Lung cancer is a malignant tumor with high incidence and mortality rate in China and the world. Small cell lung cancer (SCLC) accounts for 13% -17% of lung cancer. SCLC is well known for its high degree of malignancy and tendency to metastasize early, leading to poor prognosis in many patients who are already at an advanced stage when diagnosed. According to the extent of disease extension, SCLC can be divided into limited stage and extensive stage. Because SCLC often metastasizes at an early stage, only a few patients with limited disease are suitable for radical resection. Therefore, for most patients, the treatment mainly depends on chemotherapy, radiotherapy and immunotherapy, and there are many treatment methods at present.
1. First, treatment of brain metastases: Patients with brain metastases should usually be routinely treated with whole brain radiotherapy (WBRT); however, some patients with fewer brain metastases can be applied. Stereotactic radiotherapy (SRT)/radiosurgery (SRS) is used locally. A current randomized trial [NRG CC009] is comparing SRS versus WBRT plus memantine with hippocampal avoidance in this setting. The recommended dose for WBRT is 30 Gy/10 f/once daily. Consider giving memantine during and after radiation therapy (see dose recommendations for memantine in prophylactic craniocerebral irradiation). Patients who have previously received prophylactic brain irradiation (PCI) should be carefully selected for retreatment with whole brain radiotherapy (WBRT). If conditions permit, SRS is preferred. For some patients with a good prognosis (e.g., life expectancy ≥ 4 months), IMRT hippocampus-protected WBRT plus memantine is preferred, which may result in less cognitive impairment than conventional brain radiotherapy plus memantine. However, in the NRG CC001study, patients with metastases within 5 mm of the hippocampus, leptomeningeal metastases, and other high-risk features were not eligible for WBRT to preserve the hippocampus. Although CC001 did not include SCLC patients with brain metastases, it is reasonable to generalize the findings to SCLC.
2. Second surgical resection diagnoses stage 1-IIA SCLC in less than 5% of patients with SCLC. Patients most likely to benefit from surgery are those with clinical stage I-IIA (T1-2, N0, M0) SCLC after standard staging evaluation, including CT, brain imaging, and PET/CT imaging of the chest and upper abdomen. Before resection, all patients should undergo mediastinoscopy or other mediastinal staging to exclude occult lymph node metastasis, which may also include endoscopic staging. For patients undergoing radical surgical resection, the preferred manual approach is lobectomy with mediastinal lymph node dissection or systematic lymph node sampling (eg, ≥ 3 N2 and ≥ 1 N1). In patients who do not smoke, small lesions presumed to be small cell carcinoma on biopsy should be resected because they are likely to be misdiagnosed carcinoid tumors. For some patients with elective T3 (size-based), N0 SCLC, surgery may be considered if the invasive mediastinal lymph node staging is negative. Patients with a possible intraoperative diagnosis of SCLC without prior biopsy are advised to undergo mediastinal lymph node dissection or systemic lymph node sampling plus frozen sections to assess disease extent and overall disease burden. If the primary site and lymph nodes are likely to be resected, an anatomical resection, preferably lobectomy, is performed. Pneumonectomy should not be performed if metastatic disease of the lymph nodes needs to be included. Patients with complete resection should be treated with postoperative systemic therapy. Patients without lymph node metastasis should be treated with systemic therapy alone. Patients with N 2 or N 3 lymph node metastases should be treated with concurrent or sequential systemic therapy and mediastinal radiotherapy. Postoperative mediastinal radiotherapy may be considered for patients with N1 lymph node metastasis. The benefit of PCI in patients with pathological stage I (T1-2a, N0, M0) after radical therapy is unknown.
3. The third supportive treatment, granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte colony-stimulating factor (G-CSF) is not recommended during concurrent systemic therapy plus radiotherapy (Class 1 recommendation without GM-CSF). When extensive stage SCLC (ES-SCLC) is treated with a platinum/etoposide ± immune checkpoint inhibitor (ICI) -containing regimen or a topotecan-containing regimen, either trasyclide or G-CSF can be used as a prophylactic option to reduce the incidence of chemotherapy-induced myelosuppression. Fluid restriction for SIADH (syndrome of inappropriate secretion of antidiuretic hormone). Demeclocycline was administered by saline infusion in symptomatic patients. For refractory hyponatremia, vasopressin receptor inhibitors (i.e., conivaptan, tolvaptan) are used. Consider ketoconazole for Cushing’s syndrome; if ineffective, consider metyrapone. Consider referral to an appropriate endocrinology subspecialist.
Small Cell Lung Cancer
