Do higher thoracic irradiation doses improve time to progression and overall survival in patients with small cell lung cancer?

Abstract

7587 Background: Small cell lung cancer (SCLC) is highly chemo and radio sensitive tumor. We evaluated two different radiotherapy (RT) doses applied sequentially with chemotherapy (CT) on time to progression (TTP) and overall survival (OS) of the patients (pts) with SCLC. Methods: From 1998 till 2003, 81 pts were treated for SCLC, intrathoracic stage of disease. Median age was 56 years (yrs) (min=36, max=72). Female : male = 1 : 4. Patients were initially treated with four doses of CT (cisplatin 80mg/m2 i.v. day 1 and etoposide 100 mg/m2 i.v. days 1 - 3, 3 weeks). One month later, pts received up to 45 Gy, 2 Gy per day, 5 days per week (41 pts) or above 45 Gy, classical fractionation (40 pts), to mediastinum and tumor. Range of higher RT doses was 55 Gy to 60 Gy, classical fractionation. No prophylactic brain irradiation was applied. We evaluated if different RT doses had influence on TTP and OS. Results: The median follow-up time was 12 months (min=3, max=60) for all group of pts (81 pts). The median TTP in first group of pts (41 pts) was 2 months (min=1, max=20) while median TTP in second group of pts (40 pts) was 10 months (min=6, max=60). There were no statistically significant difference in relapse rate between two groups of pts (p>0.05, Fisher test). However, there was difference but not statistically significant in 1 year TTP (p=0.05, chi-square) while there was statistically significant difference in 2 years TTP favoring higher doses of RT (p<0.05, chi-square). The median OS was 8 months for first group of pts (41 pts) (min=3, max=26) while 16 months (min=6, max=60) for second group of pts (40 pts). There were no statistically significant advantage among two groups of pts for 1 year OS (p>0.05, chi-square). However, there were statistically significant difference in OS favoring higher RT doses for 2 years OS (p<0.05, chi-square). Conclusions: CT remains the corner stone therapy of SCLC. We found that higher RT doses applied sequentially with CT had influence on long term TTP and OS (2 years). No significant financial relationships to disclose.