Three dimensional conformal radiation therapy for non-small cell lung cancer: a phase I/II dose escalation clinical trial

Objective To find and depict the maximal tolerance dose(MTD) of 3-dimension a l conformal radiation therapy (3DCRT) for non-small cell lung cancer (NSCLC). Methods Fifty NSCLC patients's completed this trial. MTD was reached by dose escalatio n , after 42?Gy/21fx,4.2wks by co nventional fractionation irradiation delivered through anterioposterior/posterio anterior fields. 3DCRT was started as a boost. The planning of total dose escala tion depended on the percentage of normal lung volume irradiated to over 20 ? Gy. According to lung volume which received 20 ?Gy, the patients were divided to 3 s ubgroups: 25%, 25%～37%, and37%. The scheduled dose escalation ranged from 6 9 ?Gy to 78 ?Gy. The boost doses were delivered with 3 ?Gy per fraction , once a day , 5 fractions a week. 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 The planned dose escalation was finished in all subgroups. Grade 1 or 2 acute radiation pneumonitis developed in 36% of patients and grade 3 in 2% of patients. Grade 1 or 2 acute radiation esophagiti s occurred in 56% of patients and grade 3 in 10%. Grade 1 or 2 hematopoietic tox icity was observed in 58% of patients and grade 3 in 8%. 30% of patients developed g rade 1 or 2 radiation pulmonary fibrosis. The overall immediate tumor response r ate (CR+PR) was 86%. The median survival for the entire group was 22 months.1- a nd 2-year overall survival rates were 70% and 47%. 1- and 2-year local contro l r ates were 80% and 62%. Conclusions The maximal tolerance dose of late complicat ions are to be determined after further follow-up. The immediate tumor response an d 2-year survival rates are encouraging,but the long-term survival needs further follow-up.