This trial aims to evaluate the efficacy and safety between radiotherapy alone and concurrent chemo-radiotherapy after 3-4 cycles of chemotherapy in LS-SCLC.

Small cell lung cancer (SCLC) represents 15-30% of all lung malignancies in China. Limited-stage small cell lung cancer (LS-SCLC) represents approximately 40% of cases. The current standard of care in limited-stage disease is systemic chemotherapy plus concurrent thoracic radiotherapy. Early concurrent chemo-radiotherapy is recommended for patients with limited-stage SCLC based on randomized trials. But, the administration of thoracic radiotherapy requires the assessment of several factors, including the volume of the radiation port, dose of radiation, and fractionation of radiotherapy. Parts of the LS-SCLC are local advanced stage (stage Ⅲa and Ⅲb), which can not tolerate concurrent chemo-radiotherapy because of large size in tumor and extensive metastasis of lymph nodes. At present, it is usually use 3-4 cycles of introduction chemotherapy to decrease the tumor size followed by definitive radiotherapy. But it is unclear whether this scheme is tolerant well or it could improve the overall survival in patients with LS-SCLC. As a result, we designed a prospective phase II randomized controlled trial in order to compare the tolerance and therapeutic effects between radiotherapy alone and concurrent chemo-radiotherapy after 3-4 cycles of chemotherapy in LS-SCLC.

Inclusion Criteria:

Age 18- 75 years; ECOG performance status 0 or 1; Pathological or cytological confirmation of SCLC; Local stage small cell lung cancer with stage Ⅲa and Ⅲb; Receive 3-4 cycles of chemotherapy with etoposide plus cisplatin; Measurable disease using RECIST criteria with at least one lesion;

Adequate hematological, renal, hepatic and pulmonary functions defined as:

granulocytes ≥ 2.0×109/L, platelets ≥ 100 x 109/L, hemoglobin ≥ 8g/L, total bilirubin ≤ 1.5 x upper normal limit, aspartate aminotransferase, alanine aminotransferase≤2.5 × upper normal limit,, creatinine ≤ 1.5mg/L, FEV1 ≥ 1.5 L Ability to understand and willingness to sign a written informed consent form;

Exclusion Criteria:

History of operation of lung cancer; PD after 3-4 cycles chemotherapy; Patients with sever infection; Patients with uncontrollable diabetes; Patients in pregnancy or lactation; Patients who are currently receiving or have received other clinical trail for radioprotection within the prior six months are excluded; Patient with history of malignancy other than skin cancer or Carcinoma in-situ within 2 years; History of cardiovascular diseases that might include one of the following: myocardial infraction, angina, coronary angioplasty, congestive heart failure, stroke, or coronary bypass surgery in the last 6 months; Concomitant treatment with other anticancer drugs;