Effects of low dose radiation on survival of lung cancer patients

Objective: Some previous studies have shown that low-dose radiotherapy (RT) can increase tumor invasion and metastasis. Multiple RT fields are usually used to prevent the damage to the organs at risk. We performed a clinical study with a concern that low-dose RT might increase invasion or metastasis. Ionizing radiation (IR) can enhance the potential tumor micro-environment by modifying the host micro-metastatic cancer cells. Methods: We conducted a retrospective study on 50 patients aged between 45 and 87 years, who were applied RT and/or chemotherapy, had the Eastern Cooperative Oncology Group performance status (ECOG) between 1 and 3 and stage II-III lung cancer, and were without any metastasis. RT was applied at daily fractions of 180–200 cGy (5 days/week) and a 54-66 Gy total dose. V5, V10, V20, V40, V50, and V60 values of the lung in a disease-free life, and general life effects statistically analysed with MannWhitney U and L Par testS. Results: A lower RT dose range, which produced V5, V10, and V20 volume values of the lung, was analyzed. It was observed that the V5, V10, and V20 RT volumes of the lung provided a minimal positive effect on relapse-free and general survival according to the Rcorrelation values. Conclusion: Larger studies are necessary according to these results to evaluate the impact of low-dose radiation and to increase the survival rates.