Multiple primary malignancies involving lung cancer: A survival analysis of 94 cases

Objective To explore the prognostic factors of patients with multiple primary malignancies (MPM) involving lung cancer, and try to find some clues for prevention and clinical treatment of these patients. Methods Clinical data about 94 hospitalized patients with multiple primary malignancies involving lung cancer in Chinese PLA General Hospital from January 2005 to May 2015 were reviewed. Follow-up was done in those patients. The prognostic factors were analyzed including gender, smoking history, family history, tumor stage of lung cancer, order of occurrence, time inteval of occurrence of multiple primary malignancies and treatment of lung cancer. Results A total of 94 cases were enrolled in this study and 2 patients were (2.1%) lost to follow-up until October 2015. Of the 94 patients, 30 had lung cancer diagnosed first (LCF) and 64 had other cancers diagnosed first (OCF). OCF patients showed significantly better overall survival (OS) than LCF patients (median OS, 39 months vs 97 months, P< 0.001). Twenty-two cases had synchronous multiple primary malignancies (SMPM) and 72 had metachronous multiple primary malignancies (MMPM), with a median OS of 23 and 96 months, respectively. MMPM patients demonstrated significantly better OS than SMPM patients (P< 0.001). COX regression analysis indicated that stage of lung cancer, order of occurrence, lung cancer treatment and time inteval of occurrence of multiple primary malignancies were independent prognostic factors of patients with multiple primary malignancies involving lung cancer. Conclusion Advanced lung cancer stage, lung cancer diagnosed first and synchronous multiple primary malignancies are significantly associated with poor OS among the patients with multiple primary malignancies involving lung cancer. Surgical resection for lung cancer is the independent predictive factor for longer survival time.