Locoregional Extension Patterns of Nasopharyngeal Carcinoma Detected by FDG PET/MR

Caineng Cao; Yuanfan Xu; Shuang Huang; Feng Jiang; Ting Jin; Qifeng Jin; Yonghong Hua; Qiaoying Hu; Xiaozhong Chen

doi:10.3389/fonc.2021.763114

Locoregional Extension Patterns of Nasopharyngeal Carcinoma Detected by FDG PET/MR

Front Oncol. 2021 Dec 13:11:763114. doi: 10.3389/fonc.2021.763114. eCollection 2021.

Authors

Caineng Cao^{1

2}, Yuanfan Xu³, Shuang Huang^{1

2}, Feng Jiang^{1

2}, Ting Jin^{1

2}, Qifeng Jin^{1

2}, Yonghong Hua^{1

2}, Qiaoying Hu^{1

2}, Xiaozhong Chen^{1

2}

Affiliations

¹ Department of Radiation Oncology, Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Cancer Research and Basic Medicine (ICBM), Chinese Academy of Sciences, Zhejiang Provincial Key Laboratory of Radiation Oncology, Hangzhou, China.
² Key Laboratory of Head and Neck Cancer Translational Research of Zhejiang Province, Hangzhou, China.
³ Hangzhou Universal Medical Imaging Diagnostic Center, Hangzhou, China.

Abstract

Purpose: We sought to define the locoregional extension patterns of nasopharyngeal carcinomas (NPCs) by positron emission tomography (PET)/magnetic resonance imaging (MRI) and to improve clinical target volume (CTV) delineation.

Methods: Between May 2017 and March 2021, 331 consecutive patients with nonmetastatic NPCs who underwent pretreatment, simultaneous whole-body PET/MRI for staging were included in this study.

Results: The high-risk regions included the base of the sphenoid bone, the prestyloid compartment, prevertebral muscle, foramen lacerum, medial pterygoid plate, sphenoidal sinus, clivus, petrous apex, and foramen ovale. When the high-risk regions were invaded, the incidence rates of tumor invasion into the medium-risk regions increased. In contrast, when the high-risk regions were not involved, the incidence rates of tumor invasion into the medium-risk regions were mostly less than 10%, excluding the post-styloid compartment and oropharynx. According to the updated consensus guidelines of the neck node levels for head and neck tumors from 2013, level IIa (77.3%, 256/331), level IIb (75.8%, 251/331), and level VIIa (71.3%, 236/331) were the most frequently involved levels, followed by levels III (42.6%), Va (13.9%), IVa (8.8%), IVb (3.6%), Ib (3.6%), Vb (2.4%), VIIb (2.4%), VIII (1.8%), Vc (0.9%), and Xa (0.3%). Skip lymph node metastasis occurred in only 1.9% of patients.

Conclusions: For NPCs, primary disease and regional lymph node spread follow an orderly pattern, and a skip pattern of lymph node metastasis was unusual. Involved level radiotherapy might be feasible for cervical lymph node levels below the caudal border of cricoid cartilage and level VIIb.

Keywords: clinical target volume; local extension; lymph node spread; nasopharyngeal carcinoma; simultaneous PET/MRI.