Well, if the brain metastasis is an isolated metastasis amenable to surgical removal, EGFR mutation showing good activating mutation, then, the cannot-change-the-overall-stage's "staging mediastinoscopy" may help a patient to forego a curative-intent lung tumor resection and mediastinal lymph node resection surgery if the result turns out to be more than unresectable N2 status. But this form of practice is mostly protocol-based and exceptional for certain patients only. 

 There is one case series suggesting if you  select+++ you may get good results in primary resection with isolated metastasis that you can resect. In a patient with unresectable metastases or multiple metastases the only reason i can consider is to get a pathological diagnosis if no simpler way exists.

Eur J Cardiothorac Surg. 2012 Mar;41(3):617-22. 

Which metastasis management allows long-term survival of synchronous solitary M1b non-small cell lung cancer?

Mordant P1, Arame A, De Dominicis F, Pricopi C, Foucault C, Dujon A, Le Pimpec-Barthes F, Riquet M.

Author information

Abstract

OBJECTIVES; Patients with extrathoracic synchronous solitary metastasis and non-small cell lung cancer (NSCLC) are rare. The effectiveness of both tumour sites resection is difficult to evaluate because of the high variability among clinical studies. We reviewed our experience regarding the management and prognosis of these patients.

METHODS:

The charts of 4668 patients who underwent lung cancer surgery from 1983 to 2006 were retrospectively reviewed. We analysed the epidemiology, treatment, pathology and prognostic characteristics of those with extrathoracic synchronous solitary metastasis amenable to lung cancer surgery on a curative intend.

RESULTS:

There were 94 patients (sex ratio M/F 3.2/1, mean age 56 years). Surgery included pneumonectomy (n = 27), lobectomy (n = 65) and exploratory thoracotomy (n = 2). Pathology revealed adenocarcinomas (n = 57), squamous cell carcinoma (n = 20), large cell carcinoma (n = 14) and other NSCLC histology (n = 3). Lymphatic extension was N0 (n = 46), N1 (n = 17) and N2 (n = 31). Metastasis involved the brain (n = 57), adrenal gland (n = 12), bone (n = 14), liver (n = 5) and skin (n = 6). Sixty-nine metastases were resected. Five-year survival rate was 16% (median 13 months). Induction therapy, adenocarcinoma, N0 staging and lobectomy were criteria of better prognosis, but metastasis resection was not.

CONCLUSIONS:

These results suggest that extrathoracic synchronous solitary metastasis of pN0 adenocarcinoma may achieve long-term survival in the case of lung resection with or without metastasis resection. This pattern may reflect a specific tumour biology whose solitary metastasis benefits both from surgical or non-surgical treatment.

• Well if the  patient  is. Having solitary  metastatic lesion amenable for. Resection