Locoregional disease control after external beam radiotherapy in 91 patients with differentiated thyroid carcinoma and pT4 tumor stage - a single institution experience

Abstract

BackgroundLocoregional recurrence is common in patients with locally advanced differentiated thyroid carcinoma (DTC). Our aim was to find out the rate of locoregional control of the disease after external beam radiotherapy (EBRT) of the neck and mediastinum in patients with DTC and pT4 tumor.Patients and methodsAltogether 91 patients (47 males, 44 females, median age 61 years) with DTC had EBRT of the neck and mediastinum as part of the multimodal treatment of pT4 tumor (63 cases pT4a, 28 cases pT4b) from the year 1973 to 2015. Data on clinical factors, histopathology and recurrence were collected. Disease-free, disease-specific and overall survival was calculated.ResultsMedian tumor size was 5 cm (range 1–30 cm). Out of 91 patients, 23 had distant and 38 regional metastases. A total or near-total thyroidectomy, lobectomy, subtotal thyroidectomy and lymph node dissection was performed in 70%, 14%, 2% and 30% of cases, respectively. Thirteen percent of patients were not treated with surgery. All patients had EBRT and 39 had chemotherapy. Radioiodine (RAI) ablation of thyroid remnant and RAI therapy was applied in 90% and 40% of cases, respectively. Recurrence was diagnosed in 29/64 patients without a persistent disease: locoregional and distant in 16 and 13 cases, respectively. Five-year and ten-year disease-free survival rate was 64% and 48%, respectively.ConclusionsThe majority of patients with DTC and pT4 tumors who were treated with EBRT of the neck and mediastinum region as part of multimodal treatment have long-lasting locoregional control of the disease.

Treatment of Unresectable Differentiated Thyroid Carcinoma With Upfront External Radiotherapy and Salvage Surgery: A STROBE-Compliant Retrospective Cohort Study

“…Some isolated case-series exist where DTC cases considered unresectable receive chemotherapy, targeted agent therapy or EBRT and then subjected to a surgical procedure, occasionally attaining complete resection ( 7 , 8 ). The objective of these anecdotal reports is to underscore palliation, with an R0 resection obtained in one or two cases.…”

“…When the extent of malignancy is associated with invasion to vascular structures of the base of the neck and upper mediastinum precluding a safe and clear resection, the therapeutic options are limited to observation, symptomatic treatment, and/or palliative EBRT. Some isolated case-series exist where DTC cases considered unresectable receive chemotherapy, targeted agent therapy or EBRT and then subjected to a surgical procedure, occasionally attaining complete resection (7,8). The objective of these anecdotal reports is to underscore palliation, with an R0 resection obtained in one or two cases.…”

“…Series on unresectable DTC analyze patients who have received upfront, non-operative treatment, with EBRT, some including chemotherapy and target-aimed agents, but clinical responses or subsequent surgical resection are not described, aside from anecdotal cases (7)(8)(9). Moreover, current American Thyroid Association (ATA) guidelines do not clearly define the role of EBRT in cases with advanced unresectable DTC (10), although other guidelines suggest a palliative role of EBRT with improvement in quality of life and local disease control (11,12).…”