Lung cancer is mainly divided into four basic pathological types, namely lung squamous cell carcinoma, lung adenocarcinoma, large cell lung cancer, small cell lung cancer, the first three are collectively referred to as non-small cell lung cancer, the reason why it is divided is because the growth habits, metastasis methods, treatment and prognosis of these three are significantly different from small cell lung cancer, of course, there is also a big difference in treatment.
Today we will focus on large cell lung cancer.
In 2015, the World Health Organization defined large cell lung cancer as follows: large cell lung cancer is an undifferentiated non-small cell lung cancer, which lacks the characteristics of small cell carcinoma, adenocarcinoma and squamous cell carcinoma in terms of cytology, tissue structure and immunophetype, and must be surgically removed to make the diagnosis of large cell carcinoma, and is not suitable for small specimens and cytology specimens for biopsy. Immunohistochemistry and mucus staining are necessary for the diagnosis of macrocytic carcinoma. It can be seen that large cell lung cancer is an exclusive diagnosis, which refers to the exclusionary diagnosis after excluding small cell carcinoma, adenocarcinoma and squamous cell carcinoma.
Large cell lung cancer is an undifferentiated carcinoma with a high degree of malignancy and less common, with an overall incidence of about 3% to 5%. According to the pathological subtype, large cell lung cancer is divided into four types: 1. large cell neuroendocrine carcinoma; 2. basal cell-like carcinoma; 3. lymphoepithelid tumor-like carcinoma; 4. clear cell carcinoma. Of the four types, large cell neuroendocrine carcinoma is relatively common, while other types are rare.
Clinically, pulmonary macrocytocinoma is mostly male and has a long history of smoking. Large cell lung cancer often occurs in the upper lobe of the lung, mostly peripheral, accounting for more than 80%, larger in volume, and the mass is often a huge clump-like shadow with uniform density, with clear boundaries, lobes, and rare cavities.
Treatment of pulmonary macrocytic carcinoma is the same as other non-small cell lung cancers, and if there is no extensive lymph node metastasis, surgical resection is preferred, and further adjuvant therapy is carried out according to the pathological stage after surgery. Since pulmonary macrocytic carcinoma is often a peripheral giant mass, surgery requires removal of the entire lobe, or even two lobes.
Compared with lung squamous cell carcinoma and lung adenocarcinoma, lung macrocytic carcinoma exhibits aggressive growth, easily invades adjacent lobes, destroys local tissues and other adjacent tissues, and can appear lymphatic and hematogenous metastases at an early stage. In short, large cell lung cancer proliferates quickly, has poor differentiation, and has a short course of disease, and is a highly malignant neuroendocrine tumor. Foreign reports have shown that the 5-year survival rate of patients with large cell neuroendocrine cancer is 13%-57%. According to domestic reports, the 5-year survival rate of patients with pulmonary macrocytic carcinoma is 11.6%-21.4%, and the 5-year survival rate after surgery is close to 30%. The reasons for the failure of treatment of pulmonary macrocytic carcinoma are local recurrence and distant metastasis, the main reason is distant metastasis, about 80% of patients have lung, pleural, brain, bone, liver and other organ metastases, so that treatment fails.
Chemotherapy can be considered for advanced large-cell neuroendocrine carcinoma, but chemotherapy is not sensitive, and chemotherapy generally refers to the treatment plan of small cell lung cancer, such as EP, CE, CAP, MVP regimen, etc. In terms of targeted therapy, the common gene mutation types of large cell lung cancer are TP53, KRAS, CDKN2A gene, etc., and there is currently no effective corresponding targeted drug available. About 5% of patients have EGFR gene mutations, can use gefitinib, osimtinib and other targeted drugs, 2% of patients have MET genes, can be considered carbotinib, clozotinib, sivatinib, cablotinib and other drugs.