Prognostic factors for follicular thyroid carcinoma: the importance of vascular invasion

Management of thyroid tumors diagnosed cytologically as follicular neoplasms in a high-volume center: utility of a scoring system using serum thyroglobulin level, tumor size, ultrasound testing, and cytological diagnosis

Managing thyroid nodules diagnosed cytologically as follicular neoplasms (FN) is challenging for patients and clinicians. Gene panel testing was recently introduced to determine the management strategy for FN; however, it is unavailable in Japan. In this study, we assessed FN management. This study included 2,144 FNs from 2,067 patients diagnosed between 2012 and 2018. Of these, 952 (44.5%) tumors underwent active surveillance, and 1,188 (55.6%) underwent immediate surgery (IS). Tumors of young patients (<55 years), male patients, and patients with serum thyroglobulin (Tg) ≥500 ng/mL, ultrasound diagnoses as FN or malignancy, large tumors (>4 cm), non-oxyphilic cytology, and cytological findings favoring malignancy and multiplicity underwent IS more frequently. Of the 1,412 tumors that underwent surgery, 279 (19.8%) and 1,133 (80.2%) were pathologically diagnosed as malignant and benign tumors or low-risk neoplasms, respectively. High Tg levels, non-benign ultrasound findings, cytological findings favoring malignancy, non-oncocytic cytology, and large tumor size were related to malignant pathology; however, tumor enlargement was not. The former three were independent predictors of malignancy in the multivariate logistic analysis. After assigning scores of 2 and 1 for cytological findings favoring malignancy and others, respectively, a receiver operating characteristic curve analysis indicated a score of 3 as the optimal cutoff for predicting malignant diagnosis; however, the area under the curve remained low, at 0.642. Accurately predicting the malignant pathology of FNs is challenging, and inducing gene panel testing will be helpful for managing FN tumors. Our scoring system would also be useful in estimating the risk of malignancy.

Prognostic impact of fibrosclerotic changes in non-papillary, non-anaplastic, follicular cell-derived thyroid carcinomas

In non-papillary follicular cell-derived thyroid carcinomas, prognostic factors are scarce. Intratumoral fibrosis was identified as an adverse factor in papillary and medullary carcinomas, but it has not been investigated in other subtypes. We aimed at exploring the presence of intratumoral fibrosclerosis in a cohort of 132 non-papillary follicular cell-derived thyroid carcinomas (53 follicular and 31 oncocytic carcinomas, including 10 high grade differentiated thyroid carcinomas and 48 poorly differentiated carcinomas) and correlating its presence and extent with clinical and pathological features and survival. For each case, all available hematoxylin and eosin slides were reviewed, and the presence of fibrosclerosis was assessed as the percentage of tumor area and semi-quantitatively scored as absent, mild (≤ 10%) or extensive (> 10%). In addition, digital image analysis was applied in 65 cases. Scoring of intratumoral fibrosis showed a strong agreement between two observers and between observers and digital image quantification. The presence and extent of intratumoral fibrosis were significantly associated with poorly differentiated carcinoma histology, large tumor size, extent of vascular invasion, presence of necrosis, high mitotic index, positive nodal status, and aggressive clinical outcome, and with a shorter disease-free and disease-specific survival, the former also in follicular and oncocytic carcinomas analyzed separately. These data support the potential use of fibrosis in the clinical practice since it is both easily assessable and significantly associated with the presence of parameters of aggressiveness. In addition, fibrosis is correlated with decreased survival rate independently from the tumor histotypes, suggesting its potential role as novel prognostic factor in non-papillary follicular cell-derived thyroid carcinomas.

Prognostic Factors for Cancer-Specific Survival and Disease-Free Interval in 130 Patients with Follicular Thyroid Carcinoma: Single Institution Experience

BACKGROUND

Follicular thyroid carcinoma (FTC) is categorized into three groups: minimally invasive FTC (MIFTC), encapsulated angioinvasive FTC (EAIFTC), and widely invasive FTC (WIFTC). FTC is the second most common type of thyroid tumor, though it remains relatively rare in the general population. This study aimed to examine the prognosis and prognostic factors in patients with follicular thyroid carcinoma.

METHODS

Data were obtained from a tertiary referral center for 130 FTC patients, covering the period from 1995 to 2020. Clinical data included demographic characteristics, tumor features, type of surgery, tumor recurrence, and vital status. Descriptive statistical methods, Kaplan-Meier survival curves, and Cox proportional hazard regression were used for statistical analysis to identify independent predictors.

RESULTS

Distant metastases occurred in 12 patients during the follow-up period. The 5-year, 10-year, 15-year, and 20-year cancer-specific survival (CSS) rates were 98.1%, 92.3%, 83.5%, and 79.8%, respectively. Independent unfavorable prognostic factors for CSS included widely invasive tumor type (hazard ratio [HR] 3.63, 95% CI 1.29-10.18), multifocality (HR 6.7, 95% CI 1.37-32.72), and presence of distant metastases (HR 2.29, 95% CI 1.08-4.84). When disease-free interval (DFI) was considered, the 5-year, 10-year, 15-year, and 20-year rates were 92.3%, 85.3%, 82.0%, and 76.6%, respectively. Independent unfavorable prognostic factors for DFI were widely invasive tumor type (HR 2.53, 95% CI 1.02-6.28) and tumor multifocality (HR 7.69, 95% CI 1.07-55.17).

CONCLUSIONS

The 10-year survival rate for patients with FTC is relatively favorable. Factors associated with poorer prognosis include the presence of distant metastases, WIFTC, and multifocality. Factors linked to disease recurrence are WIFTC and multifocality.

Predictive value of serum HIF-1α/HIF-2α and YKL-40 levels for vascular invasion and prognosis of follicular thyroid cancer

OBJECTIVE

This study investigated the significance of serum hypoxia-inducible factor (HIF)-1α/HIF-2 α and Chitinase 3-Like protein 1 (YKL-40) levels in the assessment of vascular invasion and prognostic outcomes in patients with Follicular Thyroid Cancer (FTC).

METHODS

This prospective study comprised 83 patients diagnosed with FTC, who were subsequently categorized into a recurrence group (17 cases) and a non-recurrence group (66 cases). The pathological features of tumor vascular invasion were classified. Serum HIF-1α/HIF-2α and YKL-40 were quantified using a dual antibody sandwich enzyme-linked immunosorbent assay, while serum Thyroglobulin (Tg) levels were measured using an electrochemiluminescence immunoassay method. The Spearman test was employed to assess the correlation between serum factors, and the predictive value of diagnostic factors was determined using receiver operating characteristic curve analysis. A Cox proportional hazards regression model was utilized to analyze independent factors influencing prognosis.

RESULTS

Serum HIF-1α, HIF-2α, YKL-40, and Tg were elevated in patients exhibiting higher vascular invasion. A significant positive correlation was observed between Tg and HIF-1α, as well as between HIF-1α and YKL-40. The cut-off values for HIF-1α and YKL-40 in predicting recurrence were 48.25 pg/mL and 60.15 ng/mL, respectively. Patients exceeding these cut-off values experienced a lower recurrence-free survival rate. Furthermore, serum levels surpassing the cut-off value, in conjunction with vascular invasion (v2+), were identified as independent risk factors for recurrence in patients with FTC.

CONCLUSION

Serum HIF-1α/HIF-2α and YKL-40 levels correlate with vascular invasion in FTC, and the combination of HIF-1α and YKL-40 predicts recurrence in patients with FTC.

Correlation of pN Stage and Hypoechogenicity with Tumour Encapsulation and Vascular Invasion in Thyroid Cancer (TC): A Comprehensive Analysis and Clinical Outcomes

In this retrospective study, the relationship between the pN stage of TC and the ultrasound hypoechogenicity of tumour encapsulation and vascular invasion was investigated. The data of a total of 678 TC patients were analysed. The goal of this study was to assess the significance of the pTNM score and preoperative ultrasound features in predicting cancer prognosis and guiding therapeutic decisions in patients with TC. The main research methods included a retrospective analysis of patient data, mainly the pTNM score and presence of tumour encapsulation and vascular invasion obtained from histopathological results and preoperative ultrasound imaging. Patients with well-differentiated TCs (papillary and follicular) were extracted from TC patients to better unify the results because of similar clinical strategies for these TCs. Significant associations were observed between advanced pN stage and the presence of encapsulation and vessel invasion. The majority of pN1a patients exhibited encapsulation (77.71%; p < 0.0001) and vascular invasion (75.30%; p < 0.0001), as did the majority of pN1b patients (100%; p < 0.0001 and 100%; p < 0.0001, respectively). Less than half of the patients with hypoeghogenic patterns presented with encapsulation (43.30%; p < 0.0001) and vascular invasion (43.52%; p < 0.0001), while the vast majority of patients without hypoechogenicity did not present with encapsulation (90.97%; p < 0.0001) or vascular invasion (90.97%; p < 0.0001). Hypoechogenicity was found to be indicative of aggressive tumour behaviour. The results of this study underscore the importance of accurate N staging in TC and suggests the potential use of ultrasound features in predicting tumour behaviour. Further research is needed to confirm these findings and explore additional prognostic markers to streamline TC management strategies and improve patient outcomes.

Role of the Degree of Vascular Invasion in Predicting Prognosis of Follicular Thyroid Carcinoma

OBJECTIVE

The present study investigated the prognostic factors for follicular thyroid carcinoma (FTC) with the incorporation of the histologic subtype and degree of vascular invasion (VI).

PATIENTS

The records of 474 patients with FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were reviewed in this retrospective cohort study. The Cox proportional hazard model was used to determine factors associated with disease-free survival (DFS) and distant metastasis-free survival.

RESULTS

Of the 474 patients, 140 (30%) had minimally invasive FTC, 260 (55%) had encapsulated angio-invasive FTC, and 74 (16%) had widely invasive FTC. Among the 428 patients with M0 FTC, the 10-year DFS rates of patients with minimally invasive FTC (n = 133), encapsulated angio-invasive FTC (n = 247), and widely invasive FTC (n = 48) were 97.3%, 84.2%, and 69.9% (P < .001), respectively. A multivariate analysis identified aged ≥55 years (hazard ratio [HR], 2.204; 95% CI, 1.223-3.969; P = .009), histologic subtype (HR, 2.068; 95% CI, 1.064-4.021; P = .032), VI of ≥2 (HR, 6.814; 95% CI, 3.157-14.710; P < .001), and tumor size >40 mm (HR, 2.014; 95% CI, 1.089-3.727; P = .026) as independent negative prognostic factors for DFS.

CONCLUSION

Our study results may enable us to stratify the prognosis of FTC more accurately by combining the histologic subtype with the degree of VI ≥2, aged ≥55 years, and tumor size >40 mm.

Prognosis and influencing factors of follicular thyroid cancer

OBJECTIVES

Follicular thyroid cancer (FTC) is prone to distant metastasis, and patients with distant metastasis often have poor prognosis. In this study, the impact of metastasis and other relevant factors on the prognosis of follicular thyroid carcinoma was examined.

METHODS

This was a retrospective study. Data were obtained from Zhejiang Cancer Hospital, Sun Yat-sen University Cancer Center and Hangzhou First People's Hospital affiliated with Zhejiang University School of Medicine, from January 2009 to June 2021 for 153 FTC patients. The patients were assigned into three groups according to their distant metastasis: distant metastasis at initial diagnosis (M1), distant metastasis during follow-up (M2), and no evidence of distant metastasis over the course of the study (M0). Data were collected and summarized on clinical data, laboratory parameters, imaging features, postoperative pathologic subtypes, and metastases. The Cox proportional hazard model was used to perform the univariate and multivariate analysis. Kaplan-Meier curves were used to evaluate cancer-specific survival (CSS).

RESULTS

Based on metastasis, the patients were assigned into three groups, including 31 in the M1 group, 15 in the M2 group, and 107 in the M0 group. These individuals were followed up for an average of 5.9 years, and the group included 46 patients with distant metastasis (31 confirmed at diagnosis and 15 found during follow-up). Univariate Cox regression analysis showed that age, Hashimoto's thyroiditis (HT), surgery method, postoperative adjuvant therapy, histologic subtype, nodule size, calcification, TSH, and distant metastasis all impacted prognosis. Multivariate Cox regression analysis suggested that histologic subtype (widely invasive; HR: 7.440; 95% CI: 3.083, 17.954; p < 0.001), nodule size (≥40 mm; HR: 8.622; 95% CI: 3.181, 23.369; p < 0.001) and distant metastasis (positive; HR: 6.727; 95% CI: 2.488, 18.186; p < 0.001) were independent risk factors affecting the prognosis of follicular thyroid cancer.

CONCLUSIONS

Histologic subtype, nodule size, and distant metastasis are important risk factors for the prognosis of follicular thyroid cancer. Patients with metastatic follicular thyroid cancer have a poor prognosis, especially with metastasis at the time of initial diagnosis. As a result, this group of patients requires individualized treatment and closer follow-up.

New Insights on the Importance of the Extent of Vascular Invasion in Widely Invasive Follicular Thyroid Carcinoma

BACKGROUND

This study aimed to investigate the association between the extent of vascular invasion (VI) and the outcome of widely invasive follicular thyroid carcinoma (WI-FTC).

METHODS

The records of 107 patients with WI-FTC confirmed by surgical specimens from January 2005 to December 2016 were retrospectively reviewed.

RESULTS

Among the 107 patients with WI-FTC, those with a VI of < 4 (n = 62) and ≥ 4 (n = 45) had a 10 year cause-specific survival (CSS) rate of 97.7% and 89.4% (p = 0.008), respectively. Univariate analysis identified M1 (p = 0.001), and the number of VI of ≥ 4 as significant negative prognostic factors for CSS. Multivariate analysis identified M1 (hazard ratio [HR] = 9.366) as independent negative prognostic factor for CSS. Among the 72 patients with M0 WI-FTC, those with a VI of < 2 (n = 33) and ≥ 2 (n = 39) had a 10-year distant metastasis-free survival (DMFS) rate of 96.8% and 56.8% (p = 0.001), respectively. Univariate analysis identified age ≥ 55 years (p = 0.011), presence of VI, the number of VI of ≥ 2, and resection margin status (p < 0.001) as significant negative prognostic factors for DMFS. Multivariate analysis identified the number of VI ≥ 2 (HR = 9.137), and resection margin status (HR = 5.853) as independent negative prognostic factors for DMFS.

CONCLUSIONS

It may be unnecessary that WI-FTC with curative resection margin status and a VI of < 2, especially in capsular invasion only, routinely undergo completion thyroidectomy and postoperative ablation.

The Prognostic Impact of Extent of Vascular Invasion in Follicular Thyroid Carcinoma

BACKGROUND

Encapsulated angioinvasive follicular thyroid carcinoma (EAFTC) is associated with an increased risk of distant metastasis and reduced survival compared to minimally invasive follicular thyroid carcinoma (MIFTC). There is controversy regarding the extent of surgery and adjuvant radioactive iodine therapy for angioinvasive follicular thyroid carcinoma when stratified by number of foci of angioinvasion.

METHODS

All follicular thyroid carcinoma cases from 1990-2018 were identified from a thyroid cancer database. Primary outcomes were distant metastasis-free survival (DMFS) and disease-specific survival (DSS) with factors of interest being age, gender, tumour size, treatment, foci of angioinvasion and histological subtype.

RESULTS

A total of 292 cases were identified; 139 MIFTC, 141 EAFTC and 12 widely invasive follicular thyroid carcinoma (WIFTC). Over a follow-up period of 6.25 years, DMFS was significantly reduced (p < 0.001) with 14.2% (EAFTC) and 50% of WIFTC developing metastasis. The risk of metastasis in EAFTC with ≥ 4 foci of angioinvasion was 31.7% (HR = 5.89, p = 0.004), 6.3% for EAFTC with < 4 foci of angioinvasion (HR = 1.74, p = 0.47), compared to 3.6% MIFTC. Age ≥ 50 years (HR = 4.24, p = 0.005) and tumour size (HR = 1.27, p = 0.014) were significantly associated with increased risk of distant metastasis. DSS was reduced significantly (p < 0.001), with 7.8% EAFTC patients dying of disease. For EAFTC patients, DSS was 96.8% for < 4 foci and 82.6% for ≥ 4 foci of angioinvasion (p = 0.003).

CONCLUSION

EAFTC is at increased risk of distant metastasis related to the extent of angioinvasion. Tumours with < 4 foci of angioinvasion should be considered for a total thyroidectomy, particularly in older patients.