Thoracic Consolidation Radiotherapy for ES-SCLC Treated With Chemo-immunotherapy

Inclusion Criteria:

Inclusion criteria:

1. age ≥ 18 years;
2. ECOG performance status score 0-2 points;
3. pathologically confirmed small cell lung cancer;
4. complete baseline imaging data (including brain enhanced MRI/CT, PET-CT or chest enhanced CT + bone scan + neck and abdominal B ultrasound/CT) before first-line treatment;
5. stage extensive-stage SCLC at initial diagnosis, and first-line treatment received standard platinum-based doublet chemotherapy combined with immunotherapy (PD-1 or PD-L1) for at least 4 cycles after the efficacy assessment of SD or PR (residual lesions assessed by chest CT);
6. no history of other malignancies;
7. reproductive age male/female agreed to contraception during the trial (surgical ligation or oral contraceptives/intrauterine devices + condom contraception);
8. life expectancy ≥ 3 months
9. 1 week before enrollment, the investigator judged that the patient could continue immune maintenance therapy at the same time, And the organ function level meets the following criteria:

1\) bone marrow function: hemoglobin ≥ 80 g/L, white blood cell count ≥ 4.0 \* 10 \^ 9/L or neutrophil count ≥ 1.5 \* 10 \^ 9/L, platelet count ≥ 100 \* 10 \^ 9/L; 2) liver: serum total bilirubin level ≤ 1.5 times the upper limit of normal, when serum total bilirubin level \> 1.5 times the upper limit of normal direct bilirubin level must be ≤ the upper limit of normal,Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 times of the upper limit of normal; serum albumin ≥ 27 g/L; 3) Kidney: serum creatinine level \< 1.5 times of the upper limit of normal or creatinine clearance ≥ 50 ml/min, urea nitrogen ≤ 200 mg/L; 10.Patients must have the ability to understand and voluntarily sign an informed consent form.

Exclusion Criteria:

1. baseline pathological examination found mixed with non-small cell lung cancer components;
2. patients who had used any anti-tumor therapy before the diagnosis of ES-SCLC;
3. patients who had received anti-tumor therapy other than standard chemotherapy + immunotherapy regimen;
4. patients who had PD assessed by chemotherapy combined with immunotherapy efficacy;
5. patients who had no residual thoracic lesions (lung, mediastinal and supraclavicular metastatic lymph nodes, thoracic efficacy CR) on chest enhanced CT during efficacy assessment;
6. patients with severe immune-related toxicities after treatment;
7. symptomatic interstitial lung disease or active infection/non-infectious pneumonia;
8. patients who required long-term use of cortisol or immunosuppressive agents;
9. allergic to PD-1 or PD-L1 monoclonal antibody immunotherapy or other causes of inability to perform immune maintenance therapy;
10. lactating or pregnant women;
11. patients with severe autoimmune diseases: active inflammatory bowel disease (including Crohn 's disease, ulcerative colitis), rheumatoid arthritis, scleroderma, systemic lupus erythematosus, autoimmune vasculitis (such as Wegener' s granulomatosis), etc.;
12. researchers believe that physical examination or clinical trials may interfere with the results or increase the risk of treatment complications, or other uncontrollable diseases;
13. patients with mental illness, substance abuse, social problems affecting compliance are not enrolled after the doctor 's review.