This protocol is a phase III randomized controlled trial (RCT) evaluating the efficacy of induction chemotherapy followed by accelerated hypofractionated vs. conventionally fractionated concurrent chemo-radiotherapy for limited-stage small cell lung cancer.

Small-cell lung cancer accounts for approximately 13% of all lung cancers, and one-third of these patients present with limited stage SCLC at diagnosis. Currently the standard of care for LS-SCLC is concurrent chemotherapy and thoracic radiation therapy, with prophylactic cranial irradiation for those who achieve a good response after combined chemoradiotherapy, which has yielded a median survival of 15 to 23 months and 5-year survival rate up to 26%.

The optimal dose/fraction for LS-SCLC remains debatable. For SCLC with the characteristic of rapid doubling time and high growth fraction, there is also evidence suggesting that prolonged or interrupted overall radiation time contributes to treatment failure and poor outcome because of accelerated repopulation.In our previous study we also found that overall radiation time might play an important role in the treatment of LS-SCLC and that patients treated with a high biologically effective dose (BED, including time factor) of >57 Gy have favorable local control and survival.

This is a randomised prospective phase III study based on patients with limited stage SCLC, defined as disease confined to one hemithorax and hilar,mediastinal, or supraclavicular nodes without pleural effusion, which can be safely encompassed within a tolerable radiation field. The purpose of this study is to add more information to the current medical literature about the efficacy and safety of accelerated hypofractionated vs. conventionally fractionated concurrent chemo-radiotherapy for limited-stage SCLC.

Patients will be randomized into two groups. The control group will undergo the induction chemotherapy followed by conventionally fractionated concurrent chemo-radiotherapy.The experimental group will receive induction chemotherapy followed by accelerated hypofractionated concurrent chemo-radiotherapy.The investigators compare overall survival (OS) of the two groups.

Inclusion Criteria:

• Histologically or cytologically confirmed SCLC.
• Male or female, aged 18-70 years.
• ECOG performance status 0 to 2.
• Limited-stage SCLC was defined as disease confined to one hemithorax and hilar,mediastinal, or supraclavicular nodes without pleural effusion, which can be safely encompassed within a tolerable radiation field.
• No prior thoracic RT.
• Weight loss in six months less than or equal to five percent.
• FEV1 greater than 0.75L.
• No severe internal diseases and no organ dysfunction.
• No prior history of any tumor.
• Skin test of CT contrast agents was negative.
• Had received 1-6 cycles of VP16 plus DDP/carboplatin.
• Voluntarily participated in this study and signed the informed consent form by himself or his agent. Had good compliance with the study procedures, and can cooperate with the relevant examination, treatment and follow-up.

Exclusion Criteria:

• Other tumor history(Except skin cancer/breast cancer/oral cancer/cervical cancer with expected lifespan more than or equal to 3 months).
• Multiple primary lung cancer.
• Any unstable systemic disease, including active infection, uncontrolled high blood pressure, unstable angina, newly observed angina pectoris within the past 3 months, congestive heart failure (New York heart association (NYHA) class II or higher), myocardial infarction onset six months before included into the group, and severe arrhythmia, liver, kidney, or metabolic disease in need of drug therapy. Human immunodeficiency virus (HIV) infection.
• Women in pregnancy or lactation .
• Patients with mental illness, considered as "can't fully understand the issues of this research".
• Had received other chemotherapy regimens,any radiotherapy or TKI.
• Refuse to write informed consent.