Abstract：
BACKGROUND: To summarize the characteristics of local invasion and distribution of metastatic lymph nodes in unilateral nasopharyngeal carcinoma (NPC) by magnetic resonance imaging (MRI) to provide references for the optimization of clinical target volume.
METHODS: MRI and clinical data of 176 cases of unilateral NPC admitted to the Hunan Cancer Hospital from January 2019 to December 2019 were collected. Unilateral NPC was defined as a lesion confined to the one side of the nasopharynx and had not exceeded the midline as judged by MRI.
RESULTS: Ipsilateral levator veli muscle (63.1%, 111/176), tensor veli palatini muscle (55.7%, 98/176), parapharyngeal space (50.0%, 88/176), and prevertebral muscle (43.7%, 77/176) were more likely to be invaded. Contralateral parapharyngeal space and skull base foramina were not invaded. All local invasions presented as continuous invasion from gross lesions and discontinuous invasions were not observed. The overall lymph node metastatic rate was 89.8% (158/176), of which bilateral metastasis accounted for 56.3% (89/158), and ipsilateral metastasis accounted for 88.1% (155/176), which was higher than the contralateral metastatic rate (55.4%, 94/176) (P < 0.001). The most common regions of lymph node metastasis were level IIb (82.4%), VIIa (69.9%), IIa (54.0%), and III (54.0%). Only one patient had skipping lymph node metastasis (0.6%).
CONCLUSIONS: Local invasion of unilateral NPC was characterized by continuous invasion from proximal to distal sites, and lymph node metastasis occurred from the upper to lower neck. Contralateral parapharyngeal space and skull base foramina had a very low probability of invasion, and routine prophylactic radiation may not be necessary.
METHODS: MRI and clinical data of 176 cases of unilateral NPC admitted to the Hunan Cancer Hospital from January 2019 to December 2019 were collected. Unilateral NPC was defined as a lesion confined to the one side of the nasopharynx and had not exceeded the midline as judged by MRI.
RESULTS: Ipsilateral levator veli muscle (63.1%, 111/176), tensor veli palatini muscle (55.7%, 98/176), parapharyngeal space (50.0%, 88/176), and prevertebral muscle (43.7%, 77/176) were more likely to be invaded. Contralateral parapharyngeal space and skull base foramina were not invaded. All local invasions presented as continuous invasion from gross lesions and discontinuous invasions were not observed. The overall lymph node metastatic rate was 89.8% (158/176), of which bilateral metastasis accounted for 56.3% (89/158), and ipsilateral metastasis accounted for 88.1% (155/176), which was higher than the contralateral metastatic rate (55.4%, 94/176) (P < 0.001). The most common regions of lymph node metastasis were level IIb (82.4%), VIIa (69.9%), IIa (54.0%), and III (54.0%). Only one patient had skipping lymph node metastasis (0.6%).
CONCLUSIONS: Local invasion of unilateral NPC was characterized by continuous invasion from proximal to distal sites, and lymph node metastasis occurred from the upper to lower neck. Contralateral parapharyngeal space and skull base foramina had a very low probability of invasion, and routine prophylactic radiation may not be necessary.
摘要：
背景：总结单侧鼻咽癌（NPC）磁共振成像（MRI）局部浸润及转移淋巴结的分布特点，为临床靶区的优化提供参考。
方法：收集湖南省肿瘤医院2019年1月至2019年12月收治的176例单侧鼻咽癌患者的MRI及临床资料。单侧NPC定义为局限于鼻咽一侧的病变，并且根据MRI判断未超过中线。
结果：同侧提肌（63.1%，111/176),帕拉蒂尼肌张量(55.7%，98/176)，咽旁间隙(50.0%,88/176），和椎前肌(43.7%，77/176）更有可能被入侵。对侧咽旁间隙和颅底孔未侵入。未观察到所有局部入侵，表现为总体病变的连续入侵和不连续入侵。总淋巴结转移率为89.8%(158/176),其中双侧转移占56.3%(89/158)，同侧转移占88.1%(155/176),高于对侧转移率（55.4%，94/176)(P<0.001)。淋巴结转移最常见的区域为IIb级(82.4%),VIIa（69.9%），IIa（54.0%），和III（54.0%）。只有1例患者有淋巴结跳跃转移（0.6%）。
结论：单侧NPC的局部侵袭特征为从近端到远端持续侵袭，淋巴结转移发生在上颈部到下颈部。对侧咽旁间隙和颅底孔的侵入概率非常低，和常规的预防性辐射可能是不必要的。
方法：收集湖南省肿瘤医院2019年1月至2019年12月收治的176例单侧鼻咽癌患者的MRI及临床资料。单侧NPC定义为局限于鼻咽一侧的病变，并且根据MRI判断未超过中线。
结果：同侧提肌（63.1%，111/176),帕拉蒂尼肌张量(55.7%，98/176)，咽旁间隙(50.0%,88/176），和椎前肌(43.7%，77/176）更有可能被入侵。对侧咽旁间隙和颅底孔未侵入。未观察到所有局部入侵，表现为总体病变的连续入侵和不连续入侵。总淋巴结转移率为89.8%(158/176),其中双侧转移占56.3%(89/158)，同侧转移占88.1%(155/176),高于对侧转移率（55.4%，94/176)(P<0.001)。淋巴结转移最常见的区域为IIb级(82.4%),VIIa（69.9%），IIa（54.0%），和III（54.0%）。只有1例患者有淋巴结跳跃转移（0.6%）。
结论：单侧NPC的局部侵袭特征为从近端到远端持续侵袭，淋巴结转移发生在上颈部到下颈部。对侧咽旁间隙和颅底孔的侵入概率非常低，和常规的预防性辐射可能是不必要的。
