Dose-escalation in non-small-cell lung cancer treatment using 3-dimensional conformal radiotherapy:preliminary results

Purpose:To evaluate the feasibility of dose escalation in non small cell lung cancer(NSCLC) treatment using 3 dimensional conformal radiotherapy and to assess the immediate responses and acute side effects.Methods:25 patients with inoperable NSCLC were evaluated from October 2000 to July 2001. Conventional irradiation technique was used until the tumor dose reached 40 41.4Gy. FOCUS2.6.1 of CMS three dimensional treatment planning system(3D TPS) was used to design the dose escalation treatment plan and DVHs was used to optimize it.The planning target volume (PTV)encompassed 1 1.5cm outside the clinical target volume(CTV).The irradiation doses of dose escalation treatment plan ranged from 25Gy to 30Gy,and were delivered in daily fractions of 2.5 3 Gy,5 days a week. WHO criteria and RTOG/EORTC grading scheme were used to assess the immediate responses and acute side effects.Results:All 25 patients completed the treatment successfully. The median radiation dose to the gross tumor volume(GTV) was 7012cGy(62 45 Gy 71 40 Gy).The overall immediate response rate (CR+PR)was 72.0%(18/25). According to the RTOG grading scheme , acute radiation esophagitis occurred in 24.0%(6/25)of patients with Grade 1 2 and 4.0%(1/25)with Grade 3 respectively. Acute radiation pneumonitis occurred in 16.0%(4/25)of patients with Grade 1 2 and 4.0%(1/25)with Grade3 respectively. The bone marrow toxicity occurred in 16.0%(4/25)with Grade 1 2. Damage to the heart occurred in 12.0%(3/25) with grade1 2. Median follow up is 14 months.Conclusions:Dose escalation in NSCLC treatment using 3 dimensional conformal radiotherapy has an encouraging immediate response rate with lower acute complication. Late side effects of irradiated and survival will be observed. [