Mecapegfilgrastim Prevents Neutropenia and Radiation Esophagitis

Inclusion Criteria:

* Patients with limited small cell lung cancer diagnosed by histopathology;
* ECOG 0-1 points;
* Weight ≥ 45 kg;
* Age 18-75 years old;
* It is expected that at least 2 cycles of EP chemotherapy will be completed as planned; once thiophene penicillin is used, chemotherapy should not be re-dosed within 12 days.
* Bone marrow hematopoietic function is normal, no bleeding tendency (INR\<1.5);
* Laboratory tests are subject to: (1) Blood routine examination: Hb≥90g/L; WBC≥4.0×109/ L; ANC≥2.0×109/L; PLT≥100×109/L. (2) Liver function, biochemical examination: ALT and AST≤1.5×ULN; TBIL≤1.5×ULN; Serum creatinine≤1.5×ULN.
* According to the researcher's judgment, the test plan can be observed;
* Volunteer to participate in this clinical trial, understand the research process and be able to sign informed consent in writing.

Exclusion Criteria:

* There are currently uncontrolled infections or systemic antibiotics within 72 hours of receiving chemotherapy;
* Any abnormal bone marrow hyperplasia and other hematopoietic dysfunction;
* Patients who have received bone marrow or hematopoietic stem cell transplantation within the past 3 months;
* Patients with previous malignant tumors that have not been cured or have brain metastases;
* Liver function tests Total bilirubin (TBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) are \>2.5 times the upper limit of normal; if due to liver metastasis, the above indicators are \>5 times the upper limit of normal;
* Renal function test: serum creatinine (Cr) \> 1.5 times the upper limit of normal;
* Those who are allergic to this product;
* suffering from mental or neurological disorders that cannot be matched;
* Female patients during pregnancy or lactation; women of childbearing age who refuse to receive contraception;
* The investigator believes that it is not suitable for inclusion.