Clinical and surgical approaches for malignant pulmonary lesions after a previous extrapulmonary malignancy

In our study, since the operative histopathological distinction of new malignant pulmonary lesions as either a primary lung cancer or a pulmonary metastasis is difficult, we aimed to identify the clinical variables which might allow distinction between a new lung cancer and a pulmonary metastasis, and the appropriate surgical management.

We divided 55 cases into two groups: patients with new lung cancer (NLC, n = 32) and patients with pulmonary metastases (PM, n = 23). Based on the primary organ, the previous malignancy was classified into four categories: head and neck, colorectal, genitourinary, and breast cancer. The parameters included in the study were age, sex, smoking history, a family history of cancer, disease-free interval, primary organ, treatments for previous malignancies, size, and SUV max of the lung lesion on 18F-fluorodeoxyglucose positron emission tomography scan and high-resolution computed tomography findings of the lung lesion.

A predisposition for larger lesions was found in the NLC group. In addition, in the NLC group, disease-free interval was noted to be longer, patients were significantly older and SUV-max values of solitary pulmonary lesions were significantly higher than in the PM group. Pulmonary lesions in patients with prior head and neck cancers were more likely to develop NLC. No significant difference in statistical analysis was observed between the groups in terms of sex, smoking, a family history of cancer, a history of adjuvant therapy, radiological pulmonary lesions signs, and localization.

PL monitoring on CT surveillance is essential, particularly in patients with previous head and neck cancers, who appear to have a higher risk for NLC. If pathological MLN accompanies PL in a patient with previous extrapulmonary malignancy, cervical mediastinoscopy may help acquire a possible PL diagnosis besides mediastinal staging. Intraoperative frozen section may have difficulty in distinguishing between PM and NLC when the lesion is of the same histological type as the previous malignancy. When precise distinction cannot be achieved by frozen section, we speculate that DFI, age, and radiological findings of the PL may help thoracic surgeons take initiative peroperatively while designating the subsequent surgical intervention. Lastly, pulmonary segmentectomy is also better be considered along with lobectomy in NLC cases.