Could Tumor Size Be A Predictor for Papillary Thyroid Microcarcinoma: a Retrospective Cohort Study

Abstract

Background: Central lymph node metastasis(CLNM) is common in papillary thyroid microcarcinoma (PTMC). The aim of this study was to define the pathohistologic risk grading based on surgical outcomes. Materials and Methods: Statistical analysis was performed to figure out the optimal cut-off values of size in preoperative ultrasound images for defining the risk of CLNM in papillary thyroid microcarcinoma. Receiver operating characteristic curves (ROC) studies were carried out to determine the cutoff value(s) for the predictor(s). All the patients were divided into two groups according to the above size and the clinic-pathological and immunohistochemical parameters were compared to determine the significance of findings. Results: The optimal cut-off value of tumor size to predict the risk of CLNM in papillary thyroid microcarcinoma was 0.575 cm (area under the curve 0.721) according to the ROC curves. Significant differences were observed on the multifocality, extrathyroidal extension and central lymph node metastasis between two groups which were divided according to the tumor size by the cutoff values. Patients in two groups showed different positive rate and intensity of Ki67. Conclusions: The size of PTMC in ultrasound images are helpful to predict the aggressiveness of the tumors, it could be an easy predictor for PTMC prognosis and assist us to choose treatment.

A favorable tumor size to define papillary thyroid microcarcinoma: an analysis of 1176 consecutive cases

“…Although PTMC is considered an indolent cancer with relatively benign biologic behavior and an excellent prognosis, certain aspects of PTMC biologic behavior are quite poor, which may present as lymph node metastasis, distant metastasis, recurrence, and may even cause death. 22 – 24 As the reported mortality rate of PTMC ranges from 0% to 1% and presents relatively benign biologic behavior, 8 some researchers reported that PTMC should not be overtreated. Rather, periodic observation without surgical treatment 1 has been suggested, and in the American Thyroid Association and the British Thyroid Association guidelines, lobectomy was described as the primary operative management of PTMC without aggressive features, for example, extrathyroidal extension, multifocality, and central or lateral lymph node metastasis; 25 , 26 moreover, prophylactic central lymph node dissection was not recommended without a suspicious enlarged lymph node in the treatment of PTC 27 because it provides no survival benefit 28 and may even increase the incidence of postoperative complications.…”

“…In previous studies, investigators have attempted to identify the tumor diameter cut-off value predictive of aggressiveness by ROC curves in PTMC (tumor size ≤10 mm) and have proposed a further subdivision of PTMC by cut-off point related to lymph node metastasis to guide management of these minute lesions. 8 , 9 This proposal has had highly variable results, with some studies reporting that tumors ≤5 mm are less likely to metastasize, while other studies have reported a cut-off of 6, 7, or 8 mm. 37 – 39 …”

“… 6 Importantly, as there is still no consensus regarding the optimal treatment strategy for PTMC, the management of PTMC ranges from observation alone to total thyroidectomy plus central lymph node dissection and postoperative radioiodine ablation therapy. 7 Some investigators proposed a further subdivision of PTMC to aid optimal treatment selection, such as “micromini” 8 or “minute” 9 for foci 5 mm in diameter or less. Collectively, the reason for the persistent controversy is our inability to accurately predict the aggressiveness of PTMC tumors and choose the optimal individualized management for those patients before surgery.…”

Values of ultrasound features and MMP-9 of papillary thyroid carcinoma in predicting cervical lymph node metastases

“…Recent studies showed that US features may be also useful in predicting the biological behaviors of PTC. As the tumor size on ultrasound images is the most available preoperative parameter, someone reported 26 that the maximum diameter of tumor was associated with a significantly increased risk of cervical LNM. Our results was in accord with this opinion, and the optimal cut-off value of tumor size obtained based on the ROC curve was 0.95 cm (AUC = 0.72).…”

Papillary thyroid microcarcinoma (Black Ink)

“…Wang et al claim that the size of PTMC in ultrasound images are helpful to predict the aggressiveness of the tumors, it may become an easy predictor for PTMC prognosis and assist us to choose treatment (Wang et al, 2015) [ 45 ].…”