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Surgical Management of Lung Metastases: Selection Factors and Results

Surgical Management of Lung Metastases: Selection Factors and Results

Drs. Dresler and Goldberg review the role of resection of metastatic tumors to the lung. It is a difficult topic, with the exception of osteosarcoma, for which the practice of secondary resection is common and clearly of benefit. For lung metastases from other tumors, however, the use of resection is based largely on sporadic and anecdotal reports.

Patients with osteosarcoma are usually followed by strict protocols, often in major sarcoma centers, and the vast majority of such patients with lung metastasis are identified early in the course of metastatic disease. About 15% to 20% of patients with osteosarcoma present with metastatic lung disease; these individuals have a much lower salvage rate than the 25% to 35% of patients relapsing after neoadjuvant or adjuvant chemotherapy and surgical control of the primary site. The only sites involved in these patients are distant bone and the local site. The information available for this group includes virtually all such patients, and the salvage rates for pulmonary resection in centers with large sarcoma practices are remarkably similar.

In the case of epithelial malignancies, very little literature exists other than anecdotal reports from centers with large thoracic surgical services. The number of patients who must be screened for metastatic disease limited to the lung is unknown, but this is certainly a very uncommon event in patients with epithelial malignancies. The authors' contention that 20% to 25% of patients dying with metastatic disease to the lung will be free of metastasis elsewhere is based on a small autopsy series done more than 60 years ago and is not likely to be valid today.

Unanswered Questions

Many questions remain with regard to surgical resection of both metastatic disease of osteosarcoma and epithelial malignancies with limited, surgically treatable metastases. Probably the most exciting recent development is the role of adjuvant (chemo)therapy for such patients. Given that the majority of patients in the western world who develop cancer today will have a primary from the lung, breast, or colon, for which adjuvant or neoadjuvant therapy may be of benefit, the obvious question of whether such therapy should be used in patients destined for resection should be considered and should be the basis of clinical trials.

In the case of osteosarcoma, breast cancer, and colon cancer, adjuvant chemotherapy has clearly been of benefit in eradicating micrometastatic disease. The role of further adjuvant therapy is unclear. However, few patients with osteosarcoma ever undergo only one thoracotomy, suggesting that micrometastatic disease is still present.

Obviously, a number of factors must be considered in such patients, in addition to the pulmonary factors detailed by Drs. Dresler and Goldberg. These include control of the primary tumor, the interval between development of the primary and metastatic lesion, and prior treatment, as well as the age of the patient.

Solitary metastases or even multiple but resectable metastases limited to the lung are uncommon feature of both breast and colon cancer, however. Nevertheless, they do occur, and Drs. Dresler and Goldberg suggest an excellent starting place for what hopefully may become a national or international trial.

Historical Perspective on Surgical Resection for Pulmonary Metastases

In 1882, Weinlechner carried out the first resection of a secondary sarcoma of lung, which was performed en bloc with a primary sarcoma of the chest wall [1]. In 1884, Kronlein resected a metastatic sarcoma to the lung in conjunction with a recurrent sarcoma of the chest wall. The first elective pulmonary metastatectomy was performed in 1939 by Barney and Churchill for a solitary lesion from a renal adenocarcinoma that had been previously resected. That individual subsequently lived free of malignancy for 23 years [2]. In 1947, Alexander and Haight reported on the first group of patients to undergo elective resection for metastatic disease and demonstrated a significant 3-year survival [3].

The modern age of resection for metastatic disease began in 1965 when Thomford reported a 5-year survival of 31% for unilateral metastatectomies of both single and multiple secondaries [4]. The feasibility of safe and curative resections was demonstrated in the 1970s by Martini and Morton, who showed that, regardless of whether the metastatic disease is solitary, unilateral and multiple, or bilateral and multiple, extended survival was possible [5,6].

References

1. van Dongen JA, van Slooten EA: Cancer Treat Rev 5:29-48, 1978.

2. Barney JD, Churchill ED: J Urol 42:269-276, 1939.

3. Alexander J, Haight C: Surg Gynecol Obstet 85:129, 1947

4. Thomford NR, Woolner LB, Clagett OT: J Thorac Cardiovasc Surg 49:357-363, 1965.

5. Martini N, Huvos AG, Mike U, et al: Ann Thorac Surg 12:217-280, 1971.

6. Morton DL, Joseph WL, Ketcham AS, et al: Am Surg 1788:360-366, 1973.

 
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