Papillary Microcarcinoma of the Thyroid: How Should It Be Treated?

Abstract

We previously demonstrated that (1) most papillary microcarcinomas can be followed without surgical treatment and (2) when surgery is performed, patients with lateral lymph node metastasis detected on preoperative ultrasonography (US) are more likely to develop recurrence. In this study, we further investigated the application of these strategies. To date, we have observed 211 patients (average follow-up 47.9 months). In more than 70% of these patients the tumor size did not increase during the follow-up period. There were no clinicopathologic features linked to tumor enlargement except in tumors > or = 7 mm, which tended to enlarge in patients followed for 4 years. To evaluate not only whether observation can continue but also how to dissect the lymph nodes optimally at surgery, US diagnosis for lateral node metastasis is essential because the presence of US-diagnosed lateral metastasis is an even stronger predictive marker for recurrence than the presence of pathologically confirmed node metastasis. The positive predictive value (PPV) was 80.6% for US but reached 100% if fine-needle aspiration biopsy (FNAB) of nodes or FNAB-thyroglobulin measurement is added. Furthermore, carcinomas occupying the upper region of the thyroid more frequently showed US-diagnosed and pathologically confirmed lateral metastasis, and those measuring > or = 7 mm were more likely to show pathologically confirmed lateral metastasis. These findings suggest that, for papillary microcarcinoma: (1) US-diagnosed lateral metastasis is a strong marker predicting a worse relapse-free survival; (2) FNAB of nodes and FNAB-thyroglobulin measurement are useful tools for evaluating lymph node metastasis; and (3) careful US evaluation for lateral metastasis is necessary in patients with a tumor measuring > or = 7 mm or that is located in the upper region of the thyroid both during observation and preoperatively.

Role of prophylactic ipsilateral central compartment lymph node dissection in papillary thyroid microcarcinoma

“…Numerous studies have documented the beneficial effects on one hand and supported arguments against prophylactic CCND on the other hand. A high proportion of autopsy findings and pathological specimens have shown metastasis in CCLN [14][15][16][17]. Although US has been regarded as a sensitive imaging modality for thyroid screening and diagnosis, US has a low sensitivity in evaluation of metastasis in CCLN [19].…”

An Observational Trial for Papillary Thyroid Microcarcinoma in Japanese Patients

“…Diagnosis of PMC and recommendation of observation were performed as described in our previous reports [20][21][22][23]. Briefly, when patients are diagnosed with nodules measuring 1 cm or less that showed as papillary carcinoma on ultrasonography-guided FNAB, we presented two therapy options: observation and surgical treatment.…”

“…In contrast, however, the prevalence of clinical thyroid papillary carcinoma was 1.9-11.7 per 100,000 females of all ages [3,10], which is about 1,000 times lower than that of PMC detected on ultrasonography. The marked difference between these prevalences suggests that PMC rarely grow and become clinically apparent, prompting the question of whether immediate surgery is mandatory for all PMC detected on mass screening, although PMC is also known to show multicentricity in 15-44% of lesions and regional lymph node metastasis in 14-64% of lesions [11][12][13][14][15][16][17][18][19][20].…”

Practical Management of Well Differentiated Thyroid Carcinoma in Korea

“…In contrast, papillary microcarcinoma defined as a tumor smaller than 1 cm [3], may show different clinical behaviors than small papillary thyroid carcinoma. Thus, in our questionnaire, T1 tumors subdivided into three groups; smaller than 0.5 cm, 0.5-1.0 cm, and 1.0-2.0 cm.…”