Can low-dose radiotherapy volumes be one of the contributing factors to early relapses in lung cancer patients?

Abstract

© 2018 The Authors. Precision Radiation Oncology published by John Wiley & Sons Australia, Ltd on behalf of Shandong Cancer Hospital & Institute.Objective: Several studies have shown that low-dose radiotherapy (RT) might increase tumor invasion and metastases. Whereas multiple RT fields that increase low-dose RT areas are often used to prevent damage to organs at risk. We carried out a clinical trial with the concern that low-dose RT sites could increase invasions or metastases when multiple sites were used. Methods: A clinical retrospective study was carried out on 50 lung cancer patients with stage II–IIIB cancer, who underwent RT and/or chemotherapy, had Eastern Cooperative Oncology Group performances 1–3, were aged 45–87 years, and without metastases. RT was carried out for 5 days with 180–200 cGy fractions per day with a total dose of 54–66 Gy. The radiation dose volume areas V5, V10, V20, V40, V50, and V60 of lung were calculated and analyzed by Mann–Whitney U-test and L par test on disease-free and overall survival statistically. Results: It was determined that V5, V10, and V20, which constitute the low RT dose areas of the lung, positively affected the recurrence-free and overall survival minimally according to r correlation values. Conclusion: Low-dose RT volumes were positively affected minimally by recurrence-free survival and overall survival in the present study. The effects of low-dose radiation must be evaluated more clearly in studies.