Pulmonary metastases of breast cancer. When is resection indicated?

While resection of pulmonary metastases is a common treatment in other primaries, the role of breast cancer metastasectomy is still unclear. The objective of the present study was to investigate the clinical outcome of our operated patients with pulmonary breast cancer metastases and discuss the different indications for metastasectomy.

From January 1998 to December 2007 we retrospectively analysed 47 patients with histologically proven pulmonary metastases from breast cancer. The mean age of the 47 female patients was 56.2 years, the median disease-free interval (DFI) was 3.66 (0-25.8) years and the median follow-up was 20.6 months (3.2-110).

The grading of the metastases was higher than the primary tumour in 12 of 45 (26.7%) and lower in 6 of 45 (13.3%) patients. R0, R1 and R2 resections were achieved in 27, 6 and 14 cases. The oestrogen receptor status of the metastases differed from the primary tumour in 11 out of 39 (28.2%) tested cases. Her2-neu receptor status differed in 4 out of 16 tested patients. The histological reports described a tumour spread around the metastasis in lymph or blood vessels in at least one resection specimen in 25 out of 47 (53.2%) patients. The rate of major complications was 5.8%. The overall survival from the first pulmonary metastasectomy was 32 months with a 5-year survival of 36%. The main prognostic factor was the oestrogen receptor status with a 5-year survival for receptor positive patients of 76% and 12.1% for receptor negative ones (p=0.002). A similar survival difference was found for the status of Her2-neu receptor (p=0.037). No prognostic influence could be demonstrated for age, number of metastases, initial tumour stage, complete versus incomplete resection, lymphatic spread, lymph node or parietal pleural involvement.

The gain in life expectancy in breast cancer patients with pulmonary metastases is based on chemotherapy and antihormone treatment. Tissue of the lung metastasis is needed to adjust medical therapy to oestrogen and Her2-neu expression and to reliably rule out primary lung cancer. In case of proved pulmonary metastases, the level of evidence for a curative approach is low but some patients might benefit.