Preoperative PET-CT in papillary thyroid cancer

Chung-Ang University, KoreaDepartment of Surgery

Byung Seup Kim, Ju Won Seok, Han suk Ryu, Kyung Ho Kang, Sung Jun Park, Bo Youn Cho

Introduction

PET – CT 2-[fluorine-18]fluoro-2-deoxy- glucose

FDG

Introduction

Meaning of FDG -uptake

Rate of uptake of FDG is proportional to

metabolic activity

An introduction to PET-CT imaging. Radigraphics 2004; 523-543

Uptake of FDG

Metabolic activity

Flip – flop phenomenon

PTC

Introduction

About Primary le-sion

We evaluated the FDG uptake of papillary thy-roid cancer in preoperative PET CT.

Method

FNAB :Papillary thy-roid cancer

Preoperative PET-CT

Operation

Period : 2011.3.1 ~ 2012. 2. 29PTC was preoperatively confirmed by FANBCND was routinely performed.Preoperative PET CT was performed when patient argeed it Enrolled patients : 194

Divided into PET negative(-) and positive(+) group

Negative ;Absence of FDG up-tatke

Postive ;Presence of FDG up-take

VS.

Method

Backgroud : surrounding thyroid tis-sue

Method

1. Analyze the cliniopathologic factors related to PET (+)2. .Analyze quantity of SUVmax value according to clinicopathologic factors

SUVmax : maximal standardized uptake value SUVmax of PET negative patient = SUV of surrounding thy-roid tissue

ResultsPET sensitivity

① Primary tumor : 71.7% (138/194 pa-tients)

② Central lymph node metz. : 4.3% (3/70 patients)

③ Lateral lymph node metz. : 62.5% (15/24 pa-tients) False positive : 1.1%

ResultsTable 1-1. PET-CT and clinicopathologic parameters

　 Variables 　 PET (-) PET (+) P value(n=56, 28.9%) (n=138, 71.7%)

Sex Male 19 (33.9 %) 21 (15.2%) 0.004

　 Female 37 (66.1%) 117 (84.8%) 　Age < 45 years 22 (39.3%) 61 (44.2%) 0.530

　 ≥ 45 years 34 (60.7%) 77 (55.8%) 　Size ≤ 1cm 49 (87.5%) 77 (55.8%) <0.001

　 > 1cm 7 (12.5%) 61 (44.2%) 　Multicenticity Absence 31 (55.4%) 71 (51.4%) 0.621

　 Presence 25 (44.6%) 67 (48.6%) 　Extrathyroidal extension Absence 43 (76.8%) 87 (63.0%) 0.065

　 Presence 13 (23.2%) 51 (37.0%) 　Lymph node metastasis Absence 33 (58.9%) 67 (48.6%) 0.190

　 Presence 23 (41.1%) 71 (51.4%)

Table 1-2. PET-CT and clinicopathologic parameters

　 Variables 　 PET (-) PET (+) P value(n=56, 28.9%) (n=138, 71.7%)

Coexisting pathology 0.001 None 31 (55.4%) 41 (29.7%) 　 Nodular hyperplasia (NH) 18 (32.1%) 40 (29.0%) Hashimoto thyroiditis (HT) 5 (8.9%) 36 (26.1%) NHa+ HTb 2 (3.6%) 21 (15.2%)Subtype of PTC 0.001 Classic 38 (67.9%) 110 (79.7%) Follicular variant 17 (30.4%) 12 (8.7%) Oncocytic variant 1 (1.8%) 14 (10.1%) Solid 0 (0%) 1 (0.7%) Tall cell variant 0 (0%) 1 (0.7%)

Coexisting pathology 0.001 Abscence 31 (43.1%) 41 (56.9%) 　 Presence 25 (20.5%) 97 (79.5%)Subtype of PTC <0.001 Non-follicular variant 39 (23.6%) 126 (76.4%) Follicular variant 17 (58.6%) 12 (41.4%)

ResultsTable 2. PET positivity and cliniocopathologic parameters by logistic regression

Variable 　 Hazard ratio (95% CIb) P value

Sex Male 1 (reference) 0.021

　 Female 2.843 ( 1.171 - 6.905) 　

Size ≤ 1cm 1 (reference) < 0.001

　 > 1cm 8.090 (3.000 - 21.813) 　

Coexisting pathology Absence 1 (reference) 0.005

　 Presence 2.983 (1.393 - 6.386) 　

Subtype of PTCa Follicular variant 1 (reference) 0.003

　 Non-follicular variant 4.032 (1.619 - 10.038) 　PTCa Papillary thyroid cancer

2. Analysis for quantity of FDG uptake

SUVmax

Kolmogorov-Smirnove goodness

P < 0.001

Non normally distributed data

Table 3. SUVmax by clinicopathologic parameters

　 Variables 　 N Median Q25 - Q75 P valueSex Male 40 1.850 1.000 - 4.175 0.042　 Female 154 2.700 1.575 - 4.400 　Age < 45 years 83 2.700 1.000 - 4.200 0.658　 ≥ 45 years 111 2.500 1.000 - 4.400 　Tumor size ≤ 1cm 126 2.100 1.000 - 3.000 0.001　 > 1cm 68 4.900 2.900 -10.200 　Multicenticity Absence 102 2.600 1.000 - 4.525 0.888　 Presence 92 2.600 1.000 - 4.300 　Extrathyroidal extension Absence 130 2.300 1.000 - 3.300 < 0.001　 Presence 64 4.00 1.900 - 9.400 　Lymph node metastasis Absence 100 2.400 1.000 - 3.400 0.017　 Presence 94 3.000 1.125 - 5.000 　Coexisting pathology 0.253 None 72 2.150 1.875 - 4.225 　 Nodular hyperplasia (NH) 58 2.300 1.000 – 4.150 Hashimoti thyroiditis (HT) 35 2.800 2.400 – 4.100 NH + HT 22 3.450 2.475 – 4.475Subtype of PTC (Papillary thyroid cancer) 0.001 Classic 148 2.750 1.000 – 4.875 Follicular variant 29 1.000 1.000 – 2.450 Oncocytic variant 15 2.900 2.300 – 3.200 Solid 1 2.100 Not availabled

Tall cell variant 1 8.300 Not availabled

d The number of case was only one so that quartile was not available

P value < 0.001

SUVmax 2.6 sensitivity 70.3% specificity 60.0%

Analysis for quantity of FDG uptake

Relationship between extrathyroidal extension and SUVmax

ROC curve

1-specificity

Results

　 ETE (-) (n=130, 67.0%)

ETE (+)(n=64, 33.0%) P value

Lymph node metz.

(+) 52 (40.0%) 42 (65.6%) 0.001

Size > 1cm 31 (23.8%) 64 (33.0%) < 0.001

Age ≥ 45 years 74 (56.9%) 37 (57.8%) 0.906

Female 107 (82.3%) 47 (73.4%) 0.151

Multicenticity 59 (45.7%) 33 (51.6%) 0.446

SUVmax ≥ 2.6 55 (42.3%) 45 (70.3%) <0.001

Subtype (follicular) 24 (18.5%) 4 (6.3%) 0.029

Coexisting pathology 82 (63.1%) 40 (62.5%) 0.938

Cliniopathologic factors and Extrathyroidal exnte-sion by univariate analysis

Extrathyroidal extension and clinicopathologic factors by mulivariate analysis

Variable 　 Hazard ratio (95% CI) P-value

Lymph node metz. Absence 1 (reference) 0.046

　 Presence 2.063 ( 1.014 – 4.199)

Size ≤ 1cm 1 (reference) 0.016

> 1cm 2.552( 1.193 – 5.460)

SUVmax < 2.6 1 (reference) 0.316

≥ 2.6 1.488 (0.684 – 3.238)

Subtype Follicular variant 1 (reference) 0.114

Non follicular variant 4.469 (1.757 – 11.371)

→ SUVmax was not related to extrathyroidal ex-tension

Results

　 LN metz. (-) (n=100, 51.5%)

LN metz. (+)(n=94, 48.5%) P-value

Extrathyroidal ext.

(+)22 (22.0%) 42 (44.7%) 0.001

Size > 1cm 25 (25.0%) 43 (45.7%) 0.002

Age ≥ 45 years 72 (72.0%) 39 (41.5%) <0.001

Female 81(81.0%) 73 (77.7%) 0.565

Multicenticity 45 (45.5%) 47 (50.0%) 0.527

SUVmax ≥ 2.9 38 (38.0%) 49 (52.1%) 0.048

Subtype(follicular) 20 (20.0%) 8 (8.5%) 0.023

Coexisting pathology 65 (65.0%) 57 (60.6%) 0.530

Cliniopathologic factors and lymph node metastasis by univariate analysis

Variable 　 Hazard ratio (95% CI) P value

ETE Absence 1 (reference) 0.011

　 Presence 2.503 ( 1.231 – 5.090)

Size ≤ 1cm 1 (reference) 0.081

> 1cm 1.972( 0.919 – 4.234)

Age < 45 years 0.245 (0.129 – 0.466) <0.001

≥ 45 years 1 (reference)

SUVmax < 2.9 1 (reference) 0.884

≥ 2.9 0.947 (0.455 – 1.971)

Subtype Follicular variant 1 (reference) 0.103

Non-follicular variant 2.255 (0.848 – 5.993)

Lymph node metastasis and clinicopathologic factors by mulivariate analysis

→ SUVmax was not related to lymph node metastasis

Subtype

P value < 0.001

FDG 2.0 sensitivity 70.9% specificity 69.0 %

Relationship between Non-follicular subtype and SUVmax

ROC curve

1-specificity

Results

　 Non follicular (n=165, 85.1%)

follicular(n=29, 14.9%) P-value

Extrathyroidal ex-tension 60 (36.1%) 4 (14.3%) 0.018

Lymph node metz. 86 (51.8) 9 (28.6%) 0.042

Size > 1cm 62 (37.3%) 6 (21.4%) 0.079

Age ≥ 45 years 94 (56.6%) 17 (60.7) 0.686

Female 133 (80.7%) 21 (71.4%) 0.261

Multicenticity 81 (49.1%) 12 (39.3%) 0.337

SUVmax ≥ 2.0 117 (70.9%) 9 (28.6%) <0.001

Coexisting pathology 107 (64.5%) 15 (53.6%) 0.270

Cliniopathologic factors and subtype of PTC by univariate analysis

Non-follicular variant and clinicopathologic fac-tors

by mulivariate analysis

Variable 　Hazard ratio (95%

CI)P value

Extrathyroidal

extensionAbsence 1 (reference) 0.092

　 Presence2.690 (0.851 -

8.502)　

Lymph node

metastasisAbsence 1 (reference) 0.141

　 Presence1.964 (0.800 –

4.820)　

SUVmax of primary

lesion< 2.0 1 (reference) <0.001

≥ 2.05.044 (2.111 –

12.056)

Conclusion

The usefulness of preoperative PET-CT for PTC was not yet certain.

PET positive results and SUVmax had no relation to signifi-cant clinical factors such as extrathyroidal extension and lymph node metastasis.

PET negative results or low SUVmax indicate the possibility of follicular variant subtype in papillar thyroid cancer.

Thank you for your at-tention