[MDT Treatment of Small Cell Lung Cancer Complicated with Adenocarcinoma: 
A Case Report and Literature Review].

Small cell lung cancer (SCLC) is the most malignant lung cancer with the highest mortality. At present, the first-line standard treatment is still based on Etoposide and Platinum chemotherapy. However, for SCLC that progresses after first-line therapy, the treatment options are still very limited. Since the molecular mechanism of first-line drug resistance of SCLC is still unclear, and the precision medicine strategy after first-line drug resistance is still in the pre-clinical stage. The proportion of secondary biopsy and genetic testing is very low after the progress of first-line treatment of SCLC. In this study, we report a case of a middle-aged woman who was first diagnosed with SCLC. Adenocarcinoma with sensitive gene mutations and repeated changes of small cell carcinoma were detected by multiple biopsies during the course of the disease, suggesting that the patient may be a special subtype of SCLC - mixed SCLC (M-SCLC). In this case, the patient has been treated with radiotherapy and chemotherapy, immunotherapy and targeted therapy successively, and the survival time has reached 2 years and 8 months. Through the case report and literature review retrospectively, this study aimed to explore the part patients may start to present hybrid histopathologic types or tissue type change after treatment of SCLC. Biopsy pathologic histology and genetic testing is necessary after disease progression to look for potential therapeutic targets, so as to give precise treatment based on molecular markers detection results and provide the patient with the benefit of survival for as long as possible.
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