NONINVASIVE FOLLICULAR TUMOR WITH PAPILLARY-LIKE NUCLEAR FEATURES: NOT A TEMPEST IN A TEAPOT.

Objective: Encapsulated non-invasive follicular variant papillary thyroid cancer (ENIFVPTC) has recently been retermed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This designation specifically omits the word "cancer" to encourage conservative treatment since patients with NIFTP tumors have been shown to derive no benefit from completion thyroidectomy or adjuvant radio-active iodine (RAI) therapy.

Methods: This was a retrospective study of consecutive cases of tumors from 2007 to 2015 that met pathologic criteria for NIFTP. The conservative management (CM) group included patients managed with lobectomy alone or appropriately indicated total thyroidectomy. Those included in the aggressive management (AM) group received either completion thyroidectomy or RAI or both.

Results: From 100 consecutive cases of ENIFVPTC reviewed, 40 NIFTP were included for the final analysis. Of these, 10 (27%) patients treated with initial lobectomy received completion thyroidectomy and 6 of 40 (16%) also received postsurgical adjuvant RAI. The mean per-patient cost of care in the AM group was $17,629 ± 2,865, nearly twice the $8,637 ± 309 costs in the CM group, and was largely driven by the cost of completion thyroidectomy and RAI.

Conclusion: The term NIFTP has been recently promulgated to identify a type of thyroid neoplasm, formerly identified as a low-grade cancer, for which initial surgery represents adequate treatment. We believe that since the new NIFTP nomenclature intentionally omits the word "cancer," the clinical indolence of these tumors will be better appreciated, and cost savings will result from more conservative and appropriate clinical management.

Abbreviations: AM = aggressive management CM = conservative management ENIFVPTC = encapsulated noninvasive form of FVPTC FVPTC = follicular variant of papillary thyroid carcinoma NIFTP = noninvasive follicular thyroid neoplasm with papillary-like nuclear features PTC = papillary thyroid carcinoma PTMC = papillary thyroid microcarcinoma RAI = radio-active iodine US = ultrasound.