Development of a simplified scoring system for MRI-detected retropharyngeal lymph node features to optimize AJCC 9th
Qin Liu1, Jing-Ni Wei2, Jia-Yu Zhou1
1State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Department of Nasopharyngeal Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China.
Purpose:
To develop a retropharyngeal lymph node (RLN)-based scoring system using anatomical features and to evaluate its utility in optimizing N classification in patients with nasopharyngeal carcinoma (NPC).
Materials And Methods:
This retrospective cohort study included patients with nonmetastatic NPC treated at two tertiary referral cancer centers in China between January 2012 and December 2018. Univariate and multivariate analyses were used to evaluate the association between MRI-based RLN features and multiple survival endpoints. A simplified RLN risk scoring (RRS) system (incorporating RLN multiplicity, MID, adENE and CNN) was developed in SYSUCC cohort and validated in the GMUCH cohort. A new N classification system was proposed and compared with the 9th edition of AJCC N staging system using C-index.
Results:
Positive RLNs were observed in 68.3 % of all patients, including 66.7 % (690/1035) in the SYSUCC cohort and 72.0 % (340/472) in the GMUCH cohort. High RRS (defined as RRS > 2) was independently associated with worse OS (hazard ratio [HR], 2.22; 95 % CI, 1.56-3.15, P < 0.001), PFS (HR, 2.45; 95 % CI, 1.87-3.20, P < 0.001), DMFS (HR, 2.71; 95 % CI, 1.88-3.91, P < 0.001), and RFS (HR, 2.20; 95 % CI, 1.51-3.20, P < 0.001). The proposed N classification system incorporated high RRS as a criterion for N3 disease, demonstrated higher C-index values compared with the 9th edition AJCC staging system for OS (0.666 vs 0.659), PFS (0.659 vs 0.639), DMFS (0.682 vs 0.663), and RFS (0.644 vs 0.629).
Conclusions:
High RRS was strongly correlated with inferior survival outcomes in NPC patients. Integrating high RRS into the current staging system by reclassifying these patients as N3 might improve prognostic stratification and offer more precise treatment guidance.
