We performed this study to define the incidence of radiographic retropharyngeal lymph node (RPLN) involvement in oropharyngeal cancer (OPC) and its impact on clinical outcomes, neither of which has been well established to date.METHODS
Our departmental database was queried for patients irradiated for OPC between 2001 and 2007. Analyzable patients were those with imaging data available for review to determine radiographic RPLN status. Demographic, clinical, and outcome data were retrieved and analyzed.RESULTS
The cohort consisted of 981 patients. The median follow-up was 69 months. The base of the tongue (47%) and the tonsil (46%) were the most common primary sites. The majority of patients had stage T1 to T2 primary tumors (64%), and 94% had stage 3 to 4B disease. Intensity-modulated radiation therapy was used in 77% of patients, and systemic therapy was administered in 58% of patients. The incidence of radiographic RPLN involvement was 10% and was highest for the pharyngeal wall (23%) and lowest for the base of the tongue (6%). RPLN adenopathy correlated with several patient and tumor factors. RPLN involvement was associated with poorer 5-year outcomes on univariate analysis (P<.001 for all) for local control (79% vs 92%), nodal control (80% vs 93%), recurrence-free survival (51% vs 81%), distant metastases-free survival (66% vs 89%), and overall survival (52% vs 82%) and maintained significance on multivariate analysis for local control (P = .023), recurrence-free survival (P = .001), distant metastases-free survival (P = .003), and overall survival (P = .001).CONCLUSIONS
In this cohort of nearly 1000 patients with radiographic RPLN adenopathy in OPC, RPLN involvement was observed in 10% of patients and indicates a negative influence on disease recurrence, distant relapse, and survival. In this cohort of nearly 1000 patients investigating radiographic RPLN adenopathy in OPC, RPLN involvement was observed in 10% of patients and portends a negative influence on disease recurrence, distant relapse, and survival. Cancer2013;119:3162–3169. © 2013 American Cancer Society.CONCLUSIONS
In a cohort of nearly 1000 patients with oropharyngeal cancer who were staged and irradiated in the modern era, radiographic retropharyngeal lymph node (RPLN) involvement conveys a negative influence on disease recurrence, distant relapse, and patient survival. These benchmark findings highlight the importance of adequate RPLN radiographic assessment, demonstrate why RPLNs are clinically important when formulating therapeutic strategies, and may have implications for design of future clinical studies.