Abstract
PURPOSE Plasma osteopontin (OPN) levels in advanced non-small-cell lung cancer (NSCLC) correlate with therapeutic response and survival, but the utility of plasma OPN for diagnosis and monitoring of early-stage NSCLC has not been investigated. We hypothesize that plasma OPN levels are elevated in early-stage NSCLC and decrease with resection. PATIENTS AND METHODS Presurgery plasma OPN levels (in ng/mL) were measured by enzyme-linked immunosorbent assay (ELISA) in a discovery set of 60 patients with early-stage NSCLC and were compared with data from 56 cancer-free smokers. Presurgery OPN was validated in an independent cohort of 96 patients with resectable NSCLC. The presurgery levels in the latter cohort were compared with matched postsurgery levels. Perioperative OPN levels were correlated with demographics, tumor characteristics, and perioperative events. OPN was monitored during follow-up. Results Discovery set presurgery NSCLC OPN (271 +/- 31 ng/mL) was higher than smokers (40 +/- 2 ng/mL; P = .001). Presurgery OPN was similar in the NSCLC validation cohort (324 ng/mL +/- 20 ng/mL; P = .134). Postsurgery OPN (256 ng/mL +/- 21 ng/mL) measured at mean of 9.8 weeks (range, 2 to 46 weeks) was lower than presurgery OPN (P = .005). Time from surgery significantly impacted postsurgery OPN: OPN < or = 6 weeks postsurgery (303 n/mL +/- 26 ng/mL) was higher than OPN greater than 6 weeks postsurgery (177 ng/mL +/- 29 ng/mL; P = .003). Multivariate analysis noted correlations between albumin and creatinine to presurgery OPN and use of thoracotomy to postsurgery OPN. Recurrence rate was 5% at 29 weeks mean follow-up. OPN at recurrence was elevated from postsurgery nadir. CONCLUSION Plasma OPN levels are elevated in early-stage NSCLC. They are reduced after resection and appear to increase with recurrence. Plasma OPN may have utility as a biomarker in early-stage NSCLC.