A metastasis is a type of lung tumor that develops when cancer from another body site (for example, the breast or colon) spreads to the lung. When this occurs, the tumors in the lung are referred to as metastatic lung (pulmonary) tumors. Because it acts as a sieve for all of the blood that passes through the body, the lung is a very common site for metastatic tumors to lodge. Fortunately, patients with tumors that spread to the lung from other sites often still have a chance to be cured by surgical removal of these tumors, frequently in combination with chemotherapy.
There are several criteria that generally should be met for it to be reasonable to surgically remove (or "resect") such cancerous lung tumors that originate from other body sites:
a) patients should have their primary tumor site controlled
b) there should be no uncontrollable extra-pulmonary disease (disease outside the confines of the lungs)
c) all visible lung metastases, including bilateral disease, should be resectable while leaving the patient with adequate lung function for a good quality of life
When deciding to undergo lung surgery to treat metastases from different types of cancers, you and your surgeon may discuss:
- The Rationale for Lung Resection
- The Number of Tumors
- The Use of Minimally Invasive Techniques
- The Type of Cancer that Has Spread to the Lung
See the individual headings below for more information on each.
Patients with untreated metastatic disease have a 5-year survival rate of less than 5 to 10% on average. For a patient with isolated metastatic disease to the lungs (i.e., with no metastases to other parts of the body), pulmonary metastasectomy (surgical removal of the lung tumors) is the best hope for cure. Numerous studies have demonstrated 5-year survival rates of 30 to 50% for a variety of primary tumors when they spread to the lungs but then are surgically removed. These survival rates are far superior to any other treatment currently available. Regardless of the primary tumor, completeness of resection is the key to achieving long-term survival/cure. Since these operations can be performed with very low morbidity and mortality rates, and offer a chance for cure in otherwise incurable patients, surgery is very often recommended.
The number of tumors found in the lung is a factor when determining whether or not to undergo surgery. In general, the presence of fewer, or solitary, tumors occurring at a remote time from the primary cancer diagnosis will factor favorably into the decision to offer a lung operation. However, the presence of multiple metastatic tumors does not preclude lung resection, and even if the metastases are present at the time of (synchronous with) identification of the primary tumor, resection can be considered.
Our group favors a relatively aggressive approach, and we do not consider the number of metastases per se to be limiting. What is more important is the feasibility of resecting all sites of disease in the context of leaving adequate lung function in reserve.
The newest surgical approach to pulmonary metastasectomy is by video-assisted thoracoscopic surgery (VATS). This minimally invasive approach provides excellent exposure of the lung surface, and by palpation nodules below the surface. It reduces surgical trauma, minimizes postoperative pain, provides earlier patient mobilization, and decreases hospital length of stay. Pulmonary metastases are often small nodules located in the periphery of the lung, well suited for wedge resection by stapler and the VATS approach when they are limited in number (generally 3 or less). In case of recurrence of pulmonary disease, and if the patient fulfils the initial criteria for pulmonary metastasectomy, repeat surgery can be performed.
When more nodules are present, or more complex resections are required, thoracotomy may be recommended. This allows the surgeon to carry out bimanual palpation of the entire lung, and it likely reduces the chance of tiny, more difficult-to-find nodules being missed. This comes at the cost, however, of greater patient discomfort and greater difficulty if later reoperation is required.
Our group has a diverse experience removing pulmonary metastases. Some of the more common cancers that lead to lung metastases that we have removed here at Stanford are listed below:
- Colorectal cancer
- Head and neck cancer
- Malignant melanoma
- Renal cell cancer
- Soft tissue sarcoma (extremity, retroperitoneal, bowel)
- Testicular cancer
Following surgery, close scheduled postoperative follow-up with serial radiographic imaging (CT scanning, generally) is warranted. Our patients are treated in close collaboration with a dedicated team of thoracic specialists including the medical oncologist (your local oncologist or a Stanford oncologist), diagnostic radiologist, radiation oncologist when needed, and thoracic surgeon.
The Division of Thoracic Surgery in the Department of Cardiothoracic Surgery at the Stanford School of Medicine is located in the San Francisco Bay Area in northern California. For more information about our services, please contact Donna Minagawa at (650) 721-2086 or Angela Lee, RN, MS, at (650) 721-5402. For new patient Thoracic Surgery Clinic Scheduling, please call (650) 498-6000.