Adjuvant external beam radiotherapy in high risk well-differentiated thyroid cancer

Radioiodine Refractory Follicular Thyroid Cancer and Surgery for Cervical Relapse

Compared to its more common counterpart papillary thyroid cancer (PTC), follicular thyroid cancer (FTC) has a less favorable outcome, due to its higher incidence of distant metastases and advanced stages at diagnosis. Despite radioiodine (RAI) avidity, metastatic FTC often progresses after radioiodine treatment (RAIT). We aimed at evaluating the indications and outcomes of surgery for cervical relapse of radioiodine refractory FTC. Patients receiving RAIT between 2005 and 2015 at the University Hospital of Cologne, Germany, were screened. Patients with FTC were identified. Demographics, clinic-pathologic characteristics, treatment, and outcome of patients diagnosed with RAI refractory FTC, who underwent cervical surgery in the course of disease, were analyzed. FTC accounted for 8.8% of all thyroid carcinomas undergoing RAIT. In 35.2% of FTC patients, disease persisted or recurred despite a cumulative mean RAI activity of 18.7 GBq ± 11.6 (follow-up 83.5 ± 56.7 months). Distant metastases were diagnosed in 75% of these patients, as bone (57.6%), lung (54.6%), and liver metastases (12.1%). Cervical relapse occurred in 63.6% of these patients and was treated in 57.1% with surgery with, and without, external beam radiation therapy (EBRT). Despite surgery and EBRT, in 75% of patients, cervical relapse recurred again. In conclusion, surgery for cervical radioiodine refractory FTC relapse is often performed in metastatic setting. With and without EBRT, cure is rare, although metastases can appear radioiodine avid. Early biological marker and systemic treatments for these patients are still needed.

Radiotherapy in well-differentiated thyroid cancer: is it underutilized?

BACKGROUND

The usual management of thyroid cancer is surgery and radioactive iodine. The role of external beam radiotherapy (EBRT) in well-differentiated thyroid carcinoma remains controversial. Indications for the use of EBRT, contained within both the American and British Thyroid Association published guidelines, include unresectable or non-iodine avid disease, extra-thyroidal extension or distant metastatic disease.

METHODS

A retrospective review of prospectively collected data from a single Australian institution was conducted, analysing patients referred and treated with EBRT for well-differentiated thyroid carcinoma between November 1992 and July 2013.

RESULTS

Of 36 patients referred, 32 were treated with EBRT. Sixteen patients in total received locoregional treatment (six radical, 10 palliative), of whom 81% (13/16) had gross disease and 88% (14/16) had recurrent disease (eight with multiple recurrences). Additionally, 63% (10/16) had multiple surgical resections and 50% (8/16) had previously received multiple courses of radioactive iodine. Overall, 67% (4/6) of patients treated with radical intent had no locoregional recurrence or progression. Thirteen of the 16 patients who received locoregional EBRT remained asymptomatic from their locoregional disease at the time of last follow-up or death. The most commonly treated distant metastatic disease site was bone, with a total of 45 sites irradiated. Of these patients, 93% and 78% were symptom-free at two and four years, respectively.

CONCLUSION

Our study suggests that in a select group of patients with well-differentiated thyroid carcinoma, EBRT treatment appears to provide durable tumour and symptom control.