PURPOSE: Nodal involvement is an independent risk factor of recurrence in papillary thyroid cancer (PTC). Neither the international guidelines nor the recently introduced ongoing risk adaptation concept consider the extent of initial surgical clearance of radioiodine sensitive lymph node metastases in their stratification systems. We investigated the prognostic relevance of incomplete initial surgical clearance in patients with purely lymphogeneous metastatic PTC (pN1 M0) despite successful radioiodine therapy. Accurate assessment of pre-ablative nodal status was attempted using PET/CT studies with both (124)I-NaI and (18)F-FDG along with high-resolution cervical ultrasound. METHODS: Sixty-five patients with histologically diagnosed lymph node metastases (pN1 M0) were retrospectively analyzed. Patients with iodine-negative lymph node metastases diagnosed by (18)F-FDG PET/CT or distant metastases were excluded from the analysis. The association of disease recurrence with the pre-ablative nodal status, as well as other baseline characteristics, were examined applying nonparametric tests for independent samples and multiple regression analysis. Patients with persistent lymph node metastases in (124)I-NaI PET/CT were further divided according to the additional presence or absence of FDG-uptake in (18)F-FDG PET/CT. Survival analyses were performed using Kaplan-Meier curves and the Cox proportional hazards model for uni- and multivariate analyses to assess the influence of prognostic factors on progression free survival (PFS). RESULTS: Incomplete metastatic lymph node resection captured by (124)I-NaI PET/CT (n = 33) was an independent risk factor for recurrence (61 % vs 25 %, p = 0.006) and shorter PFS (46 months vs not reached, HR 4.0 [95 %-CI, 1.7-9.2], p = 0.001). Ultrasound could detect lymph node metastases only in 19/33 patients (58 %). Among patients with positive nodal status, FDG-avidity of metastatic iodine positive lymph nodes worsened the outcome (16 vs 69 months, p = 0.047). From all other investigated factors including age, N-stage (N1a vs N1b), and T-Stage (T4 vs T1-3), only large tumor size (pT4) had a significant impact on PFS (HR 2.9 [95 %-CI, 1.3-6.4], p = 0.007). CONCLUSIONS: Incomplete initial surgical clearance of lymph node metastases even after successful radioiodine therapy may increase the chances of recurrence and is an independent risk factor for impaired survival of patients with PTC. Pre-ablative (dual tracer PET/CT) imaging with (124)I-Na and (18)F provides a prognostic tool for these patients and may considerably complement the current risk stratification systems.
PURPOSE: Nodal involvement is an independent risk factor of recurrence in papillary thyroid cancer (PTC). Neither the international guidelines nor the recently introduced ongoing risk adaptation concept consider the extent of initial surgical clearance of radioiodine sensitive lymph node metastases in their stratification systems. We investigated the prognostic relevance of incomplete initial surgical clearance in patients with purely lymphogeneous metastatic PTC (pN1 M0) despite successful radioiodine therapy. Accurate assessment of pre-ablative nodal status was attempted using PET/CT studies with both (124)I-NaI and (18)F-FDG along with high-resolution cervical ultrasound. METHODS: Sixty-five patients with histologically diagnosed lymph node metastases (pN1 M0) were retrospectively analyzed. Patients with iodine-negative lymph node metastases diagnosed by (18)F-FDG PET/CT or distant metastases were excluded from the analysis. The association of disease recurrence with the pre-ablative nodal status, as well as other baseline characteristics, were examined applying nonparametric tests for independent samples and multiple regression analysis. Patients with persistent lymph node metastases in (124)I-NaI PET/CT were further divided according to the additional presence or absence of FDG-uptake in (18)F-FDG PET/CT. Survival analyses were performed using Kaplan-Meier curves and the Cox proportional hazards model for uni- and multivariate analyses to assess the influence of prognostic factors on progression free survival (PFS). RESULTS: Incomplete metastatic lymph node resection captured by (124)I-NaI PET/CT (n = 33) was an independent risk factor for recurrence (61 % vs 25 %, p = 0.006) and shorter PFS (46 months vs not reached, HR 4.0 [95 %-CI, 1.7-9.2], p = 0.001). Ultrasound could detect lymph node metastases only in 19/33 patients (58 %). Among patients with positive nodal status, FDG-avidity of metastatic iodine positive lymph nodes worsened the outcome (16 vs 69 months, p = 0.047). From all other investigated factors including age, N-stage (N1a vs N1b), and T-Stage (T4 vs T1-3), only large tumor size (pT4) had a significant impact on PFS (HR 2.9 [95 %-CI, 1.3-6.4], p = 0.007). CONCLUSIONS: Incomplete initial surgical clearance of lymph node metastases even after successful radioiodine therapy may increase the chances of recurrence and is an independent risk factor for impaired survival of patients with PTC. Pre-ablative (dual tracer PET/CT) imaging with (124)I-Na and (18)F provides a prognostic tool for these patients and may considerably complement the current risk stratification systems.
Authors: R Michael Tuttle; Hernan Tala; Jatin Shah; Rebecca Leboeuf; Ronald Ghossein; Mithat Gonen; Matvey Brokhin; Gal Omry; James A Fagin; Ashok Shaha Journal: Thyroid Date: 2010-10-29 Impact factor: 6.568
Authors: Lutz S Freudenberg; Walter Jentzen; Alexander Stahl; Andreas Bockisch; Sandra J Rosenbaum-Krumme Journal: Eur J Nucl Med Mol Imaging Date: 2011-04-12 Impact factor: 9.236
Authors: W Wang; S M Larson; M Fazzari; S K Tickoo; K Kolbert; G Sgouros; H Yeung; H Macapinlac; J Rosai; R J Robbins Journal: J Clin Endocrinol Metab Date: 2000-03 Impact factor: 5.958
Authors: Henning Dralle; Thomas J Musholt; Jochen Schabram; Thomas Steinmüller; Andreja Frilling; Dietmar Simon; Peter E Goretzki; Bruno Niederle; Christian Scheuba; Thomas Clerici; Michael Hermann; Jochen Kußmann; Kerstin Lorenz; Christoph Nies; Peter Schabram; Arnold Trupka; Andreas Zielke; Wolfram Karges; Markus Luster; Kurt W Schmid; Dirk Vordermark; Hans-Joachim Schmoll; Reinhard Mühlenberg; Otmar Schober; Harald Rimmele; Andreas Machens Journal: Langenbecks Arch Surg Date: 2013-03-03 Impact factor: 3.445