Surgical Management of Lung Metastases: Selection Factors and Results

Drs. Dresler and Goldberg review the role of resection of metastatictumors to the lung. It is a difficult topic, with the exceptionof osteosarcoma, for which the practice of secondary resectionis common and clearly of benefit. For lung metastases from othertumors, however, the use of resection is based largely on sporadicand anecdotal reports.

Patients with osteosarcoma are usually followed by strict protocols,often in major sarcoma centers, and the vast majority of suchpatients with lung metastasis are identified early in the courseof metastatic disease. About 15% to 20% of patients with osteosarcomapresent with metastatic lung disease; these individuals have amuch lower salvage rate than the 25% to 35% of patients relapsingafter neoadjuvant or adjuvant chemotherapy and surgical controlof the primary site. The only sites involved in these patientsare distant bone and the local site. The information availablefor this group includes virtually all such patients, and the salvagerates for pulmonary resection in centers with large sarcoma practicesare remarkably similar.

In the case of epithelial malignancies, very little literatureexists other than anecdotal reports from centers with large thoracicsurgical services. The number of patients who must be screenedfor metastatic disease limited to the lung is unknown, but thisis certainly a very uncommon event in patients with epithelialmalignancies. The authors' contention that 20% to 25% of patientsdying with metastatic disease to the lung will be free of metastasiselsewhere is based on a small autopsy series done more than 60years ago and is not likely to be valid today.

Unanswered Questions

Many questions remain with regard to surgical resection of bothmetastatic disease of osteosarcoma and epithelial malignancieswith limited, surgically treatable metastases. Probably the mostexciting recent development is the role of adjuvant (chemo)therapyfor such patients. Given that the majority of patients in thewestern world who develop cancer today will have a primary fromthe lung, breast, or colon, for which adjuvant or neoadjuvanttherapy may be of benefit, the obvious question of whether suchtherapy should be used in patients destined for resection shouldbe 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 eradicatingmicrometastatic disease. The role of further adjuvant therapyis unclear. However, few patients with osteosarcoma ever undergoonly one thoracotomy, suggesting that micrometastatic diseaseis still present.

Obviously, a number of factors must be considered in such patients,in addition to the pulmonary factors detailed by Drs. Dreslerand Goldberg. These include control of the primary tumor, theinterval 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 metastaseslimited to the lung are uncommon feature of both breast and coloncancer, however. Nevertheless, they do occur, and Drs. Dreslerand Goldberg suggest an excellent starting place for what hopefullymay become a national or international trial.

Historical Perspective on Surgical Resection for PulmonaryMetastases

In 1882, Weinlechner carried out the first resection of a secondarysarcoma of lung, which was performed en bloc with a primary sarcomaof the chest wall [1]. In 1884, Kronlein resected a metastaticsarcoma to the lung in conjunction with a recurrent sarcoma ofthe chest wall. The first elective pulmonary metastatectomy wasperformed in 1939 by Barney and Churchill for a solitary lesionfrom 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 groupof patients to undergo elective resection for metastatic diseaseand demonstrated a significant 3-year survival [3].

The modern age of resection for metastatic disease began in 1965when Thomford reported a 5-year survival of 31% for unilateralmetastatectomies of both single and multiple secondaries [4].The feasibility of safe and curative resections was demonstratedin the 1970s by Martini and Morton, who showed that, regardlessof whether the metastatic disease is solitary, unilateral andmultiple, 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 Surg49:357-363, 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.