Incidence of hypothyroidism following multimodality treatment for advanced squamous cell cancer of the head and neck

Extent of thyroidectomy and paratracheal lymph node dissection in total pharyngolaryngectomy for pyriform sinus cancer, and recurrence, survival, and postoperative hypoparathyroidism: A multicenter retrospective study

BACKGROUND

Total pharyngolaryngectomy (TPL) is standard treatment for hypopharyngeal cancer. However, extensive thyroidectomy and paratracheal nodal dissection (PTND) can cause hypoparathyroidism. We sought to determine the optimum extent of resection.

METHODS

We analyzed the clinicopathological information of 161 pyriform sinus cancer patients undergoing TPL from 25 Japanese institutions. Rates of recurrence and risk factors for hypoparathyroidism, as well as incidence of pathological contralateral level VI nodal metastasis and stomal recurrence, were investigated.

RESULTS

The extent of thyroidectomy and nodal dissection were not independent risk factors for recurrence. Incidences of contralateral level VI nodal involvement and stomal recurrence were 1.8% and 1.2%, respectively. Patients undergoing hemithyroidectomy/ipsilateral PTND did not develop stomal recurrence and had the lowest incidence of hypoparathyroidism. Prognosis in patients without tracheostomy prior to hemithyroidectomy/ipsilateral PTND was comparable to that with more extensive resections.

CONCLUSIONS

Hemithyroidectomy/ipsilateral PTND may be sufficient for pyriform sinus cancer cases without tracheostomy.

Primary Hypothyroidism in Patients Exposed to Therapeutic External Beam Radiation: Non-randomized Comparative Study

Background Cancer patients are not routinely assessed for thyroid function after external beam radiotherapy (EBRT) to the neck, despite hypothyroidism being a known side effect of EBRT. So, this study aimed to assess the incidence of hypothyroidism after therapeutic external beam radiotherapy to the neck and to determine the time for the development of hypothyroidism. Methodology A non-randomized prospective comparative study was done at a tertiary care center from April 2018 to September 2020. Any cancer patients who were euthyroid before radiotherapy and are planned to receive EBRT to the neck were included as cases, whereas controls were selected from the patients who were euthyroid before radiotherapy and were planned to receive EBRT to the site other than the neck. A total of 100 participants in each case and control group were selected. Data were collected on participants' age, gender, primary tumor site, treatment modality, total radiation dose along with concurrent chemoradiation regimens. Details of blood chemistry including thyroid hormone levels were collected during the pre-radiation phase and post-radiation phase. After the completion of radiotherapy, both the patients and controls were followed up periodically at three months, six months, nine months, 12 months, and finally at 15 months post-radiation. Data were analyzed and interpreted to pursue defined objectives by using tables and graphs using Microsoft Excel and IBM SPSS, version 26.0 (Armonk, NY: IBM Corp.). The chi-square test was applied to find out the association of different variables with the development of hypothyroidism. P-values<0.05 were considered significant throughout. Results According to our findings, the incidence of hypothyroidism following external beam radiotherapy to the neck where radiation portals included a portion or the entire thyroid gland was 16% and 4%, when the radiation given to sites other than neck region. The difference in incidence between the case and control groups was found to be statically significant (p<0.05). However, it was found that age, gender, the primary tumor site, total radiation dose, and treatment modality had no significant effects on hypothyroidism development. The median time duration to become hypothyroid after EBRT was 12 months. Conclusions The monitoring of thyroid function should become a part of routine follow-up procedures in all cancer patients who receive neck radiation as part of their treatment.

Risk factors associated with patient-reported fatigue among long-term oropharyngeal carcinoma survivors

BACKGROUND

The study objective is to identify risk factors associated with fatigue among long-term OPC survivors.

METHODS

This cross-sectional study included disease-free OPC survivors treated curatively between 2000 and 2013 who were surveyed from September 2015 to July 2016. The outcome variable was patient-reported fatigue. Multivariable logistic regression was used to identify factors associated with moderate to severe fatigue.

RESULTS

Among 863 OPC survivors, 17.4% reported moderate to severe fatigue. Self-reported thyroid problems (OR: 2.01; p = 0.003), current cigarette smoking at time of survey (OR: 3.85; p = 0.001), late lower cranial neuropathy (OR: 3.44; p = 0.002), and female sex (OR: 1.91; p = 0.010) were concurrent risk factors of reporting moderate to severe fatigue. Ipsilateral intensity-modulated radiotherapy (OR: 0.18; p = 0.014) was associated with lower risk of reporting moderate to severe fatigue.

CONCLUSIONS

Our study identified thyroid problems, smoking, and late lower cranial neuropathy as associated with moderate to severe fatigue. These findings should be further validated in prospective studies to address fatigue among OPC survivors.

An Underestimated Toxicity Radiation-Induced Hypothyroidism in Patients Multimodally Treated for Breast Cancer

Radiation therapy is part of the therapeutic arsenal for breast cancer, whether it is adjuvant treatment after lumpectomy or radical mastectomy, or it is used as a palliative option in the case of metastatic or recurrent disease. Significant advances in diagnostic and therapeutic stratification of breast cancers have significantly prolonged survival, even in the metastatic stage. Exposure of patients during the course of the disease in a multidisciplinary therapeutic approach including chemotherapy, hormone therapy, targeted anti-HER therapies or CDK4/6 inhibitors had led to improved survival but with the price of additional toxicity. Among them, hypothyroidism is a well-known consequence of external radiation therapy, especially in the case of cervical region irradiation, including supraclavicular and infra-clavicular nodal levels. In this situation, the thyroid gland is considered as an organ at risk (OAR) and receives a significant dose of radiation. Subclinical hypothyroidism is a common endocrine disorder characterized by elevated TSH levels with normal levels of FT4 (free T4) and FT3 (free T3), and as a late effect, primary hypothyroidism is one of the late effects that significantly affects the quality of life for patients with breast cancer receiving multimodal treatment. Hypothyroidism has a significant impact on quality of life, most often occurring as late clinical toxicity, secondary to thyroid irradiation at doses between 30 and 70 Gy. Dose-volume parameters of irradiation, gland function at the beginning of the treatment and associated systemic therapies may be factors that alter thyroid radio-sensitivity and affect thyroid gland tolerance. In the case of head and neck tumor pathology, in which doses of >50 Gy are routinely used, the thyroid gland is generally considered as an OAR, the rate of radio-induced hypothyroidism being estimated at rates of between 20% and 52%. For breast cancer, the thyroid is often neglected in terms of dosimetry protection, the rate of late dysfunction being 6–21%.

Functional and biochemical changes in the thyroid gland following exposure to therapeutic doses of external beam radiotherapy in the head-and-neck cancer patients

Context

Majority of the head-and-neck cancers are locoregionally advanced at the time of diagnosis. Hence, radiotherapy (RT) portals will invariably cover the whole neck and thus, the thyroid gland which may lead to its dysfunction.

Aims

The purpose of this study is to identify the functional and biochemical changes in the thyroid gland following RT to the neck using single-photon emission computed tomography-computed tomography (SPECT-CT) and thyroid function tests (TFTs).

Subjects and Methods

In this prospective study, 45 patients of the head-and-neck cancer, receiving RT with or without chemotherapy were investigated. Baseline TFTs and thyroid scans (on SPECT-CT) were done, and the same were repeated at the completion of RT, at 3 and 6 months.

Results

All patients received a minimum of 30 Gy to the whole neck. Baseline TFTs and thyroid scans were normal. None of them developed hypothyroidism clinical or subclinical (C/S) at the completion of RT. Six patients developed hypothyroidism (four subclinical, two clinical) at 3 months of the completion of treatment. At 6 months of follow-up 14 patients (31.1%) developed hypothyroidism (ten subclinical, four clinical) with P≤ 0.01. All patients having clinical or subclinical hypothyroidism had decreased uptake on thyroid scan. Patients having decreased uptake on thyroid scan only, with normal TFTs and no symptoms of hypothyroidism were zero at the completion of RT, 1 at 3 months follow-up, and seven at 6 months follow-up.

Conclusions

Hypothyroidism (C/S) is an under-recognized but significant complication of therapeutic doses of RT to the neck. In our study, we recognized hypothyroidism as early as 3 months following the completion of RT. Hence, tests to evaluate functional and biochemical changes in the thyroid gland should be instituted as early as 3 months following RT.

Does thyroid-sparing total laryngectomy decrease the risk of hypothyroidism?

BACKGROUND

Thyroid lobectomy is recommended with total laryngectomy for laryngeal cancer in the National Comprehensive Cancer Network ('NCCN') guidelines. However, it is associated with a 32-89 per cent risk of hypothyroidism, with or without adjuvant radiotherapy.

OBJECTIVE

The study aimed to determine whether preserving the whole thyroid, compared to a single lobe, does indeed significantly lower the incidence of hypothyroidism in the setting of total laryngectomy.

METHOD

A retrospective study was conducted at Groote Schuur Hospital in Cape Town, South Africa.

RESULTS

Eighty-four patients met the inclusion criteria. The overall incidence of hypothyroidism was 45.2 per cent. The incidence of hypothyroidism was significantly reduced in patients who underwent thyroid-sparing total laryngectomy compared to hemithyroidectomy (p = 0.037). Adjuvant radiotherapy was associated with a higher incidence of hypothyroidism (p = 0.001).

CONCLUSION

Thyroid-preserving laryngectomy should be advocated in carefully selected patients with advanced laryngeal carcinoma, as it reduces the incidence of hypothyroidism.

The incidence of hypothyroidism in patients of head and neck carcinoma treated with radiotherapy and added risk of hypothyroidism with the addition of chemotherapy

Background:

Head and neck cancer (HNC) is the most common malignancy in the Indian males. Most of the cases of HNC present in locally advanced stage and requires a multidisciplinary management approach. Radical or adjuvant external beam radiotherapy (EBRT) is one of the important integral components of the management of HNC.

Aim:

To find the incidence of hypothyroidism (HT) in patients of HNC treated with radiotherapy with or without concurrent chemotherapy.

Methods:

A prospective, single institutional longitudinal observational study conducted at the department of radiotherapy, Institute of Post Graduate Medical Education and Research, Kolkata.

Results:

In this study, data of 118 patients were analysed. The median age at presentation was 56 years. The most common primary site of malignancy was oral cavity (39%). The patients were stage I, stage II and stage III as 11, 37·3 and 51·7% respectively. The median dose of EBRT was 66 Gy. HT statistically significantly correlated with primary site of malignancy (p = 0·001), dose of EBRT (p = 0·005). At the end of follow-up of 6 months, 39·8% developed HT.

Conclusion:

The thyroid gland is an important organ at risk while considering EBRT to neck region. The inclusion of thyroid function test in routine follow-up is mandated.

Thyroid Dysfunction Following Management of Non-thyroid Head and Neck Cancers

Head and neck cancers are one of the commonest malignancies in India. Majority of cases of head and neck malignancy undergo chemoradiation with or without surgery. Thyroid bears the brunt in terms of either excision or the gland tends to get irradiated and fibrosed. In either scenario the functionality of gland is lost leading to hypothyroidism and other clinical manifestations. It tends to get subclinical and goes unnoticed. To identify the occurrence of clinical and subclinical hypothyroidism among head and neck cancer patients receiving radiation to the neck and to justify routine use of thyroid function tests during follow up. It was a prospective non randomized control study of 100 patients of head and neck cancer receiving radiotherapy for duration of 1 year. Thyroid stimulating hormone and T3 and T4 estimations were done at baseline and at 3 and 9 months following radiotherapy. Out of 100 patients, 72 (72%) were males and 28 (28%) were females. All the patients received radiation to the neck to a dose of > 30 Gy. 35 patients received concurrent chemotherapy. 11 patients were found to have subclinical hypothyroidism while 32 patients developed significant clinical hypothyroidism (P value of 0.001). Thus a total of 43 patients developed radiation induced hypothyroidism. 20 of the 32 patients who developed clinical hypothyroidism were in the age group of 41-50 years. 11 of 32 patients who developed clinical hypothyroidism received chemoradiation while rest 21 received radiotherapy alone. Mean period for developing radiation induced hypothyroidism was 4.5 months. Hypothyrodism (clinical or subclinical) is an under recognised morbidity of external radiation to the neck which is seen following a minimum dose of 30 Gy to the neck. Recognising hypothyroidism (clinical or subclinical) early and treating it prevents thyroid dysfunction related complications. Hence, thyroid function tests should be made routine during follow up in all patients undergoing radiotherapy.

Free thyroid transfer to anterolateral thigh for prevention of radiation induced hypothyroidism: An initial experience

AIM

Radiation induced hypothyroidism (RIHT) is one of the commonest late side effects of radiation therapy and is seen in more than half of patients and affects quality of life significantly. We report our initial experience on feasibility of free microvascular transfer of thyroid gland out of radiation field to prevent development of RIHT.

MATERIAL AND METHODS

A prospective pilot study was undertaken during August 2017 to May 2018. Six Patients with stage III/IV patients of oral cavity cancers who required wide excision/composite resections with microvascular free flap (ALT) reconstruction and adjuvant radiation therapy were enrolled. A written informed consent was obtained from all patients prior to the procedure.

RESULTS

The mean age of cohort was 51 years with tongue most common site of primary cancer. The free transfer of thyroid gland to anterolateral thigh was done using microvascular technique. The mean additional time for procedure was 51 min. All patients had successful transfer with no associated immediate complications. Patients were followed up with Tc99 scan, USG Doppler and biochemical assay at routine intervals in peri and postoperative period to assess the anatomical and physiological function of the transferred gland. At median follow up of 8 months, 5 patients were euthyroid and remaining one had biochemical hypothyroidism. All patients had functional thyroid gland in anetrolateral thigh. Five patient were alive, one patient died due to disease.

CONCLUSION

This is a small and early feasibility study for free thyroid gland transfer and validates the previously published data. The selected group of patients who have high chances of developing RIHT may benefit from this strategy. Further validation of the technique may be explored in a larger cohort.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

Assessment of Treatment-Related Thyroid Dysfunction in Patients with Head and Neck Cancer

Objective

To assess thyroid dysfunction in head and neck cancer patients who have received external beam radiotherapy according to radiotherapy fields and dose, tumor site and other local or systemic treatments retrospectively and prospectively and propose a follow-up schedule.

Material and methods

A total of 378 patients was classified into two groups. Group I (n = 345) consisted of surgically treated 153 laryngeal, 80 nasopharyngeal and 112 oral cavity/oropharyngeal carcinoma patients; these patients were evaluated retrospectively for treatment-related thyroid dysfunction using their data files. Group II included 33 patients with head and neck cancer who were evaluated prospectively. Thyroid function tests were performed at the beginning of the radiotherapy and every three months after the radiotherapy course, and thyroid dysfunction regarding surgery, radiotherapy and chemotherapy was evaluated.

Results

In Group I, the median follow-up for 153 operated laryngeal carcinoma patients was 44 months. Four (2.6%) of them were found to have clinically apparent hypothyroidism. After a median follow-up of 36 months, none of the 80 nasopharyngeal carcinoma patients showed signs of hypothyroidism. Clinically apparent hypothyroidism was detected in only 1 (0.8%) of the oral cavity/oropharyngeal carcinoma patients after a median follow-up of 25 months. In Group II, 1 (3%) patient was found to have thyroid dysfunction postoperatively prior to radiotherapy. At the time of analysis, 29 (87.8%) patients were euthyroidic, 2 (6.1%) patients had subclinical and 2 (6.1%) patients had clinical hypothyroidism. All patients with thyroid dysfunction have had combined surgery and radiotherapy, and none of the patients treated with radical radiotherapy has experienced hypothyroidism.

Conclusions

Even after a short follow-up, the incidence of thyroid dysfunction was 12.2% in head and neck cancer patients treated with combined surgery and radiotherapy. We recommend thyroid function tests in these patients prior to and once every 3–6 months after the radiotherapy course.

Hypothyroidism in Carcinoma of the Tongue with Adjuvant Treatment

OBJECTIVE

The objective of this study was to evaluate the incidence of hypothyroidism with adjuvant treatment in oral tongue carcinoma patients treated primarily with surgery.

MATERIALS AND METHODS

A retrospective review was carried out to analyze hypothyroidism incidence and its relation to adjuvant treatment (radiation/radio-chemotherapy) in oral tongue carcinoma after the primary surgical ablation and neck dissection. Hypothyroidism was analyzed in relation with dose of radiation, gender, and adjuvant treatment modality.

RESULTS

The study analyzed the patients who were treated between January 2012 and June 2015. Among 705 patients with carcinoma of the tongue treated primarily with wide local excision and neck dissection, 383 received adjuvant treatment. A total of 215 patients received radiation, and 168 received concurrent radio-chemotherapy. Of 378 patients, 78 developed hypothyroidism during follow-up: 27 patients received concurrent radio-chemotherapy, and the remaining 51 received only radiation. Lower neck received 40-48 Gy in 2 patients, 50 Gy in 74 patients, and 60-70 Gy and concurrent radio-chemotherapy in 27 patients. Median follow-up was 32 months. Hypothyroidism occurred in 21.5% of patients with squamous cell carcinoma of the oral tongue. The minimum period to develop hypothyroidism was 3 months in this study. Gender and adjuvant treatment were not found to be significant for the incidence of hypothyroidism.

CONCLUSIONS

A significant number of patients with carcinoma of the tongue who receive adjuvant treatment will develop hypothyroidism, hence frequent monitoring of thyroid function is advised during follow-up.

Guidelines for the Surgical Management of Laryngeal Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to develop clinical practice guidelines for the surgical treatment of laryngeal cancer. This Task Force conducted a systematic search of the EMBASE, MEDLINE, Cochrane Library, and KoreaMed databases to identify relevant articles, using search terms selected according to the key questions. Evidence-based recommendations were then created on the basis of these articles. An external expert review and Delphi questionnaire were applied to reach consensus regarding the recommendations. The resulting guidelines focus on the surgical treatment of laryngeal cancer with the assumption that surgery is the selected treatment modality after a multidisciplinary discussion in any context. These guidelines do not, therefore, address non-surgical treatment such as radiation therapy or chemotherapy. The committee developed 62 evidence-based recommendations in 32 categories intended to assist clinicians during management of patients with laryngeal cancer and patients with laryngeal cancer, and counselors and health policy-makers.

The threshold of hypothyroidism after radiation therapy for head and neck cancer: a retrospective analysis of 116 cases

The purpose of the present study was to determine the risk factors for developing thyroid disorders based on a dose-volume histograms (DVHs) analysis. Data from a total of 116 consecutive patients undergoing 3D conformal radiation therapy for head and neck cancers was retrospectively evaluated. Radiation therapy was performed between April 2007 and December 2010. There were 108 males and 8 females included in the study. The median follow-up term was 24 months (range, 1-62 months). The thyroid function was evaluated by measuring thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels. The mean thyroid dose, and the volume of thyroid gland spared from doses ≥10, 20, 30 and 40 Gy (VS10, VS20, VS30 and VS40) were calculated for all patients. The thyroid dose and volume were calculated by the radiotherapy planning system (RTPS). The cumulative incidences of hypothyroidism were 21.1% and 36.4% at one year and two years, respectively, after the end of radiation therapy. In the DVH analyses, the patients who received a mean thyroid dose <30 Gy had a significantly lower incidence of hypothyroidism. The univariate analyses showed that the VS10, VS20, VS30 and VS40 were associated with the risk of hypothyroidism. Hypothyroidism was a relatively common type of late radiation-induced toxicity. A mean thyroid dose of 30 Gy may be a useful threshold for predicting the development of hypothyroidism after radiation therapy for head and neck cancers.

Thyroid dysfunction after intra-arterial chemotherapy for hypopharyngeal and laryngeal cancer

OBJECTIVE

Hypothyroidism is a late side effect after curative radiotherapy in the head and neck region. Superselective intra-arterial chemotherapy (SSIAC), when combined with radiation (SSIAC-R), shows higher control potential for locally advanced head and neck cancers, which is attributable to a delivery of higher concentrations of chemotherapeutic agents. However, it could enhance damages in the normal tissues. Hypothyroidism is a late adverse effect after curative radiotherapy in the head and neck region. This study focuses on the toxic effect of treatment modality for thyroid function.

METHODS

A retrospective analysis was performed to examine patients' thyroid function after SSIAC-R for laryngeal and hypopharyngeal cancer.

RESULTS

Hypothyroidism was observed in 21 (77.8%) of 27 patients receiving SSIAC-R, 4 (33.3%) of 12 patients treated with radiation alone, and 7 (41.1%) of 17 who underwent systemic chemoradiotherapy. The number of administered vessels significantly correlated with the incidence of developing hypothyroidism among SSIAC-R treated patients (P=0.03).

CONCLUSION

Concurrent setting of SSIAC with radiation significantly raises the possibility of hypothyroidism. Therefore, monitoring late complications of therapeutic procedures is essential during follow-up visits.

V30 as a predictor for radiation-induced hypothyroidism: a dosimetric analysis in patients who received radiotherapy to the neck

INTRODUCTION

The purpose of this study is to evaluate the possible predictors of thyroid disorders after neck radiotherapy, with a focus on radiation dose-volume factors.

METHODS

Thyroid function was measured in 100 patients who had received radiotherapy to the neck, including the thyroid. All radiation-induced thyroid dysfunctions were determined with an endpoint of abnormal thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and thyroxine (fT4) and thyroid peroxidase antibodies and (TPA). The total volume of the thyroid, mean radiation dose to the thyroid (Dmean) and thyroid volume percentage that received radiation doses of 10-50 Gy (V10-V50) were calculated in all patients. The evaluated risk factors for thyroid dysfunction included dose-volume parameters, sex, age, previous surgery, chemotherapy and comorbidity.

RESULTS

There were 52 patients with hypothyroidism and V30 (p = 0.03), thyroid volume (p = 0.01) and Dmean (p = 0.03) appeared to be correlated with hypothyroidism in univariate analysis. However, there was not association found in multivariate analysis for these factors.

CONCLUSIONS

Thyroid disorders after radiation therapy to the neck still represent a clinically underestimated problem. V30 may be a useful tool for evaluating the risk of hypothyroidism when determining an individual patient's treatment.

Incidence of primary hypothyroidism in patients exposed to therapeutic external beam radiation, where radiation portals include a part or whole of the thyroid gland

INTRODUCTION

Hypothyroidism is a known consequence of external-beam radiotherapy to the neck encompassing a part or whole of the thyroid gland. In this non-randomized prospective study, we have tried to evaluate the response of the thyroid gland to radiation by assessing thyroid function before irradiation and at regular intervals after irradiation.

AIMS AND OBJECTIVES

THE AIM OF THIS STUDY WERE TO ASSESS IN THE CANCER PATIENTS, WHO WERE EXPOSED TO THE THERAPEUTIC EXTERNAL BEAM RADIATION, WHERE RADIATION PORTALS INCLUDE A PART OR WHOLE OF THE THYROID GLAND: the incidence of primary hypothyroidism, the time required to become hypothyroid, any relation between the total dose for the development of hypothyroidism, and whether there are any patient or treatment-related factors that are predictive for the development of hypothyroidism, including the use of concurrent chemotherapy.

MATERIALS AND METHODS

This non-randomized, prospective study was conducted for a period of 2 years in which thyroid function was assessed in 59 patients (cases) of head and neck cancer, breast cancer, lymphoma patients and other malignancies, who had received radiotherapy to the neck region. 59 euthyroid healthy patients (controls) were also taken, who had not received the neck irradiation. These patients/controls were assessed periodically for 2 years.

RESULTS

The incidence of hypothyroidism after external beam radiation therapy (EBRT) to neck where radiation portals include part or whole of the thyroid gland was 16.94%, seven cases had subclinical hypothyroidism (11.86%) and three cases had clinical hypothyroidism (5.08%). Mean time for development of hypothyroidism was 4.5 months. There was no effect of age, gender, primary tumor site, radiation dose and chemotherapy, whether neoadjuvant or concurrent with the development of hypothyroidism.

CONCLUSION

In summary, we found that thyroid dysfunction is a prevalent, yet easily treatable source of morbidity in patients undergoing radiation therapy to neck where radiation portals include a part or whole of the thyroid gland.

How common is hypothyroidism after external radiotherapy to neck in head and neck cancer patients?

PURPOSE

To identify the occurrence of clinical and subclinical hypothyroidism among head and neck cancer patients receiving radiation to the neck and to justify routine performing of thyroid function tests during follow-up.

MATERIALS AND METHODS

This is a prospective nonrandomized study of 45 patients of head and neck cancer, receiving radiotherapy (RT). Thyroid stimulating hormone and T4 estimations were done at baseline and at 4 months and 9 months following RT.

RESULTS

Of the 45 patients, 37(82.2 %) were males and eight (17.8 %) were females. All patients received radiation to the neck to a dose of >40Gy. 35.6% received concurrent chemotherapy. Two patients underwent prior neck dissection. Fourteen patients (31.1%) were found to have clinical hypothyroidism (P value of 0.01). Five (11.1%) patients were found to have subclinical hypothyroidism with a total 19 of 45 (42.2%) patients developing radiation-induced hypothyroidism. Nine of 14 patients with clinical hypothyroidism were in the age group of 51 to 60 years (P=0.0522). Five of 16 patients who received chemoradiation and nine of 29 who received RT alone developed clinical hypothyroidism. Above 40 Gy radiation dose was not a relevant risk factor for hypothyroidism.

CONCLUSION

Hypothyroidism (clinical or subclinical) is an under-recognized morbidity of external radiation to the neck which is seen following a minimum dose of 40 Gy to neck. Recognizing hypothyroidism (clinical or subclinical) early and treating it prevents associated complications. Hence, thyroid function tests should be made routine during follow-up.

Thyroid gland invasion in laryngopharyngeal squamous cell carcinoma: prevalence, endoscopic and CT predictors

OBJECTIVES

The authors studied the prevalence of histological thyroid gland invasion in laryngopharyngeal cancer and the preoperative endoscopic and CT signs predictive of this invasion.

PATIENTS AND METHODS

Retrospective study of patients with laryngopharyngeal squamous cell carcinoma (T3 and T4) treated by total laryngectomy or total laryngopharyngectomy associated with concomitant total thyroidectomy or ipsilateral lobectomy and isthmectomy.

RESULTS

Eighty-seven patients were included. Eleven patients (12.6%) presented thyroid gland invasion. Subglottic tumour extension greater than or equal to 10mm (P=0.008) and cricoid cartilage destruction on CT (P=0.001) were statistically correlated with histological thyroid gland invasion. An intact appearance of the laryngeal cartilages on CT was associated with a low probability of thyroid gland invasion.

CONCLUSION

Thyroid gland invasion must not be underestimated in patients with advanced laryngopharyngeal cancer. Preoperative CT is an essential part of the preoperative work-up. Thyroidectomy must not be performed systematically.

Thyroid dysfunction in patients treated with radiotherapy for neck

PURPOSE

The aim of the present study was to retrospectively evaluate the early and late changes in thyroid dysfunction after radiation therapy for head and neck cancer either with or without surgery.

PATIENTS AND METHODS

Sixty-three patients receiving neck irradiation including the thyroid gland were recruited in the study. Thirty-six patients had undergone either a functional or radical neck dissection, and radiotherapy was the primary treatment in 27 patients.

RESULTS

Of 63 patients, 24 (38%) were diagnosed with hypothyroidism (HT), 8 (12.7%) with clinical HT, and 16 (25.4%) with subclinical HT. The median time to the development of clinical HT was 15 months (range, 0-36 months) and subclinical HT was 3 months (range, 0-24 months). Eleven (17.5%) of the patients were diagnosed with subclinical hyperthyroidism. The median time to the development of the subclinical hyperthyroidism was 0 months (completion of radiation therapy) (range, 0-3 months). Univariate analyses of age, smoking history, neck RT dose, clinical stage, concurrent chemotherapy, and surgery failed to identify a clinically relevant risk factor for HT. Univariate analysis of clinical HT revealed that the elevated pre-radiation therapy thyroid-stimulating hormone level was significant factor (P = 0.021).

CONCLUSION

HT associated with head and neck irradiation. We recommend that thyroid function should be evaluated periodically in patients who have undergone neck radiation.

Hypothyroidism as a consequence of intensity-modulated radiotherapy with concurrent taxane-based chemotherapy for locally advanced head-and-neck cancer

PURPOSE

To conduct a retrospective review of 168 consecutively treated locally advanced head-and-neck cancer (LAHNC) patients treated with intensity-modulated radiotherapy (IMRT)/chemotherapy, to determine the rate and risk factors for developing hypothyroidism.

METHODS AND MATERIALS

Intensity-modulated radiotherapy was delivered in 33 daily fractions to 69.3 Gy to gross disease and 56.1 Gy to clinically normal cervical nodes. Dose-volume histograms (DVHs) of IMRT plans were used to determine radiation dose to thyroid and were compared with DVHs using conventional three-dimensional radiotherapy (3D-RT) in 10 of these same patients randomly selected for replanning and with DVHs of 16 patients in whom the thyroid was intentionally avoided during IMRT. Weekly paclitaxel (30 mg/m(2)) and carboplatin area under the curve-1 were given concurrently with IMRT.

RESULTS

Sixty-one of 128 evaluable patients (47.7%) developed hypothyroidism after a median of 1.08 years after IMRT (range, 2.4 months to 3.9 years). Age and volume of irradiated thyroid were associated with hypothyroidism development after IMRT. Compared with 3D-RT, IMRT with no thyroid dose constraints resulted in significantly higher minimum, maximum, and median dose (p < 0.0001) and percentage thyroid volume receiving 10, 20, and 60 Gy (p < 0.05). Compared with 3D-RT, IMRT with thyroid dose constraints resulted in lower median dose and percentage thyroid volume receiving 30, 40, and 50 Gy (p < 0.005) but higher minimum and maximum dose (p < 0.005).

CONCLUSIONS

If not protected, IMRT for LAHNC can result in higher radiation to the thyroid than with conventional 3D-RT. Techniques to reduce dose and volume of radiation to thyroid tissue with IMRT are achievable and recommended.

Thyroid Dysfunction after Combined therapy for Laryngeal Cancer: A Prospective Study

Objective

The purpose of this study was to assess the incidence of the thyroid dysfunction in a group of patients treated with laryngectomy and radiotherapy for larynx cancer and to analyze the risk factors related to the development of hypothyroidism.

Study Design

This was a prospective study conducted in a tertiary center hospital.

Subjects and Methods

Thyroid function tests have been applied to 75 patients treated with surgery and radiotherapy preoperatively, before radiotherapy, and postoperatively. Risk factors have been analyzed by carrying out a multivariate analysis.

Results

All the patients were men with the mean age of 59.4 and an average follow-up of 28.6 months. The incidence of hypothyroidism was 49.3 percent. The average time to detection of hypothyroidism was 6 months after the completion of treatment. Radiotherapy dose, type of laryngectomy, extent of neck dissection, implementation of thyroid lobectomy, and presence of thyroiditis in specimens were risk factors for thyroid dysfunction.

Conclusions

It is important to check the thyroid function periodically in these patients especially with risk factor to obtain early diagnosis and appropriate treatment.

Thyroid dysfunction in laryngectomees—10 years after treatment

BACKGROUND

Hypothyroidism is 1 of the complications that follow treatment of various head and neck cancers. In the literature, reviews using different primary sites and differences in treatment modalities make comparison of post-treatment hypothyroidism not possible. The objective of this study was to evaluate the incidence of hypothyroidism in a homogenous group of patients who were treated with total laryngectomy and irradiation for laryngeal carcinoma and to assess the importance of different variables in the occurrence of hypothyroidism.

METHODS

A retrospective review of 147 total laryngectomy patients between 1993 and 2003 was carried out. Serum thyroxine level and free T4 levels were assessed in all patients. Hypothyroidism was classified as subclinical (increased thyroid-stimulating hormone and normal free T4 levels) and clinical (increased thyroid-stimulating hormone and decreased free T4 levels).

RESULTS

The results showed that the overall incidence of hypothyroidism was 49% (44% subclinical and 5% clinical). Hemithyroidectomy and advanced tumor staging were risk factors for the development of hypothyroidism in these patients (p < .05) with a relative risk of 2.1 (CI 95%, 1.4-3.1) and 1.3 (CI 95%, 1.1-1.6), respectively. During follow-up, 19.9% of patients developed hypothyroidism at 3 years, 38.6% at 6 years; at 10 year follow-up, 93.3% of them had hypothyroidism.

CONCLUSIONS

In conclusion, hypothyroidism is a frequent complication in patients treated with radiotherapy and total laryngectomy for laryngeal cancer, especially when treatment includes hemithyroidectomy. These patients should have their thyroid function evaluated periodically even 10 years after treatment.

Hypothyroidism after radiotherapy for patients with head and neck cancer

We report on 2 cases of hypothyroidism presenting clinical symptoms that occurred after radiotherapy for cancer of the head and neck and on the results of estimating thyroid function in patients with head and neck cancer who received radiotherapy. The first patient underwent total laryngectomy for laryngeal cancer without sacrificing the thyroid gland and partial gastrectomy for gastric cancer. Radiotherapy of the neck was carried out postoperatively. Two years later, the patient developed chest pain; pericardial effusion was detected, leading to a diagnosis of myxedema caused by hypothyroidism. The second patient received radiotherapy alone for laryngeal cancer. Two months later, low serum sodium concentration and anemia were detected in this patient. The cause of these changes was subsequently found to be hypothyroidism. Based on our experience with these 2 cases, we measured thyroid function in 35 patients who had undergone neck radiation for head and neck cancer at our hospital over the past 10 years. Hypothyroidism was observed in 13 of the 35 patients (37%). The prevalence of hypothyroidism was 46% (6/13) for patients treated with both radiation and surgery, as compared with 32% (7/22) for those who received radiation alone. The risk factors responsible for hypothyroidism were not evident from the statistical analysis of these cases. We believe that thyroid function should be evaluated periodically in patients who have undergone neck radiation because it is often difficult to diagnose hypothyroidism only from clinical symptoms.

Thyroid disorders in patients treated with radiotherapy for head-and-neck cancer: a retrospective analysis of seventy-three patients

PURPOSE

To evaluate the incidence of thyroid disorders and dose distribution to the thyroid in patients treated with radiotherapy for head-and-neck carcinomas.

METHODS AND MATERIALS

A retrospective evaluation of data from 73 patients treated for head-and-neck cancers in our department was performed. Thyroid function was evaluated mainly by the measurement of thyrotropin (thyroid stimulating hormone [TSH]). A retrospective analysis of treatment plans was performed for 57 patients. Percentages of thyroid glandular volume absorbing 10, 30, and 50 Gy (V10, V30, and V50 respectively) were considered for statistical analysis.

RESULTS

A majority of patients (61%) had a normal thyroid function whereas 19 patients (26%) had hypothyroidism. Mean thyroid volume was 30.39 cc. Point 3 (located at isthmus) absorbed lower doses compared with other points (p < 0.0001). Median values of V10, V30, and V50 were 92% (range, 57-100%), 75% (range, 28.5-100%), and 35% (range, 3-83%) respectively. Gender was associated with toxicity (presence of any kind of thyroid disorders) (p < 0.05), with females displaying higher levels of TSHr (relative TSH = patient's value/maximum value of the laboratory range) (p = 0.0005) and smaller thyroid volume (p = 0.0012) compared with male population. TSHr values were associated with thyroid volume, and the presence of midline shielding block in the anterior field was associated with relative free thyroxine (FT4r = patient's value/maximum value of the laboratory range) values.

CONCLUSIONS

Gender and thyroid volume seem to play an important role in the occurrence of thyroid toxicity, but further studies on dose-effect relationship for radiotherapy-induced thyroid toxicity are needed.

Hypothyroidism when the thyroid is included only in the low neck field during head and neck radiotherapy

OBJECTIVE

The minimum dose required to electively irradiate all of part of the low neck for squamous cell carcinoma of the oropharynx is 50 Gy in 25 fractions or its radiobiological equivalent. The purpose of our study is to determine the incidence of hypothyroidism when the thyroid is treated only in the low-neck radiotherapy (RT) field to approximately 50 Gy.

METHODS AND MATERIALS

390 patients with oropharyngeal carcinoma received RT between 1990 and 2000, had no prior thyroid disease or surgery, and had RT involving the standard anterior low-neck field including the thyroid with a dose equivalent to 50 Gy at 2Gy/fx with or without a boost to a portion of the field to 60 to 70 Gy. The end point was hypothyroidism defined as thyroid stimulating hormone (TSH) above the upper limit of the normal range.

RESULTS

As we did not routinely monitor TSH during this study, it was obtained in 169 of 390 patients. Median follow-up on all 390 patients was 6.1 years. The incidence of hypothyroidism was calculated for 2 groups: 169 patients with TSH data and the total population of 390 patients. For both analyses, patients were censored at last follow-up if the TSH level was normal, or if TSH was not checked. The incidence of hypothyroidism at 5 years was 31% for all 390 patients and 54% for the subset of 169 patients with TSH data. Adjuvant chemotherapy and/or planned neck dissection may be associated with a small increased risk of hypothyroidism.

CONCLUSIONS

Including the thyroid in the low-neck field to 50 Gy results in hypothyroidism in 30% to 50% of patients at 5 years, suggesting that the threshold for this complication is <50 Gy.

Thyroid Function Should Be Monitored Following Radiotherapy to the Low Neck

The purpose of this study was to determine whether the incidence of hypothyroidism following radiotherapy (RT) to the low neck is high enough to justify the routine monitoring of thyroid function in asymptomatic patients. A retrospective study of 504 patients with head and neck cancer whose RT fields included the thyroid gland was conducted. Patients were treated either with definitive or postoperative RT. Hypothyroidism was defined as a thyroid stimulating hormone (TSH) level > or =4.5 mIU/L, regardless of whether the patient had clinical symptoms. Of the 504 total patients, 206 had a serum TSH level checked at some point posttreatment. If we assume that patients who had no data did not have hypothyroidism, the actuarial freedom from hypothyroidism in the entire group was 78% at 5 years and 51% at 10 years. Of the 206 patients who had a documented posttreatment TSH, the actuarial freedom from hypothyroidism was 58% at 5 years and 26% at 10 years. Univariate analysis and multivariate analysis confirmed treatment modality to be a significant predictive factor. Definitive initial surgery that removed part of the thyroid gland increased the risk of developing hypothyroidism. Overall stage was also predictive on multivariate analysis. Head and neck irradiation results in biochemical hypothyroidism in at least 50% of patients. Thyroid function should be tested on a regular basis following RT to the low-neck region. Serum TSH should be checked every 6 months for the first 5 years and yearly thereafter. Thyroid hormone replacement should be initiated in any patient with a TSH of more than 4.5 mIU/L.

Hypothyroïdie après irradiation cervicale dans le traitement des cancers du nasopharynx et du sein : étude prospective à propos de 84 patients

PURPOSE

1/ To evaluate the incidence of hypothyroidism following radiotherapy in the management of breast and nasopharyngeal carcinomas, 2/ to define the role of a systematic post therapeutic screening.

PATIENTS AND METHODS

From January 1996 through March 2001 a systematic evaluation of the clinical and the biological thyroid function was performed on a cohort of 84 patients that received supraclavicular irradiation. Selected patients had either a mammary (37 cases) or a nasopharyngeal (47 cases) carcinoma. Initial work up included thyroid inspection and palpation, and biological tests: serum FT4 and TSH levels, radioimmunochemistry, completed by dynamic thyroid stimulation, using TRH, in case of border line low T4 or isolated high TSH levels. Tests were repeated every three months the first year, and then every six months. Replacement therapy with L Thyroxin was administered in case of hypothyroidism.

RESULTS

All selected patients had a normal function initially. With a mean two years follow up (1-5 years), 24 patients (29%) experienced hypothyroidism, half of whom (13 cases) being purely biological. Five patients (11%), with a nasopharyngeal carcinoma, presented also with associated pituitary failure. Clinical symptoms were minor or mild in all cases. Hypothyroidism was detected at a mean 21 months follow up. In 2 patients, hypothyroidism disappeared spontaneously within 6 months. Possible predictive factors were evaluated: age of the time of radiation, gender, percentage of irradiated thyroid, total dose, dose per fraction, tumour type and chemotherapy. Only age appeared significantly correlated with thyroid dysfunction (range: 10-30 years, P=0.002).

CONCLUSION

Hypothyroidism is a frequent and certainly underestimated complication following radiotherapy of the neck. In such patients, a systematic clinical and biological evaluation every three months the first year, and then every six months until five years is recommended.

Long-term incidence of hypothyroidism after radiotherapy in patients with head-and-neck cancer

PURPOSE

To determine the long-term incidence of postirradiation hypothyroidism (HT) in patients with head-and-neck cancer.

METHODS AND MATERIALS

The incidence of overt HT was assessed prospectively in 391 patients with nonthyroid head-and-neck cancer admitted for radiotherapy (RT) consecutively between 1990 and 1996. Eighty-three patients were excluded from the analysis because of known thyroid disease before treatment (n = 27), no RT was given (n = 15), or inadequate follow-up (n = 41). Overt HT was defined as increased thyroid-stimulating hormone (TSH) in combination with decreased fT4/T4 or in combination with initiation of thyroxine replacement therapy.

RESULTS

With a median follow-up of 4.2 years (range, 3 months to 10.9 years) for 308 evaluable patients, the 5- and 10-year Kaplan-Meier actuarial risks of HT were 20% and 27%, respectively. The median time until development of HT was 1.8 years (3 months to 8.1 years). Multivariate analysis showed that patients with bilateral RT to the neck had a higher risk of HT in comparison with unilateral neck RT (relative hazard, 0.37; p = 0.02). The addition of surgery to RT increased the overall risk of HT (p < 0.001); and if surgery involved the thyroid gland, the relative hazard was 4.74 (p < 0.001). For an elevated pre-RT TSH value, the relative hazard was 1.58 (p < 0.001).

CONCLUSION

The incidence of overt HT after locoregional RT for nonthyroid head-and-neck cancer continues to increase with time, even after long-term follow-up. We recommend life-long TSH testing in these patients.

Radiotherapy-induced thyroid disorders

Despite their specific functional consequences, radiotherapy-induced thyroid abnormalities remain under-estimated and underreported. These sequelae may include primary or central hypothyroidism, thyroiditis, Graves' disease, euthyroid Graves' ophthalmopathy, benign adenomas, multinodular goitre and radiation-induced thyroid carcinoma. Primary hypothyroidism, the most common radiation-induced thyroid dysfunction, affects 20-30% of patients administered following curative radiotherapy to the neck region, with approximately half of the events occurring within the first 5 years after therapy. The relative risk of radiation-induced cancer (mainly well-differentiated tumours) is 15-53-fold higher than in non-irradiated population. The aetiology of radiation-induced thyroid injury includes vascular damage, parenchymal cell damage and auto-immune reactions. Total radiotherapy dose, irradiated volume of the thyroid gland, and the extent of prior thyroid resection are among the most important factors associated with the risk of hypothyroidism. The contribution of other treatment modalities (chemotherapy, endocrine therapy) as well as patient- and tumour-related factors is less clear. Reduction in radiation dose to the thyroid gland and hypothalamic/pituitary complex should be attempted whenever possible. New radiotherapy techniques, such as stereotactic radiosurgery, three-dimensional conformal irradiation, intensity modulated radiotherapy and proton therapy allow generally better dose distribution with lower dose to the non-target organs. The diagnostic approach to thyroid radiation injury includes baseline thyroid function assays in all patients undergoing thyroid or parasellar irradiation. Recommended follow-up procedures include at least annual evaluation with a history for symptoms of thyroid dysfunction, clinical examination, and measurement of thyroid hormones and thyrotropin. Management of overt hypothyroidism is based on hormone replacement therapy. Thyroid hormone therapy is also recommended in cases of subclinical hypothyroidism. Treatment of other radiation-induced thyroid disorders (thyroiditis, Graves' disease, thyroid cancer) is similar to that employed in spontaneously occurring conditions. Further improvements in radiotherapy techniques and progress in endocrine diagnostics and therapy may allow better prevention and management of radiation-related thyroid injury.

Thyroid Function Studies in Patients with Cancer of the Larynx: Preliminary Evaluation

OBJECTIVE: Our goal was to evaluate thyroid function before and after surgery only or radiotherapy plus surgery for laryngeal neoplasms.

STUDY DESIGN AND SETTING: The study group consisted of a total of 30 patients with laryngeal cancer (22 treated with surgery only and 8 treated with surgery plus radiotherapy) who were evaluated by ultrasensitive thyroid-stimulating hormone, free T4, and antithyroid antibodies both preoperatively and at 6 and 12 months after surgery.

RESULTS: All patients had normal thyroid function before treatment (1 patient had elevated antithyroid autoantibodies); after 1 year, 4 (13.34%) patients were hypothyroid. In 3 patients, it was sub-clinical (ie, elevated thyroid-stimulating hormone with normal free T4), and in 1 patient, it was symptomatic.

CONCLUSION: Our preliminary data suggest that hypothyroidism occurs in a small but substantial proportion of patients undergoing surgery with or without adjuvant radiotherapy for laryngeal cancer.

SIGNIFICANCE: Thyroid hormone dosing should be routinely included in the assessment of patients with laryngeal cancer, because it is simple and inexpensive and may allow the early diagnosis and management of hypothyroidism. (Otolaryngol Head Neck Surg 2003;129:733-8.)

A prospective evaluation of early thyroid dysfunction on completion of neck radiotherapy

The purpose of this study was to examine thyroid dysfunction in the early phase of radiotherapy to the head and neck region. Forty-seven patients receiving neck irradiation including the thyroid gland were included. Twenty-eight patients had undergone either a functional or radical neck dissection and in 19 patients radiotherapy was the primary treatment. Compared to the pre-treatment values, there was a significant fall in the TSH level at completion of radiotherapy in the non-operated patients and a non-significant fall in the operated patients. The TSH was also significantly lower in the non-operated group at the end of treatment compared to the operated group. There was a significant fall in the FT3 and significant higher in the FT4 at the end of radiotherapy for both groups. This study shows that even during completion of radiotherapy to the head and neck region changes in thyroid function were observed for both previously operated and non-operated patients.

Hypothyroidism: a frequent event after radiotherapy and after radiotherapy with chemotherapy for patients with head and neck carcinoma

BACKGROUND

The incidence of hypothyroidism was assessed retrospectively from a data base of 155 patients with head and neck carcinoma who were treated at the Cleveland Clinic Foundation between 1990 and 1997.

METHODS

One hundred patients were randomized between radiotherapy (RT) (66-72 grays in single daily fractions) and RT with concurrent chemotherapy (CT) using 5-fluorouracil and cisplatin. An additional 55 patients received RT and CT without randomization. Primary site surgery was performed for tumor persistence or recurrence and included a thyroidectomy in nine patients. These nine patients, along with three patients who had hypothyroidism prior to treatment, were excluded from the analysis. At regular intervals after the completion of treatment, all patients were evaluated for the development of hypothyroidism, defined as a serum thyroid-stimulating hormone (TSH) level > 5.5 microU/mL.

RESULTS

With a median follow-up for 143 evaluable patients of 4.4 years (range, 1.5-9.2 years), the 5-year Kaplan-Meier projected incidence rate of hypothyroidism was 48%, and the 8-year projected incidence rate was 67%. The median time to the development of hypothyroidism was 1.4 years (range, 0.3-7.2 years). The likelihood of developing hypothyroidism could not be predicted according to age, gender, primary site, tumor or lymph node status, overall stage, RT dosage to the primary site or to the neck, or inclusion of CT in the treatment plan. Only race proved predictive, with no African-American patients developing hypothyroidism (P = 0.02).

CONCLUSIONS

The authors conclude that the incidence rate of hypothyroidism after patients undergo RT for head and neck carcinoma is higher than generally reported and that TSH screening after treatment appears justified.

Hypothyroidism incidence after multimodality treatment for stage III and IV squamous cell carcinomas of the head and neck

PURPOSE

Treatment of head-and-neck cancer patients with surgery, radiotherapy (RT), and chemotherapy has been associated with posttherapy hypothyroidism (HT). We evaluated the rate of posttherapy HT in patients with locally advanced squamous cell carcinoma of the head and neck, treated with multimodality therapy to determine which factors might predict this condition and at what interval the condition developed.

METHODS

We reviewed the prospectively collected thyroid function data of patients treated with sequential chemotherapy, RT, and neck dissection. The incidence of posttherapy HT was estimated. The patient, tumor, and treatment factors possibly associated with HT were evaluated.

RESULTS

Of 203 patients, 118 had data adequate for evaluation. HT developed in 45% at a median of 24.4 months after therapy. HT occurred in 14% and 27% of patients at 6 months and 1 year after treatment, respectively. Univariate and multivariate analyses of sex, age, RT dose, RT fractionation, T and N stage, tumor site, and neck dissection failed to identify a clinically relevant risk factor.

CONCLUSIONS

A high number of patients undergoing aggressive organ-sparing multimodality therapy for advanced squamous cell carcinoma of the head and neck are at risk for subsequent HT. We recommend that all patients definitively irradiated to the head and neck region undergo frequent serum thyroid-stimulating hormone screening for HT, beginning 6 months after RT.

Pretreatment prevalence of hypothyroidism in patients with head and neck carcinoma

BACKGROUND

Hypothyroidism in the normal population age > 60 years is encountered in the range of 0.5-5% clinically, and 5-20% have subclinical hypofunction. Hypothyroidism is recognized as a common complication of treatment in patients with head and neck carcinoma (HNC) and is reported in up to 75% of patients who receive combined treatment. Surprisingly, base-line pretreatment measurements of thyroid function in large series of patients have not been reported.

METHODS

Serum thyroid-stimulating hormone, free T4, and total T3 levels were recorded in 110 patients with nonthyroid HNC prior to treatment in a prospective, controlled study.

RESULTS

The mean patient age (+/- standard deviation) was 65 years +/- 13.8 years, and 82% of patients had squamous cell carcinoma. A diagnosis of hypothyroidism already was established in 4.5% of patients, and subclinical hypothyroidism was discovered in an additional 6.4% of patients. Sixteen patients had other equivocal anomalies in thyroid function and were referred for further endocrine evaluation. No patients with formerly unrecognized clinical hypothyroidism were found.

CONCLUSIONS

Hypothyroidism in patients with head and neck carcinoma in Israel corresponds with the reported incidence in the general population. Hypothyroidism after treatment for head and neck carcinoma stems from the effects of treatment. The need for pretreatment evaluation of thyroid function should be considered.

[Hypothyroidism after external radiotherapy. Fifteen cases]

Hypothyroidism frequency is estimated to be between 10 and 45% after radiotherapy alone, and 40 to 67% after radiotherapy associated with thyroidectomy. This hypothyroidism is infraclinical in 60% of the cases. Our study concerned 15 cases of hypothyroidism after external radiotherapy delivered between and 1991 and 1999. An irradiation of the cervical, cerebral and thorax regions was indicated for different types of cancers. Larynx carcinoma epidermoid was the most frequent cancer (seven cases); the radiation treatment used cobalt 60 with conventional fractionation, i.e., 2 Gy per treatment, five treatments a week. In nine cases, the hypothyroidism was discovered during a systematic examination; it was clinically evident in the six remaining cases. Hypothyroidism appeared after an irradiation dose average of 50 Gy (extremes 30-65 Gy). The average duration of the irradiation was about 7 weeks and the hypothyroidism appeared in a mean 22 months. In all cases, the substituting treatment was initiated with a favorable progression. Faced with the risk of hypothyroidism, it is necessary to check patients who have undergone external irradiation of the neck.

Long-term effects in children treated with radiotherapy for head and neck rhabdomyosarcoma

PURPOSE

To examine the long-term effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma.

METHODS

From 1967 to 1994, a total of 30 children with head and neck rhabdomyosarcoma received megavoltage radiotherapy at one institution. Seventeen patients (57%) have survived and have at least a 5-year follow-up. There were 11 males and 6 females, with a median age of 5.7 years (range 2.2-11.6) at the time of radiotherapy. Tumor location was orbit in 6 patients, infratemporal fossa in 4, paranasal sinuses in 2, and supraglottic larynx in 2; the nasopharynx, pterygopalatine fossa, and parotid gland were sites for the remaining children. All but 2 patients had tumors of embryonal histology. The Intergroup Rhabdomyosarcoma Study (IRS) Group was I in 2, II in 3, and III in 11 children; 1 patient had a recurrent tumor after surgery alone. Radiotherapy volume was the primary tumor or tumor bed in 13, tumor and whole brain in 3, and tumor and craniospinal axis in 1. Median radiotherapy dose to the primary site was 5,040 cGy (range 4,140-6,500) and to the whole brain was 3,000 cGy. All but 1 were treated with 150-200-cGy fractions; 1 patient received 250-cGy fractions for a tumor in the larynx. Chemotherapy was vincristine (V), actinomycin-D (A), and cyclophosphamide (C) in 10 patients, VAC + adriamycin in 2, VA in 1, VA + ifosfamide in 1, VC + adriamycin in 1, and none in 2. One patient had salvage chemotherapy consisting of cisplatin and etoposide. Median follow-up time was 20 years (range 7.5-33).

RESULTS

Late effects of treatment were seen in all patients and included facial growth retardation in 11, neuroendocrine dysfunction in 9, visual/orbital problems in 9, dental abnormalities in 7, hearing loss in 6, and hypothyroidism in 3. Intellectual and academic delays were documented in 3 patients who had received whole brain radiotherapy. While neuroendocrine, thyroid, dental, and cognitive sequelae were primarily attributed to radiotherapy, hearing loss was thought to be a direct result of tumor destruction and, in 1 case, cisplatin chemotherapy. Late effects at or beyond 10 years from radiotherapy were few, but severe, and included chondronecrosis, esophageal stenosis, second malignancy, and brain hemorrhage.

CONCLUSION

Late effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma are frequent. Although radiotherapy is a significant contributor of neuroendocrine, dental, thyroid, and cognitive toxicity, it is not usually implicated with hearing loss. Late toxicity of treatment beyond 10 years is not as frequent as those occurring within 10 years of therapy.

Hypothyroidism after radiotherapy for laryngeal cancer

PURPOSE

To investigate the incidence of hypothyroidism after radiotherapy of laryngeal cancer, including the possible factors that could predict the onset of hypothyroidism.

MATERIALS AND METHODS

We report this study on patients treated by radiotherapy as part of the treatment for laryngeal cancer in the Department of Oncology in Eastern Finland. Sixty-five males and seven females were treated with radiotherapy between 1974-1995.Thyroid function was determined by measuring serum thyroid stimulating hormone, and serum free thyroxine (FT4). The studied risk factors for hypothyroidism included age, treatment modalities, radiation dose and energy, height of the radiation field, and follow-up time.

RESULTS

Hypothyroidism was detected in 17 (24%) of the 72 patients. Hypothyroidism was clinically unsuspected in all but one patient. Hypothyroidism was more common, if the height of the radiation field was >/=7 cm, or the patient had been operated. Hypothyroidism was less common if less than a half of the thyroid bed was irradiated.

CONCLUSION

The detection of hypothyroidism clinically is difficult, and the rate of hypothyroidism warrants routine assessment of thyroid function after irradiation of laryngeal cancer.

Risk factors associated with hypothyroidism after laryngectomy

Hypothyroidism is a well-documented complication after treatment of head and neck cancer and is particularly significant among patients undergoing laryngectomy. The objective of this study was the identification of factors associated with the development of hypothyroidism in this population. Records of 136 patients treated with laryngectomy were retrospectively reviewed in an attempt to define a risk factor profile for patients in whom hypothyroidism is most likely to develop after laryngectomy. The Cox proportional hazards model was used to identify factors significantly related to an increased risk for development of hypothyroidism. The actuarial method was used to estimate the period of greatest risk for the development of hypothyroidism. Increased risks were found for patients who were female (P = 0.0049), received preoperative radiation therapy (P = 0.0022), had invasion of the thyroid gland by tumor (P = 0.0003), had presence of cervical metastases (P = 0.0022), and had postoperative fistula (P = 0.0095). From the actuarial method, we estimated that the period of time when patients were at greatest risk for development of hypothyroidism was between 0 and 14 months after surgical intervention. Wound complications were twice as frequent in hypothyroid patients. Perioperative awareness of risk factors associated with the development of hypothyroidism in patients undergoing laryngectomy allows for early recognition and management of hypothyroidism and may reduce the number of complications related to wound healing and fistula.

[Late effects of ionizing radiations on the thyroid gland]

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.