2018-19 Section 7-Neoplastic and Inflammatory Diseases of the Head and Neck eBook

Original Article

TABLE 3. Resected Nodules With Sonographic Pattern According to ATA 2015 Guidelines Stratified by Results of ThyroSeq and Afirma GEC

ThyroSeq Resected Nodules With US Category (N 5 26)

Nodule Histology on Surgical Resection

ATA Sonographic Pattern

Benign

(%)

Malignant or NIFTP

(%)

Total

High suspicion

1 1

50.0% 100.0%

1

50.0%

2 1 1 8 7 1 9 6 1 1

No HR mutations HR mutations found Intermediate suspicion No HR mutations HR mutations found

0.0%

0.0%

1 1 1

100.0% 12.5% 14.3%

7 6 1 9 2 1 1

87.5% 85.7% 100.0% 73.3% 100.0% 33.3% 100.0% 100.0% 76.9%

0.0%

Low suspicion

11

4

26.7%

15

No HR mutations HR mutations found

0.0%

4

66.7%

Very low suspicion No HR mutations

0.0% 0.0%

Total

20

6

23.1%

26

Afirma GEC Resected Nodules With US Category (N 5 70)

Nodule Histology on Surgical Resection

ATA Sonographic Pattern

Benign

(%)

Malignant or NIFTP

(%)

Total

High suspicion

6 1 5

60.0% 100.0% 55.6% 76.2% 100.0% 70.6% 74.3% 100.0% 71.0% 100.0% 100.0% 100.0% 74.3%

4

40.0%

10

GEC “benign”

0.0%

1 9

GEC “suspicious”

4 5

44.4% 23.8%

Intermediate suspicion

16

21

GEC “benign”

4

0.0%

4

GEC “suspicious”

12 26

5 9

29.4% 25.7%

17 35

Low suspicion

GEC “benign”

4

0.0%

4

GEC “suspicious”

22

9

29.0%

31

Very low suspicion

4 1 3

0.0% 0.0% 0.0%

4 1 3

GEC “benign”

GEC “suspicious”

Total

52

18

25.7%

70

Abbreviations: ATA 2015, 2015 American Thyroid Association guideline; GEC, gene expression classifier; HR, high risk; NIFTP, noninvasive thyroid neoplasm with papillary-like nuclear features; US, ultrasound.

mutations by ThyroSeq both for nodules that did and did not meet the ATA 2015 criteria for biopsy; however, only 1 case was present that had HR mutations and did not meet the ATA 2015 criteria for biopsy (Table 4). DISCUSSION The goal of the molecular testing of cytological samples from indeterminate thyroid nodules is to add evidence in support of or against the need for surgical treatment and the extent of surgery (lobectomy or total thyroidectomy). Molecular testing offers additional prognostic evidence in terms of ROM that is intended to help endocrinologists and surgeons decide between lobectomy and total thyroid- ectomy for patients with cytologically indeterminate thy- roid nodules or, conversely, no surgery at all.

Currently published ROMs with results of these molecular tests were established before the nomenclature revision of the encapsulated follicular variant of papillary thyroid carcinoma to NIFTP. Removal of the word “cancer” from this entity’s name reflects the indolent be- havior of this lesion. Just as this nomenclature revision alters ROM in different categories in TBSRTC, especially the indeterminate categories, 9,10 molecular testing panels are likely to note a decrease in the ROM associated with “positive” results. In light of the likely decrease in the ROM for muta- tions commonly associated with thyroid cancer due to the establishment of the NIFTP nomenclature, it is important to broaden validation of molecular panels to include this entity. Validation studies including updated classifications of thyroid tumors will result in more accurate PPVs and

Cancer Cytopathology

158