Background: As the overall survival of patients with
cancer continues to improve, the incidence of second primary
malignancies seems to be increasing. Previous studies have shown controversial results regarding the survival of patients with primary
lung cancer with previous extrapulmonary
malignancies. This study aimed to determine the clinical picture and outcomes of this particular subgroup of patients. Materials and Methods: We included 2,408 patients who underwent pulmonary resection for primary
lung cancer at our institute between January 1, 2011 and December 30, 2017 in this retrospective study. Medical records were extracted and clinicopathological parameters and postoperative prognoses were compared between patients with
lung cancer with and without previous extrapulmonary
malignancies. Results: There were 200 (8.3%) patients with previous extrapulmonary
malignancies.
Breast cancer (30.5%),
gastrointestinal cancer (17%), and
thyroid cancer (9%) were the most common previous extrapulmonary
malignancies. Age, sex, a family history of
lung cancer, and preoperative
carcinoembryonic antigen levels were significantly different between the two groups. Patients with previous breast or
thyroid cancer had significantly better overall survival than those without previous
malignancies. Conversely, patients with other previous extrapulmonary
malignancies had significantly poorer overall survival (p < 0.001). The interval between the two
cancer diagnoses did not significantly correlate with clinical outcome. Conclusion: Although overall survival was lower in patients with previous extrapulmonary
malignancies, previous breast or
thyroid cancer did not increase mortality. Our findings may help surgeons to predict prognosis in this subgroup of patients with primary
lung cancer.