Recently, the online consultation platform received a lung cancer patient whose pathological type was lung sarcoma-like carcinoma, and PET-CT showed multiple metastases throughout the body. Family members repeatedly asked the patient about the follow-up treatment method and treatment effect. It is regrettable to say that this type of malignancy grows very quickly, has a very poor prognosis, and even surpasses the type of small cell lung cancer in terms of mortality.
Sarcoma-like carcinoma, which is essentially a cancer of epithelial origin, but contains sarcoma-like components. The WHO defines it as a rare class of low-differentiated, non-small cell lung cancers that contain sarcoma components or sarcoma-like differentiation. Pulmonary sarcoma-like carcinoma is a rare malignancy of the lungs with a very low incidence of 0.1% to 0.5% of all lung malignancies. It occurs more in men than in women, more smokers than non-smokers, and the average age at diagnosis is 60 years. That is to say, older men, heavy smokers are more common. It is characterized by rapid growth, invasion, early recurrence and metastasis, and the common metastasis sites are in the lungs, bones, adrenal glands, pleura and brain.
In 2004, the WHO divided lung tumors into five types based on their pathological morphological characteristics: polymorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pneumocytoma. Because diagnosis is relatively difficult, immunohistochemistry and some special staining are usually required to confirm the diagnosis. Clinically, pulmonary sarcoma-like carcinoma is non-specific and similar to other types of lung cancer, including cough, chest pain, hemoptysis, and dyspnea.
How bad is lung sarcoma-like cancer?
Lung sarcoma-like carcinoma is highly invasive, 70% of patients are already in the middle and advanced stages of the disease at the time of presentation, due to the presence of sarcoma components, 90% of patients have vascular invasion, so it is easy to hematogenous metastasis. It is no exaggeration to say that lung sarcoma-like carcinoma can be regarded as the "cancer king" in non-small cell lung cancer. Surgery is the treatment of choice for early patients. Studies have found that nearly half of patients who undergo early surgical resection will have recurrence or metastasis, with an average postoperative recurrence time of 6.8 months. The 5-year survival rate for stage I patients is only 37%, while the 5-year survival rate for stage II pulmonary sarcoma-like carcinoma is only 24.5%, while other non-small cell lung cancer patients with the same stage can reach more than 50% overall.
Treatment-based lung sarcoma-like carcinoma has low sensitivity to chemoradiation and chemotherapy, and most of the patients in these studies have poor treatment results, both in terms of median survival and disease progression. Nevertheless, chemoradiation is recommended for people with large tumors, tumors that invade the chest wall, or those with lymph node metastases, as there is really no other treatment that is too good.
With the advancement of targeted therapy, in the WHO lung cancer classification, it is recommended that the genetic testing of sarcoma-like cancer containing adenocarcinoma components can bring new treatment opportunities to some advanced patients. The MET gene of the proto-oncogene is one of the more common genetic alterations in patients with lung sarcoma-like carcinoma, suggesting that MET inhibitors may exert an expected effect in lung sarcoma-like carcinoma. In addition, immunotherapy can be combined with chemotherapy to treat lung sarcoma-like carcinoma, which may also improve prognosis.