Stereotactic hypofractive radiotherapy in the treatment of patients with lung cancer

Abstract

Introduction. Nowadays the stereotactic radiotherapy (SRT) of patients with clinical stage I-II lung cancer is the choice of the treatment modality for functionally inoperable patients. It shows safety and high efficiency in reaching the local control. Though there is a range of unsolved issues connected with the prediction of treatment efficiency and frequency of complications, an integration of new technologies in the planning and treatment process allows to widen the search of the predictive factors.Materials and methods. Since 2014, 42 patients (T1N0M0 – 16 patients, T2N0M0 – 26 patients) with clinical stage I-IIa lung cancer have underwent SRT. The majority of patients (38) have been recognized as functionally inoperable due to the concurrent broncho-pulmonary pathology, 4 conditionally operable patients have refused an operation. 11 patients had the primary multiple tumors in their anamneses, 3 patients had a сentral tumor. Used dose fractionation options were: 10 Gy х 5 fractions (n = 29) and 7 Gy х 8 fractions (n = 13) – BED = 100 Gy.Resuts. The median follow-up was 32 months (range 6–56 months). The 3-year local control was 94%. The isolated local recurrences were not registered. Overall 3-year survival rate was 74% (95% CI, 60–90) and a 3-year tumor-specific survival rate – 84% (95% CI, 71–98). During one-factor analysis a reliable influence on the prognosis of the fractionation regimen (р = 0,04) and, close to reliability, the initial SUVmax level influence (р = 0,07) were revealed. Grade 3 pulmonary toxicity was observed in 4 (9%) patients, one patient with a Central tumor died from pulmonary hemorrhage (grade 5 toxicity). Grade 3 chest pain was observed in 3 (7%) patients, two of them had a rib fracture.Conclusions. With modern approaches to SRT treatment planning and delivery there should be a search for additional treatment efficiency and toxicity predictors. The total dose delivery regimen and initial tumor SUVmax can be predictive efficiency factors, while the pulmonary tissue volume can be a predictive toxicity factor.