Practice patterns in management of differentiated thyroid cancer since the 2014 British Thyroid Association (BTA) guidelines.

BACKGROUND: The updated 2014 BTA guidelines emphasised a more conservative, risk adapted model for the management of low-risk differentiated thyroid cancer (DTC). In comparison to historical approach of total thyroidectomy combined with radioactive iodine, treatment de-escalation is increasingly supported. AIMS: To evaluate the impact of the updated BTA guidelines on the management of DTC cases at regional UK centre. METHODS: All DTC patients were retrospectively identified from regional thyroid MDT database between Jan2009-Dec2020. Oncological treatment and clinico-pathological characteristics were analysed. RESULTS: 623 DTC cases were identified; 312 (247 female: 65 male) between 2009 and 2014 and 311 (225 female: 86 male) between 2015 and 2020. Median age is 48 years (range 16-85). By comparing pre- and post-2015 cohorts, there was a significant drop in total thyroidectomy (87.1% vs 76.8%, p = 0.001) and the use of radioactive iodine (RAI) (73.1% vs 62.1%, p = 0.003) in our post-2015 cohort. When histological adverse features were analysed, extra-thyroidal extension (4.2% vs 17.0%, p=< 0.001), lymphovascular invasion (31.4% vs 50.5%, p=<0.001) and multi-centricity (26.9% vs 43.4%, p = 0.001) were significantly increased in the post 2015 cohort. Nonetheless, total thyroidectomy (TT) remains the treatment choice for low risk T1/2 N0 M0 disease in 65.3% (124/190) in post-2015 cohort for several reasons. Reasons include adverse histological features (50.8%), benign indications (32.5%), contralateral nodules (11.7%), patient preference (2.5%), and diagnostic uncertainty (2.5%). CONCLUSION: Our study confirms a move towards a more conservative approach to patients with low-risk DTC in the UK, which is in keeping with the BTA 2014 guideline and international trends, but total thyroidectomy remains prevalent for low risk T1/2 N0 M0 disease for other reasons.

A quantitative assessment of the number of disease foci in papillary thyroid cancer.

AIM: Multifocality is a frequent feature of papillary thyroid carcinoma (PTC). Its prognostic value is controversial although national guidelines recommend treatment intensification if present. However, multifocality is not a binary but discrete variable. This study aimed to examine the association between increasing number of foci and risk of recurrence following treatment. METHODS: 577 patients with PTC were identified with median follow-up of 61 months. Number of foci were taken from pathology reports. Log-rank test was used to assess significance. Multivariate analysis was performed and Hazard Ratios were calculated. RESULTS: Of 577 patients, 206(35%) had multifocal disease and 36(6%) recurred. 133(23%), 89(15%) and 61(11%) had 3+, 4+ or 5+ foci respectively. The 5-year RFS stratified by number of foci was 95%v93% for 2+foci (p = 0.616), 95%v96% for 3+foci (p = 0.198) and 89%v96% for 4+foci (p = 0.022). The presence of 4 foci was associated with an over 2-fold risk of recurrence (HR 2.296, 95% CI 1.106-4.765, p = 0.026) although this was not independent of TNM staging. Of the 206 multifocal patients, 31(5%) had 4+foci as their sole risk factor for treatment intensification. CONCLUSION: Although multifocality per se does not confer worse outcome in PTC, finding 4+foci is associated with worse outcome and could therefore be appropriate as a cut-off for treatment intensification. In our cohort, 5% of patients had 4+foci as a sole indication for treatment intensification, suggesting that such a cut off could impact clinical management.