In our cohort, pT8 was inferior to pT7 in patients ≥55 years old without macroscopic ETE or distant metastases in whom T classification affects TNM stage. Microscopic ETE was strongly associated with other adverse prognostic factors and reduced DFS in this patient subgroup and may be an effective surrogate for disease biology in PTC, irrespective of whether it is an independent prognostic factor.

In our PTC cohort, the impact of tumor size on RFS was limited to patients aged ≥55 years. A single size threshold of 2 cm maximized prognostic discrimination with tumors >2 cm associated with a five times higher risk of recurrence than those ≤2 cm. These findings need to be validated in independent large cohorts and the potential management and staging implications further studied.

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.

In this observational study, limited by the absence of a placebo control group, SNS significantly improved continence and quality of life, and patient satisfaction was high.