Main Session
Sep
30
QP 08 - Head and Neck 3: Quick Pitch: Prognosis in Focus: Predicting Outcomes in Head and Neck Cancer
1047 - Proposal for Future Refinement of N Category in Version-Nine of AJCC/UICC TNM Staging System for Nasopharyngeal Carcinoma based on the International Consensus Recommendations for Diagnosing Extranodal Extension
Presenter(s)
Jing Zhong, MD, PhD - Fujian Cancer Hospital, Fuzhou, Fujian
J. Zhong1, H. Chen2,3, H. Xu2, J. Pan4,5, and Q. Guo2; 1Department of Radiology, Clinical Oncology School of Fujian Medical University, Fujian Cancer Hospital, Fuzhou, Fujian, China, 2Department of Radiation Oncology, Clinical Oncology School of Fujian Medical University, Fujian Cancer Hospital, Fuzhou, Fujian, China, 3Department of Radiation Oncology, Shaowu Municipal Hospital of Fujian Province, Nanping, Fujian, China, 4Oncology Department, Zhangzhou Zhengxing Hospital, Zhangzhou, Fujian, China, 5Department of Radiation Oncology, Xiamen Humanity Hospital,, Xiamen, Fujian, China
Purpose/Objective(s):
This study aims to ascertain the prognostic value of MRI-detected grade 2 radiologic extranodal extension (G2 rENE), specifically known as matted nodes(MNs), in nasopharyngeal carcinoma (NPC), in accordance with the consensus recommendations for diagnosing rENE formulated by the Head and Neck Cancer International Group (HNCIG). Additionally, this study proposes potential future refinement of N categoty for the 9th version of AJCC/UICC TNM staging system (TNM-9).Materials/Methods:
Patients with histologically confirmed non-metastatic NPC and be diagnosed between January 2017 and December 2018 at our institution were candidates for this study. MRI data of all N positive patients were re-evaluated to record the status of rENE. Survival endpoint including 5-year overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRRFS), distant metastasis-free survival (DMFS) were calculated and differences were compared. The Cox proportional hazards model analysis was used to verify the prognostic values of MNs. Recursive-patitioning analysis (RPA) based on the ordinal N category of TNM-9 and the status of MNs were performed to proposed a refined N category. The performances of the N category in TNM-9 and the proposed N category were compared with the Akaike information criterion (AIC) and Harrell’s concordance index (c-index).Results:
A total of 1334 patients were included, with 462 (34.6%) patients presented with MNs at baseline. The kappa coefficients for inter-rater and intra-rater agreement in the assessment of MNs were 0.868 and 0.929, respectively. MNs showed independent prognostic value for survival endpoints including OS (HR: 1.465, 95%CI: 1.022-2.100, p=0.038) PFS (HR: 1.299, 95%CI: 0.997-1.693, p=0.053) and DMFS (HR: 1.369, 95%CI: 1.015-1.846, p=0.039). Survival analysis indicated that survival outcomes of N1 patients with MNs had comparable survival outcomes with N2 disease, while had significantly worse survival than N1 patients without MNs. The RPA algorithm was then applied to derived a RPA-N category as following: RPA-N0 (N0), RPA-N1 (N1 without MNs), RPA-N2 (N1 with MNs and N2), and RPA-N3 (N3). In brief, N1 with MNs were upgraded to N2 in the RPA-N category, with N0 and N3 remained unchanged. The RPA-N classification had a lower AIC and higher c-index for OS, PFS, LRRFS and DMFS (AIC: 809.6 vs. 816.4, 1419.4 vs. 1425.3, 1251.8 vs. 1258.1, 1153.6 vs. 1158.4; c-index: 0.723 vs. 0.714, 0.682 vs. 0.672, 0.673 vs. 0.664, 0.713 vs. 0.713) versus TNM-9. Compared to the current system, the proposed N category performed better in hazard consistency, hazard discrimination, sample size balance and outcome prediction.Conclusion:
MNs, based on the diagnosing criteria of HNCIG, constitute an independent adverse prognostic factor for NPC based on TNM-9. The RPA-N category, which integrated N category and MNs, demonstrated better performance than N category in TNM-9, further validation in multicenter cohorts is warranted.