Biochemical and structural response in patients with tall cell papillary thyroid cancer: a dual centre retrospective study : Early Recurrence in Tall Cell PTC.

Purpose: Tall cell papillary thyroid cancer (tcPTC) is traditionally considered to be an aggressive subtype of differentiated thyroid cancer, although its independent prognostic value is unclear. To investigate the independent prognostic value of tall cell morphology a tcPTC cohort was compared with a classical PTC (cPTC) cohort.

Methods: A retrospective longitudinal study was performed using a cohort of tcPTC patients treated at Royal North Shore Hospital and Westmead Hospital in Sydney, Australia, and a cohort of cPTC patients treated at Westmead Hospital. Clinicopathological tumour characteristics and treatment pathways were analysed. Thyroglobulin and thyroglobulin antibody levels and further neck surgeries in the two years post thyroidectomy were used as a surrogate marker for early disease recurrence.

Results: Presentation and treatment were analysed for 51 tcPTC patients and a comparator group of 365 cPTC patients. On univariate analysis, tcPTC was found to present at an older age (53.6 years v 46.4 years, p < 0.01), with greater rates of positive surgical margins (31.37% v 16.44%, p < 0.05), and greater rates of microscopic (47.06% v 22.74%, p < 0.001) and gross extrathyroidal extension (15.69% v 6.30%, p < 0.05). Longitudinal analysis was conducted for 236 patients (n = 24 for tcPTC, n = 212 for cPTC). Multivariate analysis found no difference in the odds of developing early recurrence between the tcPTC cohort and the cPTC cohort (OR = 0.65, p > 0.1).

Conclusion: tcPTC is associated with more aggressive features compared with cPTC. Tall cell morphology was not found to be an independent predictor of early recurrence.