(P099) Influence of Surveillance PET/CT on Detection of Early Recurrence Following Definitive Radiation in Stage III Non–Small-Cell Lung Cancer

Jay Reddy, MD, PhD, Chad Tang, MD, Zhongxing Liao, MD, Daniel Gomez, MD; UT MD Anderson Cancer Center

PURPOSE/OBJECTIVES: There are little data to support the use of varying imaging modalities in evaluating recurrence in non–small-cell lung cancer (NSCLC). We compared the efficacy of surveillance positron emission tomography–computed tomography (PET-CT) vs CT scan of the chest in detecting recurrences following definitive radiation for NSCLC.

MATERIALS AND METHODS: We retrospectively analyzed 189 patients treated between 2000 and 2011 who met the inclusion criteria of biopsy-proven stage III NSCLC and completion of definitive radiation treatment (dose ≥ 60 Gy). These patients were then grouped based on the ratio of PET-CT scans: CT scans of the chest during the postradiation surveillance window, defined as 2–18 months posttreatment. A ratio of 0 described the CT-only group, and a ratio of > 1 described the PET-high group. We compared survival times from the end of treatment to the date of death or last follow-up utilizing log-rank tests. Multivariate analysis was conducted to identify factors associated with decreased survival.

RESULTS: In the entire cohort, median event-free survival (EFS) was 8.7 months, and median overall survival (OS) was 29.9 months. The CT-only group had a median EFS of 9 months vs 8.7 months for the PET-high group (P = .85). There was no difference in OS between the CT-only and PET-high groups (median OS: 35.3 mo and 29.3 mo, respectively; P = .66). There was also no difference in local recurrence-free survival or distant metastases-free survival between the CT-only and PET-high groups (P = .06 and P = .32, respectively). Similarly, on multivariate analysis, stratification into the PET-high group was not associated with improved EFS (hazard ratio [HR] = 0.978; 95% confidence interval [CI], 0.688–1.391; P = .902) or OS (HR = 1.032; 95% CI, 0.723–1.472; P = .864).

CONCLUSIONS: In stage III NSCLC patients treated with definitive radiation, increased frequency of PET-CT scan surveillance did not result in decreased time to detection of locoregional or distant recurrence or improved survival. If validated, further investigation is warranted to elucidate the benefit, if any, of NSCLC posttreatment surveillance with PET-CT scan.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org