1. Hong CM, Ahn BC, Jeong SY, Lee SW, Lee J
AOTA
Discovery Kartika Plaza Hotel, Bali, Indonesia
Fate of Residual Cervical Metastatic Lymph nodes Found on I-131 Post-ablation SPECT/CT in Patients with Differentiated Thyroid Cancer
Hong CM, Ahn BC, Jeong SY, Lee SW, Lee J
Department of Nuclear Medicine
Kyungpook National University
School of Medicine & Hospital

2. Metastatic lymph nodes in thyroid cancer
Background
Metastatic lymph nodes in thyroid cancer
Residual metastatic lymph nodes are the most common site of disease persistence or recurrence in thyroid cancer.
Completeness of surgical resection is an important determinant of outcome in thyroid cancer.

3. Metastatic lymph nodes in thyroid cancer
Background
Metastatic lymph nodes in thyroid cancer
Prevalence of cervical metastatic lymph nodes (MLN) is known to be relatively high (20~50%) , even in small intrathyroidal tumor.
Incidence of lymph node resection and prevalence of MLN are not that high in certain surgery units.

4. Metastatic lymph nodes in thyroid cancer
Background
Metastatic lymph nodes in thyroid cancer
Late local recurrence of thyroid cancer is reported to be relatively high (exceeds 25%) and it might be related to the hidden residual cancers in the cervical lymph nodes.

5. Background
I-131 ablation in DTC
I-131 ablation is known to decrease risk of recurrence and disease specific mortality
by the destruction of the suspected, but unproven metastatic disease.
A number of studies showed a significant reduction in the rates of disease recurrence and cause-specific mortality by the I-131 ablation

6. Background
Post I-131 ablation WBS
Post ablation I-131 Whole body scan (WBS) is one of the most powerful imaging tools to detecting residual thyroid cancers
Planar WBS visualizes both residual normal thyroid tissues and persistent DTC;
There is a difficulty to differentiate the metastatic lesion of a focal cervical radioiodine uptake in unusual cases.

7. Post I-131 ablation SPECT/CT
Background
Post I-131 ablation SPECT/CT
SPECT/CT provides the synergistic combination of functional and anatomic information and has many advantages over the planar imaging in many clinical settings.
I-131 SPECT/CT is able to allows more precise differentiation between malignant and benign radioiodine activities.

8. Objectives
Aims of this study
To evaluate prevalence of clinical metastatic cervical lymph nodes based on postablation I-131 SPECT/CT in thyroidectomized DTC patients with suspicious pathologic tracer uptake at neck area on the planar imaging.
To elucidate fate of iodine avid cervical metastatic lesions by the I-131 ablation in DTC patients.

9. Subjects
Subjects
194 DTC patients who underwent postablation I-131 SPECT/CT owing to suspicious pathologic uptake at neck on planar WBS were enrolled.
F/M=138:56
Age; 48.6±12.2 yr

10. Methods
Methods
The patients were divided into remnant and metastasis groups based on postablation I-131 SPECT/CT finding.
Clinicopathological characteristics were compared between the two groups.
Fate of the residual MLN were assessed at 8 months after the ablation with TSH stimulated Tg, ultrasonography, chest X-ray, I-123 WBS, and etc.

11. Statistics Independent student-T test
Methods
Statistics
Independent student-T test
Chi-square test, Fisher’s exact test
P<0.05

12. Prevalence of cervical lymph node metastases
Results
Prevalence of cervical lymph node metastases
Prevalence of cervical lymph node metastases based on postablation SPECT/CT findings in patients with suspicious pathologic uptake at neck on postablation planar WBS are following:
Metastasis group : 73 patients (37.6%)
Remnant group : 121 patients (62.4%)

13. Patients characteristics (I)
Results
Patients characteristics (I)
Metastasis group
(n=73)
Remnant group
(n=121)
P value
Age
48.6±12.3
48.6±12.2
0.9664
Sex (F:M)
50:23
88:33
0.6405
Histologic type
(papillary:follicular)
73:0
118:3
0.4501
All 3 patients of follicular type were included in the remnant group.

14. Patients characteristics (II)
Results
Patients characteristics (II)
Metastasis group
(n=73)
Remnant group
(n=121)
P value
T stage
(1:2:3:4)
12:3:47:5
31:2:74:12
0.3595
N stage
(0:1a:1b)
16:30:19
17:63:26
0.2038
AJCC Stage
(I:II:III:IV)
23:2:31:15
44:0:56:9
0.2223

15. TSH stimulated Tg at I-131 ablation Metastasis group vs. Remnant group
Results
TSH stimulated Tg at I-131 ablation Metastasis group vs. Remnant group
ng/mL
P=0.033

16. Clinical outcomes at 8 months after the ablation
Results
Clinical outcomes at 8 months after the ablation
Metastasis group (22)
A patient ; persistent lymph node metastasis
21 patients : no evidence of persistent or recurrent disease
Remnant group (26)
All 26 patients : no evidence of persistent or recurrent disease

17. Results
TSH stimulated Tg at 8 mo W/U disease free in metastasis group vs. remnant group
ng/mL
P=0.1905
Disease free
in metastasis group
Disease free
in remnant group

18. CASE
Case 1
M/56, papillary type, T3N1aMx, TSH: 41.16uIU/mL, Tg: 397.9ng/mL, anti-Tg: 118.8U/mL
Post I-131 ablation WBS and SPECT/CT
Right lateral
Left lateral
SPECT/CT
anterior
Diagnosed as lymph node metastases.

19. Case 1 CASE Recur work up at 8 month after the ablation
TSH: 80.9uIU/mL, Tg: 284.3ng/mL, anti-Tg: U/mL
FDG PET
Ultrasound
Surgical removal is planned for the metastastic lesions

20. CASE
Case 2
M/56, papillary type, III, T3NxMx, TSH: 77.76uIU/mL, Tg: 6.10ng/mL, anti-Tg: U/mL
Post I-131 ablation WBS and SPECT/CT
anterior
posterior
SPECT/CT
remnant at thyroid bed
Diagnosed as lymph node metastases.
lymph node metastasis

21. Case 2 CASE Recur work up at 8 month after the ablation
TSH: 80.9uIU/mL, Tg: 0.92ng/mL, anti-Tg: 95.37U/mL
Neck ultrasonography ; negative
I-123WBS
Regular follow up was recommended.

22. Summaries (I)
Prevalence (37.6%) of cervical lymph node metastases based on postablation SPECT/CT findings was quite high in patients with suspicious pathologic uptake at neck on postablation planar WBS.
Patients with metastatic cervical lymph modes had higher TSH stimulated Tg compared to patients without metastasis.

23. Summaries (II)
Only 1 of 22 patients with cervical lymph nodes metastases found on postablation SPECT/CT had persistent the metastases at 8 months after the ablation.
Although statistically not significant, TSH stimulated Tg was higher in disease free patients of metastasis group than that of remnant group at 8 month after the ablation.

24. Conclusions
Postablation SPECT/CT visualized residual metastatic lymph nodes (MLN) after surgery and prevalence of cervical MLN is high in patients showing suspicious pathologic uptake at neck on the postablation WBS.
More than 95% of patients with residual cervical MLN receiving radioiodine ablation were in remission status at the 8 month after the ablation.