title: The Role of SPECT/CT Lymphoscintigraphy and Radioguided Sentinel Lymph Node Biopsy in Managing Papillary Thyroid Cancer.
abstract: Single-photon emission computed tomography/computed tomography (SPECT/CT) and radioguided sentinel lymph node biopsy (rSLNB) are techniques that could potentially benefit surgeons and pathologists in the identification of sentinel lymph node (SLN) metastases in patients with papillary thyroid carcinoma (PTC). Evidence suggests that these novel techniques lead to substantial changes in PTC management by reducing understaging and of occult lymph node (LN) metastases and optimizing neck surgery by increasing the necessity of lateral lymphadenectomy and decreasing central lymphadenectomy.
  
  
  
  To correlate the presence of LN metastases in PTC with clinical and pathological features using SPECT/CT and rSLNB.
  
  
  
  For this prospective cohort study from June 2010 to November 2013, 42 patients with thyroid nodules suspicious for papillary carcinoma or classified as malignant on cytology examination without suspicion of lymph node metastases by clinical and ultrasound examinations were recruited from a single public medical institution.
  
  
  
  All 42 patients underwent preoperative lymphoscintigraphy after an ultrasound-guided peritumoral injection of Technetium Tc 99m nanocolloid. Cervical images were acquired with a SPECT/CT scanner 15 minutes after radiotracer injection. Approximately 2 hours after lymphoscintigraphy, the patients were submitted to intraoperative rSLNB using a handheld gamma probe. All SLNs identified were removed alongside with non-SLNs from the same compartment. Papillary thyroid carcinoma, SLNs and non-SLNs were submitted for histopathology and immunohistochemical analyses.
  
  
  
  Of the 42 patients initially enrolled, 37 were included in analysis, including 6 men and 31 women with a mean (range) age of 47 (22-83) years. Overall, T stage was as follows: T1, 23 patients (62.2%); T2, 8 patients (21.6%); and T3, 6 patients (16.2%). Sentinel lymph nodes were identified in 92% of the patients, and among these metastases were present in 17 patients (46%). The SLNs were false-negative in 3 patients. Metastases in the lateral compartment ocurred in 7 patients (18%). There was a significant association between LN metastases and tumor size (odds ratio, 1.06; 95% CI, 1.00-1.13; P = .02), with a Cohen d effect of 0.683 (medium to large effect). Overall, 17 patients (46%) with LN metastases had management changed because they were submitted to higher radioiodine ablation doses and closer clinical surveillance.
  
  
  
  Radioguided SLNB is able to detect occult cervical lymph node metastases in patients with papillary thyroid carcinoma, and in 7 patients (18%) rSLNB detected lymph node metastases in the lateral compartments. The rSLNB technique lead to management change in 14 patients (37.8%).
authors.affiliation: Division of Nuclear Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Raquel Novas
authors.initials: RN
authors.lastname: Cabrera
authors.affiliation: Department of Otorhinolaringology, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Carlos T
authors.initials: CT
authors.lastname: Chone
authors.affiliation: Division of Endocrinology of the Department of Internal Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Denise E
authors.initials: DE
authors.lastname: Zantut-Wittmann
authors.affiliation: Department of Pathology, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Patrcia S
authors.initials: PS
authors.lastname: Matos
authors.affiliation: Department of Radiology, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Ferreira
authors.affiliation: Department of Otorhinolaringology, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Pablo S
authors.initials: PS
authors.lastname: Pereira
authors.affiliation: Division of Nuclear Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Mariana P
authors.initials: MP
authors.lastname: Ribeiro
authors.affiliation: Division of Nuclear Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Allan O
authors.initials: AO
authors.lastname: Santos
authors.affiliation: Division of Nuclear Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Celso D
authors.initials: CD
authors.lastname: Ramos
authors.affiliation: Department of Otorhinolaringology, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Agrício N
authors.initials: AN
authors.lastname: Crespo
authors.affiliation: Division of Nuclear Medicine, Campinas State University (UNICAMP), Campinas, Brazil.
authors.forename: Elba C
authors.initials: EC
authors.lastname: Etchebehere
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000473:pathology*; D002291:Carcinoma, Papillary; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D061305:Lymphoscintigraphy; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D000072098:Single Photon Emission Computed Tomography Computed Tomography; D013668:Technetium Tc 99m Aggregated Albumin; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology*; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; C083602:technetium Tc 99m nanocolloid