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 patients with early stage (I/II) non-small-cell lung cancer (NSCLC) treated with radiation therapy (RT) alone. PATIENTS AND METHODS: Seventy-eight patients had been treated with conventionally fractionated (CF) RT (1982 to 1987), and 116 patients had been treated with hyperfractionated (Hfx) RT (1988 to 1993). Tumor doses were 60 Gy for CF and 69.6 Gy (1.2 Gy bid) for Hfx.
RESULTS: A total of 26 patients developed second cancers. The cumulative incidence 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 developing second cancer per patient per year was 4.3% (95% confidence intervals [CI], 2.7% to 5.9%), with the rates being 1.4% (CI, 0.5% to 2.3%) for the second lung cancers and 2.8% (CI, 1.5% to 4.1%) for second nonlung cancers. 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%), respectively, 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 compared with those of the published literature.