HIGH-TECH RADIATION THERAPY WITH LOCAL DOSE ESCALATION IN CHEMO-RADIATION TREATMENT OF PATIENTS WITH LOCALLY ADVANCED NON-SMALL CELL LUNG CANCER. PREDICTORS OF EFFECTIVENESS

Abstract

Relevance: Chemo-radiotherapy of patients with locally advanced forms of NSCLC is the standard of treatment and, with all modern approaches to planning and implementing radiotherapy applied, a median survival of more than 28 months can be achieved. Ways to increase the effectiveness of treatment are now associated with local escalation of radiation dose to the tumor and implementation of the personalized approach concept in chemo-radiotherapy.

Materials and methods: Since 2013 chemo-radiotherapy has been performed for 51 patients with lung cancer of inoperable III stage: IIIA stage-15; IIIB - 36 patients. The treatment was carried out using high-tech radiotherapy (simultaneous integrated boost - SIB-IMRT) and dose escalation up to the zones of hypermetabolism from PET / CT to BED10 = 70-74 Gy for 22-25 fractions. The fractionation regimen for SIB-IMRT was determined by dosimetry: the average dose for lungs was MDL 2) was conducted with a consolidation course after the end of CLT.

Results: With a median follow-up of 42 months 1-, 2-, and 3-year local control rates were 94%, 76%, and 61%, respectively. The maximum registered effect after chemo-radiotherapy in 6 (12%) patients was complete regression of the tumor and, in the remaining cases, partial regression (29-57%) and stabilization (16-31%). Overall 1-, 2- and 3-year survival in the group of patients who received CRT was 80.8% (95% CI, 69.7 - 93.7); 64.6% (95% CI, 50.4 - 82.9); 54.2% (95% CI, 38.3 - 76.9), respectively. Recurrence-free 1-, 2- and 3-year survival: 77.3% (95% CI, 56.7 - 90.2); 48.7% (95% CI, 32.3 - 70.1); 29.2 (95% CI, 18.7 - 43.2), respectively. In 2 patients (5%), isolated local relapse (ILI) was noted at the time of 9 months and 13 months. In the remaining cases there were a simultaneous combination of all types of progression - 17 patients (39%) and distant progression (24 patients (56%)). The third degree pulmonary toxicity was noted in 7 (14%). third degree radial esophagitis was observed in 4 (7%) patients. Single-factor analysis revealed the significant effect on the prognosis of an isolated local recurrence and a near-certain effect on the outcome of treatment of the level of SUVmax in the tumor.

Conclusion: With modern high-tech approaches to the planning and implementation of radiotherapy a personalized local escalation of the irradiation dose is possible, taking into account the predictor effect of SUVmax in the tumor.