Preoperative imaging for staging of cutaneous melanoma in the United States: A population-based analysis.

Abstract

9034 Background: Routine imaging for staging of early stage cutaneous melanoma is not recommended by National Comprehensive Cancer Network (NCCN) guidelines. Besides the low probability of finding metastatic disease, detrimental aspects include false-positives and additive cost. We sought to investigate the use of imaging for staging of cutaneous melanoma in the United States. Methods: Patients with newly diagnosed clinically node negative cutaneous melanoma between 2000-2007 were identified from the Surveillance Epidemiology End Results-Medicare registry. Any imaging performed within 90 days following diagnosis was considered a staging study. Patients with metastatic disease were excluded. Results: A total of 25,643 patients were identified, of whom 10,775 (42%) underwent imaging. The mean age was 76.1 years, with the majority being male (61.8%) and Caucasian (98.4%). Breakdown by T classification of the primary was as follows: T1 (63%), T2 (17%), T3 (12%), and T4 (8%). A chest Xray was performed for 9,737 (38.0%), while 3,176 (12.4%) underwent advanced staging imaging studies; PET (7.2%), CT (5.9%), MRI (0.6%), and Ultrasound (0.4%). The use of advanced imaging steadily increased over the period of our study from 9.0% in 2000 to 16.3% in 2007 (p<0.001). When stratified by T classification, advanced imaging was used for 8.9% of T1, 14.5% of T2, 18.8% of T3 and 27.0% of T4 tumors (p<0.001). Similarly, node positive patients (4.7%) underwent advanced imaging 33.4% of the time compared to 11.3% for node negative patients (p<0.001). On multivariate analysis, factors predictive of advanced imaging include higher T classification (OR 3.12 T4 vs. T1, CI 2.77-3.52, p<0.001), node positivity (OR 2.70, CI 2.36-3.09, p<0.001), more recent year of diagnosis (OR 2.01 2007 vs. 2000, CI 1.71-2.37, p=0.006), high school education (OR 1.62, CI 1.43-1.83, p<0.001), non-Caucasian race (OR 1.37, CI 1.05-1.77, p=0.018), and male gender (OR 1.12, CI 1.03-1.21, p=0.006). Conclusions: Contrary to current recommendations, performance of advanced imaging for staging of early stage cutaneous melanoma is increasing in the Medicare population. Further research is needed to identify factors driving this increase.