Relationship between Pretreatment FDG Uptake and Local Control after Stereotactic Body Radiotherapy in Stage I Non-small-cell Lung Cancer: The Preliminary Results

Objective: Relationship between pretreatment uptake of F-fluoro-2-deoxy-D-glucose and local control after stereotactic body radiotherapy in stage I non-small-cell lung cancer was examined. Methods: Between June 2006 and June 2009, 90 clinically diagnosed stage I primary lung cancer in 86 patients were treated with stereotactic body radiotherapy in Shikoku Cancer Center. Among these, 51 tumors in 51 patients were evaluated by positron emission tomography using F-fluoro-2-deoxy-D-glucose before treatment. Twenty-six tumors of histopathologically confirmed non-small-cell lung cancer were reviewed in this study. Tumors were divided into two groups by the threshold maximum standardized uptake value of 5.0 (high-uptake tumors, 9; low-uptake tumors, 17). One tumor with low uptake was pure ground-glass opacity. Typically, 48 Gy in four fractions was given at the isocenter. Results: Follow-up time was 4–44 months (median, 21 months). Local failure-free rates at 15 months of the high-uptake group and the low-uptake group were 40% and 93% for all tumors (P 1⁄4 0.0001), 0% and 91% for tumors 3 cm or less (P 1⁄4 0.0004), 50% and 100% for tumors larger than 3 cm, and 40% and 89% for the mainly solid tumors (P 1⁄4 0.0010). There were no statistically significant differences of local failure-free rates according to age, sex and tumor size (P 1⁄4 0.4804, P 1⁄4 0.4170 and P 1⁄4 0.3638, respectively). Conclusions: High uptake of F-fluoro-2-deoxy-D-glucose in a primary tumor was the significant unfavorable factor for local control after stereotactic body radiotherapy in stage I non-small-cell lung cancer.