A Phase I/II Study of Dose Escalation in Non-Small-Cell Lung Cancer Using Three-Dimensional Conformal Radiotherapy

Objective To obtain the maximum tolerated dose(MTD) of three-dimensional conformal radiotherapy in non-small-cell lung cancer and observe its therapeutic effect.Methods Involved field of 84 patients with stage Ⅰ-Ⅲnon-small-cell lung cancer were treated by three-dimensional conformal radiotherapy(3-DCRT).Dose escalation to the GTV began after the CTV had received 60Gy.The escalation doses were given in 3 to 11 fractions,2Gy per fraction.According to the percentage of lung volume receiving 20 Gy,the patients were divided into two groups(V2025%or V20 25%～36%).The groups based on the total dose were divided into subgroup.The incidence of radiotherapy induced lung damage and therapeutic effect were analyzed.The criteria for cessation of further dose escalation was that more than or equal to 15%of patients developed grade 3 radiation pneumonitis(RTOG).Results A total dose of 70 Gy,74 Gy,78 Gy or 82Gy was given to 45 patients with V2025%,and 4.4%(2/45) patients experienced grade 3 pneumonitis;Whereas the total dose given to the 39 patients with V20 25%～36%was 66 Gy,70 Gy,74 Gy or 78 Gy,and 5.1%(2/39) patients experienced grade 3 pneumonitis.The median survival time of the entire groups was 14 months.The 1,2-year overall survival rate were 69.5%and 52.8%,and the 1,2-year local control rate were 79.7%and 53.6%.There was trend toward increased overall survival and local control with the increase of the total dose(P0.05).Conclusion 82 Gy and 76Gy could be tolerated by patients with V2025%and 25%～36%.With V2030%,any dose escalation should be prudent.The value of dose escalation to overall survival and local control in patients with non small cell lung cancer needs further study.