Pulmonary metastasectomy has evolved into a widely accepted and successful treatment strategy for patients with advanced disease of various tumor types. The growth of this surgical practice reflects the frequency in which the metastatic focus resides in the lung.1 Initial reports represented the findings of retrospective case series and large, registry data which did not provide any true understanding of the impact of surgical intervention in patients presenting with advanced, metastatic disease.2,3 Accordingly, the paradigm shift from primary medical management of distant disease to operative intervention was slow to gain momentum as early results failed to show consistent improvement in survival outcomes. Diagnostic imaging modalities and surgical technique have continued to improve over the past two to three decades, however, affording select patients with aggressive cancers (e.g., primary colorectal, soft tissue, and genitourinary tumors) substantial benefit from pulmonary resection for metastatic lesions. In this chapter, we will focus on soft tissue and abdominal malignancies that commonly metastasize to the lung and will structure our discussion to be of highest value for those within the surgical field.
It is important to evaluate a new pulmonary nodule in the context of the patient’s oncologic history as it could represent a benign finding, new primary process, or metastatic disease—the rate of the latter increasing substantially depending on the histologic subtype of the primary tumor. For example, patients with melanoma or sarcoma are 10 times more likely to have metastatic disease than a second primary if a new pulmonary nodule is diagnosed. Similarly, in patients with colonic or genitourinary cancers, a nodule represents metastatic disease nearly 50% of the time.4 Accordingly, the preoperative evaluation must be tailored to the patient’s unique situation and a high degree of suspicion maintained in specific cases.
Prior to embarking upon surgery, a series of diagnostic studies should be obtained to further characterize the disease and its resectability. Per the European Society of Thoracic Surgeons (ESTS) Lung Metastasectomy Project, the following conclusions regarding appropriate imaging emerged after an extensive review of the literature5:
Helical computed tomography (CT) of the chest with a minimum of 3- to 5-mm slick thicknesses should be obtained. There are no current data advocating for the application of 64-, 128- or 256-slice CT scanners.
Given the risk of disease progression, recent imaging within 4 weeks of the planned metastasectomy is strongly recommended.
If positron emission tomography is available at the surgical center, it is recommended that it be employed, especially in patients with PET-avid primary lesions. This will help to identify extrathoracic foci of disease.
A baseline image should be obtained 4 to 6 weeks following metastasectomy. Additional images should be obtained at regular, 6-month intervals for the first 2 years, after which the interval can be lengthened to yearly for at least 5 years following the resection.