Local and regional control in patients with papillary thyroid carcinoma: specific indications of external radiotherapy and radioactive iodine according to T and N categories in AJCC 6th edition

Abstract

To identify indications for external radiotherapy (EXT) and radioactive iodine (RAI) in papillary thyroid carcinoma (PTC), we conducted a retrospective study of local and regional control in 1297 patients diagnosed with PTC in a tertiary referral center. Managed by surgery alone, patients with bilateral thyroidectomy had a lower rate of local relapse compared with lobectomy (PZ0.02). EXT improved locoregional (LR) failure-free survival (FFS) (P!0.001) and survival (PZ0.01) in patients with gross postoperative LR residual disease. EXT also improved local FFS in patients with pathologically confirmed positive resection margins (P!0.001) and reduced local failures in patients with T4 disease (PZ0.002). In patients with lymph nodes (LN) metastasis, more extensive surgery by functional or radical neck dissection resulted in less LN relapse compared with excision alone (P!0.001). EXT improved 10-year LN FFS in patients with N1b disease (PZ0.005) and patients with LN metastasis of size O2 cm (PZ0.02). RAI was effective in improving local control in patients with T2 to T4 diseases and LN control in patients with N0, N1a, and N1b categories. Local or LN relapses were associated with worse survival (P!0.001 and P!0.0001). The survival of patients with PTC could be improved by reducing local or LN relapses. RAI is indicated in patients with T2 to T4 disease. EXT is indicated in patients with gross postoperative disease, positive resection margins or T4 disease, N1b, or a LN size of O2 cm. LN relapse can be reduced by RAI in N0, N1a, and N1b disease.

Osteosarcoma of the Clavicle and Scapula Secondary To the Radiotheraphy for Servical Metastases of the Differentiated Thyroid Cancer: Case Report

“…RT is in di ca ted in DTC fol lo wing ini ti al thyro i dec tomy when the sur gi cal spe ci men demons tra tes a posi ti ve mar gin, in va si on of nor mal tis su es, a me tas ta tic lymphe no de > 2 cm, or no dal me tas ta ses with ex ten si ve ex tra cap su lar tu mor exten si on. 3 Se ve ral se ri es al so no ted that ol der pa tients (> 40 ye ars of age) with mul tip le po si ti ve lymph no des or ex trath yro i dal ex ten si on had bet ter lo co re gi o nal con trol when ra di ot he raphy was added to treatment regimen. 1,4,5 Bo ne scan in os te o sar co ma is use ful for de line a ting the ex tent of the pri mary le si on and for early de tec ti on of lo cal re cur ren ce and me tas ta tic di se a se.…”

“…[1][2][3][4][5][6] Approximately 5 % of sarcomas develop after therapeutic or accidental irradiation.7 In osteosarcomas, three-phase bone scintigraphy is often used to evaluate the primary lesion and to search for bone metastases. In this paper, we present a radiation induced osteosarcoma of the clavicle and scapula in a DTC patient in whom three-phase bone scan and I-131 radioiodine scan are used for diagnosis.…”

“…[1][2][3][4][5][6] Approximately 5 % of sarcomas develop after therapeutic or accidental irradiation.…”

Management of Invasive Differentiated Thyroid Cancer

“…In contrast, if disease extends into the mediastinum and surgical resection would require sternotomy, there are patients who are considered insufficiently physiologically fit to justify such an approach to resect disease even if major arteries are not grossly involved. In such patients, although treatment intent is palliative, disease control can be achieved in a high percentage of patients (61)(62)(63)(64).…”

Radioiodine Therapy for Thyroid Cancer in the Era of Risk Stratification and Alternative Targeted Therapies

“…This possibility would imply no benefit for adjuvant radiotherapy, suggesting that, in the absence of residual macroscopic disease with clear iodine uptake, lower radioiodine doses designed for thyroid remnant are sufficient and higher doses should not be used. On the other hand, there are studies indicating reduced local recurrence with postoperative radioiodine ablation (12,20), suggesting a benefit for radioiodine beyond remnant ablation-that is, an adjuvant effect. Resolving this conflict may require a trial in patients with disease at higher risk for local recurrence (nodal metastases, extrathyroidal extension), randomizing patients to low-dose radioiodine for remnant ablation only versus higher doses that may be needed to treat comparatively less iodine-avid and, potentially, smaller residual cancer deposits.…”