title: Acknowledging gray areas: 2015 vs. 2009 American Thyroid Association differentiated thyroid cancer guidelines on ablating putatively low-intermediate-risk patients.
abstract: OBJECTIVE
  Typically formulated by investigators from "world centres of excellence," differentiated thyroid carcinoma (DTC) management guidelines may have more limited applicability in settings of less expert care and fewer resources. Arguably the world's leading DTC guidelines are those of the American Thyroid Association, revised in 2009 ("ATA 2009") and 2015 ("ATA 2015"). To further explore the issue of "real-world applicability" of DTC guidelines, we retrospectively compared indications for ablation using ATA 2015 versus ATA 2009 in a two-centre cohort of ablated T1-2, M0 DTC patients (N = 336). Based on TNM status and histology, these patients were low-intermediate risk, but many ultimately had other characteristics suggesting elevated or uncertain risk.
  
  
  METHODS
  Working by consensus, two experienced nuclear medicine physicians considered patient and treatment characteristics to classify each case as having "no indication," a "possible indication," or a "clear indication" for ablation according to ATA 2009 or ATA 2015. The physicians also identified reasons for classification changes between ATA 2015 versus ATA 2009. Classification was unblinded, but the physicians had cared for only 138/336 patients, and the charts encompassed September 2010-October 2013, several years before the classification was performed.
  
  
  RESULTS
  One hundred of 336 patients (29.8 %) changed classification regarding indication for ablation using ATA 2015 versus ATA 2009. Most reclassified patients (70/100) moved from "no indication" or "clear indication" to "possible indication." Reflecting this phenomenon, "possible indication" became the largest category according to the ATA 2015 classification (141/336, 42.0 %, versus 96/336, 28.6 %, according to ATA 2009). Many reclassifications were attributable to multiple clinicopathological characteristics, most commonly, stimulated thyroglobulin or anti-thyroglobulin antibody levels, multifocality, bilateral involvement, or capsular/nodal invasion.
  
  
  CONCLUSIONS
  Regarding indications for ablation, ATA 2015 appears to better "acknowledge grey areas," i.e., patients with ambiguous or unavailable data requiring individualised, nuanced decision-making, than does ATA 2009.
authors.affiliation: Department of Nuclear Medicine, Bank of Cyprus Oncology Centre, 32 Acropoleos Avenue, Strovolos, Nicosia, 2006, Cyprus. savvas.frangos@gmail.com.
authors.forename: Savvas
authors.initials: S
authors.lastname: Frangos
authors.affiliation: Department of Nuclear Medicine, Papageorgiou Hospital, Aristotle University, 56403, Thessaloniki, Greece.
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Iakovou
authors.affiliation: Spencer-Fontayne Corporation, 33 Bentley Avenue, Jersey City, NJ, 07304-1901, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Marlowe
authors.affiliation: Department of Nuclear Medicine, Bank of Cyprus Oncology Centre, 32 Acropoleos Avenue, Strovolos, Nicosia, 2006, Cyprus.
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Eftychiou
authors.affiliation: Department of Nuclear Medicine, Bank of Cyprus Oncology Centre, 32 Acropoleos Avenue, Strovolos, Nicosia, 2006, Cyprus.
authors.forename: Loukia
authors.initials: L
authors.lastname: Patsali
authors.affiliation: Department of Nuclear Medicine, Bank of Cyprus Oncology Centre, 32 Acropoleos Avenue, Strovolos, Nicosia, 2006, Cyprus.
authors.forename: Anna
authors.initials: A
authors.lastname: Vanezi
authors.affiliation: Department of Nuclear Medicine, Bank of Cyprus Oncology Centre, 32 Acropoleos Avenue, Strovolos, Nicosia, 2006, Cyprus.
authors.forename: Androulla
authors.initials: A
authors.lastname: Savva
authors.affiliation: Department of Nuclear Medicine, Papageorgiou Hospital, Aristotle University, 56403, Thessaloniki, Greece.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Mpalaris
authors.affiliation: Department of Nuclear Medicine, Papageorgiou Hospital, Aristotle University, 56403, Thessaloniki, Greece.
authors.forename: Evanthia I
authors.initials: EI
authors.lastname: Giannoula
mesh_terms: D000328:Adult; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D006115:Greece; D006801:Humans; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D009683:Nuclear Medicine / Q000592:standards*; D017410:Practice Guidelines as Topic; D011878:Radiotherapy / Q000592:standards*; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000532:radiotherapy* / Q000601:surgery*; D013965:Thyroidectomy / Q000592:standards*; D016896:Treatment Outcome
keywords: 2009 revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer; 2015 American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer; Decision-making; Differentiated thyroid cancer management guidelines; Recommendations; Thyroid remnant ablation