Surgical Treatment of Metastatic Disease to the Lung

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Surgical Treatment of Metastatic Diseaseto the
Lung

• Semin Oncol 35134-146 April 2008Roderick M.
  Quiros and Walter J. Scott
• 4B Intern ???

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Incidence

• In autopsy studies of patients who died of
  extrathoracic malignancies
• 20 to 50 had pulmonary metastases. In this
  subset of patients, 10 to 15 had metastatic
  disease limited to the lung.

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Pathophysiology

• Via the pulmonary arteries and disseminating
  within the capillary beds.
• Less commonly, pulmonary metastases occur as a
  consequence of lymphatic spread.
• Spread to mediastinal lymph nodes occurs most
  commonly with melanoma, and breast, colorectal,
  and RCC
• 18 involving bronchi, lt3 amenable to
  bronchoscopic detction

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Imaging and Diagnosis

• Patients previously treated for extrathoracic
  malignancies who were found to have a new lung
  lesion
• metastasis in 46 of patients
• new lung primary tumor in 32
• benign disease in 18.

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Imaging and Diagnosis

• CXR nonspecific, often calcified to various
  degrees
• Chest CT main method used
• gt10mm 100, 6-10mm 66, lt6mm 48
• PET most useful in determining extent of disease
  in patients with pulmonary metastases from
  carcinoma
• Tissue sampling

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Prognostic Factors

• International Registry of Lung Metastases (1997)
  
• Length of disease-free interval (DFI)
• Number of metastases
• Resectability/completeness of resection

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Surgical Treatment Principles

• Selection Criteria
• The primary tumor is controlled
• There is no evidence of widespread extrapulmonary
  metastases
• The patient is a good surgical candidate who is
  expected to have adequate postoperative pulmonary
  function

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Surgical Treatment Principles

• Other indications for resection
• The need to establish a diagnosis
• Removal of residual lesions after chemotherapy
  (Germ cell tumor)
• Obtaining tissue for biochemical or
  immunohistochemical studies

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Surgical Treatment Principles

• Goal to obtain clear margins with removal of as
  little normal lung tissue as possible.
• Inadequacy of margins mandates re-excision to
  reduce the possibility of local recurrence.
• Most pulmonary metastases tend to be peripherally
  located? wedge resection is usually sufficient

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Unilateral or Bilateral Exploration

• Contralateral recurrence vs. bilateral metastases
  who had undergone bilateral thoracotomy? No
  significant difference in overall survival.
• Bilateral exploration for unilateral disease is
  not indicated
• Delaying contralateral thoracotomy until disease
  becomes radiologically apparent does not affect
  survival.

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Lymph Node Dissection

• Presence of metastatic nodal involvement a
  direct, negative effect on survivorship
• 3-yr survial 69 vs 38
• Systematic mediastinal and hilar LN dissection
  should be performed routinely with pulmonary
  metastasectomy ? accurate staging and guide
  postoperative treatment.

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Surgical Procedures

• Survival rates between these approaches are
  similar, assuming all gross disease is resected
• Median Sternotomy
• Transverse Sternotomy/Clamshell Incision
• Posterolateral Thoracotomy
• Video-Assisted Thoracic Surgery

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Median Sternotomy

• Allows exploration of both thoracic cavities, and
  affords good visualization of the lungs, hila,
  and chest wall.
• Exposure of the posterior costovertebral lung
  fields and the lateral left lower lobe are
  difficult

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Clamshell Incision

• Excellent exposure to the posterior aspect of
  both lungs.
• Increased postoperative pain

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Posterolateral Thoracotomy

• Standard approach for unilateral pulmonary
  resection
• Adequate access to all areas of the hemithorax
  and allows wedge or anatomic resection under
  direct vision

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VATS

• Loss of ability to palpate the lung to detect
  metastases, possibly leading to incomplete
  metastasectomy ? pre-op imaging
• Natural history of micrometastatic disease not
  detectable by pre-op CT
• Considered for diagnosis of metastases, and for
  resection in patients with one to a few,
  peripherally located tumors

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Extended Resection

• From wedge resection to pneumonectomy
• Median survival and initial disease-free survival
  between these patients did not differ based on
  extent of operation
• Endobronchial metastases and metastases located
  near tracheobronchial structures ? considered
  resectable by pneumonectomy ? higher complications

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Repeat Resection

• Presuming that the patient remains free of
  widespread metastases to other sites ? repeat
  resection
• Survival was fairly stable until the fifth or
  more procedure unless loss of local control
• DFI greater than 40 months between
  metastasectomies had a significant survival
  advantage

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Tumor Histologies

• Role of metastasectomy in their treatment
• Osteogenic Sarcoma
• Soft Tissue Sarcoma
• Colorectal Cancer
• Breast Cancer
• Melanoma
• Renal Cell Carcinoma
• Germ Cell Tumors

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Osteogenic Sarcoma

• 10 and 20 of patients are diagnosed with
  distant parenchymal metastases by imaging. Of
  these, 85 have metastases to the lungs
• Predict outcome the number of nodules on
  preoperative CT scan correlated (inversely)
• Histologic response to pre-op chemotherapy

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Soft Tissue Sarcoma

• Lung is often the only site of metastasis
• Surgical excision is considered first-line
  therapy assuming that complete resection is
  possible
• When pulmonary metastases recur, reoperation may
  yield good outcomes

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Colorectal Cancer

• Colorectal cancer spreads either regionally, into
  draining nodal basins, or systemically into the
  liver or lungs.
• Pulmonary metastases were found at a median of
  37.5 months after primary colorectal resection.
• Prognostic factor presence of a single
  metastasis, DFI gt 36 months, and a normal
  preoperative CEA level

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Colorectal Cancer

• Metachronous vs Synchronous resections of liver
  and lung metastases ?
• Patients with metachronous resections had a
  longer post-op survival (70 vs 22 months)
• No difference in overall survival between
  patients with synchronous and metachronous liver
  and lung mets ? supports aggressive pulmonary
  metastasectomy even in the presence of hepatic
  mets

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Tumor Histologies

• Breast Cancer In cases of isolated pulmonary
  metastases, resection remains an option
• Melanoma The majority of patients with melanoma
  metastatic to the lungs have extrapulmonary
  disease as well, resulting in a poor overall
  survival. (5-yr 22)
• Renal Cell Carcinoma 5-yr 42

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Germ Cell Tumors

• Lung is the most common site of distant
  metastases
• Metastasectomy is performed after completion of
  cisplatin-based C/T
• Good survival rate 5-year survival rates of up
  to 82

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CONCLUSIONS

• Metastases limited to the lung may be resected
  with prolonged survival.
• Selection Criteria the primary tumor is
  controlled, there is no evidence of widespread
  extrapulmonary metastases, and the patient is a
  good surgical candidate
• Prognostic Factor completeness of resection

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• Thank You For Your Attention