Multicenter Study Differentiated Thyroid Carcinoma (MSDS)

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.

Neutron radiation therapy for advanced thyroid cancers

PURPOSE

The aim of this study was to review institutional outcomes for advanced thyroid cancers treated with fast neutron radiation therapy (FNRT) and photon radiation therapy (RT).

METHODS AND MATERIALS

In all, 62 consecutive patients were analyzed. Fifty-nine had stage IV disease. Twenty-three were treated with FNRT and 39 with photon RT. Median follow-up was 14 months. The primary endpoint was overall survival (OS).

RESULTS

There was no significant difference in median OS between FNRT and photon RT (26 vs 16 months; P = .49). Patients with well-differentiated histologies had superior median OS with photon RT (17 vs 69 months; P = .04). There was a nonsignificant trend toward improved OS with FNRT for medullary and anaplastic histologies.

CONCLUSIONS

Outcomes in this study are in line with historical results. There is an apparent detriment in OS with FNRT for well-differentiated histologies and a trend toward improved OS with medullary and anaplastic histologies that warrants further investigation.

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.

Differentiated thyroid cancer-personalized therapies to prevent overtreatment

The concept of individualized therapy is rapidly gaining recognition in the management of patients with differentiated thyroid cancer (DTC). This Review provides an overview of the most important elements of this paradigm shift in DTC management and discusses the implications for clinical practice. In the majority of patients with DTC who have an inherently good prognosis, the extent of surgery, the dosage of (131)I therapy and the use of levothyroxine therapy are all aspects suitable for individualization, on the basis of both the stage of disease and the response to treatment. In individuals with advanced disease, newer imaging techniques, advances in (131)I therapy and the use of targeted molecular therapies (such as multitargeted kinase inhibitors) have provided new options for the personalized care of patients, for whom until recently no effective therapies were available. Individualized therapies could reduce adverse effects, including the sometimes debilitating hypothyroidism that used to be required before initiation of (131)I treatment, and major salivary gland damage, a common and unpleasant side effect of (131)I therapy. Highly individualized interdisciplinary treatment of patients with DTC might lead to improved outcomes with reduced severity and frequency of complications and adverse effects. However, in spite of ongoing research, personalized therapies remain in their infancy.

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.

[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.

Primary tumour size is a prognostic parameter in patients suffering from differentiated thyroid carcinoma with extrathyroidal growth: results of the MSDS trial

OBJECTIVE

The Multicentre Study Differentiated Thyroid Cancer (MSDS) collective represents a well-defined group of patients with thyroid carcinomas with extrathyroidal extension. The aim of the present study was to evaluate the relationship of the primary tumour size with clinicopathological features as well as the outcome of patients with minimum and extensive extrathyroidal growth (pT3b- and pT4a-tumours; UICC 2002/2003, 6th ed).

METHODS

The tumour diameter was available in 324 out of 351 MSDS patients (244 females, 80 males). Mean age of patients was 47.7±12.0 years (range, 20.1-69.8 years), and the median follow-up was 6.2 years. The relationship between primary tumour size and the following clinicopathological data was investigated: age, gender, histological tumour type (papillary thyroid carcinomas (PTC) versus follicular thyroid carcinomas (FTC)) and UICC/AJCC TNM classification. In addition, the correlation between primary tumour size and event-free and overall survival was assessed.

RESULTS

The FTC of our series were significantly larger than PTC (3.46 vs 1.84 cm; P<0.001). Patients suffering from pT3b-tumours presented with significantly smaller tumour size than those with extensive extrathyroidal growth (pT4a-tumours) (1.9 vs 3.0 cm; P<0.01). All patients with distant metastases suffered from tumours >2 cm. Furthermore, event-free and overall survival were significantly correlated with increasing tumour size (P<0.05). Using multivariate analysis, a pT4a-category and a tumour diameter >2 cm remained independent predictors of survival.

CONCLUSIONS

In patients suffering from differentiated thyroid carcinoma with extrathyroidal growth (pT3b and pT4a), the tumour size is an independent predictor of event-free and overall survival.

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.

Update on recent developments in the therapy of differentiated thyroid cancer

In the past decade, the management of differentiated thyroid carcinoma changed significantly and thus contributed to the improvement of the already favorable prognosis of this malignant disease. Surgical treatment techniques improved and the extent of initial surgery is more individualized. Radioiodine therapy is an essential part of therapeutic regimens in almost all cases, and the use of recombinant human thyroid-stimulating hormone has established for ablation of remnant tissue, treatment of iodine-positive cancer, and sensitive thyroglobulin measurement during follow-up. Risk stratification has become more important to plan treatment and follow-up individually, particularly to evaluate the need for thyroid-stimulating hormone suppression therapy. Especially for inoperable and radioiodine-negative thyroid carcinomas, novel treatment options such as tyrosine kinase inhibitor therapy have emerged. This article deals with the current options of optimal therapy regimens in differentiated thyroid carcinoma.

Role of surgeons in clinical trials for thyroid cancer

Properly performed clinical trials provide a foundation for evidence-based medical practice. The surgeon plays a central role in the management of patients with malignant solid tumors, including thyroid cancer, because operative extirpation of the malignancy is the essential first step in effective therapy. This article discusses the role of the surgeon in the clinical research of thyroid cancer and also reviews the important clinical trials that have influenced the treatment of patients with thyroid cancer. Recent discoveries defining the genetic mutations underlying the various types of thyroid cancers have led to the development of targeted therapies. These chemical compounds, which are now being evaluated in clinical trials, hold great promise for the treatment of patients with locally advanced and distant metastatic disease. The surgical investigator also plays an important role in procuring tumor tissue from patients in clinical trials. The molecular analysis of these tissues is of critical importance in selecting specific therapies and predicting patient response and prognosis.