Neck lymph node metastasis detection in patients with differentiated thyroid carcinoma (DTC) in long-term follow-up: a 131I-SPECT/CT study

Abstract Background: The identification of neck lymph node (LN) metastases represents a very important issue in the management of patients with differentiated thyroid carcinoma (DTC). To this purpose, in the present study, we used 131I-SPECT/CT as a diagnostic imaging procedure. Methods: A consecutive series of 224 DTC patients with ascertained neck radioiodine-avid foci at ¹³¹I-SPECT/CT during long-term follow-up was evaluated. All patients had already undergone total thyroidectomy and radioiodine therapy and had been classified as follows: 62 at high risk (H), 64 at low risk (L) and 98 at very low risk (VL). ¹³¹I-Whole body scan (WBS) followed by SPECT/CT was performed in all cases. Results: In the 224 patients, 449 neck iodine avid foci were ascertained at SPECT/CT, while 322 were evidenced at WBS in 165/224 patients. WBS classified as residues 263/322 foci and as unclear 59/322 foci; among the former foci SPECT/CT correctly characterized 8 LN metastases and 3 physiologic uptakes and among the latter, it pinpointed 26 LN metastases, 18 residues, and 15 physiologic uptakes. SPECT/CT also classified 127 foci occult at WBS as 59 LN metastases and 68 residues. Globally, SPECT/CT identified 93 LN metastases in 59 patients (26 H, 20 L, 13 VL), while WBS evidenced 34 in 25 cases. All 13 VL patients, T1aN0M0, 5 of whom with LN near sub-mandibular glands, had thyroglobulin undetectable or <2.5 ng/ml. Globally, SPECT/CT obtained an incremental value than WBS in 45.5 % of patients, a more correct patient classification changing therapeutic approach in 30.3 % of cases and identified WBS false-positive findings in 8% of cases. Conclusions: ¹³¹I-SPECT/CT proved to correctly detect and characterize neck LN metastases in DTC patients in long-term follow-up, improving the performance of planar WBS. SPECT/CT routine use is thus suggested; its role is particularly relevant in patients with WBS inconclusive, VL, T1aN0M0 and with undetectable or very low thyroglobulin levels. Keywords: Differentiated thyroid carcinoma (DTC), Neck lymph node metastases, Long-term follow-up, 131I-Whole body scan (WBS), 131I-SPECT/CT

Download Full-text

Neck Lymph Node Metastasis Detection in Patients with Differentiated Thyroid Carcinoma (DTC) in Long-Term Follow-up: a ¹³¹I-SPECT/CT Study

10.21203/rs.2.17530/v1 ◽

2019 ◽

Author(s):

Angela Spanu ◽

Susanna Nuvoli ◽

Andrea Marongiu ◽

Ilaria Gelo ◽

Luciana Mele ◽

...

Keyword(s):

Lymph Node ◽

Thyroid Carcinoma ◽

Differentiated Thyroid Carcinoma ◽

Low Risk ◽

Whole Body ◽

Neck Lymph Node ◽

Incremental Value ◽

Long Term Follow Up

Abstract Background: The prognostic importance of neck lymph node (LN) metastases in differentiated thyroid carcinoma (DTC) is controversial even if their presence at surgery often correlates with tumor recurrences that it is mandatory to identify. To this purpose, in the present study, we used 131 I-SPECT/CT as diagnostic imaging procedure. Methods: We retrospectively evaluated 224 consecutive DTC patients already submitted to total thyroidectomy and radioiodine therapy, all of them with ascertained neck radioiodine-avid foci at ¹³¹I-SPECT/CT during long-term follow-up; at surgery, 62 patients were classified at high risk (H), 64 at low risk (L), 98 at very low risk. All patients underwent ¹³¹I-Whole body scan (WBS) followed by SPECT/CT. Result: In the 224 patients, 449 neck iodine avid foci were ascertained at SPECT/CT, while 322 were evidenced at WBS in 165/224 patients. WBS classified as residues 263/322 foci and as unclear 59/322 foci; among the former foci SPECT/CT correctly characterized 8 LN metastases and 3 physiologic uptakes and among the latter it pinpointed 26 LN metastases, 18 residues and 15 physiologic uptakes. SPECT/CT also classified 127 foci occult at WBS as 59 LN metastases and 68 residues. Globally, SPECT/CT identified 93 LN metastases in 59 patients (26 H, 20 L, 13 VL), while WBS evidenced 34 in 25 cases. All 13 VL patients,T1aN0M0, 5 of whom with LN near sub-mandibular glands, had thyroglobulin undetectable or <2.5 ng/ml. Globally, SPECT/CT obtained an incremental value than WBS in 45.5 % of patients, a more correct patient classification changing therapeutic approach in 30.3 % of cases and identified WBS false positive findings in 8% of cases. Conclusion: ¹³¹I-SPECT/CT proved to correctly detect and characterize neck LN metastases in DTC patients in long-term follow-up, improving WBS performance. SPECT/CT routine use is suggested, its role being particularly significant in patients with WBS inconclusive, VL, T1aN0M0 and with undetectable or very low thyroglobulin levels.

Download Full-text

Neck Lymph Node Metastasis Detection in Patients with Differentiated Thyroid Carcinoma (DTC) in Long-Term Follow-up: a ¹³¹I-SPECT/CT Study

10.21203/rs.2.17530/v2 ◽

2020 ◽

Author(s):

Angela Spanu ◽

Susanna Nuvoli ◽

Andrea Marongiu ◽

Ilaria Gelo ◽

Luciana Mele ◽

...

Keyword(s):

Lymph Node ◽

Thyroid Carcinoma ◽

Differentiated Thyroid Carcinoma ◽

Whole Body ◽

Whole Body Scan ◽

Body Scan ◽

Neck Lymph Node ◽

Long Term Follow Up

Abstract Background: The prognostic importance of neck lymph node (LN) metastases in differentiated thyroid carcinoma (DTC) is controversial even if their presence at surgery often correlates with tumor recurrences that it is mandatory to identify. To this purpose, in the present study, we used 131I-SPECT/CT as a diagnostic imaging procedure. Methods: We retrospectively evaluated 224 consecutive DTC patients already submitted to total thyroidectomy and radioiodine therapy, all of them with ascertained neck radioiodine-avid foci at ¹³¹I-SPECT/CT during long-term follow-up; at surgery, 62 patients were classified at high risk (H), 64 at low risk (L) and 98 at very low risk (VL). All patients underwent ¹³¹I-Whole body scan (WBS) followed by SPECT/CT. Results: In the 224 patients, 449 neck iodine avid foci were ascertained at SPECT/CT, while 322 were evidenced at WBS in 165/224 patients. WBS classified as residues 263/322 foci and as unclear 59/322 foci; among the former foci SPECT/CT correctly characterized 8 LN metastases and 3 physiologic uptakes and among the latter, it pinpointed 26 LN metastases, 18 residues, and 15 physiologic uptakes. SPECT/CT also classified 127 foci occult at WBS as 59 LN metastases and 68 residues. Globally, SPECT/CT identified 93 LN metastases in 59 patients (26 H, 20 L, 13 VL), while WBS evidenced 34 in 25 cases. All 13 VL patients, T1aN0M0, 5 of whom with LN near sub-mandibular glands, had thyroglobulin undetectable or <2.5 ng/ml. Globally, SPECT/CT obtained an incremental value than WBS in 45.5 % of patients, a more correct patient classification changing therapeutic approach in 30.3 % of cases and identified WBS false-positive findings in 8% of cases. Conclusions: ¹³¹I-SPECT/CT proved to correctly detect and characterize neck LN metastases in DTC patients in long-term follow-up, improving WBS performance. SPECT/CT routine use is suggested; its role is particularly significant in patients with WBS inconclusive, VL, T1aN0M0 and with undetectable or very low thyroglobulin levels. Keywords: Differentiated thyroid carcinoma (DTC), Neck lymph node metastases, Long-term follow-up, 131I-Whole body scan (WBS), 131I-SPECT/CT

Download Full-text