Influence Of Inductive Chemotherapy On Radiotherapy Producing Tumor Shrinkage Of Patients With Limited-stage Small Cell Lung Cancer

OBJECTIVE: The aims of this project is to observe and record the tumor regression of limited-stage small cell lung cancer(LS-SCLC) during chemoradiotherapy and explore the relationship between clinical pathological factors and tumor regression. Analyze the effects of these factors on short-term effects and the progression free survival time of patients with SCLC.METHODS: Sixty patients with LS-SCLC were treated with chemoradiotherapy in Shandong Tumor Hospital from Jan 2014 to Sep 2015, and were enrolled in this study. Clinical data and chest CT images before and after chemotherapy and radiotherapy of the patients were collected. Based on the CT images, tumor size was measured and recorded. Fisher exact test and Logistic regression was applied in the univariate analysis of age, tumor size before the comprehensive treatment, number of chemotherapy cycles, radiotherapy dose and other factors which may affect the tumor regression rate. The Kaplan-Meier method was used to calculate the progression free survival time. Cox proportional hazards regression was used to analyze the prognostic factors in patients with LS-SCLC.RESULTS: All patients received 1 to 6 cycles of EP regimen before radiotherapy. Nineteen patients received accelerated fractionation radiotherapy(45Gy at 1.5Gy twice daily). 41 patients received conventional fractionated radiotherapy, median dose 56Gy(30-66Gy). The average length of the tumor was 4.94 + 2.09 cm before the comprehensive treatment. The average length of the tumor was 2.08 + 1.79 cm before the radiotherapy, the shrinkage the tumor was 60.87 + 27.61%. When the radiotherapy ended the tumor length was reduced to 0.90 + 0.84 cm, and the shrinkage the tumor was 21.47 + 22.31%. At the end of the treatment, the average shrinkage length of tumor was 81.87 + 19.98%. Logistic regression method was used to analyze the data of age, T stage, tumor length before radiotherapy, chemotherapy cycle number, radiotherapy dose and other factors may cause impact on the tumor regression, and the number of cycles of chemotherapy before radiotherapy has a significant impact on the regression rate of tumor during radiotherapy. The median progression free survival time was 12 months by Kaplan-Meier method. Patients with the tumor regression rate is greater than 60% during induction chemotherapy, the total cycles of chemotherapy was 6, and the total tumor regression rate is more than 85% have a longer progression free survival time. Cox regression analysis found that pleural effusion before treatment, the number of induced chemotherapy cycles and the total regression amplitude of the tumor after receiving the combined treatment were independent prognostic factors of LS-SCLC patients.CONCLUSIONS: In this study, we found that the length of tumor and the number of cycles of chemotherapy before radiotherapy were the influencing factors of tumor regression of LS-SCLC. Systemic chemotherapy before radiotherapy for more than 2 cycles will reduce the short-term efficacy of radiotherapy. Pleural effusion, induction chemotherapy cycle number and the total regression amplitude of the tumor were the independent prognostic factors for progression free survival time of patients with LS-SCLC. Patients with no pleural effusion, received less than 2 cycles of induction chemotherapy before radiotherapy, tumor regression for more than 85% after the chemoradiotherapy have a good prognosis.