Local radiation-induced injuries after radiation therapy and combined treatment of head and neck cancer

Causes of local radiation-induced injuries after radiation therapy and combined treatment of head and neck cancer in 1192 patients are reported. The cohort of study subjects was divided in 4 groups in accordance with the used plan of treatment of a disease. Patients of group 1 (486; 40.8 %) were treated with external beam radiation therapy (EBRT) using conventional fractionation of 1.8-2.3 Gy, 5 times a week, total focal dose was 60 Gy. Patients of group 2 (244; 20.5 %) underwent combined treatment: RF hyperthermia, chemotherapy and hyperglycemia. Patients of group 3 (204; 17.1 %) underwent accelerated fractionation radiation therapy, altered regimen, one-time focal dose 1+1.5/2 Gy to total focal dose 60 Gy in combination with non-adjuvant polychemotherapy: cisplatin (100 mg/m2 of a body surface), 5 Fluorouracil (5-FU, 72 hour continuous infusion of 3000 mg). Neutron beam therapy combined with radiation therapy was delivered to 258 (21.6 %) patients of the group 4; 36 (3.0 %) patients underwent neutron beam therapy and 222 (18.6 %) underwent combined gamma-neutron therapy with 252Cf. In 285 (23.9 %) cases with detected residual tumors and in 184 (15.4 %) patients with incomplete regression of regional metastases surgery interventions were made. The main factors of risk of delayed complications are tumor site, radiation dose, surgery as a part of combined treatment. Delayed radiation-induced injuries were detected in 252 (21.1 %) cases. The most part of complications was detected in patients (115; 23.7 %) undergone conventional EBRT. The least frequency of complications (35; 15.7 %, р=0.00963) was found in patients undergone brachytherapy with 252Cf. So, brachytherapy is the sparing treatment with homogeneous irradiation of a target. This modality causes the least damage to surrounding normal tissue and allows to escalate a total focal dose to maximum dose to a primary tumor site.