Secondary Lung Tumors Treatment & Management

Updated: Feb 08, 2019
  • Author: Daniel S Schwartz, MD, MBA, FACS; Chief Editor: John Geibel, MD, DSc, MSc, AGAF  more...
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Treatment

Approach Considerations

Surgical treatment of secondary lung tumors should be considered for a pulmonary metastasis of primary lung cancer and, infrequently, for metastases of other types of primary cancer.

Surgical resection of a lung metastasis should not be performed unless, as indicated by predictive postoperative pulmonary function testing or cardiopulmonary exercise testing, the procedure has a significant likelihood of being curative and not disabling.

A metastatic nodule in the same lobe as a primary lung tumor was once considered a T4 tumor, as designated in the 1997 tumor-node-metastasis (TNM) classification scheme of the American Joint Committee on Cancer (AJCC) and the Union for International Control of Cancer (UICC). In the revised seventh edition of the TNM staging system, however, it was classified as a T3 lesion instead [30] ; the same was true in the eighth edition. [31]

According to the 1997 classification, the presence of two malignant nodules of the same histologic type in two different lobes on the ipsilateral side of the lung indicated metastatic disease or stage IV lung cancer. According to the seventh and eighth editions of the staging system, however, this was indicative of potentially resectable T4 lesions. [30, 31]

In both cases, surgical management that is more aggressive than is otherwise recommended for the same stage of the disease has been advocated. Every effort should be made to document the diagnosis of both individual nodules if they are located in different lung lobes, because the approach is more aggressive if two separate synchronous lung cancers are documented. (Synchronous lung cancers are staged separately, but the overall prognosis is poorer than for a single lung cancer of a similar stage.) This becomes particularly important if one the lesions proves benign.

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Surgical Resection

Primary cancers

Surgical procedures of choice for the treatment of primary lung cancer tend to be lobectomy or pneumonectomy, depending on the size and the location of the tumor. Surgical decisions are also dictated by the involvement of regional lymph nodes. Meticulous evaluation of preoperative lung function with pulmonary function testing (PFT), possibly pulmonary perfusion scanning, and possibly cardiopulmonary exercise testing (CPET) is crucial in the marginal group of patients.

Surgery is also indicated for patients with selected primary extrapulmonary cancers in which the lung is identified as the sole site of metastatic disease and in which alternative therapy alone would not likely be effective, provided that the patient is otherwise able to tolerate the required lung resection. Favorable outcomes have been reported in cases of resection of multiple lung nodules for select tumors.

Metastasectomy

The procedure of choice for the treatment of secondary lung tumors is metastasectomy (wedge resection of the malignant nodule) by means of thoracotomy or video-assisted thoracoscopic surgery [32] (VATS). In the case of bilateral metastasis, median sternotomy may be preferable to staged thoracotomy, particularly if VATS is contraindicated. Surgical resection of pulmonary metastasis is always performed with curative intent.

Some authors believe that a thoracotomy is preferable to VATS, solely because, they reason, tactile evaluation is important to the resection of all metastatic disease. [33]  It can be counterargued, however, that the efficiency of multislice computed tomography (CT) has improved the ability to detect even subcentimeter lesions.

Patient selection

In general, good surgical candidates for pulmonary metastasectomy meet all of the following criteria:

  • No other known extrapulmonary metastases - If additional metastases are present, they should be considered amenable to surgical or some other form of therapy
  • Good surgical candidates from the standpoint of cardiopulmonary and other comorbid conditions
  • The location of the metastatic lesion is such that it can be completely resected with reasonable (depending on baseline pulmonary status) preservation of the remaining normal lung
  • The primary tumor site has been controlled or resected

Sometimes the resection is done to confirm the diagnosis (eg, to rule out a new primary cancer that might require a different approach to therapy).

A retrospective series from the National Cancer Institute spanning the period from 1979 to 2010 reported that given the dearth of effective systemic therapies, pulmonary metastasectomy may be the most beneficial treatment in patients who meet established selection criteria. [34]

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Bronchoscopic Intervention

Local control by bronchoscopic intervention is reserved for symptomatic patients with tracheobronchial metastasis, provided that a reasonable life expectancy may be anticipated with successful resection. Options are as follows:

  • Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser resection of the endoluminal tumor
  • Electrocauterization
  • Argon plasma coagulation
  • Cryotherapy
  • Brachytherapy
  • Mechanical removal of the obstruction with rigid bronchoscopy
  • Endoluminal stent placement
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Chemotherapy and Other Nonresective Treatments

Chemotherapy remains the treatment of choice for advanced cancer. Metastatic cancers known to respond favorably to chemotherapy include Hodgkin lymphoma, non-Hodgkin lymphoma, germ cell tumors, and thyroid cancer. A fair response to chemotherapy is expected for carcinomas of the breast, prostate, and ovary. Immunotherapy is an additional option for the treatment of metastatic malignant melanoma.

Several other therapies are currently being used as alternatives to surgical resection, including radiofrequency ablation (RFA), [35, 36, 37] cryoablation, [38] and conventional radiotherapy. However, most of these have limited availability, and most involve enrollment in a structured clinical trial. [39, 40, 41, 42]

These treatments are usually performed at experienced centers for patients who have lung malignancies (primary lung cancer or pulmonary metastases) and who are not candidates for surgery with the intent to resect. These therapies may also be used in conjunction with other treatments (ie, chemotherapy or radiotherapy) for better disease control. Repeat irradiation has been used for treatment of secondary lung tumors previously treated with radiotherapy. [43]

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