Ultrasonographic differentiation of cervical lymph nodes in patients with papillary thyroid carcinoma after thyroidectomy and radioiodine ablation: a prospective study

A roadmap for a comprehensive diagnostic approach to fine needle cytology of lymph node metastases

OBJECTIVE

Fine needle cytology (FNC) is widely used as a first-line procedure in the diagnostic algorithm of lymphadenopathies. In a metastatic setting, a first-line diagnostic approach identifies non-haematopoietic malignancy; however, cytopathologists could also provide a second diagnostic level, identifying the origin of the primary tumour. This paper outlines a comprehensive and practical approach to the cytological diagnosis of lymph node metastases.

METHODS

Cytological diagnoses of lymph node metastases performed over a 10-year period were selected and divided into two groups. The first group, labelled "oncological," comprised patients with a previous history of malignancy; the second group, labelled "naïve," included patients with no relevant history. Pathology records were retrieved to record microscopic findings, namely, background appearance, group architecture, and specific cell features; data from cell block (CB) preparations were also collected.

RESULTS

Overall, 982 cases were selected: 497 cases (50.61%) in the naïve group, and 485 (49.39%) in the oncological group. Overall, a second diagnostic level was achieved in 834/982 cases (84.92%); cases diagnosed as carcinoma not otherwise specified were more frequent in the naïve group than in the oncological group (17.51% vs. 8.04%, P < 0.01). Notably, although CB material was available in only 44.87% of the naïve cases, we were able to achieve a second diagnostic level thanks to the integration of clinical and cytomorphological findings, plus lymph node topography, in 82.49% of the cases.

CONCLUSION

Our results confirmed that in a metastatic setting, FNC can reliably lead to the identification of the origin of the primary tumour.

Natural history, predictive factors of apparent disease (structural or biochemical) and spontaneous excellent response in patients with papillary thyroid carcinoma and indeterminate response to initial therapy with radioiodine

BACKGROUND

About 20% of patients with papillary thyroid carcinoma (PTC) submitted to total thyroidectomy followed by radioactive iodine (RAI) exhibit an indeterminate response to therapy. The aim was to evaluate the natural history, predictive factors of apparent disease (structural or biochemical), and spontaneous excellent response in patients with PTC and an initial indeterminate response to RAI therapy defined based on unstimulated Tg (u-Tg).

METHODS

We evaluated 164 patients who were initially treated with total thyroidectomy and RAI and who had an indeterminate response to therapy (u-Tg between 0.2 and 1 ng/ml, undetectable anti-Tg antibodies [TgAb], and neck ultrasonography [US] without anomalies). None of the patients received empirical therapy with RAI. The patients were followed up for 24 to 144 months (median 72 months).

RESULTS

Apparent disease occurred in 16 patients (9.7%), including 13 with structural disease and 3 with u-Tg elevation > 1 ng/ml, but no tumor was detected by the imaging methods (biochemical disease). A higher frequency of disease was observed in patients with >3 lymph node metastases (LNM) and initial u-Tg >0.35 ng/ml. The frequency was only 2% among patients with ≤3 LNM and u-Tg ≤0.35 ng/ml and 9.7% among patients with > 3 LNM or u-Tg >0.35 ng/ml, while the frequency was 27% in patients with >3 LNM and u-Tg >0.35 ng/ml. In the absence of any additional therapy, u-Tg was <0.2 ng/ml (excellent response) in the last assessment in 70 patients (42.7%). Only initial u-Tg was associated with a higher probability of spontaneously achieving an excellent response: 40/72 patients (55.5%) with u-Tg ≤0.35 ng/ml versus 30/92 patients (32.6%) with u-Tg >0.35 ng/ml.

CONCLUSIONS

A minority of patients with PTC and an initial indeterminate response to RAI defined based on u-Tg develop apparent disease (structural or biochemical) and many spontaneously achieve an excellent response. The risk of disease can be refined based on parameters such as the extent of lymph node involvement and initial Tg concentration.

A comparison of the efficiency of diagnostic ultrasound and magnetic resonance imaging of cervical lymph nodes in papillary thyroid carcinoma

OBJECTIVE

To compare and evaluate diagnostic capabilities of preoperative ultrasonography (US) and magnetic resonance imaging (MRI) in the cervical lymph nodes of patients with papillary thyroid cancer.

METHODS

A retrospective dataset involving 156 patients who had undergone thyroidectomy and preoperative US and MRI was assembled. Among these, 69 had cervical lymph node metastasis and 87 did not. At least four radiologists unilaterally and spontaneously investigated the US and MRI attributes of the cervical lymph nodes. The efficiency of diagnostic imaging for cervical lymph nodes, including their true-positive rate or sensitivity, true-negative rate or specificity, positive predictive value, negative predictive value, and predictive accuracy were analysed and assessed.

RESULTS

In the assessment of cervical lymph node metastases of papillary thyroid cancer, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of diagnostic US vs. MRI were 58.0% vs. 79.7%, 69.0% vs. 83.9%, 59.7% vs. 79.7%, 67.4% vs. 83.9%, and 64.1% vs. 82.1%, respectively. The accuracy consistency of the two imaging modalities was 83.5%.

CONCLUSIONS

MRI is more effective than US in diagnosing and assessing cervical lymph node metastases of papillary thyroid cancer.

Can patients with papillary thyroid carcinoma and low postoperative thyroglobulin in the presence of clinically apparent lymph node metastases (cN1) be spared from radioiodine?

BACKGROUND

The study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) and clinically apparent lymph node metastases (LNM) (cN1) who had low thyroglobulin (Tg) after total thyroidectomy and who were not submitted to adjuvant therapy with ¹³¹I.

METHODS

This was a prospective study. It included 82 cN1 patients (≤3 LNM ≤1.5 cm without macroscopic extracapsular extension) with tumors ≤4 cm without macroscopic extrathyroid invasion (T1-2) and who after thyroidectomy had unstimulated Tg (u-Tg) < 0.3 ng/ml, negative antithyroglobulin antibodies (TgAb), and neck ultrasonography (US) showing no anomalies. The patients were not submitted to therapy with ¹³¹I.

RESULTS

The time of follow-up ranged from 24 to 156 months (median 84 months). Seventy-nine patients (96.3%) continued to have u-Tg < 0.3 ng/ml and negative US. Three patients (3.6%) exhibited an increase in Tg and structural recurrence was detected in two. After treatment, these patients achieved u-Tg < 1 ng/ml and the imaging methods revealed no apparent tumor.

CONCLUSIONS

The results suggest that even cN1 patients, given the absence of extensive LNM or other adverse findings, who have low Tg and neck US showing no anomalies after thyroidectomy do not require radioiodine.

Role of adjuvant therapy with radioactive iodine in patients with elevated serum thyroglobulin after neck reoperation due to recurrent papillary thyroid cancer: a monoinstitutional comparative study

BACKGROUND

Most patients with papillary thyroid cancer (PTC) and lymph node metastases (LNM) undergoing reoperation do not show apparent disease after this procedure, but serum thyroglobulin (Tg) continues to be elevated in part of them. This study evaluated adjuvant therapy with ¹³¹I in these patients.

METHODS

Patients with PTC and LNM diagnosed after initial therapy were selected. Patients undergoing reoperation and those without apparent disease after this procedure, but with nonstimulated Tg ≥1 ng/ml 6 months after reoperation, were included. The first 25 patients were submitted to therapy with ¹³¹I (groups A) and the subsequent 30 patients did not receive this therapy (group B).

RESULTS

Groups A and B were similar. During further follow-up, 21 patients developed structural disease and 34 continued without detectable disease (eight achieved complete remission). The outcomes were similar in groups A and B. Patients with Tg reduction >50% after reoperation tended to have a lower risk of recurrence (22.7 versus 48.5%), notably distant metastases (0 versus 15.1%), and were more likely to achieve complete remission (28 versus 3%). Patients with LNM FDG-positive had a higher risk of recurrence (54.5 versus 11.7%) and were less likely to achieve complete remission (3 versus 29.4%) after reoperation.

CONCLUSION

Our results suggest that therapy with ¹³¹I apparently does not prevent recurrences among patients who continue to have elevated Tg after neck reoperation. Further studies involving these patients are necessary, especially those who are at high risk of recurrence.

Value of Qualitative and Quantitative Contrast-Enhanced Ultrasound Analysis in Preoperative Diagnosis of Cervical Lymph Node Metastasis From Papillary Thyroid Carcinoma

OBJECTIVES

To investigate the qualitative and quantitative characteristics of contrast-enhanced ultrasound (CEUS) in assessing cervical lymph node metastasis from papillary thyroid carcinoma (PTC) and to evaluate its value in the preoperative diagnosis of cervical lymph node metastasis from PTC.

METHODS

A total of 55 lymph nodes in 46 patients were enrolled retrospectively, including 29 metastases from PTC and 26 normal/reactive ones. All lymph nodes were evaluated by conventional ultrasound (US) and CEUS before biopsy or surgery. A receiver operating characteristic curve analysis was used to analyze the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US and CEUS features in the diagnosis of lymph node metastasis as well as the overall diagnostic performance of US, CEUS, and a combination of the two.

RESULTS

Significant differences were found in the enhancement direction, enhancement type, and enhancement range between metastatic and normal/reactive lymph nodes on CEUS (P < .05). Quantitative CEUS parameters were not statistically significant (P > .05). The combination of US and CEUS had the highest diagnostic accuracy (92.7%) compared with US (80.8%) and CEUS (89.1%) alone in the diagnosis of lymph node metastasis from PTC.

CONCLUSIONS

The characteristics of cervical lymph node metastasis from PTC on CEUS include centripetal perfusion, peripheral or mixed enhancement, and an enlarged range on CEUS compared with US, and the first feature was the most meaningful. The combination of CEUS and US is a promising imaging tool for the preoperative diagnosis of cervical metastatic lymph nodes in patients with PTC.

Risk of recurrence in patients with papillary thyroid carcinoma and minimal extrathyroidal extension not treated with radioiodine

PURPOSE

This study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) and minimal extrathyroidal extension (mETE) who had low thyroglobulin (Tg) after total thyroidectomy, and therefore, did not receive radioactive iodine (RAI).

METHODS

This was a prospective study including 182 patients with tumors ≤ 4 cm and mETE without aggressive histology or clinically apparent lymph node involvement (cN0pNx). After thyroidectomy, all patients had nonstimulated Tg ≤ 0.3 ng/ml, negative antithyroglobulin antibodies (TgAb), and neck ultrasonography (US) showing no anomalies. Because of these results, the patients were not submitted to RAI.

RESULTS

The time of follow-up ranged from 24 to 132 months (median 72 months). One hundred and seventy-eight patients (97.8%) continued to have nonstimulated Tg ≤ 0.3 ng/ml and negative US. Four patients (2.2%) exhibited an increase in Tg and lymph node metastases (structural recurrence). After surgery, these patients obtained nonstimulated Tg < 1 ng/ml and no apparent tumor was detected by the imaging methods.

CONCLUSION

The results suggest that patients with mETE and without other adverse features, who have low nonstimulated Tg and negative neck US after thyroidectomy, do not require ablation with RAI.

Repeat Ultrasonography in the First Years after Therapy with Radioiodine Is Not Necessary in Most Patients with Papillary Thyroid Carcinoma when Postoperative Ultrasonography Is Negative: A Reduction of Costs and False-Positives

BACKGROUND

Periodic ultrasonography (US) examination is recommended in many patients with papillary thyroid carcinoma (PTC) after treatment with radioactive iodine (RAI), but recurrences are confirmed in few cases. This study determined whether the indication of US in the first years after treatment with RAI can be selective when postoperative US and posttherapy whole-body scanning (RxWBS) ruled out persistent neck disease.

METHODS

This was a prospective study. Two hundred and fifty-four patients with PTC (242 of intermediate risk) undergoing thyroidectomy and RAI, who had no apparent disease at the time of initial therapy (including negative postoperative US and RxWBS), were studied. The patients were followed up for 5 years after treatment with RAI by annual US.

RESULTS

At the end of 5 years, 47 patients (18.5%) had at least one suspicious US, but neck recurrence was confirmed in only 4 patients (1.5% of all patients and 8.5% of those with suspicious US). The remaining cases were considered false-positives. US did not reveal disease in the first or second year after treatment with RAI in any patient. In the third, fourth, and fifth year after treatment with RAI, considering only patients with unstimulated Tg < 1 ng/mL in these assessments, US revealed disease in 0, 1 (0.4%), and 1 (0.4%) patient, respectively.

CONCLUSION

The results suggest that low- or intermediate-risk patients with PTC without persistent disease after thyroidectomy (including negative postoperative US and RxWBS) do not require repeat US examination in the first two years after treatment with RAI. In the following years until the fifth year, US can be restricted to patients with Tg ≥1 ng/mL.

Are Papillary Thyroid Carcinomas That Are Candidates for Active Surveillance in Fact Classical Microcarcinomas Restricted to the Gland?

BACKGROUND

Patients with small papillary thyroid carcinomas (PTC) can currently be maintained under active surveillance (AS). The recommended criteria are the following: adult individual, tumor ≤1 cm and not adjacent to the trachea or recurrent laryngeal nerve, cytology non-suggestive of the aggressive subtype, absence of lymph node (LN) involvement and extrathyroidal extension (ETE) on ultrasonography (US), and absence of clinical distant metastases. This study aimed to evaluate the frequency of the following peri- and postoperative findings in patients who met the criteria for PTC being candidate for AS: tumor > 1 cm, aggressive subtype or vascular invasion, ETE, clinical LN metastases (cN1), and distant metastases.

METHODS

We reviewed the results of peri- and postoperative evaluation and histology of patients with a preoperative diagnosis of PTC who would currently be candidates for AS.

RESULTS

There were 124 patients (102 women) with nodules ≤1 cm (range 4-10 mm). All nodules corresponded to papillary microcarcinomas on histology and none of them were > 1 cm. Only one microcarcinoma (0.8%) was of the tall-cell subtype. Vascular invasion was found in 10 microcarcinomas (8%). None of the microcarcinomas were staged as T3b or T4, although microscopic ETE was observed in 25 tumors (20%). In 8 patients (6.4%), central LN involvement was suspected during perioperative evaluation and was confirmed by histology (cN1a). None of the patients had distant metastases (M0).

CONCLUSION

Findings that define an intermediate risk of recurrence and favor total thyroidectomy were observed in 31.5% of patients with PTC who are candidates for AS.

Clinical Validation of a Predictive Model for the Presence of Cervical Lymph Node Metastasis in Papillary Thyroid Cancer

BACKGROUND AND PURPOSE

Ultrasound is a standard technique to detect lymph node metastasis in papillary thyroid cancer. Cystic changes and microcalcifications are the most specific features of metastasis, but with low sensitivity. This prospective study compared the diagnostic accuracy of a predictive model for sonographic evaluation of lymph nodes relative to the radiologist's standard assessment in detecting papillary thyroid cancer metastasis in patients after thyroidectomy.

MATERIALS AND METHODS

Cervical lymph node sonographic images were reported by a radiologist (R method) per standard practice. The same images were independently evaluated by another radiologist using a sonographic predictive model (M method). A test was considered positive for metastasis if the R or M method suggested lymph node biopsy. The result of lymph node biopsy or surgical pathology was used as the reference standard. We estimated relative true-positive fraction and relative false-positive fraction using log-linear models for correlated binary data for the M method compared with the R method.

RESULTS

A total of 237 lymph nodes in 103 patients were evaluated. Our analysis of relative true-positive fraction and relative false-positive fraction included 54 nodes with pathologic results in which at least 1 method (R or M) was positive. The M method had a higher relative true-positive fraction of 1.46 (95% CI, 1.12-1.91; P = .006) and a lower relative false-positive fraction of 0.58 (95% CI, 0.36-0.92; P = .02) compared with the R method.

CONCLUSIONS

The sonographic predictive model outperformed the standard assessment to detect lymph node metastasis in patients with papillary thyroid cancer and may reduce unnecessary biopsies.

Clinical Impact of Detectable Antithyroglobulin Antibodies Below the Reference Limit (Borderline) in Patients with Papillary Thyroid Carcinoma with Undetectable Serum Thyroglobulin and Normal Neck Ultrasonography After Ablation: A Prospective Study

BACKGROUND

Interference of antithyroglobulin antibodies (TgAb) with serum thyroglobulin (Tg) can occur even at detectable TgAb concentrations below the reference limit (borderline TgAb). Thus, borderline TgAb is considered as TgAb positivity in patients with thyroid cancer. This prospective study evaluated patients with papillary thyroid carcinoma with undetectable Tg and normal neck ultrasonography (US) after total thyroidectomy and ablation with ¹³¹I, and compared tumor persistence/recurrence and long-term Tg and TgAb behavior in those with borderline versus undetectable TgAb.

METHODS

A total of 576 patients were evaluated, divided into two groups: group A with undetectable TgAb (n = 420), and group B with borderline TgAb (n = 156).

RESULTS

Groups A and B were similar in terms of patient and tumor characteristics. The time of follow-up ranged from 24 to 120 months. During follow-up, 11 (2.6%) patients in group A and 5 (3.2%) in group B developed a recurrence (p = 0.77). In group A, recurrences occurred in 9/390 patients who continued to have undetectable TgAb and in 1/9 patients who progressed to borderline TgAb. In group B, recurrences were detected in 1/84 patients who progressed to have undetectable TgAb, in 1/45 who still had borderline TgAb, and in 3/12 who developed elevated TgAb. In the presence of Tg levels <0.2 ng/mL, recurrences were detected in 2/486 patients with undetectable TgAb, in 0/67 with borderline TgAb, and in 3/12 with elevated TgAb. The results of post-therapy whole-body scanning (RxWBS) of 216 patients with Tg ≤0.2 ng/mL and normal US at the time of ablation were also analyzed. In low-risk patients, none of the 40 patients with borderline TgAb and none of the 94 with undetectable TgAb exhibited ectopic uptake on RxWBS. In intermediate-risk patients, lymph node metastases were detected by RxWBS in 1/25 (4%) with borderline TgAb and in 2/57 (3.5%) with undetectable TgAb.

CONCLUSIONS

The results suggest that among low- or intermediate-risk patients with undetectable Tg and normal US after thyroidectomy, those with borderline TgAb are at no greater risk of tumor persistence or recurrence than those with undetectable TgAb. When undetectable Tg levels persist, recurrence should be suspected in the case of a TgAb elevation above the reference limit.

Recognition of sentinel lymph nodes in patients with papillary thyroid cancer by nano-carbon and methylene blue

Objective:

To compare the accuracy and feasibility of methylene blue and nano-carbon in clinical tracing of sentinel lymph nodes (SLNs) in patients with papillary thyroid cancer (PTC).

Methods:

Ninety-six PTC patients were selected and randomly divided into a methylene blue group and a nano-carbon group (n=48). During surgery, tracer agent was injected around the tumor, and SLNs were resected and subjected to frozen pathological examination. The results were compared with those of routine pathological examination after surgery.

Results:

Latent lymph node metastasis (level VI and lateral neck) was detected in both groups, with neck distribution of SLNs. There was no significant difference in the detection rate or accuracy of SLNs between two groups (P>0.05). The incorrect resection rate of parathyroid gland and incidence of temporary hypoparathyroidism in the methylene blue group were significantly higher than those of the nano-carbon group (t=4.137, P<0.05).

Conclusions:

The state of PTC lymph nodes can be well evaluated by SLN biopsy using both methylene blue and nano-carbon as tracers, but using nano-carbon has a lower incidence rate of parathyroid injury, with great clinical prospects accordingly.

Persistent and recurrent disease in patients with papillary thyroid carcinoma with clinically apparent (cN1), but not extensive, lymph node involvement and without other factors for poor prognosis

OBJECTIVE

Lymph node metastases (LNM) are frequent in patients with papillary thyroid cancer (PTC). The risk of persistent disease (PD) and tumor recurrence (TR) is increased when factors for poor prognosis other than LNM exist, when LNM are numerous, large, detected by preoperative ultrasonography (US), or exhibit extranodal extension. This study evaluated the risk of PD and TR in patients with LNM not exhibiting these characteristics.

SUBJECTS AND METHODS

Eighty-six patients with 5 or fewer LNM detected during intraoperative inspection, but not by preoperative US, who had no other factors for poor prognosis [tumors > 4 cm, extensive extrathyroid invasion, vascular invasion, aggressive histological subtype, distant metastases, incomplete tumor resection], were studied. All patients underwent total thyroidectomy followed by radioiodine ablation. PD was defined as metastases on initial post-therapy whole-body scans (RxWBS) or detected by imaging methods up to 12 months after ablation. TR was defined as structural disease diagnosed more than one year after ablation in patients without PD.

RESULTS

PD was diagnosed in 3/86 patients (3.5%). TR was observed in 2/83 patients (2.5%) after 62 months of follow-up. There was no case of death due to the disease. A correlation was observed between pre-ablation Tg and PD or TR [1/48 (2%) with Tg ≤ 2 ng/mL versus 2/22 (9%) with Tg > 2 ≤ 10 ng/mL versus 2/7 (28.5%) with Tg ≥ 10 ng/ml)]. It is noteworthy that 38 patients had up to 3 positive LN and pre-ablation Tg ≤ 2 ng/ml, and none of them had PD or TR.

CONCLUSIONS

The frequency of PD and TR was low in patients with PTC with 5 or fewer LNM and without other factors for poor prognosis. Low postoperative stimulated Tg was predictive of the absence of PD and TR in these patients.

Chronic lymphocytic thyroiditis does not influence the risk of recurrence in patients with papillary thyroid carcinoma and excellent response to initial therapy

BACKGROUND

This study evaluated the recurrence in patients with papillary thyroid cancer and an excellent response to initial therapy, comparing those with and without chronic lymphocytic thyroiditis.

METHODS

This was a prospective study. Patients who met the following criteria were selected: diagnosis of papillary thyroid cancer; submitted to total thyroidectomy followed or not by ablation with ¹³¹I; and neck ultrasonography without abnormalities, nonstimulated thyroglobulina (Tg) ≤0.2 ng/ml, and undetectable antithyroglobulin antibodies (TgAb) 12-18 months after initial therapy. The patients were divided into two groups: group A, with chronic lymphocytic thyroiditis on histology; group B, without chronic lymphocytic thyroiditis on histology.

RESULTS

Groups A and B were similar in terms of sex and age of the patients, characteristics of the tumor, tumor-node-metastase stage and risk category. The time of follow-up ranged from 24 to 120 months (median 66 months). During follow-up, 5 patients of group A (2.6 %) and 9 patients of group B (2 %) developed recurrence (p = 0.77). Patients with chronic lymphocytic thyroiditis were more likely to progress to persistently borderline TgAb. No patient had positive TgAb (above the reference value) during follow-up. Recurrences occurred in 12/588 patients (2 %) with undetectable TgAb in all measurements, in 1/32 (3.1 %) with detectable TgAb on some occasion but that returned to undetectable spontaneously, and in 1/13 (7.7 %) with persistently borderline TgAb. These rates did not differ significantly (p = 0.25).

CONCLUSION

The results of the present study showed the absence of an association between chronic lymphocytic thyroiditis and recurrence risk at least in patients with an excellent response to initial therapy.

Recombinant human TSH versus thyroid hormone withdrawal in adjuvant therapy with radioactive iodine of patients with papillary thyroid carcinoma and clinically apparent lymph node metastases not limited to the central compartment (cN1b)

Objective

To compare the short- and long-term outcomes of adjuvant therapy with radioactive iodine (RAI) preceded by the administration of recombinant human TSH (rhTSH) versus thyroid hormone withdrawal (THW) in patients with papillary thyroid carcinoma and clinically apparent lymph node metastases not limited to the central neck compartment (cN1b).

Subjects and methods

The sample consisted of 178 cN1b patients at intermediate risk who underwent total thyroidectomy with apparently complete tumor resection [including postoperative ultrasonography (US) without anomalies] and who received adjuvant therapy with RAI (30-100 mCi) preceded by the administration of rhTSH (n = 91) or THW (n = 87).

Results

One year after RAI, the rates of excellent response to therapy, i.e., nonstimulated thyroglobulin (Tg) ≤ 0.2 ng/mL with negative antithyroglobulin antibodies and negative neck US, and of structural disease were similar for the two preparations (84% and 4.5%, respectively, in both groups). During follow-up (median 66 months), the rate of structural or biochemical (nonstimulated Tg > 1 ng/mL, with increment) recurrence was also similar in the two groups (4.5%). In the last assessment, the percentage of patients without evidence of disease, i.e., nonstimulated Tg < 1 ng/mL and no evidence of structural disease, was similar for the two preparations [92.3% in the rhTSH group and 97.7% in the THW group (p = 0.17)].

Conclusion

Preparation with rhTSH was equally effective (short- and long-term) as THW for adjuvant RAI therapy of cN1b patients at intermediate risk and with apparently complete tumor resection.

Can the follow-up of patients with papillary thyroid carcinoma of low and intermediate risk and excellent response to initial therapy be simplified using second-generation thyroglobulin assays?

OBJECTIVE

In view of the low probability of recurrence, the cost-effective follow-up of patients with papillary thyroid carcinoma (PTC) of low or intermediate risk and excellent response to initial therapy represents a challenge. This study evaluated the cases of structural recurrence among these patients.

PATIENTS

The sample comprised 578 patients with PTC of low or intermediate risk, who were submitted to total thyroidectomy with or without (131) I therapy and exhibited an excellent response to initial therapy defined based on nonstimulated thyroglobulin (Tg) ≤0·2 ng/ml and negative neck ultrasonography (US).

RESULTS

Twelve patients (2%) showed structural recurrence. At the time when recurrence was 'confirmed', Tg elevation had not occurred in only two patients, one with lymph node metastases <1 cm detected by US and the other with pulmonary metastases. Antithyroglobulin antibodies (TgAb) were undetectable in both patients. The first alteration observed in patients with recurrence was Tg elevation in six patients, Tg elevation associated with suspicious US in three, and suspicious US in two. An increase in TgAb was not the first alteration in any of the patients. Among the 560 patients who continued to have Tg ≤ 0·2 ng/ml, US permitted the detection of only one neck recurrence. Measurement of TgAb did not detect any recurrence.

CONCLUSION

Our results confirm that in patients with PTC of low or intermediate risk an excellent response to initial therapy can be defined based on nonstimulated Tg ≤ 0·2 ng/ml. Follow-up consisting only of clinical examination and periodic measurement of Tg with a second-generation assay may be sufficient.

Low postoperative nonstimulated thyroglobulin as a criterion for the indication of low radioiodine activity in patients with papillary thyroid cancer of intermediate risk 'with higher risk features'

OBJECTIVE

This study evaluated low-activity (131) I therapy in patients with papillary thyroid carcinoma (PTC) of intermediate risk 'with higher risk features' who had low nonstimulated thyroglobulin (Tg) after thyroidectomy.

DESIGN AND PATIENTS

This was a prospective study including 102 patients with tumours >1 cm and aggressive histology; and/or >3 positive lymph node (LN) or LN >1·5 cm or exhibiting macroscopic extracapsular extension, and clinically apparent (cN1); and/or a combination of a tumour >4 cm, microscopic extrathyroidal extension and LN metastases (cN1). After thyroidectomy, all patients had nonstimulated Tg < 0·3 ng/ml and negative antithyroglobulin antibodies (TgAb) and neck ultrasonography (US). The patients were treated with a low activity of (131) I (1110 or 1850 MBq).

RESULTS

Post-therapy whole-body scanning (RxWBS) showed ectopic uptake in four patients. When evaluated 12 months after (131) I therapy, nonstimulated Tg ≤ 0·2 ng/ml with negative TgAb and US, defined as excellent response to initial therapy, was achieved in 101 patients (99%). Only one patient with positive initial RxWBS had structural disease. During follow-up, four patients (4%) relapsed, including LN metastases in two, pulmonary metastases in one, and elevated Tg in one. The other 98 patients remained with nonstimulated Tg ≤ 0·2 ng/ml and negative TgAb and US. There was no case of death due to the tumour.

CONCLUSIONS

We conclude that in intermediate-risk patients 'with higher risk features', low nonstimulated Tg measured with a second-generation assay can be used as criterion for the administration of low (131) I activities (1850 MBq or less).

Comparison of Antithyroglobulin Antibody Concentrations Before and After Ablation with 131I as a Predictor of Structural Disease in Differentiated Thyroid Carcinoma Patients with Undetectable Basal Thyroglobulin and Negative Neck Ultrasonography

BACKGROUND

Patients with differentiated thyroid carcinoma are submitted to a first assessment several months after initial therapy to evaluate their response to treatment. At that assessment, measurement of basal thyroglobulin (Tg) and antithyroglobulin antibodies (TgAb) and neck ultrasonography (US) are recommended. Serum Tg may be falsely negative in the presence of TgAb, and the management of patients with negative Tg but positive TgAb represents a challenge. The objective of this study was to correlate the variation in TgAb concentrations (comparison before and after ablation with (131)I) with the risk of structural disease.

METHODS

The sample consisted of 116 low- or intermediate-risk patients who had undetectable Tg, negative US at initial assessment, and positive TgAb 8-12 months after thyroidectomy and ablation with (131)I.

RESULTS

Comparison of TgAb concentrations before and after ablation with (131)I showed a reduction of >50% in 56 patients (group A), a reduction of <50% in 35 patients (group B), and an increase in 25 patients (group C). Metastases were detected in 5/116 (4.3%) patients during initial assessment (lymph nodes in two, pulmonary in two, and bone in one). They were diagnosed in 0/56, 2/35 (5.7%), and 3/25 (12%) patients of groups A, B, and C, respectively. During follow-up, metastases were detected in 7/111 (6.3%) patients (lymph nodes in six, and pulmonary in one). They occurred in 1/56 (1.8%), 3/33 (9%), and 3/22 (13.6%) patients of groups A, B, and C, respectively. Thus, structural disease was found in 1.8%, 14.3%, and 24% of groups A, B, and C, respectively. This rate was 4% in low-risk patients and 15.4% in intermediate-risk patients.

CONCLUSIONS

Among patients with undetectable Tg, negative US, and positive TgAb after ablation with (131)I, the frequency of structural disease was <5% in patients, with >50% reduction in TgAb. Among patients without a significant reduction in TgAb, approximately 10% of low-risk patients and >20% of intermediate-risk patients had structural disease. These results help define the indication for imaging methods other than US during initial assessment and long-term follow-up.

Is 131I ablation necessary for patients with low-risk papillary thyroid carcinoma and slightly elevated stimulated thyroglobulin after thyroidectomy?

OBJECTIVE

This prospective study evaluated the recurrence rate in low-risk patients with papillary thyroid cancer (PTC) who presented slightly elevated thyroglobulin (Tg) after thyroidectomy and who did not undergo ablation with131I.

SUBJECTS AND METHODS

The study included 53 low-risk patients (nonaggressive histology; pT1b-3, cN0pNx, M0) with slightly elevated Tg after thyroidectomy (> 1 ng/mL, but ≤ 5 ng/mL after levothyroxine withdrawal or ≤ 2 ng/mL after recombinant human TSH).

RESULTS

The time of follow-up ranged from 36 to 96 months. Lymph node metastases were detected in only one patient (1.9%). Fifty-two patients continued to present negative neck ultrasound. None of these patients without apparent disease presented an increase in Tg.

CONCLUSIONS

Low-risk patients with PTC who present slightly elevated Tg after thyroidectomy do not require ablation with 131I.

Radioiodine-induced oxidative stress in patients with differentiated thyroid carcinoma and effect of supplementation with vitamins C and E and selenium (antioxidants)

OBJECTIVE

The objective of this study, in addition to confirming that therapy with 131I causes oxidative stress, was to evaluate the effect of supplementation with vitamins C and E and selenium on this phenomenon by measuring plasma 8-epi-PGF2a, a marker of lipid peroxidation.

SUBJECTS AND METHODS

Forty patients with thyroid cancer submitted to thyroidectomy, who received 3.7 GBq 131I after levothyroxine withdrawal, were selected; 20 patients did not receive (control group) and 20 patients received (intervention group) daily supplementation consisting of 2000 mg vitamin C, 1000 mg vitamin E and 400 µg selenium for 21 days before 131I. Plasma 8-epi-PGF2a was measured immediately before and 2 and 7 days after 131I.

RESULTS

A significant increase in plasma 8-epi-PGF2a after 131I was observed in the two groups. The concentrations of 8-epi-PGF2α were significantly higher in the control group before and 2 and 7 days after 131I. The percentage of patients with elevated 8-epi-PGF2α was also significantly higher in the control group before and after 131I. Furthermore, the increase (percent) in 8-epi-PGF2α was significantly greater in the control group (average of 112.3% versus 56.3%). Only two patients (10%) reported side effects during supplementation.

CONCLUSIONS

Ablation with 131I causes oxidative stress which can be minimized by the use of antioxidants.

Low postoperative nonstimulated thyroglobulin as a criterion to spare radioiodine ablation

This study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) who had low nonstimulated thyroglobulin (Tg), measured with a second-generation assay, after total thyroidectomy and who were not submitted to ablation with (131)I. The objective was to define whether low postoperative nonstimulated Tg can be used as a criterion to spare patients with PTC from therapy with (131)I. This was a prospective study including 222 patients with PTC (except for microcarcinoma restricted to the thyroid and tumor with extensive extrathyroid invasion (pT4), aggressive histology, extensive lymph node (LN) involvement, or known residual disease). After thyroidectomy, all patients had nonstimulated Tg<0.3 ng/ml, negative antithyroglobulin antibodies (TgAb) and neck ultrasonography (US) showing no anomalies. Because of this finding, the patients were not submitted to ablation with (131)I. The time of follow-up ranged from 15 to 102 months (median 62 months). Of the 222 patients, 217 (97.7%) continued to have nonstimulated Tg <0.3 ng/ml and negative US. Tg was undetectable in the last assessment in 185 of these patients and detectable in 32. Five patients (2.2%) exhibited an increase in Tg, and LN metastases were detected in 4 (structural recurrence). One patient progressed to an increase in Tg, but disease was not detected by the imaging methods (biochemical recurrence). The results obtained here suggest that patients with PTC who have low nonstimulated Tg (measured with a second-generation assay and in the absence of TgAb) and negative neck US after thyroidectomy do not require ablation with (131)I.

A low postoperative nonstimulated serum thyroglobulin level excludes the presence of persistent disease in low-risk papillary thyroid cancer patients: implication for radioiodine indication

OBJECTIVE

To evaluate the presence of persistent disease, including on post-therapy whole-body scan (RxWBS), in low-risk patients with papillary thyroid carcinoma (PTC) >1 cm who have low nonstimulated thyroglobulin (Tg) (measured with a sensitive assay), negative anti-Tg antibodies (TgAb) and neck ultrasound (US) showing no metastases after total thyroidectomy.

PATIENTS

We studied 154 patients with PTC >1 cm classified as low risk, who had US without metastases, negative TgAb, nonstimulated Tg ≤ 0·25 ng/ml and TSH ≤ 2 mIU/l about 3 months after total thyroidectomy.

RESULTS

Tg measured immediately before (131) I was ≤ 1 ng/ml in 89·5% of the patients and >1 ng/ml in 10·5%. None of the patients showed ectopic uptake on RxWBS. Uptake in the thyroid bed was observed in 146 (94·8%) patients and was ≤ 2% in all of them. In the control assessment 9-12 months after ablation, stimulated Tg (sTg) ≤ 1 ng/ml was achieved in 150 patients (97·4%). Only one patient had sTg >2 ng/ml (2·5 ng/ml) and none of the patients had apparent disease detected by imaging methods. During further short-term follow-up after control assessment (median of 24 months), none of the patients had tumour recurrence.

CONCLUSIONS

The combination of nonstimulated Tg ≤0·25 ng/ml, negative TgAb and US without metastases after thyroidectomy rules out the presence of persistent disease (including on RxWBS) in low-risk patients with PTC >1 cm. This demonstration weakens the indication of ablation with (131) I in these cases.

Patients with Papillary Thyroid Carcinoma at Intermediate Risk of Recurrence According to American Thyroid Association Criteria Can Be Reclassified as Low Risk When the Postoperative Thyroglobulin Is Low

BACKGROUND

According to American Thyroid Association (ATA), all patients with papillary thyroid carcinoma (PTC) should initially be classified regarding the risk of tumor recurrence. If a very high postoperative thyroglobulin (Tg) classifies patients as high risk of recurrence, it is reasonable to hypothesize that, at the other extreme, a low Tg may reclassify patients from intermediate to low risk. The objective of this study was to evaluate the rate of persistent/recurrent disease in intermediate-risk patients with low postoperative (before 131I) Tg, thereby evaluating whether these patients can be reclassified as low risk based on this finding already at the time of initial therapy rather than one to two years after radioiodine therapy.

METHODS

A total of 181 patients with the following characteristics were evaluated: (i) diagnosis of PTC; (ii) submitted to total thyroidectomy with lymph node dissection in the case of a suspicion of metastases based on preoperative ultrasonography (US) or perioperative evaluation (cN1); (iii) apparently without persistent tumor after surgery; (iv) a postoperative stimulated Tg (sTg) ≤2 ng/mL and negative anti-Tg antibodies (TgAb); and (v) considered to be at intermediate risk by ATA criteria.

RESULTS

When evaluated 9-12 months after radioiodine therapy, 170 patients (94%) had a sTg <1 ng/mL and negative TgAb and a negative neck US (excellent response). Ten patients (5.5%) had a sTg >1 ng/mL (≤2 ng/mL) in the absence of apparent disease detected by imaging methods (indeterminate response). US detected cervical lymph node metastases (not detected at the time of 131I therapy) in one patient (incomplete structural response). During follow-up, recurrence was observed in 5/180 (2.7%) patients without apparent disease in the initial assessment. Thus, persistent or recurrent disease occurred in only 3.3% of cases. The 175 patients without tumor persistence/recurrence were not submitted to any additional therapy, and all had a Tg/thryoxine <1 ng/mL in the last assessment. There was no case of death related to the disease.

CONCLUSIONS

This study suggests that intermediate-risk patients (according to ATA criteria) with a postoperative sTg ≤2 ng/mL can be reclassified as low risk already at the time of initial therapy.

Day 3 thyroglobulin ≤ 1 ng/ml after recombinant human TSH just prior to radioactive iodine is predictive of low risk for persistent/recurrent disease in patients with papillary thyroid carcinoma

We evaluated the negative predictive value (NPV) of thyroglobulin obtained 24 h after the second recombinant human TSH (rhTSH) ampoule (Tg-D3), before ablation with (131)I, for persistent/recurrent disease (PRD) in low/intermediate risk patients with papillary thyroid carcinoma. One hundred and one patients with Tg-D3 ≤ 1 ng/ml without anti-Tg antibodies (TgAb) were selected. Post-therapy whole-body scanning was negative for metastases in 98 (97 %) patients, and three patients showed discrete ectopic cervical uptake, but no corresponding disease was detected by neck ultrasound or computed tomography. One year after ablation, 98 (97 %) patients were free of the disease. Three patients had stimulated Tg >1 ng/ml, but no metastases were detected by the imaging methods. During follow-up (median 50 months), tumor recurrence was observed in only one patient. Thus, the NPV of Tg-D3 ≤ 1 ng/ml for PRD was 99 %. Among the 101 patients with Tg-D3 ≤ 1 ng/ml, Tg obtained 48 h after ablation (Tg-D5) continued to be ≤ 1 ng/ml in 56, and 45 had Tg-D5 >1 ng/ml. None of these 45 patients had PRD. In conclusion, Tg-D3 ≤ 1 ng/ml had a high NPV for PRD in patients without TgAb or known persistent disease and who are not at high risk. In these patients, Tg-D5 >1 ng/ml is more likely to reflect actinic damage to the remnant thyroid tissue rather than persistence of significant normal or tumor tissue.

Is Stimulated Thyroglobulin Necessary after Ablation in All Patients with Papillary Thyroid Carcinoma and Basal Thyroglobulin Detectable by a Second-Generation Assay?

Objective. To evaluate the percentage of elevated stimulated thyroglobulin (sTg) and persistent or recurrent disease (PRD) in patients with detectable basal Tg < 0.3 ng/mL. Methods. The sample consisted of 130 patients with papillary thyroid carcinoma (PTC) who were at low risk of PRD and who had neck ultrasound (US) without abnormalities, negative anti-Tg antibodies (TgAb), and detectable basal Tg < 0.3 ng/mL about 6 months after ablation. Results. sTg was <1 ng/mL in 88 patients (67.7%), between 1 and 2 ng/mL in 26 (20%), and ≥2 ng/mL in 16 (12.3%). Imaging methods revealed the absence of tumors in 16 patients with elevated sTg. During follow-up, Tg increased to 0.58 ng/mL in one patient and lymph node metastases were detected. Sixty-nine patients continued to have detectable Tg < 0.3 ng/mL and US revealed recurrence in only one patient. Sixty patients progressed to persistently undetectable Tg without apparent disease on US. Conclusions. In low-risk patients with PTC who have detectable basal Tg < 0.3 ng/mL after ablation, negative TgAb, and US, persistent disease is rare and eventual recurrences can be detected by basal Tg elevation and/or subsequent US assessments, with follow-up without sTg being an "alternative" to Tg stimulation.

Should a family history of papillary thyroid carcinoma indicate more aggressive therapy in patients with this tumor?

OBJECTIVE

To determine whether the currently recommended therapy for papillary thyroid carcinoma (PTC) that show no classical factors indicating a poor prognosis is also effective in cases with a family history of this tumor.

SUBJECTS AND METHODS

Forty-two patients were studied; 10 were submitted to lobectomy and 32 to total thyroidectomy, including 23 without lymph node dissection and 9 with lymph node dissection. None of the patients received radioiodine or was maintained under TSH suppression.

RESULTS

No case of recurrence was detected by imaging methods and there was no increase in thyroglobulin or antithyroglobulin antibodies during follow-up (24 to 72 months).

CONCLUSION

The treatment usually recommended for patients with PTC does not need to be modified in the presence of a family history of this tumor if no factors indicating a poor prognosis are present (tumor ≤2 cm, non-aggressive histology, no extensive extrathyroid invasion or important lymph node involvement, complete tumor resection, no evidence of persistent disease after surgery).