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Microscopic positive margins in papillary thyroid cancer do not impact disease recurrence
Author(s) -
Abraham Earl,
Tran Bryan,
Roshan David,
Graham Susannah,
Lehane Christopher,
Wykes James,
Campbell Peter,
Ebrahimi Ardalan
Publication year - 2018
Publication title -
anz journal of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.426
H-Index - 70
eISSN - 1445-2197
pISSN - 1445-1433
DOI - 10.1111/ans.14490
Subject(s) - medicine , hazard ratio , lymphovascular invasion , confidence interval , papillary thyroid cancer , thyroid carcinoma , thyroid cancer , proportional hazards model , gastroenterology , retrospective cohort study , univariate analysis , multivariate analysis , cohort , cancer , thyroid , oncology , metastasis
Background The prognostic significance of microscopic positive margins in papillary thyroid carcinoma (PTC) remains unclear. The aim of this study was to determine if microscopic positive margins are associated with increased risk of disease recurrence. Methods This is a retrospective analysis of 610 patients with PTC using multivariate Cox regression to evaluate the association between microscopic positive margins and disease‐free survival. Results Microscopic positive margins were found in 67 (11%) patients and associated with extrathyroidal extension ( P < 0.001), multifocality ( P < 0.001), nodal metastases ( P < 0.001), lymphovascular invasion ( P < 0.001), age ≥55 years ( P = 0.048), administration of radioactive iodine (RAI) therapy ( P = 0.001) and a trend towards larger tumour size (18 versus 15 mm; P = 0.074). After a median follow‐up of 3.4 years, there were 83 recurrences. Although involved margins were associated with increased risk of recurrence on univariate analysis (hazard ratio 2.6, 95% confidence interval 1.5–4.6; P = 0.001), there was no association after adjusting for age, nodal metastases, tumour size and extrathyroidal extension on multivariate analysis (hazard ratio 1.5, 95% confidence interval 0.8–2.9; P = 0.242). Similar results were obtained after adjusting for RAI and if margins were analysed as focal versus widely positive. In our study cohort, patients with involved margins generally had other indications for RAI. However, in the nine patients who did not receive RAI, there was no recurrence in the thyroid bed. Conclusion Despite a strong association between microscopic positive margins and other adverse prognostic factors in PTC, there is no independent association with disease recurrence on multivariate analysis. Microscopic positive margins are rare (1.1%) in the absence of other indications for RAI.