Prognostic value of lymph node density in buccal squamous cell carcinoma
Tam-Lin Chow1, Wilson W Y Kwan1, Siu-Chung Fung1
1Division of Head and Neck Surgery, Department of Surgery, United Christian Hospital, Hong Kong, China.
Purpose:
Lymph node density(LND) has been shown to be a better prognosticator than conventional nodal classification to predict prognosis for squamous cell carcinoma(SCC) of the oral cavity. However, studies focusing on subsites of oral cancer are meager. The role of LND for buccal SCC was evaluated in this study.
Methods:
A total of 39 patients with buccal SCC primarily treated surgically with neck dissection were identified. LND was defined as the number of positive nodes over the number of nodal yield. The cut-off of LND was ≤0.07 or >0.07. Patient demographic data and clincopathologic parameters were described. Survival was expressed by Kaplan-Meier method and correlation with survival is analyzed with log-rank test. IBM SPSS Statistics version 22 was used for data computation.
Results:
The median follow-up was 79.0months and median nodes removed was 23 (range 8-93). Positive nodal involvement was found in 19(48.7%) patients. The 5-year and 10-year OS were 67.4% and 42.5% whilst for DSS were 69.2% and 65.5%, respectively. When pT-, pN-, LND-classification and AJCC stage were analyzed for the whole series, only pN- (p=0.006) and LND-classification (p=0.002) were significant factors for OS, while pT-, pN-, LND-classification and AJCC stage were all significant factors for DSS. When only cases with positive nodal spread were considered, the pN-classification (pN1 vs pN2) was not a significant risk factor for either OS (p=0.075, HR 3.10(CI 0.89-10.76)) and DSS (p=0.074, HR 3.58(CI 0.88-14.56)). By contrast, LND-classification (≤0.07 vs >0.07) remained a significant predictor for OS (p=0.03, HR 3.95(CI 1.15-13.63)), but not for the DSS (p=0.112, HR 2.92(CI 0.78-10.99)).
Conclusion:
The prognostic value of LND on buccal SCC is supported in this study. The results also suggest that LND is better than the conventional pN-classification to predict OS. Further studies on LND with big sample size for buccal SCC or other subsites of OSCC are worthwhile.
