Patients who have had curative surgery for lung cancer are at the highest risk of developing a new lung cancer. Individual studies are usually underpowered to describe the clinical characteristics and outcomes in second primary lung cancer (SPLC). The goal of this study is to determine which treatment is best associated with survival in patients who develop a new primary lung cancer. All pathologically proven stage I lung cancer cases that received cancer-directed surgery included in the Surveillance Epidemiology and End Results database between 2004 and 2010 were selected. Cases that received radiation therapy were excluded. Cases that developed a SPLC 6 or more months after the diagnosis of the first cancer were analyzed. The original data set consisted of 9564 stage I lung cancer cases treated with surgery; 520 of them developed a second primary, and completed data were available for 494 of them. Stage I disease was diagnosed in 272 patients with SPLCs (58.5%); 45.8% of these underwent cancer surgery alone, and 31.6% received radiation alone. Surgery was performed more frequently in early stages and younger patients. Surgical patients had statistically significant longer survival than patients treated with radiation (log-rank P < 0.0001) or not treated with surgery or radiation (log-rank P < 0.0001). The incidence of SPLCs was 5.4%. Stage I second primaries had improved survival when compared with later stage disease, and surgery conferred an increased survival benefit as compared with radiation.
Keywords: Cancer registry; cancer outcome; cancer treatment; epidemiology.
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