Evaluation of AJCC staging system and proposal of a novel stage grouping system in retroperitoneal liposarcoma: the Fudan Zhongshan experience

Peidang Fan; Ping Tao; Zhenyu Wang; Jiongyuan Wang; Yingyong Hou; Weiqi Lu; Lijie Ma; Yong Zhang; Hanxing Tong

doi:10.3389/fonc.2024.1373762

Evaluation of AJCC staging system and proposal of a novel stage grouping system in retroperitoneal liposarcoma: the Fudan Zhongshan experience

Front Oncol. 2024 Mar 27:14:1373762. doi: 10.3389/fonc.2024.1373762. eCollection 2024.

Authors

Peidang Fan^#^{1

2}, Ping Tao^#³, Zhenyu Wang^#⁴, Jiongyuan Wang^#¹, Yingyong Hou⁵, Weiqi Lu¹, Lijie Ma⁶, Yong Zhang^{1

7

8}, Hanxing Tong¹

Affiliations

¹ Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
² First Affiliated Hospital, Anhui University of Science and Technology, Huainan, China.
³ Department of Laboratory Medicine, Shanghai Traditional Chinese Medicine-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
⁴ Department of General Surgery, Jinshan Hospital, Fudan University, Shanghai, China.
⁵ Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China.
⁶ Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
⁷ Department of General Surgery, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China.
⁸ Xiamen Clinical Research Center for Cancer Therapy, Xiamen, China.

^# Contributed equally.

Abstract

Background: Overall survival (OS) varies significantly among individuals with heterogeneous retroperitoneal liposarcoma (RPLS), even among those with the same clinical stage. Improved staging of RPLS is a critical unmet need, given the disappointing results of external validations of the 8^th American Joint Committee on Cancer (AJCC) TNM staging system.

Methods: The cohort study included 220 consecutive patients who underwent surgical resection for primary RPLS at the largest sarcoma centre of Fudan University in China from September 2009 to August 2021, combined with 277 adult patients with RPLS in the SEER database from 1975 to 2020. Data analysis was performed from December 2021 to December 2022. Patients were retrospectively restaged according to the 8th and 7th editions of the TNM staging system as well as the new TNM (nTNM) staging system. The primary endpoint was overall survival (OS). Comparative analysis of postoperative survival was performed using the Kaplan-Meier method, and differences between subgroups were tested using the log-rank test. The OS prediction nomogram was generated based on baseline variables and tumour characteristics. Harrell's consistency index (C-index), area under the curve (AUC) of receiver operating characteristic curves (ROC), and calibration curves were used to evaluate the performance of the nomogram.

Results: A total of 497 patients were enrolled in the study, including 282 (56.7%) male patients. The median follow-up was 51 months (interquartile range, IQR, 23-83), and the OS rates at 1, 3, and 5 years were 87.9%, 75.3%, and 64.9%, respectively. According to the staging distribution of the AJCC 7th edition, 6 patients were stage IA (1.2%), 189 patients were stage IB (38%), 12 patients were stage IIA (2.4%), 150 patients were stage IIB (30.1%), 131 patients were stage III (26.3%), and 9 patients were stage IV (1.8%). With the 8th edition staging, this distribution changed: 6 patients (1.2%) were stage IA, 189 patients (38%) were stage IB, 12 patients (2.4%) were stage II, 24 patients (4.8%) were stage IIIA, 257 patients (51.7%) were stage IIIB, and 9 patients (1.8%) were stage IV. 182 patients (36.6%) were reclassified according to the nTNM staging system with the new T stage classification. The C-index and log-rank score improved after implementation of nTNM implementation. The nTNM system was associated with improved identification of high-risk patients compared with the AJCC 7^th and 8^th TNM. The FNCLCC stage proved to be highly prognostic with significant intergroup differences in OS. The calibration curve shows a high degree of agreement between the actual OS rate and the nomogram estimated OS rate.

Conclusion: Compared with 8^th AJCC TNM, 7^th AJCC TNM staging system showed a more homogeneous staging distribution and a slight improvement in the prognostic accuracy of RPLS. The revised T-stage and nTNM systems showed better risk stratification performance. The FNCLCC stage was found to have high prognostic value, further emphasising histological grade is the least negligible prognostic factor in predicting patient survival. The constructed nomogram model enables individualized prognostic analysis and helps to develop risk-adapted therapy for RPLS patients.

Keywords: FNCLCC; RPLS; modified TNM system; os; revised T stage.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by grants from Scientific Research Project of Shanghai Municipal Health Commission (20214Y0087, 20204Y0409); Hongkou District "Outstanding Young Talents in Clinical Medicine" Training Program (No. HKLCYQ2024-01); "Young Talents" Training Plan of Shanghai TCM-integrated Hospital (No. RCPY0063); Scientific Research Project of Shanghai TCM-integrated Hospital (No. 18-01-03); Scientific Research Project of Hongkou District Health Committee (No. 2003-02); Fujian Natural Science Foundation (No. 2023J011698); Xiamen Natural Science Foundation (No. 3502Z20227280).