The role of postoperative external-beam radiotherapy in the management of patients with papillary thyroid cancer invading the trachea

External beam radiation therapy for recurrent or residual thyroid cancer: What is the best treatment time and the best candidate for long-term local disease control?

INTRODUCTION

Cervical disease control might be challenging in advanced thyroid cancer (DTC). Indications for cervical external beam radiation therapy (EBRT) are controversial.

PURPOSE

To identify clinical and molecular factors associated with control of cervical disease with EBRT.

METHODS

Retrospective evaluation and molecular analysis of the primary tumor DTC patients who underwent cervical EBRT between 1995 and 2022 was performed.

RESULTS

Eighty adults, median age of 61 years, were included. T4 disease was present in 43.7%, lymph node involvement in 42.5%, and distant metastasis in 47.5%. Those with cervical progression were older (62.5 vs. 57.3, p = 0.04) with more nodes affected (12.1 vs. 2.8, p = 0.04) and had EBRT performed later following surgery (76.6 vs. 64 months, p = 0.05). EBRT associated with multikinase inhibitors showed longer overall survival than EBRT alone (64.3 vs. 37.9, p = 0.018) and better local disease control. Performing EBRT before radioiodine (RAI) was associated with longer cervical progression-free survival (CPFS) than was RAI before (67.5 vs. 34.5, p < 0.01). EBRT ≥2 years after surgery was associated with worse CPFS (4.9 vs. 34, p = 0.04). The most common molecular alterations were ERBB2, BRAF, FAT1, RET and ROS1 and TERT mutation was predictive of worse disease control after EBRT (p = 0.04).

CONCLUSION

Younger patients, with fewer affected nodes and treated earlier after surgery had better cervical disease control. Combination of EBRT with MKI improved OS. TERT mutation might indicate worse responders to EBRT; however, further studies are necessary to clarify the role of molecular testing in selecting candidates for cervical EBRT.

Salvage radiofrequency ablation followed by external beam radiotherapy for inoperable recurrent differentiated thyroid cancer

PURPOSE

The treatment of recurrent thyroid cancer with critical organ invasion is challenging. The combination of radiofrequency ablation (RFA) and external beam radiation therapy (EBRT) has been proposed as an effective option. This study evaluates outcomes for inoperable residual/recurrent differentiated thyroid cancer (rDTC) patients treated with RFA followed by EBRT.

MATERIALS AND METHODS

Patients with rDTC treated with RFA followed by EBRT were retrospectively studied. RFA was performed using a free-hand, 'moving-shot' technique under US or CT guidance. For lesions invading critical structures intolerant to 'en bloc' high-temperature RFA, limited-field EBRT using 6- or 10-MV photons was used for adjuvant treatment at a dose of 66 Gy in 33 daily fractions. Toxicities and outcomes were reviewed.

RESULTS

Between April 2020 and January 2022, 11 patients with 14 rDTC lesions underwent RFA followed by EBRT. Five patients had metastatic lesions at rDTC diagnosis. With a median follow-up period of 33.7 months, all patients maintained locoregional control, while achieving a 2-year survival rate of 90.9%. This combined treatment achieved a volume reduction ratio of 92.1% ± 5.1%. The mean nadir thyroglobulin level in patients without initial distant metastases after treatment was 1.40 ± 0.81 ng/ml. Regarding treatment-related complications, one patient (9%) experienced temporary hoarseness after RFA, grade 2 radiation dermatitis occurred in 3 patients (27.2%), and grade 2 dysphagia was noted in 4 patients (36.4%). No grade 3 or greater toxicities occurred.

CONCLUSIONS

Salvage RFA followed by EBRT is feasible, effective and safe for patients with rDTC.

The modern landscape of radiotherapy in thyroid malignancies

Thyroid carcinoma is the most common malignancy of the endocrine system and accounts for nearly 1.5% of all new cancer cases in India. The incidence of thyroid cancers is on the rise secondary to multiple factors including the widespread use of radiological imaging. Surgery remains the cornerstone of treatment, and radioactive iodine therapy plays a pivotal role in differentiated thyroid cancer. Radiation therapy appears to be an underutilized treatment modality. In this review, we have summarized the role of radiation in the treatment of thyroid cancer.

Shaving Papillary Thyroid Carcinoma Involving Functioning Recurrent Laryngeal Nerve: Safety of Incomplete Tumor Resection and Nerve Sparing

BACKGROUND

Whether to sacrifice or spare the recurrent laryngeal nerve (RLN) when papillary thyroid carcinoma (PTC) involves a functioning RLN remains controversial. Oncological outcomes after shaving PTC with gross remnant on the RLN have been rarely reported. The objective of this study was to evaluate the oncological outcomes of patients who underwent shaving of a PTC from the RLN, leaving a gross residual tumor with the intent of vocal function preservation.

METHODS

A retrospective, cohort study was conducted in 47 patients who were determined to have PTC invasion of the RLN via intraoperative inspection and underwent tumor shaving with macroscopic remnant (R2 resection) less than 1 cm in length and 4 mm in thickness. Median follow-up period was 93 (range, 60-215) months. The primary endpoint was the recurrence-free survival and the progression-free survival. Secondary endpoints were biochemical outcomes (serum thyroglobulin) and vocal cord function.

RESULTS

Of the 47 patients, five (10.6%) patients showed recurrence (central neck, 3; lateral neck, 2) without death or distant metastasis. The RLN was resected along with the tumor in one (2.1%) patient who presented with progression of the residual tumor. Postoperative temporary vocal cord paralysis occurred in six (12.8%) patients without permanent cases. The final nonstimulated serum thyroglobulin was 0.7 ± 1.8 ng/ml.

CONCLUSIONS

Shaving a tumor from a RLN with gross residual disease may be considered an alternative strategy to preserve vocal function when complete tumor resection with nerve preservation is impossible in patients with PTC invading a functioning RLN.

Prognostic value of adjuvant external beam radiotherapy for papillary thyroid cancer based on competitive risk model and propensity score matching

This study aimed to assess the impact of adjuvant external beam radiotherapy (EBRT) on the survival of patients with locally invasive papillary thyroid carcinoma. This retrospective study used data from the Surveillance, Epidemiology, and End Results database for the diagnosis of papillary thyroid carcinoma, using Cox models to screen for adverse prognostic factors. The prognostic value of using adjuvant external beam radiotherapy in papillary thyroid carcinoma was further evaluated, based on the competing risk model and propensity score matching. Based on the competitive risk model, the sub-distribution hazard ratio (SHR) of the multivariate analysis of patients receiving EBRT alone versus those receiving radioiodine-131 alone was 9.301 (95% CI 5.99-14.44) (P < 0.001), and the SHR of the univariate analysis was 1.97 (95% CI 1.03-3.78) (P = 0.042). In the propensity score-matched Kaplan-Meier analysis, patients who received EBRT still had worse OS (6-year OS, 59.62% vs 74.6%; P < 0.001) and DSS (6-year DSS, 66.6% vs 78.2%; P < 0.001) than patients who did not receive EBRT. Patients who received EBRT had a higher cumulative risk of death due to thyroid cancer after PSM (P < 0.001). Adjuvant EBRT was not associated with survival benefit in the initial management of locally invasive papillary thyroid cancer.

Propensity score matching analysis of adjuvant external-beam radiotherapy for the treatment of papillary thyroid carcinoma with other organ invasions

PURPOSE

The role of adjuvant external-beam radiotherapy (EBRT) in the treatment of locally advanced papillary thyroid carcinoma (PTC) remains controversial due to the lack of prospective data and the conflicting retrospective data. This study aimed to determine the benefits of adjuvant EBRT in patients with PTC and other organ invasions using propensity score matching to reduce the heterogeneity of the patient population.

METHODS

Data from patients with PTC with other organ invasions but no distant metastases who underwent surgery and adjuvant radioactive iodine (RAI) alone (Non-EBRT group) or adjuvant EBRT plus RAI (EBRT group) were retrospectively reviewed. Propensity matching was used to reduce heterogeneity. Survival outcomes and toxicities associated with EBRT were evaluated.

RESULTS

Between January 2005 and December 2019, 102 patients in the Non-EBRT group and 26 patients in the EBRT group were evaluated. In the 48 propensity score-matched patients, no significant differences in baseline characteristics between the Non-EBRT and EBRT groups were detected. The locoregional recurrence-free survival (LRRFS) and recurrence-free survival (RFS) rates were significantly higher in the EBRT group compared with the rates in the Non-EBRT group (5y-LRRFS: 100% vs. 74%, p = 0.003, 5y-RFS: 91% vs. 74%, p = 0.035). EBRT was well-tolerated, with no grade ≥ 3 toxicity, and all patients completed the therapy as planned.

CONCLUSION

Adjuvant EBRT plus RAI exhibited acceptable toxicity and improved LRRFS and RFS in patients with PTC with other organ invasions compared with RAI alone.

Effect of postoperative radiotherapy for patients with differentiated thyroid cancer

OBJECTIVE

We evaluated the efficacy and safety of postoperative radiotherapy (PORT) for differentiated thyroid cancer (DTC) with high risk features.

MATERIALS AND METHODS

This retrospective study analyzed 187 patients treated for DTC from 1985 to 2019. DTC referred to nonanaplastic thyroid cancer originating from follicular cells. PORT was defined as the administration of external beam radiation to the thyroid and regional lymph nodes following surgery for initially diagnosed DTC. The patients were included in the analysis if they received PORT or exhibited any of the following features: (a) pT4 or pN1b according to the 8th American Joint Committee on Cancer, (b) poorly differentiated thyroid cancer (PDTC), or (c) unfavourable variants such as anaplastic foci and etc. After 1:1 propensity matching, a total of 108 patients were analyzed according to PORT receipt. The median follow-up duration of the matched group was 10.4 years.

RESULTS

After matching, most of the variables became balanced, but the PORT group still had more PDTC and DTC with anaplastic foci. Radioactive iodine (RAI) was less frequently administered in the PORT group. PORT yielded a significantly higher 5-year locoregional recurrence free survival (LRFS) than the No PORT group (5-year LRFS 86.1% vs. 72.7%, p = 0.022), but the 10-year cancer specific survival (CSS) was similar between them (97.8% vs. 85.9%, p = 0.122). The multivariable analysis indicated that PORT was a favourable prognostic factor (Hazard ratio 0.3, 95% Confidence interval 0.1-0.8, p = 0.02) for LRFS, but not for CSS. Among 133 patients without PORT for initial disease, 39 of them received salvage surgery followed by salvage PORT. No severe toxicity after PORT was reported.

CONCLUSION

PORT reduced locoregional recurrence in DTC patients without severe toxicity. PORT can be an effective and safe treatment to improve locoregional control in DTC with high risk features. However, further study is warranted to identify those who can benefit from PORT.

The role of external beam radiation therapy in the management of thyroid carcinomas: A retrospective study in Iran Cancer Institute

BACKGROUND

Thyroid cancers are histologically classified into three types; differentiated thyroid carcinoma (DTC), medullary thyroid carcinoma (MTC), and anaplastic thyroid carcinoma (ATC). Among the several therapeutic strategies for treatment and management of thyroid cancer, surgical resection in combination with radioactive iodine therapy (RAI) is indicated for moderate to high-risk differentiated thyroid cancer (DTC) patients- according to current guidelines. However, external radiation therapy (EBRT) can be a viable alternative treatment option for these patients and scarce evidence is available regarding the efficacy and effectiveness of EBRT on thyroid cancer.

AIM

This study aims at evaluating the role of EBRT in the management of thyroid carcinomas.

METHODS AND RESULTS

In this retrospective cohort study, the records of 59 patients with thyroid cancer were accessed who were treated by EBRT from 2008 to 2016. The indications for EBRT included unresectable primary (definitive) or loco-regional recurrences (salvage) not suitable for RAI, palliation for local disease or metastatic foci (palliative), and the adjuvant treatment for suspected residual disease following resection. Progression-free survival (PFS) and overall survival (OS) were calculated for different types of cancer. PFS was measured from the start of EBRT to the last uneventful follow-up, recurrence, or death. Kaplan-Meier model was used for the survival analysis. Fifty-nine patients were evaluated. The histopathology of the tumors was differentiated and poorly-differentiated, medullary and anaplastic thyroid carcinomas in 22 and 6, 15 and 16 patients, respectively. Twenty-seven patients received external beam radiotherapy (EBRT) as adjuvant therapy and 18 of the cases as palliative therapy while the remaining received salvage or definitive primary EBRT. The stage of patients' cancer was as follows: stage II in 3 and III in 1, IVA in 18 and IVB in 18 and IVC in 19. Stage-based median overall survival was 26 months for IVA, 44 for IVB, and 29 for IVC. The median PFS was 18, 22 and 21 months for stages IVA, IVB and IVC, respectively.

CONCLUSION

Based on our findings, EBRT may still play a role in the management of patients with thyroid carcinoma and should be considered in the armamentarium against thyroid cancers.

125I Seed Brachytherapy for Refractory Loco-Regional Recurrence of Non-Anaplastic Thyroid Cancer

Purpose

The purpose of this research was to evaluate the feasibility and efficacy of ¹²⁵I seed brachytherapy as salvage treatment for recurrence from non-anaplastic thyroid cancer refractory to other modalities.

Methods

Between June 2006 and September 2019, fifteen patients with recurrent non-anaplastic thyroid cancer were treated with ¹²⁵I seed brachytherapy. ¹²⁵I seeds were implanted into the tumor under the guidance of CT and/or ultrasound images with the median prescription dose of 120 Gy (range, 100-140 Gy). The median seed number was 80 (range 10-214). Clinical efficacy was evaluated with Response Evaluation Criteria in Solid Tumors.

Findings

Fifteen patients were selected, eleven of whom had papillary carcinoma, two suffered from follicular carcinoma, and two were diagnosed with medullary carcinoma. These patients had twenty-four nodes in total. After they received salvage surgery and/or radioactive iodine (RAI) therapy, local recurrence was detected in all of them. No less than one node was observed in everyone’s cervical or supraclavicular areas, and four patients had lung metastatic. The median follow-up period lasted 48 months (range, 5-93 months). All patients did not develop locoregional recurrence after experiencing ¹²⁵I seed brachytherapy. Only three of them formed new metastases in nontarget regional nodes after brachytherapy, and additional brachytherapy can solve all regional failure problems. No significant adverse events were observed in any patient.

Implications

For the chosen patients, 125I seed brachytherapy is feasible for treating refractory local recurrence from non-anaplastic thyroid cancer. Further studies are required to determine the role of 125I seed brachytherapy in the treatment of thyroid cancer.

Postoperative external beam radiotherapy for locoregional control in iodine refractory differentiated thyroid cancer

BACKGROUND

The role of postoperative external beam radiotherapy (EBRT) in patients with residual iodine refractory-differentiated thyroid cancer (IR-DTC) is still inconclusive. The aim of this retrospective study was to evaluate locoregional control (LRC) and overall survival (OS), and potential side effects after postoperative EBRT for both microscopic and macroscopic non-radically resected, locally advanced IR-DTC.

METHODS

Between 1990 and 2016, 49 patients with locally advanced IR-DTC received EBRT for microscopic (R1; n = 28) or macroscopic (R2; n = 21) locoregional residual disease. For more insight into the added effect of EBRT, we performed an intrapatient sub-analysis in 32 patients who had undergone more than 1 surgical intervention, comparing LRC after primary, curative-intended surgery with LRC after repeated surgery plus EBRT. To estimate LRC and OS, we used Kaplan-Meier curves. From 2007 onward, we prospectively recorded toxicity data in our head and neck cancer database (n = 10).

RESULTS

LRC rates 5 years after EBRT were higher for R1 (84.3%) than for R2 (44.9%) residual disease (P = 0.016). The 5-year OS rate after EBRT was 72.1% for R1 and 33.1% for R2 disease (P = 0.003). In the intrapatient analysis (n = 32), LRC rates were 6.3% 5 years after only initial surgery and 77.9% after repeated surgery with EBRT (P < 0.001). Acute toxicity was limited to grade I and II xerostomia, mucositis, and hoarseness; only one patient developed late grade III dysphagia.

CONCLUSIONS

Postoperative EBRT is associated with long-lasting LRC and OS with acceptable toxicity in patients with locally advanced IR-DTC, especially in microscopic residual disease.

Outcomes of Tracheal Resections in Well-Differentiated Thyroid Cancer-A case series and meta-analysis

BACKGROUND

Tracheal invasion in thyroid cancer is a well-known form of advanced disease. There is an ongoing controversy over outcomes of tracheal shaving in this situation. The aim of this study was to compare the results of tracheal shaving to radical resections in patients with low-volume tracheal involvement.

METHODS

An institutional case series and a meta-analysis was conducted. All studies that included patients diagnosed with well-differentiated thyroid cancer (WDTC) and tracheal invasion were analyzed. Patients with low-volume tracheal invasion (according to the Shin classification) were extracted from the various studies and subsequently included in this study. The outcomes of tracheal shaving and radical resection were consolidated and compared. All recurrences and mortality over 10 years of follow-up were calculated using the Kaplan-Meier method.

RESULTS

Institutional case series included 22 patients diagnosed with WDTC and tracheal invasion that underwent resection. There was one case of recurrence (4.5%) during the follow-up period and no mortality. The meta-analysis yielded a total of 284 patients from six studies who met the inclusion criteria. The 10-year overall survival was 82.4% for the shave group and 80.8% for the resection group. The combined Kaplan-Meier curves revealed no statistically significant difference between the two techniques (hazard ratio [HR] = 0.86, P = .768). The combined 10-year local control rate of the shave group was 90.2%.

CONCLUSIONS

The outcomes of tracheal shaving in low-volume invasion are similar to more aggressive forms of tracheal resections. Shave resection is oncologically safe in carefully selected WDTC patients demonstrating minimal tracheal invasion.

External Beam Radiation Therapy in pT4 Well-Differentiated Thyroid Cancer: A Population-Based Study of 405 Patients

PURPOSE

The benefit of external beam radiation therapy (EBRT) in locally advanced, well- differentiated thyroid cancer (WDTC) is uncertain. The purpose of this study is to evaluate locoregional recurrence (LRR), progression-free survival, and cause-specific survival (CSS) of patients with pT4 well-differentiated thyroid carcinoma.

METHODS AND MATERIALS

A population-based retrospective review was conducted of consecutive patients with pT4 WDTC (per the American Joint Committee on Cancer, 8th edition, criteria) treated provincially between 1985 and 2013. The primary endpoints were cumulative incidence of LRR and CSS. To account for the competing risks of death from other causes, a Fine-Gray's test was used. A Cox-proportional hazards model was used to analyze overall survival (OS). Multivariate models and propensity matching were used to account for the effects of covariates.

RESULTS

A total of 405 patients were identified with a median follow-up time of 14.3 years for a total of 4209 person-years of follow up. The median age at the time of diagnosis was 53 years (range, 20-87). There were 211 patients (52%) who received EBRT. EBRT was associated with age ≥55 years (56% vs 35%; P < .001), airway involvement (42% vs 8%; P < .001), and R1/2 resection (81% vs 51%; P < .001). The 10-year outcomes for the non-EBRT and EBRT groups were 21.6% versus 11.4%, respectively, for LRR, 84.1% versus 93.1%, respectively, for CSS, and 85.7% versus 67.5%, respectively, for OS. On multivariate analysis, EBRT was associated with a lower rate of LRR (hazard ratio [HR]: 0.334; P < .001), but not associated with CSS (HR: 1.56; P = .142) nor OS (HR: 1.216; P = .335). After propensity score matching, the EBRT cohort had lower rates of LRR relative to the non-EBRT cohort (HR: 0.261; P = .0003), but there were no differences in CSS or OS.

CONCLUSIONS

In this large, population-based analysis of patients with pT4 WDTC, EBRT was associated with lower rates of LRR, but no difference in CSS or OS.

Surgical treatment of locally advanced thyroid cancer

Operations in this area are demanding and require special experience in endocrine, thoracic and vascular surgery, an experienced anaesthesiologist, as well as the interdisciplinary cooperation with other medical specialists (nuclear medicine, oncology, radiology, otolaryngology). A reliable system of surgical guidelines has been developed from a few individual publications with special impact.

The Role of postoperative external beam radiotherapy for differentiated thyroid carcinoma: A Systematic review and meta-analysis

The indications for external beam radiotherapy (RT) in differentiated thyroid carcinomas (DTC) are still undefined. The objective of this study was to synthesize current evidence defining the role of postoperative RT in patients with DTC. A systematic review and meta-analysis were done. Included studies compared oncologic outcomes and toxicity of RT vs no RT in patients with DTC. Nine studies were included, two prospective and seven retrospective cohorts. RT improved 5-year locoregional recurrence-free survival but not overall survival and distant metastasis failure-free survival. The locoregional control benefit was seen in patients at increased risk for recurrence, including those with advanced age, locoregionally advanced disease, gross or microscopic residual tumor, and structural invasion. Serious RT-related acute and late toxicities were rare. Available evidence suggests that postoperative RT can improve locoregional control in high-risk DTC with acceptable toxicity. Further prospective studies are warranted.

10-Year Locoregional Control with Postoperative External Beam Radiotherapy in Patients with Locally Advanced High-Risk Non-Anaplastic Thyroid Carcinoma De Novo or at Relapse, a Propensity Score Analysis

(1) Background: To assess the role of postoperative external beam radiotherapy (pEBRT) on locoregional failure (LRF) for patients with locally advanced high-risk non-anaplastic thyroid carcinoma (naTC) at primary event or relapse. (2) Methods: Between 1995 and 2015, postoperative naTC patients with a theoretical indication for EBRT were included based on criteria that were common to American-British-French current guidelines, i.e., pT3-4, pN+, gross or microscopic residual disease. Inverse probability of treatment weighting (IPTW) after multiple imputation was used to reduce selection biases. (3) Results: Of 254 naTC patients, 216 patients underwent pEBRT (106 de novo, 110 at relapse, median dose 60 Gy) and 38 underwent surgery only. pEBRT patients had more gross residual disease, a major prognostic factor (p = 0.027) but less perineural invasion (p = 0.008) or lymphovascular emboli (p = 0.009). pEBRT patients more frequently underwent radioiodine therapy (p = 0.026). The 10-year cumulative incidence of LRF was 56% (95% CI, 32–74%) in operated patients, and 23% (95% CI, 17–30%) in pEBRT patients. After IPTW method, pEBRT reduced the risk of LRF (hazard ratio 0.30; 95% CI [0.18–0.49], p < 0.001), but had no impact on OS. In the pEBRT group, non-Intensity Modulated RadioTherapy (IMRT) plans and interruption of the radiotherapy were associated with poorer survival, while extended versus limited field strategy and dose were not. (4) Conclusions: In naTC patients who have pT3-4, pN+ disease or R1-2 resection, pEBRT improved LRF. Limited-field IMRT is preferred.

The role of external beam radiation therapy in well-differentiated thyroid cancer

INTRODUCTION

This review article explores the use of external beam radiotherapy (EBRT) in well differentiated thyroid cancer. Areas covered: The published literature on EBRT for advanced pT4 disease and macroscopic unresectable disease to improve locoregional control is reviewed. EBRT techniques, volumes and doses are discussed in detail. The potential acute and late toxicities of EBRT are discussed in the context of the published literature. The use of EBRT for patients with metastatic disease is also described. Expert commentary: There is good retrospective evidence for EBRT in the setting of unresectable gross residual well-differentiated thyroid cancer as this can result in long-term local control. However, the benefit of EBRT in patients with locally advanced disease that is completely resected is less clear. The use of EBRT for these patients requires careful consideration of age, pathologic factors, comorbidities and patient preference, preferably by a multi-disciplinary team.

Comparison of Survival Outcomes Following Postsurgical Radioactive Iodine Versus External Beam Radiation in Stage IV Differentiated Thyroid Carcinoma

BACKGROUND

There is a lack of well-powered data regarding outcomes in stage IV differentiated thyroid carcinoma (DTC) treated with postsurgical radiation. The objective of this study was to examine survival in patients with stage IV papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) who received radioactive iodine (RAI), external beam radiation therapy (EBRT), or neither following surgery.

METHODS

In this retrospective cohort study, data collected from the National Cancer Data Base (NCDB) yielded 11,832 patients with stage IV DTC who underwent primary surgical treatment between 2002 and 2012. Patients were stratified by histology and sub-stage. Fully parametric, multilevel survival-time models were used to evaluate survival outcomes in three adjuvant treatment groups: RAI, EBRT, or no adjuvant radiation. Hazard ratios (HR) and time ratios (TR) were calculated against patients who did not receive radiation. All models were adjusted for demographic and clinical factors.

RESULTS

The mean age of all patients was 61.6 years (SD = 11.6), and 57.5% were female. Patients who received EBRT had significantly higher 5- and 10-year hazards of death in several PTC sub-stages (10-year HR_{PTC Stage IV-A} = 2.12 [confidence interval (CI) 1.79-2.52]; HR_{PTC Stage IV-B} = 2.03 [CI 1.33-3.10]). For stage IV-B PTC requiring EBRT, lifespan after diagnosis was shortened by a factor of 3 when compared to patients who did not receive radiation (TR_{PTC Stage IV-B} = 0.32 [CI 0.16-0.62]). In contrast, RAI was significantly associated with improved 5- and 10-year survival in both PTC and FTC patients regardless of pathological sub-stage. Large reductions in mortality were observed in patients with FTC who were treated with RAI (HR_{FTC Stage IV-C} = 0.19 [CI 0.06-0.65]). When patients with stage IV-C FTC were treated with RAI, life-span after diagnosis doubled (TR_{FTC Stage IV-C} = 1.98 [CI 1.31-3.00]).

CONCLUSIONS

Through the NCDB, this study sought to describe prognosis and survival for adjuvant radiation in stage IV DTC. RAI was associated with improved survival for stage IV DTC. Despite treatment benefits conferred by adjuvant EBRT, indications to treat with EBRT were associated with poorer survival outcomes in patients with advanced-stage DTC, particularly PTC.

The role of adjuvant external beam radiation therapy for papillary thyroid carcinoma invading the trachea

PURPOSE

To evaluate the effect of adjuvant external beam radiation therapy (EBRT) on local failure-free survival rate (LFFS) for papillary thyroid cancer (PTC) invading the trachea.

MATERIALS AND METHODS

Fifty-six patients with locally advanced PTC invading the trachea were treated with surgical resection. After surgery, 21 patients received adjuvant EBRT and radioactive iodine therapy (EBRT group) and 35 patients were treated with radioactive iodine therapy (control group).

RESULTS

The age range was 26-87 years (median, 56 years). The median follow-up period was 43 months (range, 4 to 145 months). EBRT doses ranged from 50.4 to 66 Gy (median, 60 Gy). Esophagus invasion and gross residual disease was more frequent in the EBRT group. In the control group, local recurrence developed in 9 (9/35, 26%) and new distant metastasis in 2 (2/35, 6%) patients, occurring 4 to 68 months (median, 37 months) and 53 to 68 months (median, 60 months) after surgery, respectively. Two patients had simultaneous local recurrence and new distant metastasis. There was one local failure in the EBRT group at 18 months after surgery (1/21, 5%). The 5-year LFFS was 95% in the EBRT group and 63% in the control group (p = 0.103). In the EBRT group, one late grade 2 xerostomia was developed.

CONCLUSION

Although, EBRT group had a higher incidence of esophagus invasion and gross residual disease, EBRT group showed a better 5-year LFFS. Adjuvant EBRT may have contributed to the better LFFS in these patients.

Hürthle cell carcinoma: current perspectives

Hürthle cell carcinoma (HCC) can present either as a minimally invasive or as a widely invasive tumor. HCC generally has a more aggressive clinical behavior compared with the other differentiated thyroid cancers, and it is associated with a higher rate of distant metastases. Minimally invasive HCC demonstrates much less aggressive behavior; lesions <4 cm can be treated with thyroid lobectomy alone, and without radioactive iodine (RAI). HCC has been observed to be less iodine-avid compared with other differentiated thyroid cancers; however, recent data have demonstrated improved survival with RAI use in patients with HCC >2 cm and those with nodal and distant metastases. Patients with localized iodine-resistant disease who are not candidates for a wait-and-watch approach can be treated with localized therapies. Systemic therapy is reserved for patients with progressive, widely metastatic HCC.

Primary ectopic substernal thyroid cancer with trachea relapse: a case report and opinions of management

Background

Ectopic substernal thyroid is a rare symptom of thyroid disease that entirely results from the developmental defects at early stages of thyroid embryogenesis and during its descent. Cases were seldom reported as primary ectopic substernal thyroid cancer, especially those with severe local invasion and tracheal relapse.

Case Presentation

In this report, the patient presented odynophagia and a sense of progressing swallowing obstruction. She underwent total thyroidectomy and lump resection. However, she refused to use postoperative radioactive iodine or take adjuvant external-beam radiotherapy, except for thyroid hormone replacement therapy. Tracheal relapse was observed after 6 months. Tracheal stent was used to reconstruct the airway twice.

Conclusions

Trachea invasion might be a worse independent predictor of prognosis than any others and should be given particular attention. Furthermore, tracheal stent might be a palliative option for patients with tracheal relapse.

The Role of Adjuvant Radiation Therapy for Locoregionally Advanced Papillary Thyroid Carcinoma

OBJECTIVES

To investigate the role of adjuvant radiation therapy in locoregional control in patients with locoregionally advanced papillary thyroid carcinoma (pT4 or pN1b) based on a comparison of a group that received radiation therapy and a group that did not receive radiation therapy.

METHODS

A retrospective analysis was performed on 165 patients with locoregionally advanced papillary thyroid carcinoma who underwent treatment between 2002 and 2011. Of these, 32 patients received adjuvant radiation therapy, and 133 patients did not receive radiation therapy.

RESULTS

The median follow-up period was 7.2 years (range, 3.4-13.6) for the overall study population. The 10-year locoregional recurrence-free survival rates for patients in the radiation therapy and no radiation therapy groups were 83.9 and 60.8%, respectively (p = 0.037). The overall survival rate and distant recurrence-free survival rate were not different between the two groups (p = 0.076 and p = 0.813, respectively). Multivariate analysis showed that adjuvant radiation therapy was an independent prognostic factor for locoregional recurrence-free survival (p = 0.040).

CONCLUSIONS

Adjuvant radiation therapy for patients with either pT4 or pN1b disease improved locoregional recurrence-free survival and might be of benefit for patients with these high-risk features by reducing the need for additional salvage treatment after locoregional recurrence.

External Beam Radiation in Differentiated Thyroid Carcinoma

The treatment of differentiated thyroid carcinoma (DTC) is surgery followed in some cases by adjuvant treatment, mostly with radioactive iodine (RAI). External beam radiotherapy (EBRT) is less common and not a well-established treatment modality in DTC. The risk of recurrence depends on three major prognostic factors: extra-thyroid extension, patient's age, and tumor with reduced iodine uptake. Increased risk for recurrence is a major factor in the decision whether to treat the patient with EBRT. Data about the use of EBRT in DTC are limited to small retrospective studies. Most series have demonstrated an increase in loco-regional control. The risk/benefit from giving EBRT requires careful patient selection. Different scoring systems have been proposed by different investigators and centers. The authors encourage clinicians treating DTC to become familiarized with those scoring systems and to use them in the management of different cases. The irradiated volume should include areas of risk for microscopic disease. Determining those areas in each case can be difficult and requires detailed knowledge of the surgery and pathological results, and also understanding of the disease-spreading pattern. Treatment with EBRT in DTC can be beneficial, and data support the use of EBRT in high-risk patients. Randomized controlled trials are needed for better confirmation of the role of EBRT.

External-beam radiotherapy for differentiated thyroid cancer locoregional control: A statement of the American Head and Neck Society

The use of external-beam radiotherapy (EBRT) in differentiated thyroid cancer (DTC) is debated because of a lack of prospective clinical data, but recent retrospective studies have reported benefits in selected patients. The Endocrine Surgery Committee of the American Head and Neck Society provides 4 recommendations regarding EBRT for locoregional control in DTC, based on review of literature and expert opinion of the authors. (1) EBRT is recommended for patients with gross residual or unresectable locoregional disease, except for patients <45 years old with limited gross disease that is radioactive iodine (RAI)-avid. (2) EBRT should not be routinely used as adjuvant therapy after complete resection of gross disease. (3) After complete resection, EBRT may be considered in select patients >45 years old with high likelihood of microscopic residual disease and low likelihood of responding to RAI. (4) Cervical lymph node involvement alone should not be an indication for adjuvant EBRT.

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.

Patients Treated at Low-Volume Centers have Higher Rates of Incomplete Resection and Compromised Outcomes: Analysis of 31,129 Patients with Papillary Thyroid Cancer

BACKGROUND

Data on the importance of margin status after total thyroidectomy for papillary thyroid cancer (PTC) remain limited. This study sought to identify factors associated with positive margins and to determine the impact of positive margins on survival for patients with PTC.

METHODS

The National Cancer Data Base (1998-2006) was queried for patients with PTC who had undergone total thyroidectomy. The patients were divided into three groups based on margin status (negative, microscopically positive, and macroscopically positive). Patient demographic, clinical, and pathologic features were evaluated. A binary logistic regression model was developed to identify factors associated with positive margins. A Cox proportional hazards model was developed to identify factors associated with survival.

RESULTS

Of the 31,129 patients enrolled in the study, 91.3 % had negative margins, 8.1 % had microscopically positive margins, and 0.6 % had macroscopically positive margins. The patients with negative margins were younger and more likely to be female, white, covered by private insurance, and treated at an academic or high-volume center (p < 0.05). They had smaller tumors and were less likely to have advanced-stage disease. After multivariable adjustment, increasing patient age [odds ratio (OR) = 1.02; p < 0.01], government insurance (OR = 1.20; p < 0.01), and no insurance (OR = 1.34; p = 0.01) were associated with positive margins. Reception of surgery at a high-volume facility (OR = 0.72; p < 0.01) was protective. After multivariable adjustment, both microscopically [hazard ratio (HR), 1.49; p < 0.01] and macroscopically positive margins (HR = 2.38; p < 0.01) were associated with compromised survival.

CONCLUSIONS

Several vulnerable patient populations have a higher risk of incomplete resection after thyroidectomy for PTC. High-risk thyroid cancer patients should be referred to high-volume centers to optimize outcomes.

External beam radiotherapy in differentiated thyroid carcinoma: A systematic review

External beam radiotherapy (EBRT) is not a first line treatment in differentiated thyroid carcinoma (DTC), but is recommended as an adjuvant treatment in certain cases. The evidence for EBRT in DTC is limited. A comprehensive literature search was performed. Data on patient demographics, disease stage, treatment characteristics, and outcomes were collected from included articles after quality appraisal. Sixteen articles met the inclusion criteria, with a pooled population of 5114. Only 1 study was prospective and there were no randomized controlled trials. Most of the evidence suggests that EBRT improves locoregional control in patients at high risk of locoregional recurrence. This was corroborated by analysis of pooled patient data. Available evidence suggests an improvement in locoregional control when EBRT is used in patients over the age of 45 at high risk for locoregional recurrence. However, there is a need for long-term prospective multicenter research on the subject. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2297-E2305, 2016.

Management of invasive well-differentiated thyroid cancer: an American Head and Neck Society consensus statement. AHNS consensus statement

BACKGROUND

Invasive differentiated thyroid cancer (DTC) is relatively frequent, yet there is a paucity of specific guidelines devoted to its management. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to provide clinical consensus statements based on review of the literature, synthesized with the expert opinion of the group.

METHODS

An expert panel, selected from membership of the AHNS, constructed the manuscript and recommendations for management of DTC with invasion of recurrent laryngeal nerve, trachea, esophagus, larynx, and major vessels based on current best evidence. A Modified Delphi survey was then constructed by another expert panelist utilizing 9 anchor points, 1 = strongly disagree to 9 = strongly agree. Results of the survey were utilized to determine which statements achieved consensus, near-consensus, or non-consensus.

RESULTS

After endorsement by the AHNS Endocrine Committee and Quality of Care Committee, it received final approval from the AHNS Council.

External beam radiotherapy with or without concurrent chemotherapy in advanced or recurrent non-anaplastic non-medullary thyroid cancer

BACKGROUND AND OBJECTIVES

To review clinical outcomes and toxicities in locally advanced differentiated thyroid cancer patients treated with external beam radiotherapy (EBRT) with or without concurrent chemotherapy (CCRT).

METHODS

Between 1990 and 2012, 66 patients with gross residual/unresectable non-anaplastic non-medullary thyroid cancer were treated with EBRT.

RESULTS

The median overall survival was 42.0 months. The overall locoregional progression-free survival (LPFS) at 3 years was 77.3%. CCRT resulted in a non-significant improvement in LPFS (90.0% vs. 73.0%, P = 0.347). Poorly differentiated histology had significantly improved LPFS (89.4% vs. 66.1%, P = 0.020), despite a significantly worse distant metastasis-free survival (43.9% vs. 82.5%, P = 0.023). Acute treatment-related toxicity included dermatitis, mucositis, and dysphagia with grade three rates of 12.1%, 19.7%, and 16.7%, respectively. The incidence of late toxicity was low. CCRT was only associated with a significant greater rate of acute grade 3 hoarseness (10.0% vs. 0.0%, P = 0.033), but with no difference in the rate of grade 2 late toxicity.

CONCLUSIONS

EBRT is a safe and effective treatment modality with 90% LPFS at 3 years in patients with gross residual or unresectable non-anaplastic, non-medullary thyroid carcinoma treated with CCRT. Further incorporation of EBRT with concurrent chemotherapy may result in improved disease control.

Role of adjuvant postoperative external beam radiotherapy for well differentiated thyroid cancer

PURPOSE

To analyze the outcome of adjuvant postoperative external beam radiotherapy (EBRT) in well-differentiated thyroid cancer (WDTC).

MATERIALS AND METHODS

We identified 84 patients treated with EBRT for WDTC from February 1981 to December 2010. Among them, we analyzed 39 patients who received EBRT after initial radical surgery. Twenty-four females and 15 males were included. The median age was 49 years (range, 16 to 72 years). There were 34 papillary thyroid carcinomas and 5 follicular thyroid carcinomas. Most patients showed pathologic T3/T4 stage (54%/26%). Ten patients (25.6%) had gross residual tumors. Five patients (12.8%) had tumor cells at the margin. The median EBRT dose and fraction size were 62.6 Gy and 1.8 to 2.0 Gy, respectively.

RESULTS

The median follow-up was 73 months (range, 21 to 372 months). The five-year overall survival (OS) and locoregional recurrence free survival (LRFS) were 97.4% and 86.9%, respectively. Locoregional failures occurred in 5 and all failure sites were the neck node area. In univariate analysis, OS was significantly influenced by invasion of the trachea (p = 0.016) or esophagus (p = 0.006). LRFS was significantly decreased by male (p = 0.020), gross residuum after resection (p = 0.002), close or positive tumor at surgical margin involvement (p = 0.044), and tracheal invasion (p = 0.040). No significant prognostic factor was identified in the multivariate analysis. No patient experienced the Radiation Therapy Oncology Group grade 3 or more toxicity.

CONCLUSION

Our locoregional control rate of 87.2% is comparable to historical controls with surgery alone, even though our study had a large proportion of advanced stage. Adjuvant EBRT may an effective and safe treatment option in patients with WDTC.

[Radiation therapy in thyroid cancer]

Anaplastic thyroid cancers represent 1-2% of all thyroid tumours and are of very poor prognosis even with multimodality treatment including external beam radiation therapy. Conversely, differentiated thyroid carcinomas (at least 80% of thyroid cancers) hamper good prognosis with surgery with or without radioiodine and there is hardly any room for external beam radiation therapy. Insular and medullar carcinomas have intermediary prognosis and are rarely irradiated. We aimed to update recommendations for external beam irradiation in these different clinical situations and put in light the benefits of new irradiations techniques. A search of the French and English literature was performed using the following keywords: thyroid carcinoma, anaplastic, chemoradiation, radiation therapy, surgery, histology and prognostic. Non-mutilating surgery (often limited to debulking) followed by systematic external beam radiation therapy is the standard of care in anaplastic thyroid cancers (hyperfractionated-accelerated radiation therapy with low-dose weekly doxorubicin with or without cisplatin if possible). Given anaplastic thyroid cancers' median survival of 10 months or less, neoadjuvant and adjuvant chemotherapy may also be discussed. Ten-year survival rates for patients with papillary, follicular and Hürthle-cell carcinomas are 93%, 85%, and 76%, respectively. Massive primary incompletely resected iodine-negative disease indicates external beam radiation therapy. Older age (45 or 60-year-old), poor-prognosis histological variants (including tall cell cancers) and insular cancers are increasingly reported as criteria for external beam radiation therapy. Massive extracapsular incompletely resected nodal medullary disease suggests external beam radiation therapy. Radiation therapy morbidity has been an important limitation. However, intensity modulated radiation therapy (IMRT) offers clear dosimetric advantages on tumour coverage and organ sparing, reducing late toxicities to less than 5%. The role of radiation therapy is evolving for anaplastic thyroid cancers using multimodal strategies and new chemotherapy molecules, and for differentiated cancers using minor criteria, such as histological variants, with IMRT becoming a standard of care.

The effect of external beam radiotherapy volume on locoregional control in patients with locoregionally advanced or recurrent nonanaplastic thyroid cancer

PURPOSE

We evaluated outcomes of patients treated with external beam radiotherapy (EBRT) for locoregionally advanced or recurrent nonanaplastic thyroid cancer and analyzed the effect of EBRT volume on locoregional control.

METHODS

This study included 23 patients with locoregionally advanced or recurrent nonanaplastic thyroid cancer who were treated with EBRT. Two different EBRT target volumes were executed as follows: 1) limited field (LF, n = 11) included the primary (involved lobe) or recurrent tumor bed and the positive nodal area; 2) elective field (EF, n = 12) included the primary (involved lobe) or recurrent tumor bed and the regional nodal areas in the cervical neck and upper mediastinum. Clinical parameters, such as gender, age, histologic type, recurrence, stage, thyroglobulin level, postoperative residuum, radioiodine treatment, and EBRT volume were analyzed to identify prognostic factors associated with locoregional control.

RESULTS

There were no significant differences in the clinical parameter distributions between the LF and EF groups. In the LF group, six (55%) patients developed locoregional recurrence and three (27%) developed distant metastasis. In the EF group, one (8%) patient developed locoregional recurrence and one (8%) developed a distant metastasis. There was a significant difference in locoregional control rate at 5 years in the LF and EF groups (40% vs. 89%, p = 0.041). There were no significant differences in incidences of acute and late toxicities between two groups (p >0.05).

CONCLUSIONS

EBRT with EF provided significantly better locoregional control than that of LF; however, further larger scaled studies are warranted.

Differentiated thyroid cancer with extrathyroidal extension: prognosis and the role of external beam radiotherapy

A study was performed to identify variables that affected cause-specific survival (CSS) and local relapse-free rate (LRFR) in patients with differentiated thyroid cancer (DTC) and extrathyroid extension (ETE) and to examine the role of external beam radiotherapy (XRT). Prognostic factors were similar to those found in studies of all patients with DTC. In patients with postoperative gross residual disease treated with radiotherapy, 10-year CSS and LRFR were 48% and 90%. For patients with no residual or microscopic disease, 10-year CSS and LRFR were 92% and 93%. In patients older than 60 years with T3 ETE but no gross residual disease postoperatively there was an improved LRFR at 5 years of 96%, compared to 87.5% without XRT (P = .02). Patients with gross ETE benefit from XRT and there may be a potential benefit in reducing locoregional failure in patients over 60 years with minimal extrathyroidal extension (T3).

Stereotactic body radiotherapy for refractory cervical lymph node recurrence of nonanaplastic thyroid cancer

OBJECTIVE

To investigate the feasibility and efficacy of stereotactic body radiotherapy as salvage treatment for cervical node recurrence from nonanaplastic thyroid cancer refractory to other modalities.

STUDY DESIGN

Pilot study.

SETTING

A single institution-based practice.

SUBJECTS AND METHODS

Between August 2002 and November 2007, nine patients with recurrent nonanaplastic thyroid cancer were treated with stereotactic body radiotherapy for nodal metastases. Radiotherapy was delivered in one to three fractions, and the median dose was 36 Gy (range 30-39 Gy).

RESULTS

Twenty-nine nodes in nine patients were treated. Seven patients had papillary carcinoma, and two had medullary carcinoma. These patients developed nodal recurrence after they received salvage surgery and/or radioisotope (RI) treatment for recurrent thyroid cancer. All nodes were in the cervical or supraclavicular areas, excepting one hilar node. Retropharyngeal node metastases were present in five patients. The median follow-up period was 23 months (range 4-63 mo). No local progression was observed in nodes treated by stereotactic body radiotherapy. Four patients developed new metastases in nontarget regional nodes after radiotherapy, and in two of these, regional failure was salvaged by additional stereotactic body radiotherapy. No serious adverse events were observed in any patient.

CONCLUSION

In select patients, stereotactic body radiotherapy may be a feasible option for treating refractory nodal recurrence from nonanaplastic thyroid cancer. Further studies are necessary to define the role of stereotactic body radiotherapy in the management of thyroid cancer.

Guidelines for radioiodine therapy of differentiated thyroid cancer

INTRODUCTION

The purpose of the present guidelines on the radioiodine therapy (RAIT) of differentiated thyroid cancer (DTC) formulated by the European Association of Nuclear Medicine (EANM) Therapy Committee is to provide advice to nuclear medicine clinicians and other members of the DTC-treating community on how to ablate thyroid remnant or treat inoperable advanced DTC or both employing large 131-iodine ((131)I) activities.

DISCUSSION

For this purpose, recommendations have been formulated based on recent literature and expert opinion regarding the rationale, indications and contraindications for these procedures, as well as the radioiodine activities and the administration and patient preparation techniques to be used. Recommendations also are provided on pre-RAIT history and examinations, patient counselling and precautions that should be associated with (131)I iodine ablation and treatment. Furthermore, potential side effects of radioiodine therapy and alternate or additional treatments to this modality are reviewed. Appendices furnish information on dosimetry and post-therapy scintigraphy.

External beam radiation therapy for thyroid cancer

This article discusses the role of external beam radiotherapy (XRT) in the management of well-differentiated thyroid cancer (WDTC), medullary thyroid cancer, and anaplastic thyroid cancer. Although there are no randomized controlled studies on the use of XRT in thyroid cancer, evidence supports its use to treat gross disease after surgery or unresectable cancer and its use as an adjuvant after resection of a known high-risk disease in WDTC, and, to a lesser extent, in medullary thyroid cancer. The use of XRT for the palliation of symptomatic disease and recent advances in the technology of radiation delivery also will be discussed.