Don’t be afraid if you have lung metastasis

Tumors such as breast cancer, colorectal cancer, and uterine and ovarian cancer are prone to lung metastasis. The lung is the organ most prone to cancer metastasis after the liver. About 20%-54% of cancer patients will develop lung metastasis (PM) in the natural course of the disease , of which nearly 25% are pulmonary manifestations of disseminated diseases. Regardless of the pathological type of the primary tumor, as long as there is no extrathoracic metastasis and the patient can tolerate surgical resection, single surgery or combined chemotherapy can improve the long-term survival rate of PM patients and even cure some patients. 

Single lung metastasis is a unique biological subgroup of PM, and the survival after resection is better than that of multiple lung metastases, with a 5-year survival rate of 20% to 40%. Factors that determine survival include: whether it can be completely resected, the length of tumor-free survival, the length of tumor doubling time, the number of PMs, and the histological type of primary cancer.

After long-term clinical summary, some consensus has been reached on the indications for pulmonary metastases resection and the factors affecting prognosis. Indications for surgery: (1) The primary tumor can be controlled or has been controlled; (2) There is no extrathoracic metastasis; (3) All tumors must be resectable and have sufficient lung function reserve; (4) There are no other alternatives with lower morbidity. Generally, favorable prognostic features include: (1) one or a few metastases (the number of metastatic cancers cannot be too many) ; (2) a long disease-free interval; (3) normal CEA levels in colorectal cancer. Poor prognostic features include: (1) active primary cancer; (2) extrathoracic metastasis; (3) inability to obtain surgical resection; (4) mediastinal lymph node metastasis.

Breast cancer lung metastasis

The lung is a common site of metastasis for recurrent breast cancer. Studies have reported that patients with simple lung metastasis account for about 10%-20% of breast cancer metastasis patients, and the 5-year survival rate of patients undergoing chemotherapy alone is only 2.4%; while the 5-year overall survival rate of patients undergoing lung metastasis resection is about 27%-54%, and the median survival period is about 32 months-97 months. The effect of breast cancer lung metastasis surgery is much better than that of patients who do not undergo surgery . Predictors of poor prognosis include: tumor-free interval <3 years, incomplete resection of lung metastases, more than 1 lung metastases, and negative metastatic HER2 receptors.

Colorectal cancer lung metastasis

One-quarter of colorectal cancer patients have metastatic lesions at the time of diagnosis. The most common metastatic lesions are in the liver and lungs. The 5-year survival rate after colorectal cancer lung metastasis resection is about 49.4% . Bilateral lung metastases and multiple lung metastases are poor prognostic factors for colorectal cancer, while preoperative plasma CEA level, CA19- level and primary tumor location have no statistical significance for prognosis. Stage I and II colorectal cancer with unilateral lung metastasis can benefit the most from lung metastasis resection.

Lung metastasis from urinary system malignancies

Although there is no prospective study on the clinical effect of renal cell carcinoma lung metastasis resection, its therapeutic effect has been basically recognize based on existing clinical data. Studies have reported that the 5-year overall survival rate after surgery is about 33.4%, and the median survival time is 39.2 months. Whether the lung metastasis is completely remove is a key factor affecting prognosis.

The 5-year survival rate of complete resection is 39.9% and the median survival time is 46.6 months, while the 5-year survival rate of incomplete resection is 0% and 13.3 months, respectively; in addition, the 5-year survival rate of metachronous metastasis is better than that of synchronous metastasis (43.7% vs 0%), and the 5-year survival rate of single metastasis is better than that of multiple metastasis (49% vs 23%) ; studies suggest that for patients with renal cell carcinoma lung metastasis, metastasis resection may be the best treatment option at present.

Lung metastasis of gynecological malignancies

Sarcoma and choriocarcinoma are more likely to metastasize to the lungs than epithelial tumors such as cervical cancer, endometrial cancer, and ovarian cancer. Studies have reported that the 5-year and 10-year overall survival rates after resection of gynecological malignancies with lung metastases were 40.9% and 31.4%, respectively , while the 5-year survival rate of patients who received adjuvant therapy was approximately 52.4%, and the tumor-free interval was < 24 months. Recurrence after resection of lung metastases is a predictor of poor prognosis.

For patients with lung metastases from gynecological malignancies , current studies have shown no significant statistical difference in the 5-year survival rate between lung metastases resection and chemotherapy, possibly due to the small sample size. However, the 5-year overall survival rate of the former tends to be higher than that of the latter (89.1% vs 49.5%, P =0.072), suggesting that surgical resection of solitary lung metastases ( < 3) may provide potential benefits for the prognosis of patients with a long recurrence-free interval, chemotherapy-resistant patients, and patients with tumor recurrence .