| Abstract: | The efficiency of the radiobiological and the clinical planning of the combination of the intraoperative radiation therapy (IORT) and the external beam radiation therapy (EBRT) was assessed according to the incidence of local recurrences and to the level of radiation-induced damages during 5 years for patients with malignant tumors of head and neck, lung and soft tissues. Criteria of radiobiological planning for performing IORT + EBRT using the modified model of TDF (time-dose-fractionation) for calculating a single IORT dose and total radiation doses was defined among 169 patients of the studied group. The control group included 115 patients who were treated with surgery followed by photon radiation therapy at the total dose of 40-45 Gy. The Clinical critetia for performing the combined treatment with IORT and EBRT were such like: locally-advanced tumors, multicentrical location of tumor sites and the necessity of the increasing of the total doses of the combination of IORT and EBRT. The Average rates of total doses of IORT and EBRT were 67 +/- 2.1 Gy for patients with cancer of nasal cavity and of accessory nasal sinus, 50 +/- 1.8 Gy for patients with oral cavity cancer, 60 +/- 0.7 Gy for patients with lung cancer and 75 +/- 2.0 Gy for patients with sarcomas of soft tissues. Radiation-induced damages for normal tissues such as mandible osteomyelitis, neuritis and pathological bone fracture occurred among 16.8% of patients from the studied group if the TDF factor was exceeded over 100 conventional units. The combined treatment with IORT and EBRT resulted the significant reduction of recurrence rate among 5-year as compared with the combined treatment fot the control group: 37.5 +/- 5.3% and 65 +/- 5.1% of patients with cancer of nasal cavity and accessory nasal sinus; 55.8 +/- 6.3% and 80 +/- 5.9% of patients with oral cavity cancer; 57.8 +/- 6.7% and 75 +/- 5.8% of patients with non-small cell lung cancer and 32.7 +/- 6.1% and 72 +/- 6.7% of patients with sarcomas of soft tissues, respectively. The use of criteria for radiobiological and clinical planning of the combined treatment with IORT and EBRT promotes the improvement of long-term treatment results. |
