Which papillary thyroid microcarcinoma should be treated as “true cancer” and which as “precancer”?

Abstract

Background Papillary thyroid microcarcinoma (PTMC) generally is a cancer with excellent prognosis, but the term “cancer” sounds severe and harsh, which can elicit emotional and physical responses from patients. To eliminate the word “cancer,” the term noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was introduced. However, not all PTMCs can be classified as NIFTP. Sometimes, very aggressive PTMC cases might be observed. Some authors suggest that one of the risk factors for poor prognosis is lymph node metastasis. The aim of the study was to evaluate some clinicopathological features of PTMC as the risk factors for lymph node metastasis. Material and methods We performed a retrospective chart review and selected 177 patients with PTMC. To analyze the cases with potentially aggressive behavior, we enrolled PTMC patients with lymph node metastases (pN1, central, and/or lateral) and evaluated some of their clinicopathological features. Results The logistic regression analysis results demonstrated significantly higher rates of multifocal or bilateral tumor occurrence in the PTMC patients with pN1 than in the patients with pN0 ( P < 0.0001 for both). In addition, the occurrence of thyroid tumors with sizes above 0.5 cm was a significant risk factor for lymph node metastasis ( P < 0.0001). The results of the ROC analyses showed that the presence of multifocal or bilateral tumors and tumor sizes above 0.5 cm were significant predictors of lymph node metastasis ( P < 0.0001 for all). Conclusions Multifocal and bilateral PTMC tumors with diameters above 0.5 cm should be treated aggressively as “true cancer” and might benefit from lymph node dissection. Unifocal PTMC tumors with diameters equal to or below 0.5 cm may be treated less aggressively.

Risk factors of papillary thyroid microcarcinoma that predispose patients to local recurrence

“…Next, we analyzed demographic and ultrasound features and compared them with histopathological characteristics. Some of them are considered pathognomonic for aggressive PTMC entities [ 9 ]. Univariate and multivariate logistic regression analyses were used to determine the relationships of demographic and ultrasound features with histopathological characteristics such as minETE, capsular and vascular invasion and LNM.…”

Cancer screening activity results in overdiagnosis and overtreatment of papillary thyroid cancer: A 10-year experience at a single institution

“…General practitioners' easy access to some high-quality imaging tests in their practices may also be responsible for this situation. Additionally, in Poland, we also observed that easy access to healthcare, such as additional private insurance, increases the rate of new diagnoses of small PTC tumors [8].…”

“…The next argument for the overdiagnosis and overtreatment of PTC is its very low recurrence rate after surgery [8]. In this study, we estimated that none of CSA-yes patients in whom PTC was diagnosed after surgery showed any signs of disease recurrence, while 17.8% of patients diagnosed with PTC based on clinical symptoms showed signs of TC recurrence.…”

“…Because of the harm potentially caused by overdiagnosis, the US Preventive Services Task Force has updated its recommendation to prevent routine screening activity for TC (D level recommendation) [5]. In addition, patients should be informed about their excellent prognosis, especially in cases of PTMC, and potential adverse events, which may manifest after surgical treatment [8].…”

“…The answer to these questions may be that in the case of PTC management, a screening program would cause overdiagnosis and overtreatment. However, omitting the overall statistical results [7], it is extremely difficult to judge whether an individual diagnosed with papillary thyroid microcarcinoma (PTMC) falls under the category of overdiagnosis [8]. Of course, we are aware of the potential excellent prognosis of PTC; however, in some cases, highly aggressive entities might be observed [9].…”