Are Evidence-Based Guidelines Reflected in Clinical Practice? An Analysis of Prospectively Collected Data of the Italian Thyroid Cancer Observatory

Objectives: The goal of evidence-based practice guidelines is to optimize the management of emerging diseases, such as differentiated thyroid cancer (DTC). The aim of this study was to assess therapeutic approaches for DTC in Italy and to see how closely these practices conformed to those recommended in the 2009 American Thyroid Association (ATA) guidelines. Methods: The Italian Thyroid Cancer Observatory was established to collect data prospectively on thyroid cancers consecutively diagnosed in participating centers (uniformly distributed across the nation). Data on the initial treatment of all pathologically confirmed DTC cases present in the database from January 1, 2013 (database creation) to January 31, 2016, were analyzed. Results: A total of 1748 patients (77.2% females; median age 48.1 years [range 10-85 years]) were enrolled in the study. Most (n=1640; 93.8%) were papillary carcinomas (including 84 poorly differentiated/aggressive variants); 6.2% (n=108) were follicular and Hurthle cell carcinomas. The median tumor diameter was 11mm (range 1-93mm). Tumors were multifocal in 613 (35%) and presented extrathyroidal extension in 492 (28%) cases. Initial treatments included total thyroidectomy (involving one or two procedures; n=726; 98.8%) and lobectomy (n=22; 1.2%). A quarter of the patients who underwent total thyroidectomy had unifocal, intrathyroidal tumors 1cm (n=408; 23.6%). Neck dissection was performed in 40.4% of the patients (29.5% had central compartment dissection). Radioiodine remnant ablation (RRA) was performed in 1057 (61.2%) of the 1726 patients who underwent total thyroidectomy: 460 (41.2%) of the 983 classified by 2009 ATA guideline criteria as low-risk, 570 (87.1%) of the 655 as intermediate-risk, and 82 (93.1%) of the 88 as high-risk patients (p<0.001). RRA was performed in 44% of the cases involving multifocal DTCs measuring 1cm. Conclusions: The treatment approaches for DTCs used in Italy display areas of inconsistency with those recommended by the 2009 ATA guidelines. Italian practices were characterized by underuse of thyroid lobectomy in intrathyroidal, unifocal DTCs 1cm. The use of RRA was generally consistent with risk-stratified recommendations. However, its frequent use in small DTCs (1cm) that are multifocal persists, despite the lack of evidence of benefit. These data provide a baseline for future assessments of the impact of international guidelines on DTC management in Italy. These findings also illustrate that the dissemination and implementation of guideline recommendations, and the change in practice patterns, require ongoing education and time.