The extent of extrathyroidal extension is a key determinant of prognosis in T4a papillary thyroid cancer

J Surg Oncol. 2019 Nov;120(6):1016-1022. doi: 10.1002/jso.25683. Epub 2019 Aug 26.


Background and objectives: In papillary thyroid cancer (PTC), the adverse prognostic impact of extrathyroidal extension (macro-ETE) invading the subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve (T4a disease) is well established. We investigated whether the extent of macro-ETE, defined as "limited" with single structure involvement (lim-ETE) and "extensive" with multiple structures involved (ext-ETE), influences prognosis in T4a PTC.

Methods: A retrospective analysis of 610 patients with PTC identified 39 with T4a disease, including 26 with lim-ETE and 13 with ext-ETE. Univariate Cox regression was used to assess the relationship between the extent of macro-ETE and recurrence-free survival (RFS).

Results: Ext-ETE was associated with a five times increased risk of recurrence compared to lim-ETE (HR 5.0, P < .030), with or without adjustment for radioactive iodine administration and after adjustment for margin status (HR 4.7; P = .041). A low-risk subset of T4a disease comprising of patients aged less than 55 years with lim-ETE and clear margins accounted for one-third of the cohort and demonstrated an excellent 5-year RFS of 92%.

Conclusions: The extent of macro-ETE appears to be an important determinant of prognosis in T4a PTC. A low-risk subset of T4a disease exists with an excellent prognosis.

Keywords: aerodigestive tract; extrathyroidal extension; papillary carcinoma; positive margins; radioactive iodine; thyroid cancer.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / pathology*
  • Neoplasm Recurrence, Local / surgery
  • Prognosis
  • Retrospective Studies
  • Survival Rate
  • Thyroid Cancer, Papillary / pathology*
  • Thyroid Cancer, Papillary / surgery
  • Thyroid Neoplasms / pathology*
  • Thyroid Neoplasms / surgery
  • Thyroidectomy / methods*
  • Young Adult