Mi-Sun Yoon

Results of Curative Radiation Therapy with or without Chemotherapy for Stage III Unresectable Non-Small Cell Lung Cancer

PURPOSE We retrospectively analyzed the patients who received curative radiotherapy for unresectable stage III NSCLC to investigate the impact of chemotherapy. MATERIALS AND METHODS From 1998 to 2001, the records of 224 patients who completed curative radiotherapy for NSCLC were reviewed. There were 210 males and 14 females, and their median age was 64 years (range 38 approximately 83). 54 patients had stage IIIA disease and 170 patients had stage IIIB disease. Conventional radiotherapy was given and the radiation dose ranged from 50 approximately 70 Gy with a median of 60 Gy, and chemotherapy was combined for 116 patients (52%). RESULTS The median survival, the 2-year, and 5-year actuarial survival rates of all 224 patients were 15 months, 30%, and 7%, respectively. The median survival of the patients with stage IIIA and IIIB disease were 21 months and 13 months, respectively (p=0.14). The median survival of patients who received chemoradiation was 18 months compared to 14 months for the patients who received RT alone (p=0.02). Among the chemoradiation group of patients, the median survival time of the patients who received 1 to 3 cycles of chemotherapy was 16 months and that for the patients who received more than 3 cycles was 22 months (p=0.07). We evaluated the effects of the timing of chemoradiation in 57 patients who received more than 3 cycles of chemotherapy. The median survival of the patients with the concurrent sequence was 25 months and that for the patients with the sequential chemotherapy was 19 months (p=0.81). CONCLUSIONS For advanced stage III non-small cell lung cancer patients who completed the curative radiotherapy, the addition of chemotherapy improved the survival compared to the patients who received radiotherapy alone.

Evaluation on the Functions of Setup Error Correction in the On-Board Imager (OBI) System

On-Board Imager (OBI) System which is attached to the both sides of the linear accelerator is considered as a proper tool to deliver the Image Guided Radiation Therapy (IGRT). In this study, the accuracy of the setup error correction using the OBI system is evaluated. The evaluated OBI system was the part of the Clinac iX (Varian, USA) and the accuracy of setup error correction was analyzed using the phantom provided by Varian for the quality assurance of the OBI system. In the treatment room, the phantom was located with different positions compared with the one in a test plan with a combined random shift variation in the direction of longitudinal, vertical, and lateral of couch. Additionally, the couch rotational variation was also considered. The shift variation was limited to the value of 2 cm in each direction and 2 degree was the maximum value in the rotational variation. The operation for the setup error correction in the OBI system was performed by the dosimetrist and therapist who do not know the real variation of the phantom setup location in the treatment room for the blind test. The total number of tests for the shift variations was 20 and five cases were analyzed for the couch rotational variation. The average of absolute correction errors in the case of shift variations only were 0.70 mm (longitudinal), 0.70 mm (lateral) and 0.85 mm (vertical). When the rotation was also varied combined with the shift variations, the average values were 2.8 mm (longitudinal), 3.2 mm (lateral), 2.6 mm (vertical) and 0.4 degree. The function of setup error correction in the OBI system of Clinac iX showed the verification of the accuracy in the cases of shift variations but could not be evaluated as a proper accuracy in the correction of the rotational variations.