Lung cancer patients with a previous extra-pulmonary malignancy should not be considered homogeneous: a clinicopathological analysis of 3530 surgical cases.

BACKGROUND: Lung cancer patients with a previous extra-pulmonary malignancy have been widely discussed for their postoperative prognosis. Still, whether different types of previous extra-pulmonary malignancy confer different clinicopathological features and outcomes of lung cancer patients deserves further investigation.

METHODS: The medical records of patients undergoing operation for pulmonary malignancy were retrospectively reviewed. After identifying primary lung cancer out of pulmonary metastasis in patients with a history of previous extra-pulmonary malignancy, clinicopathological parameters and postoperative prognosis were compared between lung cancer patients without and with different types of previous extra-pulmonary malignancy.

RESULTS: Approximately, 5.0% lung cancer patients undergoing surgery had a previous extra-pulmonary malignancy. Prior breast cancer (20%) and colorectal cancer (16%) formed the majority of these previous extra-pulmonary malignancies. Many clinicopathological features such as reason for visit, tumor size and histological subtype were significantly different between lung cancer patients without and with different types of previous extra-pulmonary malignancy (P < 0.05). Lung cancer patients with a previous occurrence of breast cancer were the most different type from patients without a previous extra-pulmonary malignancy in clinicopathological features (P < 0.05). The postoperative overall survival was not significantly different between lung cancer patients without and with different types of previous extra-pulmonary malignancy (P > 0.05).

CONCLUSION: Previous extra-pulmonary malignancy was confirmed to be harmless to postoperative prognosis of lung cancer patients. Lung cancer patients with a previous extra-pulmonary malignancy, especially with a previous occurrence of breast cancer, were highly heterogeneous in clinicopathological features. These findings implied there might be a unique etiology existing in lung cancer following a previous occurrence of breast cancer.