(P088) Nonadherence to NCCN Guidelines Negatively Impacts Survival in Early-Stage Squamous Cell Carcinoma of the Larynx

Chi-Hsiung Wang, PhD, Erik Liederbach, BS, Arif Shaikh, MD, Mihir K. Bhayani, MD; Center for Biomedical Research Informatics, Department of Surgery, Department of Radiation Oncology, Department of Head and Neck Surgery, NorthShore University HealthSystem

INTRODUCTION: Primary treatment for early-stage squamous cell carcinoma of the larynx (LSCC) is radiation therapy (RT) alone or larynx-preserving surgery per National Comprehensive Cancer Network (NCCN) guidelines. The guidelines do not recommend the addition of chemotherapy in this setting. We investigated the National Cancer Data Base (NCDB) to determine adherence to these guidelines and its effects on overall survival (OS).

METHODS: Utilizing the NCDB, we selected 34,461 stage I–IV LSCC patients treated with RT from 1998 to 2011. Patients who received primary surgery were excluded. Chi-square tests, logistic regression models, and Cox proportional hazards models were utilized for analyses.

RESULTS: In the cohort, there were 19,610 (56.9%) early-stage (stage I/II) LSCCs and 14,851 (43.1%) late-stage (stage III/IV) LSCCs; 1,634 (8.5%) early-stage LSCCs received chemotherapy (CRT), as did 11,468 (77.9%) of the late-stage patients, over the entire time period studied. For early-stage cancers, the proportion of patients receiving CRT increased from 3.3% in 1998 to 9.4% in 2011 (P < .001). For late-stage cancers, the proportion of patients receiving CRT increased from 55.2% in 1998 to 87.8% in 2011 (P < .001). In a multivariate model, patients with early-stage LSCC were significantly more likely to receive chemotherapy if patients were younger (aged < 50 yr), female, African American or Hispanic, treated at a community-based hospital, and living in the Middle Atlantic (NJ, NY, and PA) or East North Central (IL, IN MI, OH, and WI) regions of the United States. Survival analyses were restricted to 1998–2006, and patients had a median follow-up of 4.4 years (range: 1–13 yr). Early-stage LSCC patients receiving RT alone had superior 5-year unadjusted OS rates compared with CRT patients (64.3% vs 52.7%; P < .001). These results persisted after adjusting for patient, facility, and tumor characteristics; and patients with CRT had worse OS (hazard ratio [HR] = 1.18; 95% confidence interval [CI], 1.07–1.31; P < .001). Late-stage LSCC patients receiving CRT had superior 5-year unadjusted OS rates compared with patients treated with RT alone (42.6% vs 25.9%; P < .001), and after similar risk adjustment, patients with CRT had superior OS (HR = 0.69; 95% CI, 0.65–0.73; P < .001) compared with those who received RT alone.

CONCLUSION: NCCN guidelines were not followed in 9.4% of patients with early-stage LSCC in 2011, because chemotherapy was added to their RT-based regimen. In these patients, the addition of chemotherapy reduced patient survival by 18%. These results indicate the importance of adherence to NCCN guidelines when prescribing RT-based regimens in the early-stage LSCC setting.

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