Definitive High Dose Thoracic Irradiation by 3 Gy Fraction Size in Stage III Non-small Cell Lung Cancer

Kim, BoKyong; Ahn, Yong Chan; Lim, Do Hoon; Park, Suk Won

Abstract

PURPOSE: Definitive high dose thoracic radiation therapy (TRT) alone in stage III non-small cell lung cancer (NSCLC) has resulted in only modest survival gains that are far from satisfaction. When using conventional fractionation schedules, which usually last for about 7 weeks, issues relating to the cost versus the benefit ratio are raised, including the treatment costs, protracted side effects and inconvenience to patients and family, especially if they reside in a remote district from the hospital. A retrospective analyses on the stage III NSCLC patients who received definitive high dose TRT alone, in 3 Gy per fractions lasting less than 4 weeks, were performed.
MATERIALS AND METHODS
Between October 1994 and June 2001, 82 NSCLC patients were given definitive high dose TRT alone, in 3 Gy fractions, at Samsung Medical Center. Of these patients 37 (45.1%) had a stage IIIA and 45 (54.9%) had a IIIB disease. Squamous cell carcinomas were the most common (65.9%) pathology followed by adenocarcinomas (23.2%). External beam radiation therapy (ERT) alone was employed in 61 patients (74.4%), with additional high dose rate endobronchial brachytherapy (EBB) in 21 patients (25.6%). The TRT was typically started with the AP/PA technique using 10 MV X-rays for 30 Gy, and then a computerized CT plan was performed to keep the total spinal cord dose below 40 Gy. The median total TRT dose was 54 Gy/18 fractions (range: 39-60 Gy).
RESULTS
The median age was 68 years (43-84), with a male to female ratio of 4.9/1. After a median follow-up of 10 months (1~72), 31 (37.8%) and 24 (29.3%) developed local in-field failures and distant metastases, respectively, with the lung being the most common site (12, 38.7%). The median and overall survivals at 1-, 2-, 3- and 4-year were 10 months and 45.9, 19.4, 12.9 and 9.7%, respectively. The median relapse-free survival was 13.0 months, and relapse-free survival rates at 1-, 2-, 3-, and 4-year were 51.9, 23.3, 11.6 and 7.3%, respectively. From a univariate analysis, the performance status (p= 0.0366) and radiotherapy response (p=0.0323) were significant on the overall survival, gender (p=0.0329) and response (p=0.0107) on the relapse free survival, and histology (p=0.0466) on the local relapse. From a multivariate analysis, the nodal status, radiotherapy response and mediastinal radiation dose were significant prognostic factors on both the relapse free survival and local control. Treatment related morbidities were observed in 75 patients (91.5%), 10 of whom had grade 3 or 4 complications (12.2%), with esophagitis being the most common (73 patients). Symptomatic radiation pneumonitis occurred in 20 patients (24.4%), with 17 requiring steroid medication and a further 1 each required mechanical dilatation for an esophageal stricture and tracheal stenosis.
CONCLUSION
Based on the above results, definitive high dose TRT in 3.0 Gy per fractions was adjudged to be comparable to TRT using the conventional fractionation schedules reported in the literature, with the advantages of shorter treatment duration and less overall cost