Decoding lymph node skip metastasis: impact on long-term outcomes in stage T1 papillary thyroid carcinoma

Area of Science:

• Oncology
• Head and Neck Surgery
• Thyroid Cancer Research

Background:

• Skip metastasis to lateral cervical lymph nodes is a common but heterogeneous presentation in early papillary thyroid carcinoma (PTC).
• Limited research exists on the prognostic implications and optimal management strategies for skip metastasis in PTC.

Purpose of the Study:

• To investigate the recurrence-free survival (RFS) in T1-stage PTC patients with skip N1b (sN1b) metastasis.
• To evaluate the impact of lymph node metastasis patterns and lymph node positivity rate (LNPR) on prognosis.

Main Methods:

• Retrospective analysis of 1188 T1-stage PTC patients undergoing lobectomy (2007-2015).
• Propensity score matching (PSM) used to compare N1a, sN1b, and N1b groups (n=372) with a median follow-up of 82 months.
• Kaplan-Meier analysis assessed RFS; lymph node metastasis patterns and LNPR in the sN1b group were analyzed for prognostic significance.

Main Results:

• RFS did not significantly differ between sN1b and N1a (P=.65) or N1b (P=.66) groups post-PSM.
• The number of positive lymph nodes in the sN1b group was comparable to N1a (P=.77) but lower than N1b (P<.0001).
• Risk stratification using LNPR in the sN1b group showed significant prognostic discrimination (P=.0067).

Conclusions:

• Stage T1 PTC patients with sN1b metastasis exhibit comparable RFS to those with N1a and N1b stages.
• Lymph node positivity rate (LNPR) is a significant prognostic factor for patients with skip metastasis in T1 PTC.