Predictors of Outcomes after Surgical Treatment of Synchronous Primary Lung Cancers

Introduction: Distinguishing synchronous primary lung cancers (SPLCs) from advanced disease is important because prognosis and treatments are very different and a surgical approach to SPLC may result in survival similar to solitary cancers. Determining this distinction with certainty, however, is challenging. We reviewed our experience with surgical resection of presumed SPLC to analyze outcomes and identify factors associated with prolonged survival. Patients and Methods: A retrospective review identified patients treated for presumptive SPLC. Cases were defined using modified criteria set forth by Martini and Melamed and histologic subtyping. Survival was estimated using the Kaplan-Meier method, and factors associated with survival were evaluated using a log-rank test or Cox proportional hazards model for categorical and continuous variables, respectively. Results: From January 1995 to July 2006, 175 patients met study criteria and underwent complete resection. Tumors were more often in different lobes of an ipsilateral chest (55 of 175, 31%) or contralateral lesions (45 of 175, 26%). More than half (104 of 175, 59%) of the patients underwent a single operation. Median follow-up was 50.3 months (4.8-164.7); median overall survival (OS) for the group was 67.4 months (46.4-80.0) with a 3-year OS of 64%. On multivariable analysis controlling for stage, only female gender was a significant predictor of better OS (p = 0.001). Conclusions: An aggressive surgical approach to patients with apparent SPLC can result in survival that is comparable with patients with single lung cancers of similar stage. The Martini and Melamed criteria and histologic subtyping can identify appropriate patients for resection. Female gender was associated with superior OS.