Multifocality and Progression of Papillary Thyroid Microcarcinoma During Active Surveillance

Abstract

Background Prospective trials of active surveillance (AS) have shown low rates of progression in low‐risk papillary thyroid microcarcinoma (PTMC; T1aN0M0). However, the significance of multifocality as a prognostic factor remains controversial. Methods Data from 571 patients (mean age, 53.1 years; 495 females) who underwent AS were reviewed. PTMC was unifocal in 457 patients (80.0%) and multifocal in 114 patients (20.0%), with 2–5 lesions each (261 tumors in total). Tumor progression was defined as tumor size enlargement ≥ 3 mm and/or development of clinically evident lymph node metastasis (LNM). Results After a mean duration of AS of 7.6 years, 53 patients (9.3%) showed tumor enlargement and 8 patients (1.4%) developed LNM. The 10‐year progression rate was 13.1%. Age, sex, and calcification pattern did not differ significantly between uni‐ and multifocal diseases. However, anti‐thyroglobulin antibody and/or anti‐thyroid peroxidase antibody was more frequently positive with multifocal PTMCs (46.7%) than with unifocal disease (34.4%, p = 0.024). Patients with uni‐ and multifocal disease showed no significant differences in 10‐year rate of tumor enlargement (11.4% vs. 14.8%), LNM development (1.1% vs. 2.4%), or progression (12.4% vs 15.9%). Multivariate analysis of predictors for progression showed multifocality was not a significant risk factor (odds ratio, 1.45; 95% confidence interval, 0.79–2.54; p = 0.22). Eventually, 9 patients (7.9%) with multifocal PTMCs underwent surgery and 7 needed total thyroidectomy, although 7 still showed T1N0M0 low‐risk cancer. Conclusions Even patients with multiple PTMCs (T1amN0M0) are good candidates for AS. Many patients can avoid total thyroidectomy and subsequent surgical complications.

Progression of Low-Risk Papillary Thyroid Microcarcinoma During Active Surveillance: Interim Analysis of a Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma in Korea

“… 12 , 19 This contradicts the classical concept that old age is a poor prognostic factor for thyroid cancer, 7 although the underlying pathophysiology remains unclear. It is controversial whether tumor size, 13 , 15 presence of tumor calcification, 20 the coexistence of Graves' disease or benign nodules, 6 multiplicity, 21 , 22 and family history 12 are associated with disease progression under AS. Prospective data collected from diverse populations are needed to inform understanding of AS outcomes for PTMC.…”

The feasibility and efficacy of ultrasound-guided percutaneous laser ablation for multifocal papillary thyroid microcarcinoma

“…In addition, multifocality was not an exclusion criterion in the active surveillance protocol for low-risk PTMC in the United States, Canada, and South Korea ( 32 – 34 ). Moreover, some studies with long-term follow-up revealed no significant differences in tumor size increase, lymph node metastasis, and extra-thyroidal invasion between unifocal and multifocal PTMC ( 35 , 36 ). Although the current guidelines for the thermal ablation of PTMC did not recommend ablation of multifocal PTMC, several studies had been conducted on the clinical outcomes of RFA for multifocal PTMC ( 16 , 17 ).…”

Nomogram incorporating preoperative clinical and ultrasound indicators to predict aggressiveness of solitary papillary thyroid carcinoma

“…In fact, multiple PTCs are very common in clinical practice, and multifocality in thyroid cancer is a significant risk factor for disease progression and increases the risk of disease recurrence. Patients with multiple PTC are more likely to have ETE and CLNM ( 50 , 51 ), and the use of AS for multiple PTC is still controversial ( 52 , 53 ). DM of PTC is uncommon, but is associated with PTC aggressiveness, and DM in thyroid cancer significantly reduces survival in PTC patients ( 41 , 54 , 55 ).…”