|Ahead of print publication
Assessment of preoperative thyroglobulin levels in papillary thyroid cancer
Mehmet Ali Melik1, Ilyas Baskonus2, Latif Yilmaz2
1 General Surgery, Kilis State Hospital, Kilis, Turkey
2 Department of General Surgery, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey
|Date of Submission||29-Aug-2020|
|Date of Decision||02-Sep-2020|
|Date of Acceptance||12-Jan-2021|
|Date of Web Publication||24-Jul-2021|
Mehmet Ali Melik,
Kilis State Hospital, Kilis
Source of Support: None, Conflict of Interest: None
Background: The papillary thyroid cancers (PTCs) are the most common cancer of endocrine cancers. The primary treatment is surgery, and the prognosis is mostly well. In spite of many methods for the early diagnosis, the simpler and noninvasive methods are being sought. The aim of this study is to find out whether the value of thyroglobulin (Tg) is related with PTC.
Materials and Methods: Prospectively; we measured the preoperative Tg value of 203 (159 females and 44 males) patients who underwent a total thyroidectomy with various indications in General Surgery Department of Gaziantep University. Tg values of 61 patients with benign lesions and 142 patients with PTC were compared.
Results: In the patients with PTC, the mean preoperative Tg value was 105.05 ng/ml and 76.80 ng/ml in the benign patients. According to receiver operating characteristic analysis, the cutoff point was determined 102 ng/ml. There was a statistically significant difference in preoperative Tg values between benign group and PTC (P < 0.05).
Conclusion: Patients with a preoperative Tg values above 102 ng/mL may more likely to have PTC. It is thought that Tg levels may be accepted as a criterion for distinguish malignant/benign situations that should be supported with new studies.
Keywords: Papillary thyroid cancers, thyroglobulin, thyroid
| > Introduction|| |
The most common malignancy of endocrine system is thyroid cancers. Thyroid cancers develop from epithelial and nonepithelial parts of thyroid tissue. Papillary, follicular, and anaplastic type thyroid cancers originate from the follicular epithelium of the thyroid. Other thyroid cancers are the medullary thyroid cancer, primary lymphoma, sarcoma, and metastases., In differentiated thyroid carcinoma, 49% of all metastases are lung metastases, 24% are bone metastases, 19% are diffuse metastases, and 8% are solitary other organ metastases. Apart from these, multiple endocrine neoplasia and isolated familial medullary thyroid cancers may be also seen.
Papillary thyroid cancer (PTC) is the most common (80%) type among thyroid cancers. In all age groups, except childhood, thyroid cancers are three times more common in women than men.
In the evaluation of papillary thyroid neoplasms for distinguish benign or malignant, thyroglobulin (Tg) levels can be measured in peripheral blood. Tg level is valuable in detecting local or metastatic recurrence after total thyroidectomy in well-differentiated thyroid carcinomas. Tg measurement is a sensitive biochemical method in determining persistent tumor and used routinely in the follow-up of PTC.
Tg takes a role in the conversion of MIT and DIT to T3 and T4. During this procedure, Tg leaks into the peripheral blood circulation. The level of Tg which leaks to the peripheral blood circulation during this process is measured.
In the study, we aimed to show the correlation of preoperative Tg levels between patients who underwent thyroidectomy for PTC and for other benign thyroid diseases.
| > Materials and Methods|| |
Patients operated between September 2016 and December 2017 as a result of XXX University Surgery-Endocrine Council decision were included in the study. The patients were who had malignant/suspicious fine-needle aspiration biopsy results, toxic goiter, and symptoms of compression.
The patients were informed about the study before the operation and their informed consent was obtained.
Patients' age, gender, additional diseases, and whether they were exposed to radiation were recorded. Patients' Tg levels were measured from blood 1 day before the surgery. Total thyroidectomy was performed to the patients.
After the pathology results of the patients who underwent preoperative Tg measurement and then total thyroidectomy were screened, 142 patients who were diagnosed with PTC were included. Patients with the same conditions but without a pathological diagnosis of malignancy were included as the control group. One hundred and forty-two patients with papillary thyroid carcinoma from the malignant group were selected. This group was classified according to histological subtype, tumor diameter, and capsule presence. Sixty-one patients with benign pathology results were also determined as the control group. Preoperative Tg levels and pathology results of patients were compared.
Shapiro–Wilk test, Student's t-test, Mann–Whitney U–test, Kruskal–Wallis test, and Chi-square test were used to evaluate the data. Multiple binary logistic regression analysis was performed, and the effect of age was resolved in investigating the relationship between preoperative Tg values and malignancy. IBM SPSS Statistics 22.0 version program New York, United States, was used for statistical analysis and P < 0.05 was considered statistically significant.
| > Results|| |
The preoperative Tg value was found 105.05 ng/ml in the PTC group and 76.80 ng/ml in the control group. 102 ng/ml value was calculated as the cutoff point by receiver operating characteristic (ROC) analysis. The distribution of age-related Tg values was calculated, and there was a significant difference [Table 1].
|Table 1: Distribution of papillary thyroid cancers and benign patients by age|
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Serum Tg level was measured as 76.80 ng/ml in benign group and 105.05 ng/ml in patients with PTC [Table 2]. A significant difference was observed between the preoperative Tg values of PTC and benign group (P < 0.05) [Figure 1].
|Figure 1: Preoperative thyroglobulin values between papillary thyroid cancers and benign group|
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With the ROC curve, the cut point was tried to determine for distinguishing PTC and control group [Figure 2]. The cutoff point was found as 102 ng/ml. The specificity was 68.85, and the sensitivity was 50.00.
|Figure 2: Comparison of preoperative thyroglobulin values with receiver operating characteristic curve|
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| > Discussion|| |
In a study conducted by Petric et al. in 2011, similar to our study, it was shown that preoperative Tg levels were higher in PTC than benign groups. It was concluded that this could be an independent parameter to reduce complementary thyroidectomy operations.
According to the study conducted by Lee et al. in 2012 with 800 case series, malignant patients' Tg levels are significantly higher. In this study, even a cutoff point (188 ng/ml) was determined for follicular carcinoma. Although PTC has not been studied in this study, the high Tg levels of malignant patients are a supportive result for our study. Although this study provides superiority to our research because of the case number, our research is more specific because it is for papillary cancer.
In 2014, Oltmann et al. stated that the preoperative Tg value may be an important factor in determining metastatic thyroid cancers. Although the method of this long-term retrospective study is different, it is similar to our research in terms of its results.
In the study involving McGill scoring by Scheffler et al., the probability of the thyroid nodule to be malignant was tried to be determined., Moreover, the inclusion of the preoperative Tg levels in scoring has been shown to increase the sensitivity of scoring. This result also supports our study.
In 2014, Rinaldi et al. conducted a study on 1124 patients and found that preoperative Tg level was higher in malignant patients therewithal concluded that it was more significant in the follicular carcinoma group than papillary carcinomas. Although it provides superiority, it supports our study.
In 2017, Kim et al. in a study especially on distant metastases, they found different Tg levels on lung and bone metastases and showed that preoperative Tg levels may be used for staging in papillary and follicular carcinomas. These results also support our research, and even because our research is prospective, it provides superiority to this research.
It is stated in the one of the widest compilations made by Trimboli et al. which includes 3500 cases and 13 studies, that the only preoperative Tg values may fail to distinguish benign/malignant. However, they also stated that Tg may be an indicator of malignancy. This study, which seems to be similar to our research, has been a valuable support to our research with the high number of cases.
Eventually, the preoperative Tg levels were found significantly higher in papillary thyroid carcinomas. In the light of all these studies, we try to emphasize the importance of preoperative Tg values.
| > Conclusion|| |
As a result, it was concluded that preoperative serum Tg levels may be useful for distinguishing malignant-benign situations, and in this way, secondary operations may not be required in malignant patients.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]