Prevalence of iodine- and thyroglobulin negative findings in differentiated thyroid cancer

US diagnosis of cervical recurrence in patients operated on thyroid cancer: Sonographic features and clinical significance

OBJECTIVE

To describe the sonographic features of cervical recurrence in patient with thyroid cancer and review clinical significance.

MATERIALS AND METHODS

Twenty-two consecutive patients with 24 surgically confirmed recurrences undergoing preoperative ultrasonography (US) and US-guided fine needle aspiration biopsy (FNAB) were enrolled. Retrospective analysis was conducted on the sonographic features of recurrence including size, location, shape, echogenicity, multiplicity, laterality relative to initial primary tumor and presence of characteristic findings; cystic change and microcalcification. In addition, review was made on their clinical data including the time interval between the thyroidectomy and the recurrence, serum thyroglobulin (Tg), anti-thyroglobulin antibody (Tg Ab) and 131 iodine whole body scan (IWBS).

RESULTS

Fifteen of 24 recurrences occurred in internal jugular lymphatic chain and 9 in the postoperative paratracheal region with mostly ipsilaterally to the initial tumor (19/24). Their mean size was 1.0 cm (range: 0.5-2.5 cm) with ovoid (n=18) or lobulated (n=6) shape. They appeared hyperechoic in nine (37.5%), hypoechoic in nine (37.5%), and mixed echoic due to cystic change in six (25.0%). Microcalcification was observed in eight (33.3%) and multiplicity in seven (29.2%). US-guided FNAB established the preoperative diagnosis of recurrence in all. The mean interval between the thyroidectomy and recurrence was 59 months (range: 15-162 months). Suspicion of recurrence was possible in 8 with Tg of 2 ng/ml or greater (8/24) during thyroxine (T4) therapy and 6 (6/8) after T4 withdrawal. All of the 8 recurrences were negative on 131 IWBS. In two patients with Tg less than 2 ng/ml after T4 withdrawal, elevated Tg Ab was observed.

CONCLUSION

US and US-guided FNAB are valuable postoperative follow up modalities of thyroid cancer due to their convenience, early detection and precise localization. Therefore, it's essential to get familiar with sonographic findings of cervical recurrence.

Sonography in the diagnosis of cervical recurrence in patients with differentiated thyroid carcinoma

OBJECTIVE

To determine the sensitivity of thyroglobulin (Tg), iodine scanning, and sonography in the diagnosis of cervical recurrence of thyroid cancer.

METHODS

This prospective study assessed 81 patients with cervical metastases or extrathyroid invasion at first appearance who underwent clinical examination, scanning, measurement of Tg after thyroxine withdrawal, and sonography about 8 months after thyroidectomy followed by radioiodine treatment. Only patients without distant metastases and without anti-Tg antibodies were included.

RESULTS

Fifty patients showed persistence of the disease in the cervical region, with only 16% of them having had a suspicion on clinical examination, 33 with Tg levels of 2 ng/mL or greater (66% sensitivity), and 29 with positive scan findings (58% sensitivity). A combination of the 2 methods detected disease in 40 (80%) of 50 patients but failed to show 20% of cases that were identified by sonography and confirmed by fine-needle aspiration. Sonography had sensitivity of 96%. Specificity values for Tg, iodine scanning, and sonography were 80.6%, 90.3%, and 87%, respectively.

CONCLUSIONS

Classic follow-up methods may not detect cervical disease in some patients with differentiated thyroid carcinoma, and sonography is necessary even in patients apparently free of the disease.