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

Table 3. Risk differences in rates of malignancy Diagnostic category/study Rate of malignancy (95% CI)

I 2 ( p value)

p value

with NIFTP (new system)

without NIFTP (old system)

difference (95% CI)

Non-diagnostic Strickland

0.19 (0.11–0.31) 0.26 (0.17–0.37) 0.10 (0.03–0.25) 0.19 (0.10–0.27) 0.13 (0.09–0.19) 0.09 (0.07–0.13) 0.11 (0.05–0.21) 0.10 (0.08–0.13) 0.39 (0.30–0.49) 0.31 (0.27–0.36) 0.17 (0.11–0.27) 0.29 (0.18–0.40) 0.45 (0.35–0.56) 0.33 (0.28–0.39) 0.22 (0.15–0.32) 0.33 (0.22–0.44) 0.87 (0.79–0.93) 0.83 (0.76–0.88) 0.83 (0.65–0.92) 0.72 (0.42–1.01)

0.11 (0.05–0.23) 0.24 (0.16–0.35) 0.10 (0.03–0.29) 0.15 (0.06–0.24) 0.05 (0.03–0.10) 0.06 (0.04–0.09) 0.07 (0.03–0.17) 0.06 (0.04–0.08) 0.22 (0.15–0.31) 0.18 (0.14–0.22) 0.15 (0.09–0.24) 0.18 (0.15–0.21) 0.38 (0.28–0.48) 0.18 (0.14–0.23) 0.20 (0.13–0.30) 0.24 (0.14–0.35) 0.46 (0.36–0.56) 0.59 (0.52–0.66) 0.66 (0.47–0.80) 0.56 (0.45–0.67) 0.94 (0.89–0.96) 0.96 (0.94–0.97) 0.87 (0.92–0.97) 0.94 (0.92–0.97)

Faquin Layfield Average

–0.04 (–0.12, –0.05) 0.42

0 (0.75)

Benign Strickland Faquin Layfield Average FLUS Strickland Faquin Layfield Average

–0.04 (–0.08, –0.02) 0.003 0 (0.49)

–0.11 (–0.19, –0.04) 0.004 50 (0.13)

Follicular neoplasm Strickland

Faquin Layfield Average

–0.10 (–0.18, –0.02) 0.01 40 (0.19)

Suspicious for malignancy Strickland

Faquin Layfield Average

–0.23 (–0.33, –0.14) <0.001 70 (0.04)

Malignant Strickland Faquin Layfield Average

0.99 (0.95–1.00) 0.99 (0.98–1.00)

Excluded

0.97 (0.95–0.98) –0.03 (–0.05, –0.01) 0.004 39 (0.20) The table shows the relative risk of malignancy for each category, as determined by the Bethesda System for Reporting Thyroid Cytology. Relative risk is defined as the rate of malignancy using the new system (with the classification non-invasive follicular variant of papillary thyroid carcinoma, NIFTP) minus the malignancy rate using the old system (without NIFTP). FLUS, follicular lesion of undetermined significance.

undetermined significance (AUS/FLUS) category and a 31% malignancy rate for the “follicular neoplasm/suspi- cious for follicular neoplasm” category. The meta-analysis rates were greater than the original estimates of the risk of malignancy for AUS/FLUS category (5–15%) and for the “suspicious for follicular neoplasms/follicular neoplasm” category (15–30%). Recently, an international panel has proposed modifications and updates for a second edition of TBSRTC [17] .

A second development impacting the utility of the TBSRTC system is the reclassification of non-invasive forms of follicular variants of papillary thyroid carcino- ma as “benign” instead of malignant as they have little or no risk for metastatic disease or recurrence [2, 8] . The term “non-invasive follicular thyroid neoplasm with papillary like nuclear features” (NIFTP) has been pro- posed for these follicular patterned neoplasms [2] . Both clinical follow-up and molecular profiles justify such a reclassification.

Layfield/Baloch/Esebua/Kannuswamy/ Schmidt

Acta Cytologica 2017;61:187–193 DOI: 10.1159/000469654

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