Frozen section analysis and sentinel lymph node biopsy in well differentiated thyroid cancer

Abstract

BackgroundThe aim of this study is to prospectively review the role of sentinel lymph node (SLN) biopsy in the management of well differentiated thyroid carcinoma (WDTC), and to determine the efficacy of intraoperative frozen section analysis at detecting SLN metastasis and central compartment involvement.MethodsThe SLN biopsy protocol using 1% methylene blue was performed in 300 patients undergoing thyroidectomy for WDTC. A limited pretracheal central compartment neck dissection (CCND) was performed on all patients. Lymph nodes staining blue were considered as SLN’s. Both frozen and permanent section analyses were performed.ResultsSLN’s with metastasis were found in 14.3% (43/300) of cases. Of this, 11% (33/300) were positive on intraoperative frozen section analysis. Frozen section results failed in predicting central compartment involvement in 15 cases (5%) whereas central neck compartment involvement was missed in 5 cases (1.7%) when based on permanent section results. On frozen section analysis, the sensitivity, specificity, positive predictive value and negative predictive value (95% CI) of our SLN biopsy technique aiming to remove all disease from the central compartment was 68.8% (53.6-80.9), 100% (98.1-100), 100% (87.0-100) and 94.4% (90.7-96.7) respectively with P < 0.0001. On permanent section analysis, the values were 89.6% (76.6-96.1), 100% (98.1-100), 100% (89.8-100), and 98.1% (95.3-99.3) with P < 0.0001.ConclusionThis data series demonstrates that patients with WDTC have positive SLN’s in 14.3% of cases. Moreover, when the SLN’s are negative for metastasis on frozen section, the central compartment was disease-free in 94.4% of cases. Finally, this study shows that 23.3% of positive SLN’s were false negatives on intraoperative frozen section. According to this data, SLN involvement is an accurate predictor of central compartment metastasis, however surgeons should use caution when relying on intraoperative frozen section to determine whether to perform a CCND.

Lymphoscintigraphy in Differentiated Thyroid Cancer

“…38 Preoperative diagnosis was DTC in 4 studies 20,28,29,38 and PTC in 21 studies. [13][14][15][16][17][18][19]21,22,[24][25][26][27][30][31][32][33][34][35][36][37] In 2006, Abdalla 23 studied 30 patients with a preoperative diagnosis of benign thyroid nodule.…”

“…The histological diagnosis of PTC ranged between a minimum of 8 patients 22,29 and a maximum of 153 patients. 24 The authors used different vital dyes, in particular isosulfan blue in 7 studies, [13][14][15]18,23,29,31 methylene blue in 14 studies, 16,20,21,[25][26][27][28][30][31][32][33][34][35][36]38 and Patent Blue in 5 studies. 17,19,22,24,37 Injected volume ranged between 0.1 mL 13,14,16,19,22,23,28,29,36,37 and 2 mL.…”

“…25 Injection site was IT in 12 studies [13][14][15]19,[21][22][23][24]27,31,32,37 and PT in 15 studies. [16][17][18]20,22,25,26,[28][29][30][33][34][35][36]38,47 In 1 study, 22 the injection site was both IT and PT.…”

Utility of sentinel lymph node biopsy for thyroid cancer: a comprehensive review

“…The meta-analysis reported that for thyroid cancer SLNB the overall false-negative rate was 7.7% based upon 24 studies [68]. However, false-negatives may especially occur when relying on intraoperative frozen section diagnosis, and when evaluated by pathologists inexperienced in thyroid cancer histopathology [55,60]. In 2012, Ji et al reported a high false-negative rate (35.1%) and low sensitivity (64.9%) with the use of methylene blue for PTC SLNB [58].…”

“…False-negatives have been reported, especially with intraoperative frozen section assessment of the SLN [55,60]. In a 2013 study that reported on 300 DTC patients, comparing frozen and permanent sections of SLNs, Jozaghi et al reported that 23.3% of positive SLNs were false-negatives when assessed by intraoperative frozen section [60].…”