3-D conformal radiotherapy for malignant thoracic tumors / 中国癌症杂志

ABSTRACT

Purpose: To evaluate the efficacy and the side effects of 3 D-conformal radiotherapy for malignant thoracic tumor. Methods: Between September 1999 and August 2002, 36 patients with malignant thoracic tumor were treated with 3D-conformal radiotherapy. Twenty-two patients had primary lung cancer, 12 patients had metastatic lung cancer, and 2 patients had malignant mediastinal tumor. All 36 patients were pathologically confirmed. Squamous cell carcinoma 16 cases, adenocarcinoma 15 cases, small cell carcinoma 2 cases, embryonal carcinoma 1 case, malignant thymoma 1 case and sarcoma 1 case. For the primary tumor, conventional radiotherapy was first used to 50Gy/25F/5W, followed by 3D-conformal radiotherapy 16-20Gy(4Gy per fraction, 3 fractions per week) with MLC or cone from 5 ~6 non coplanar or coplanar static ports. For metastatic tumor, using arc therapy to only 28-40Gy(4Gy per fraction, 3 fractions per week, 7-10 fractions) with cone from 1 ~ 4 arcs. Tumor volumes from 1. 85 cm3 to 104. 61 cm3 with a median of 24. 96 cm3 in 3D-CRT. Results: To evaluate the effects, thoracic CT scan was taken two months after completion of 3D-conformal radiotherapy. In 34 evaluated patients, 13 cases obtained CR, 14 PR, 5 NC, and 2PD. The overall 1 and 2-year survival rates were 74. 1% and 38.4%. Toxicity consisted of grade 1 acute radiation pneumonitis in 17 patients, grade 2 in 10 patients, grade 3 in 1 patients, and 2 patients dead of radiation pneumonitis ( with non coplanar technique), late complication was radiation pulmonary fibrosis, grade 1 in 20 cases, grade 2 in 8 cases. Conclusions: 3D-conformal radiotherapy as complement of conventional external beam radiotherapy for malignant thoracic tumor can obtain better short-term effects, although the survival is yet to be investigated. But attention must be given to the irradiation technique, the irradiation volume should not be too large and beams angles appropriately adjusted to avoid excessive irradiated volume in normal lung.