Importance of lymph node ratio in HPV-related oropharyngeal cancer patients treated with surgery and adjuvant treatment

by Kyu Hye Choi, Jin Ho Song, Ji Hyun Hong, Youn Soo Lee, Jin Hyoung Kang, Dong-Il Sun, Min-Sik Kim, Yeon-Sil Kim

The pathologic nodal stage of human papillomavirus (HPV)-related oropharyngeal cancer (OPC) patients is classified according to the number of lymph nodes (LNs), as revised in 2018. Previous studies showed that the LN ratio (LNR) could be also a significant prognostic factor in head and neck cancer, but there are few studies on the LNR in HPV-related [HPV(+)] OPC. The aim of the present study was to analyze the predictive value of the LNR for survival and recurrence in HPV(+) OPC patients.

HPV(+) OPC patients treated with surgery with or without postoperative radiotherapy from January 2000 to March 2019 were evaluated. The patients were divided into two sets of three groups, according to LN numbers based on pathologic nodal stages, and LNRs by a cutoff value of 0.05. The medical records were reviewed, and the overall survival (OS), disease-free survival, locoregional recurrence, and distant metastasis incidence were analyzed.

Ninty patients were included and the median follow-up period was 38.2 months. There were no significant differences in OS in the LN number groups. However, there was a significant difference in OS in the LNR groups (P = 0.010). The incidence of distant metastasis in the LNR groups was significantly different (P = 0.005).

The LNR in HPV(+) OPC patients may be a more useful tool to predict survival and distant metastasis than the LN number. Additional research and consensus on surgical pathology are needed before applying the LNR to adjuvant treatment decisions and pathologic nodal staging.