Second cancers occurring in patients with early stage non-small-cell lung cancer treated with chest radiation therapy alone

Purpose: To investigate the incidence of second cancers occurring in patien ts with early stage (I/II) nonsmall-cell lung cancer (NSCLC) treated with r adiation therapy (RT) alone. Patients and Methods: Seventy-eight patients had been treated with conventi onally fractionated (CF) RT (1982 to 1987), and 116 patients had been treat ed with hyperfractionated (Hfx) RT (1988 to 1993). Tumor doses were 60 Gy f or CF and 69.6 Gy (1.2 Gy bid) for Hfx. Results: A total of 26 patients developed second cancers. The cumulative in cidence of second cancer was 21.8% (SE, 4.7%) at 5 years and 34.8% (SE, 6.7 %) at 10 years. For second lung cancers, it was 6.0% (SE, 2.8%) at 5 years and 14.2% (SE, 5.2%) at 10 years, and for second nonlung cancers, it was 16 .3% (SE, 4.2%) at 5 years and 22.2% (SE, 5.7%) at 10 years. The rate of dev eloping second cancer per patient per year was 4.3% (95% confidence interva ls [CI], 2.7% to 5.9%), with the rates being 1.4% (CI, 0.5% to 2.3%) for th e second lung cancers and 2.8% (CI, 1.5% to 4.1%) for second nonlung cancer s. The rate of developing second cancers during the first and second 5-year period after RT (0 to 5 and 5 to 10 years) was 4.3% (CI, 2.4% to 6.2%) and 4.2% (CI, 0.6% to 7.8%), respectively, for all cancers. These rates were 1 .0% (CI, 0.1% to 1.9%) and 2.2% (CI, 0% to 4.6%), respectively, for second lung cancers, and 3.2% (CI, 1.6% to 4.8%) and 1.5% (CI, 0% to 3.6%), respec tively, for second nonlung cancers. Conclusion: Long-term survivors after RT alone for early stage NSCLC carry the same risk of developing second cancer, either lung or nonlung, as their counterparts treated surgically when the results of this study are compare d with those of the published literature.