The active lines of the second implant were placed parallel to and in between the position of the lines of the first implant. Three patients did not receive the second implant (one death, one disease evolution, one necrosis). For the patient who died between the first and second implants the local control rate could not be determined. The immediate overall local control rate was 73% (16/22) with a later recurrence rate of 62% (10/16), but only in three cases was recurrence within the treated volume (19%-3/16). The local control rate was better (3/9) if the initial lymphadenopathy was greater than or equal to 4 cm less than or equal to 6 cm but worse (3/13) in those with initial lymphadenopathy greater than 6 cm. Survival of these patients overall was poor with 26% survival at 1 year and 13% at 2 years. Tolerance overall was acceptable with tissue necrosis occurring in 36.5% of cases including those with initial skin involvement. If these cases were excluded the necrosis rate was only 15.5%. In this patient population with inoperable recurrent cervical lymphadenopathy in whom a further dose of external irradiation is not possible interstitial brachytherapy should be considered. Our technique of implantation, split over two sessions with a source shift, is practicable with an acceptable toxicity. It may be used even after high dose external beam irradiation and in large volumes of disease, and it gives better results than classical brachytherapy.