Knowledge of pathologically versus clinically negative lymph nodes is associated with reduced use of radioactive iodine post-thyroidectomy for low-risk papillary thyroid cancer

Abstract

Cervical lymph node metastases are common in papillary thyroid cancer (PTC). Clinically negative lymph nodes confer uncertainty about true lymph node status, potentially prompting empiric postoperative radioactive iodine (RAI) administration even in low-risk patients. We examined the association of clinically (cN0) versus pathologically negative (pN0) lymph nodes with utilization of RAI for low-risk PTC. Using the National Cancer Database 1998–2011, adults with PTC who underwent total thyroidectomy for Stage I/II tumors 1–4 cm were evaluated for receipt of RAI based on cN0 versus pN0 status. Cut-point analysis was conducted to determine the number of pN0 nodes associated with the greatest decrease in the odds of receipt of RAI. Survival models and multivariate analyses predicting RAI use were conducted separately for all patients and patients <45 years. 64,980 patients met study criteria; 39,778 (61.2 %) were cN0 versus 25,202 (38.8 %) pN0. Patients with pN0 nodes were more likely to have negative surgical margins and multifocal disease (all p < 0.001). The mean negative nodes reported in surgical pathology specimens was 4; ≥5 pathologically negative lymph nodes provided the best cut-point associated with reduced RAI administration (OR 0.91, CI 0.85–0.97). After multivariable adjustment, pN0 patients with ≥5 nodes examined were less likely to receive RAI compared to cN0 patients across all ages (OR 0.89, p < 0.001) and for patients aged <45 years (0R 0.86, p = 0.001). Patients with <5 pN0 nodes did not differ in RAI use compared to cN0 controls. Unadjusted survival was improved for pN0 versus cN0 patients across all ages (p < 0.001), but not for patients<45 years (p = 0.11); adjusted survival for all ages did not differ (p = 0.13). Pathological confirmation of negative lymph nodes in patients with PTC appears to influence the decision to administer postoperative RAI if ≥5 negative lymph nodes are removed. It is possible that fewer excised lymph nodes may be viewed by clinicians as incidentally resected and thus may suboptimally represent the true nodal status of the central neck. Further research is warranted to determine if there is an optimal number of lymph nodes that should be resected to standardize pathological diagnosis.

Proposing prognostic thresholds for lymph node yield in clinically lymph node‐negative and lymph node‐positive cancers of the oral cavity

“…In patients with cN0 disease, we observed that higher lymph node yields were associated with a higher likelihood of identifying 1 positive lymph node. Thus, there may be a diagnostic benefit to removing more lymph nodes in facilitating accurate pathologic staging of the neck, which subsequently may have an impact on decisions regarding adjuvant therapy . Another possibility is that removing more lymph nodes serves a therapeutic role in treating occult lymph node disease.…”

“…Thus, there may be a diagnostic benefit to removing more lymph nodes in facilitating accurate pathologic staging of the neck, which subsequently may have an impact on decisions regarding adjuvant therapy. 37 Another possibility is that removing more lymph nodes serves a therapeutic role in treating occult lymph node disease. Finally, higher lymph node yields may more broadly reflect better care provided by a surgeon or hospital, resulting in improved outcomes.…”

Minimal extrathyroidal extension does not affect survival of well-differentiated thyroid cancer

“…MEE includes extension to sternothyroid muscle or perithyroid soft tissue and is classified as T3 and consequently, upstages T1 and T2 differentiated thyroid cancer (DTC) patients aged older than 45 years to stage III disease (Edge & Carducci 2009). Upstaging appears to affect the decisions involving the extent of resection and radioactive iodine therapy (RAI) (Haugen et al 2016, Ruel et al 2016. Impact of MEE on the survival is a controversial topic and was investigated by different single institution studies mostly from Asia (Ito et al 2006a,b, Hotomi et al 2012, Shin et al 2013.…”

Survival effect of postoperative radiotherapy combined with lymph nodes examined on cavity squamous cell carcinoma patients with stage T1-2N1M0: a propensity‑adjusted SEER database analysis

“…Unsatisfactory neck dissection might reduce the diagnostic bene t by removing insu cient lymph nodes, detecting a low incidence of extracapsular spread and facilitating an inaccurate N staging, which subsequently might interfere the decisions on adjuvant treatment. [26,33] Several studies had stated that extensive neck dissection could certainly reduce the regional recurrence, which might be compensated by PORT among patients who underwent unsatisfactory neck dissection or with advanced N stage. [34][35][36] The unmarried status was found correlated with decreased CSS, including windowed, single, separated and divorced.…”