Skip metastases to lateral cervical lymph nodes in differentiated thyroid cancer: a systematic review

Abstract

Papillary thyroid carcinoma is a slow-growing cancer with a generally good prognosis that sometimes have an aggressive behaviour. Metastases to neck lymph nodes is the first step of the diffusion. The central neck compartment is involved most commonly. The ipsilateral lateral neck compartments are usually involved afterwards, and the involvement of the contralateral one is considered a quite rare occurrence. In more rare cases, metastases to lateral neck compartment without central lymph node metastasis (so called “skip metastases”) could be observed. Aim of this literature review study is to analyse the average incidence, pattern and risk factors of this occurrence. This study was performed according to PRISMA criteria. A final selection of 13 articles published in English language from 1997 to 2017 was performed. Any research article, review or meta-analysis was taken into consideration. Research was expanded considering the related references of articles. The incidence of skip metastases ranged from 1.6 to 21.8%. Risk factors such as age > 45 years, size < 5 mm and tumor located in the upper pole or isthmus of thyroid gland were found. Due to the frequency of skip metastases in thyroid cancer, a careful preoperative examination of lateral lymph nodes should be necessary.

A nomogram to predict skip metastasis in papillary thyroid cancer

“…Thus, it is important for surgeons to perform precise preoperative evaluations and predictions for LNM to take an appropriate surgical management strategy. "Skip metastasis" is defined as lateral LNM without the involvement of central LNM, which is not uncommon in clinical practice, yet is difficult to predict [11,13,16,22,23]. In this study, we developed an individualized nomogram to evaluate the likelihood of skip metastasis in patients with PTC based on the pathologic and clinical characteristics, which is consistent with the current trend toward personalized and precision medicine.…”

“…Some patients develop lateral LNM without the involvement of central LNM via histopathological diagnosis, which is referred to as “skip metastasis” [ 6 , 9 , 10 ]. The rate of skip metastasis in PTC ranges from 1.6 to 21.8% [ 11 – 13 ]. The significance of skip metastasis in patients with PTC is still unclear; however, if untreated, the risk will increase for locoregional recurrence and distant metastasis.…”

A nomogram to predict skip metastasis in papillary thyroid cancer

“…Thus, it is important for surgeons to perform precisely preoperative evaluation and prediction for LNM to take an appropriate surgical management strategy. "Skip metastasis" was defined as lateral LNM without the involvement of central LNM, which is not uncommon in clinical practice and difficult to predict [11,13,16,22,23]. In this study, we developed an individualized nomogram to evaluate the likelihood of skip metastasis in patients with PTC based on the pathologic and clinical characteristics, which is consistent with the current trend toward personalized and precision medicine.…”

“…Some patients develop lateral LNM without the involvement of central LNM via histopathological diagnosis, which is referred to as "skip metastasis" [6,9,10]. The rate of skip metastasis in PTC ranged from 1.6% to 21.8% [11][12][13]. The significance of skip metastasis in patients with PTC is still unclear.…”

PTC located in the upper pole is more prone to lateral lymph node metastasis and skip metastasis

“…However, in patients with skip metastasis, only age and tumour location remained statistically significant, which was congruent with our previous study [ 28 ]. A recent meta-analysis of 13 articles [ 29 ] also found that older age and upper pole tumours were risk factors for LLNM.…”