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 (18)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 (18)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= 0.0001), 0% and 91% for tumors 3 cm or less (P= 0.0004), 50% and 100% for tumors larger than 3 cm, and 40% and 89% for the mainly solid tumors (P= 0.0010). There were no statistically significant differences of local failure-free rates according to age, sex and tumor size (P= 0.4804, P= 0.4170 and P= 0.3638, respectively). CONCLUSIONS High uptake of (18)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.