Papillary Thyroid Microcarcinomas: Big Decisions for a Small Tumor

Abstract

Background The clinical significance of papillary thyroid microcarcinoma (PTMC) is debated, and therefore the rise in incidence of PTMC creates management dilemmas. The following study evaluates factors influencing decisions to treat. Materials and Methods Between 1994 and 2007, 1361 patients underwent thyroid surgery at a single institution. Of these patients, 107 were diagnosed with PTMC. The type of surgical intervention, likelihood of referral to an endocrinologist, use of radioactive iodine, and administration of suppressive doses of levothyroxine (LT4) were analyzed in relation to patient and tumor characteristics. Results Multifocality and larger size were predictive of which patients underwent total thyroidectomy on multivariable logistic regression (P = .004 and P = .001, respectively). Larger mean tumor size, 0.62 ± 0.004 versus 0.34 ± 0.006 cm, was independently associated with increased likelihood of endocrine referral (P = .029). Multifocality, diagnosis via FNA preoperatively, larger mean size of PTMC, and endocrine referral were independently associated with increased likelihood of receiving radioactive iodine (RAI). On multivariable analysis, only total thyroidectomy and endocrine referral were independently associated with treatment with suppressive doses of LT4 (P = .001 and .001, respectively). In the 47 patients with unifocal PTMC <0.8 cm diameter, the mean size of tumor focus was larger in the subgroup undergoing total thyroidectomy (P = .004). Surprisingly, in these very low risk PTMC patients, the likelihood of RAI for remnant ablation was independently associated with younger patient age (P = .029). In the subgroup with unifocal <0.8 cm disease, the mean age of patients receiving RAI was 34 ± 3.3 years versus 48 ± 2.3 years in those not receiving RAI (P = .003). Conclusions The decision tree in the management of PTMC is beginning at the time of surgery, and referral to endocrinology is associated with a more aggressive course. Younger age is predictive of RAI administration in the lowest-risk PTMC patients.

Clinicopathological, immunohistochemical factors and recurrence associated with extrathyroidal extension in papillary thyroid microcarcinoma

“…[21,33,34] ETE in PTMC is associated with larger size, lymph node metastasis, TNM staging, multifocality, and locoregional recurrence. [13,19,22,35,36] Presently, the mean size of ETE-associated tumors was larger than that of tumor without ETE, consistent with other studies [14,24] . Moreover, the frequency of ETE also increased with increasing tumor size [ Figure 1].…”

Distinguishing classical papillary thyroid microcancers from follicular-variant microcancers

“…Despite this increase in papillary microcarcinoma incidence, there is continued debate regarding the most effective treatment for these cancers, predominately due to their excellent prognosis (3,4). Providers must weigh any potential risks of treatment against the risk of recurrence or metastases.…”

Bilateral versus unilateral papillary thyroid microcarcinoma: predictive factors and associated histopathological findings following total thyroidectomy

“…3 It is estimated that it accounts for up to 30% of all papillary thyroid cancers, although marked geographic differences in incidence rates have been noted. 4,5 Most of PTMC are not detectable on clinical examination and they are only diagnosed incidentally during pathologic examination of the thyroid after surgery. The increased accuracy of pathologic examination, in particular thanks to the greater number and thinness of the anatomical slices, has led to more frequent pathologic diagnosis of incidental PTMC.…”