Hypothyroidism after therapy for larynx and pharynx carcinoma

Incidence and complications of hypothyroidism postlaryngectomy: A systematic review and meta-analysis

BACKGROUND

Hypothyroidism is common postlaryngectomy and is associated with laryngectomy-specific complications. The objective of this study is to determine the incidence and predictors of hypothyroidism postlaryngectomy and its associated complications.

METHODS

Systematic review, data extraction, and meta-analyses were performed following the PRISMA protocol. Six databases were searched for studies reporting on postlaryngectomy thyroid status with incidence, risk factors, management, or complications.

RESULTS

Fifty-one studies with 6333 patients were included. The pooled incidence of postlaryngectomy hypothyroidism is 49% (CI 42%-57%). Subgroup analysis showed postlaryngectomy hypothyroidism rates significantly correlated with hemithyroidectomy and radiotherapy. Patients who underwent laryngectomy, hemithyroidectomy, and radiotherapy had a 65% (CI 59%-71%) rate of hypothyroidism; laryngectomy and hemithyroidectomy 46% (CI 33%-60%); laryngectomy and radiotherapy 26% (CI 19%-35%); and laryngectomy alone 11% (CI 4%-27%) (p < 0.001).

CONCLUSIONS

Laryngectomized patients with partial thyroidectomy or radiation therapy are at significant risk of postoperative hypothyroidism. Evidence-based protocols for early detection and (prophylactic) treatment should be established.

Research progress of radiation-induced hypothyroidism in head and neck cancer

This paper reviews the factors related to hypothyroidism after radiotherapy in patients with head and neck cancer to facilitate the prevention of radiation-induced hypothyroidism and reduce its incidence. Hypothyroidism is a common complication after radiotherapy in patients with head and neck cancer, wherein the higher the radiation dose to the thyroid and pituitary gland, the higher the incidence of hypothyroidism. With prolonged follow-up time, the incidence of hypothyroidism gradually increases. Intensity modulated radiotherapy should limit the dose to the thyroid, which would reduce the incidence of hypothyroidism. In addition, the risk factors for hypothyroidism include small thyroid volume size, female sex, and previous neck surgery. The incidence of radiation-induced hypothyroidism in head and neck cancer is related to the radiation dose, radiotherapy technique, thyroid volume, sex, and age. A prospective, large sample and long-term follow-up study should be carried out to establish a model of normal tissue complications that are likely to be related to radiation-induced hypothyroidism.

Is thyroid excision mandatory with laryngectomy in carcinoma larynx?

Background

Advanced stage operable cancers of larynx are treated with total laryngectomy including thyroid resection in most of the cases, which may expose patient to hypothyroidism and hypoparathyroidism. The requirement of thyroidectomy during Total Laryngectomy is controversial.

Methods

A cross sectional observational study was set out to review preoperative clinical and radiological assessment; intraoperative and histopathological findings; and follow-up data to predict thyroid gland invasion in the setting of squamous cell carcinoma of the Larynx.

Results

11 (16%) out of 69 patients had thyroid gland involvement on histopathological examination with mean age 63 years. Out of these 11 cases, 8 (72%) underwent primary total laryngectomy. 90% patients with thyroid gland involvement were male. 9 cases with thyroid gland involvement were staged as T4a preoperatively.

Conclusion

Invasion of thyroid gland by laryngeal cancer is uncommon. Unnecessary hemithyroidectomies lead to hypothyroidism and hypoparathyroidism. The study points out the clear indications of thyroid excision in patients undergoing total laryngectomy. We can suggest that total thyroidectomy should be done with total laryngectomy in cases which have gross clinical, radiological or intraoperative thyroid gland involvement, subglottic extension and thyroid cartilage invasion. This can save the patients from the brunt of unnecessary morbid hypothyroidism and hypoparathyroidism.

Correlative study of dose to thyroid and incidence of subsequent dysfunction after head and neck radiation

BACKGROUND

Thyroid dysfunction is common after radiotherapy (RT) for patients with head and neck cancers. We attempted to discover RT dose parameters that correspond with RT-induced thyroid dysfunction.

METHODS

Records of 102 patients who received RT from 2008 to 2010 were reviewed with respect to thyroid function. Abnormalities were grouped in 2 ways: (1) none, transient, or permanent; and (2) overt or subclinical.

RESULTS

At median follow-up of 33.5 months, incidence of any thyroid abnormality was 39.2% (women vs men - 50% vs 35%). Permanent dysfunction was seen in 24.5% with higher incidence in women versus men (42.9% vs 17.6%; p = .0081). Permanent abnormalities most strongly correlated with D_50% (p = .0275). V_50Gy also correlated with thyroid dysfunction post-RT (p = .0316). Concurrent chemotherapy increased permanent dysfunction (p = .0008).

CONCLUSION

Achieving D_50% <50 Gy, V₅₀ <50%, and mean dose <54.58 Gy during RT planning may decrease the incidence; whereas female sex and concurrent chemotherapy seem to increase the risk of RT-induced hypothyroidism. © 2016 Wiley Periodicals, Inc. Head Neck 39: 548-554, 2017.

Hypothyroidism in patients treated with radiotherapy for head and neck carcinoma: standardised long-term follow-up study

OBJECTIVE

Hypothyroidism is a common complication when radiotherapy is part of the treatment for head and neck tumours. This study aimed to show the incidence of hypothyroidism and possible risk factors in these patients.

METHODS

Factors related to the population, tumour, treatment and occurrence of hypothyroidism were analysed in 241 patients diagnosed with head and neck carcinoma.

RESULTS

Approximately 53 per cent of patients were diagnosed with radiation-induced hypothyroidism. Its occurrence was related to: tumour location, laryngeal surgery type, neck dissection type, post-operative complications, cervical radiotherapy and radiotherapy unit type (linear particle accelerator or telecobalt therapy technology).

CONCLUSION

Control of thyroid function should be standardised for several years after treatment, particularly in patients with risk factors, such as those treated with telecobalt therapy, those with post-operative complications and for whom the thyroid parenchyma is included in the irradiated area (laryngeal or pharyngeal location and bilateral cervical radiation).

Hypothyroidism after cancer and the ability to meet reproductive goals among a cohort of young adult female cancer survivors

OBJECTIVE

To determine whether developing hypothyroidism after cancer treatment is associated with a decreased probability of women being able to meet their reproductive goals.

DESIGN

A population-based cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 1,282 cancer survivors, of whom 904 met the inclusion criteria for the analysis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Three outcomes that may indicate reduced fertility, which include failure to achieve desired family size, childlessness, and not achieving pregnancy after at least 6 months of regular unprotected intercourse.

RESULT(S)

We used data from the Furthering Understanding of Cancer Health and Survivorship in Adult (FUCHSIA) Women's Study to examine the association between being diagnosed with hypothyroidism after cancer and meeting reproductive goals. After adjusting for age and other potential confounders, women reporting hypothyroidism after cancer treatment were twice as likely to fail to achieve their desired family size (adjusted odds ratio [aOR] 1.91; 95% confidence interval [CI], 1.09, 3.33) and be childless (aOR 2.13; 95% CI, 1.25, 3.65). They were also more likely to report having unprotected intercourse for at least 6 months without conceiving (aOR 1.37; 95% CI, 0.66, 2.83).

CONCLUSION(S)

Although cancer treatments themselves are gonadotoxic, it is important to consider other medical conditions such as hypothyroidism that occur after cancer treatment when counseling patients on the risks for impaired fertility or a shortened reproductive window.

Longitudinal study on the correlations of thyroid antibody and thyroid hormone levels after radiotherapy in patients with nasopharyngeal carcinoma with radiation-induced hypothyroidism

BACKGROUND

The purpose of this study was to evaluate the correlations of thyroid antibody and thyroid hormone in postradiotherapy (post-RT) patients with nasopharyngeal carcinoma (NPC).

METHODS

Serum thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), thyroperoxidase antibody (anti-TPO), and thyroglobulin antibody (anti-TG) levels of 55 patients with NPC were taken before RT and at 3, 6, 12, and 18 months after RT. Patients with hypothyroidism at 18 months after RT and those with normal thyroid function were categorized into the hypo and normal groups, respectively. The thyroid antibody levels were compared between the 2 groups, and the correlations of thyroid antibody and thyroid hormone were evaluated for the hypo group.

RESULTS

The anti-TPO and anti-TG of the hypo group were higher than the normal group. In the hypo group, there was a positive correlation (r = 0.51) between TSH and anti-TG and a negative correlation between fT4 and anti-TPO (r = -0.55).

CONCLUSION

There were correlations of the thyroid antibody and thyroid hormone levels in patients with radiation-induced hypothyroidism.

Evaluation of clinical hypothyroidism risk due to irradiation of thyroid and pituitary glands in radiotherapy of nasopharyngeal cancer patients

INTRODUCTION

Radiation-induced thyroid dysfunction after radiotherapy for nasopharyngeal cancer (NPC) has been reported. This study investigated the radiation effects of the thyroid and pituitary glands on thyroid function after radiotherapy for NPC.

METHODS

Sixty-five NPC patients treated with radiotherapy were recruited. Baseline thyroid hormone levels comprising free triiodothyronine (fT3), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) were taken before treatment and at 3, 6, 12 and 18 months. A seven-beam intensity-modulated radiotherapy plan was generated for each patient. Thyroid and pituitary gland dose volume histograms were generated, dividing the patients into four groups: high (>50 Gy) thyroid and pituitary doses (HTHP group); high thyroid and low pituitary doses (HTLP group); low thyroid and high pituitary doses; and low thyroid and pituitary doses. Incidence of hypothyroidism was analysed.

RESULTS

Twenty-two (34%) and 17 patients (26%) received high mean thyroid and pituitary doses, respectively. At 18 months, 23.1% of patients manifested various types of hypothyroidism. The HTHP group showed the highest incidence (83.3%) of hypothyroidism, followed by the HTLP group (50%).

CONCLUSIONS

NPC patients with high thyroid and pituitary gland doses carried the highest risk of abnormal thyroid physiology. The dose to the thyroid was more influential than the pituitary dose at 18 months after radiotherapy, and therefore more attention should be given to the thyroid gland in radiotherapy planning.

Thyroid involvement by laryngeal cancer among Iranian patients

OBJECTIVE

Asian patients with laryngeal cancer have been reported to have a high prevalence of thyroid involvement. This study aimed to investigate the prevalence of thyroid invasion in Iranian patients with laryngeal cancer.

METHODS

Hospital records for all patients with a definite diagnosis of laryngeal cancer between 1996 and 2009 (351 patients) were reviewed, and the prevalence of thyroid invasion was established based on the pathology report at the time of surgery.

RESULTS

Thyroid invasion was found in 16 patients (4.55 percent), and was limited to one thyroid lobe in two-thirds of cases. All instances of thyroid invasion occurred in patients with stage III (81.25 percent) or IV (18.75 percent) cancer. No case of metastasis was reported. The glottic region was identified as the tumour origin in most cases of thyroid invasion (56.25 percent).

CONCLUSION

Most cases of thyroid invasion by laryngeal cancer occurred in cancer stage III, at grades G1 and G2, among male patients, and arose from tumours of the glottic region.

Primary and salvage total laryngectomy

Treatment of laryngeal cancer has evolved, and newer methods of laryngeal conservation, both surgical and nonsurgical, are the primary treatment of choice. Nevertheless, total laryngectomy is not extinct and still plays an important role in primary therapy for advanced stage laryngeal cancers and as salvage therapy for failures of organ preservation strategies.

The prevalence of hypothyroidism after treatment for laryngeal and hypopharyngeal carcinomas: are autoantibodies of influence?

CONCLUSIONS

The incidence rate of hypothyroidism after treatment for laryngeal and hypopharyngeal cancer is high, especially after combination treatment. An association between hypothyroidism and autoantibodies was found.

OBJECTIVES

The incidences of hypothyroidism and autoantibodies were assessed retrospectively in 156 patients with laryngeal and hypopharyngeal carcinoma who were treated with surgery and/or radiotherapy between 1977 and 2002.

PATIENTS AND METHODS

Patients treated for T2-T4 carcinoma or a recurrence after T1 who visited the outpatient clinic for their regular follow-up visit were included. All patients were evaluated for the development of hypothyroidism, defined as increased thyroid-stimulating hormone level (>4.5 mU/L) and the presence of autoantibodies. A questionnaire regarding symptoms was administered.

RESULTS

The prevalence of undiagnosed hypothyroidism following treatment of laryngeal carcinoma was 28.2%: 18.6% subclinical hypothyroidism and 9.6% clinical hypothyroidism. The prevalence of circulating antithyroid antibodies (anti-thyreoperoxidase and/or anti-thyreoglobulin) was 10.5%. Univariate analysis showed that patients with laryngectomy, hemithyroidectomy, ipsilateral neck dissection and autoantibodies had a higher risk of hypothyroidism. The combination of surgery and radiotherapy increased the risk. Symptoms such as weight gain and cold intolerance were significantly associated with hypothyroidism. Multivariate analysis showed hemithyroidectomy, autoantibodies, weight gain and cold intolerance to be prognostic factors for the development of hypothyroidism.

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.

Physical performance, depression, immune status and fatigue in patients with hematological malignancies after treatment

BACKGROUND

Fatigue is a frequent and severe problem after treatment of patients with hematological malignancies. This symptom has been associated with anemia, reduced physical performance, mood, endocrine disorders and impaired nutritional status. Recently, it has been suggested that fatigue can be related to a persistent activation of the immune system with increased production of proinflammatory cytokines. However, there is no conclusive evidence regarding the role of the immune system in the origin of fatigue in cancer patients.

PATIENTS AND METHODS

We evaluated the correlation of fatigue with thyroid function, markers of immune activity [interleukin (IL)-1alpha, IL-1 soluble receptor, IL-6, C-reactive protein and neopterin], liver and kidney function, mood and physical ability in 71 patients with hematological malignancies. All patients had been free of relapse and not received treatment (chemotherapy, radiotherapy or immune modulators) for at least 3 months.

RESULTS

Fatigue was related to depression (r=0.84; P<0.0001) and reduced performance status (r=-0.61; P<0.0001). However, there was no correlation between fatigue and thyroid, liver and kidney function, anemia, albumin concentration or markers of immune activity (all r-values <0.20; P>0.05).

CONCLUSIONS

We conclude that fatigue in relapse-free patients with hematological malignancies is associated with depressive mood and reduced physical performance, but not with impairment of thyroid function, anemia or persistent activation of the immune system.

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.

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 in elderly people

Abnormal thyroid function tests are common for older adults, but the clinical significance of abnormal results and the need for treatment vary. Nonthyroidal illness (eg, low T3 and T4 syndromes) needs to be ruled out before making the diagnosis of hypothyroidism. Overt hypothyroidism and myxedema coma always require treatment, but treatment of subclinical hypothyroidism is not as clear. The purpose of this review article is to summarize existing data in the elderly population on the etiology, diagnosis, and management of overt hypothyroidism and subclinical hypothyroidism.