Surveillance following head, neck, and chest radiotherapy: thyroid ultrasound monitoring for secondary thyroid malignancy

Thyroid Ultrasound Screening in Childhood Cancer Survivors following Radiotherapy

INTRODUCTION

Childhood cancer survivors (CCS) are at risk for radiotherapy (RT) late effects, including second malignancies. Optimal screening for differentiated thyroid cancer (DTC) in CCS post-RT remains controversial. We assessed the outcome of thyroid ultrasound (US) surveillance in CCS exposed to RT.

METHODS

306 CCS were surveilled with thyroid US between 2002-2021. Surveillance was dependent on age at the time of primary diagnosis, interval from receipt of RT, and individual provider. Thyroid US, clinicopathologic features, and outcomes were described. Cutpoints of CCS RT age associated with varying risk of nodule presentation were explored. The selected cutpoints were used to define age categories, which were then used to compare thyroid nodule-related outcomes. Risk factors for thyroid nodule(s) were evaluated using multivariate logistic regression (odds ratio [OR] [95% confidence interval]).

RESULTS

The most common CCS diagnoses were leukemia (32%), CNS tumor (26%), and neuroblastoma (18%). Patients received TBI (45%) and/or RT to craniospinal (44%), chest (11%), and neck regions (6%). About 49% (n = 150) of patients had thyroid nodule(s). Forty-four patients underwent surgery, and 28 had DTC: 19 with American Thyroid Association (ATA) low-risk classification, 2 with ATA intermediate-risk, and 7 with ATA high-risk disease. Age cutpoint analyses identified cutpoints 3 and 10; hence, ≤3, >3 to ≤10, and >10 years were used. Of the 9 patients with intermediate- or high-risk disease, 8 were ≤10 years and 1 was >10 years at the time of RT. Female sex (OR = 1.62 [1.13-2.12] p = 0.054) and greater interval between RT and first US (OR = 1.10 [1.04-1.16] p = 0.001) were independent risk factors for nodule presentation.

CONCLUSIONS

Thyroid US surveillance may be beneficial for CCS exposed to RT at younger ages (≤10 years) for earlier detection of DTC, prior to developing advanced metastatic disease.

Patients exposed to diagnostic head and neck radiation for the management of shunted hydrocephalus have a significant risk of developing thyroid nodules

PURPOSE

External radiation to the head and neck can lead to an increased incidence of thyroid nodules. We investigated whether patients requiring repeated head and neck imaging for the management of shunted hydrocephalus had a higher incidence of ultrasound-detected thyroid nodules compared to reports of comparable age.

METHODS

Patients treated at our institution for shunted hydrocephalus from 1990 to 2003 were contacted. Enroled patients underwent a thyroid ultrasound. Demographic data and radiation exposure history were obtained retrospectively.

RESULTS

Thyroid nodules were identified sonographically in 15/112 patients (13.6 %). Patients with thyroid nodules were older (mean 24.3 ± 7.6 years) than those without (mean 18.4 ± 8.0 years) (p = 0.005). Those with a detectable thyroid nodule had a longer follow up time compared to those who did not (mean 21.9 ± 5.5 vs. 15.1 ± 7 years, respectively) (p = 0.018).

CONCLUSION

Patients with shunted hydrocephalus are exposed to substantial head and neck radiation from diagnostic imaging and have a higher incidence of thyroid nodules detected by ultrasonography. These patients should be provided ongoing surveillance for detection of thyroid nodules and the possibility of malignancy.

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

Long-term adverse health conditions, including secondary malignant neoplasms, are common in childhood cancer survivors. Although mortality attributable to secondary malignancies declined over the past decades, the risk for developing a solid secondary malignant neoplasm did not. Endocrine-related malignancies are among the most common secondary malignant neoplasms observed in childhood cancer survivors. In this systematic review, we describe risk factors for secondary malignant neoplasms of the breast and thyroid, since these are the most common secondary endocrine-related malignancies in childhood cancer survivors. Radiotherapy is the most important risk factor for secondary breast and thyroid cancer in childhood cancer survivors. Breast cancer risk is especially increased in survivors of Hodgkin lymphoma who received moderate- to high-dosed mantle field irradiation. Recent studies also demonstrated an increased risk after lower-dose irradiation in other radiation fields for other childhood cancer subtypes. Premature ovarian insufficiency may protect against radiation-induced breast cancer. Although evidence is weak, estrogen-progestin replacement therapy does not seem to be associated with an increased breast cancer risk in premature ovarian-insufficient childhood cancer survivors. Radiotherapy involving the thyroid gland increases the risk for secondary differentiated thyroid carcinoma, as well as benign thyroid nodules. Currently available studies on secondary malignant neoplasms in childhood cancer survivors are limited by short follow-up durations and assessed before treatment regimens. In addition, studies on risk-modifying effects of environmental and lifestyle factors are lacking. Risk-modifying effects of premature ovarian insufficiency and estrogen-progestin replacement therapy on radiation-induced breast cancer require further study.

Age at Primary Malignancy Determines Survival in Adolescent and Young Adults That Develop a Secondary Thyroid Cancer

PURPOSE

Second malignancy status is a risk factor for death in adolescent and young adults (AYAs) (ages 15-39) with thyroid cancer (TC). This study investigates whether age at primary malignancy (PM) is an independent predictor of overall survival (OS) for AYA patients diagnosed with secondary TC who have survived ≥5 years from their PM.

METHODS

Surveillance, Epidemiology and End Results program (SEER) multiple-primary session (SEER-9 [1973-2010] and SEER-13 [1992-2010]) identified all secondary TCs in patients <40 years of age who were also 5-year survivors. Patients with a thyroid second malignant neoplasm (SMN) diagnosed as an AYA were categorized by age at PM (pediatric <15 years vs. AYA). Kaplan-Meier and Cox proportional analysis determined OS.

RESULTS

Four hundred twenty-eight cases of secondary AYA TCs in 5-year cancer survivors were identified; 71 had a pediatric PM and 357 an AYA PM. Median OS after a pediatric PM was 35.76 years and 33.22 years after an AYA-PM (p = 0.023); only one death was due to TC. Race, site and stage of PM, marital status, and three or more independent PMs also influenced OS (all p < 0.05). However, TC characteristics, stage, and treatment did not affect OS. Cox regression demonstrated that patients with an AYA PM had a 5.84 relative risk of death (95% confidence interval [95% CI]: 1.81-18.91) compared to patients with a pediatric PM. Among AYAs who develop a TC as a second PM, OS is not affected by the TC. The OS for these patients is associated with their demographics and the characteristics of their PM: patients who are black, male, have three or more primary cancers, and a higher stage of their first malignancy are more likely to die.

CONCLUSION

For AYA patients with thyroid SMNs, having a prior AYA PM (compared to a pediatric PM), Black race, and having three or more independent tumors predicted a decreased OS, independent of PM type or PM/SMN stage.

Comparison of Thyroid Nodule Prevalence by Ultrasound in Childhood Cancer Survivors With and Without Thyroid Radiation Exposure

PURPOSE

Children receiving radiotherapy of the head, neck, or chest as treatment of primary malignancies are at increased risk for secondary thyroid malignancy. We hypothesized that current standards (yearly thyroid physical examination) lead to a substantial number of missed thyroid nodules. Our objectives were: (1) use thyroid ultrasound to assess thyroid nodules in childhood cancer survivors; and (2) compare prevalence of thyroid nodules in thyroid radiation-exposed patients as compared with cancer survivors without radiation exposure.

METHODS

We recruited 60 patients with thyroid radiation and chemotherapy exposure (median age at cancer diagnosis 10.8 y) and 59 patients with chemotherapy exposure alone (median age at diagnosis 4.3 y) from our long-term survivorship clinics. Each patient had a thyroid physical examination and thyroid ultrasound performed.

RESULTS

Thirty-three patients (27.7%) had nodules >0.3 cm of which 2 were palpated (6.1%). We found 22 radiated patients (36.7%) with nodules versus 11 nonradiated patients (18.6%) (P=0.03). Eleven patients were biopsied and 1 diagnosis of secondary papillary thyroid carcinoma was confirmed.

CONCLUSION

Our study supports further examination of incorporating thyroid ultrasounds into long-term survivorship follow-up guidelines in radiation-exposed patients for the detection of thyroid nodules and secondary malignancies.

Ultrasound Evaluation of Thyroid Gland Pathologies After Radiation Therapy and Chemotherapy to Treat Malignancy During Childhood

PURPOSE

The purpose of this study was to evaluate correlations between treatment of malignancy by radiation therapy during childhood and the occurrence of thyroid gland pathologies detected by ultrasonography in follow-up examinations.

METHODS AND MATERIALS

Reductions of thyroid gland volume below 2 standard deviations of the weight-specific mean value, occurrence of ultrasonographically detectable thyroid gland pathologies, and hypothyroidism were retrospectively assessed in 103 children and adolescents 7 months to 20 years of age (median: 7 years of age) at baseline (1997-2013) treated with chemoradiation therapy (with the thyroid gland dose assessable) or with chemotherapy alone and followed by ultrasonography and laboratory examinations through 2014 (median follow-up time: 48 months).

RESULTS

A relevant reduction of thyroid gland volume was significantly correlated with thyroid gland dose in univariate (P<.001) and multivariate analyses for doses above 2 Gy. Odds ratios were 3.1 (95% confidence interval: 1.02-9.2; P=.046) for medium doses (2-25 Gy) and 14.8 (95% confidence interval: 1.4-160; P=.027) for high doses (>25 Gy). Thyroid gland dose was significantly higher in patients with thyroid gland pathologies during follow-up (P=.03). Univariate analysis revealed significant correlations between hypothyroidism and thyroid gland dose (P<.001).

CONCLUSIONS

Ultrasonographically detectable changes, that is, volume reductions, pathologies, and hypothyroidism, after malignancy treatment during childhood are associated with thyroid gland dose. Both ultrasonography and laboratory follow-up examinations should be performed regularly after tumor therapy during childhood, especially if the treatment included radiation therapy.

Review of ultrasound image guidance in external beam radiotherapy: I. Treatment planning and inter-fraction motion management

In modern radiotherapy, verification of the treatment to ensure the target receives the prescribed dose and normal tissues are optimally spared has become essential. Several forms of image guidance are available for this purpose. The most commonly used forms of image guidance are based on kilovolt or megavolt x-ray imaging. Image guidance can also be performed with non-harmful ultrasound (US) waves. This increasingly used technique has the potential to offer both anatomical and functional information.This review presents an overview of the historical and current use of two-dimensional and three-dimensional US imaging for treatment verification in radiotherapy. The US technology and the implementation in the radiotherapy workflow are described. The use of US guidance in the treatment planning process is discussed. The role of US technology in inter-fraction motion monitoring and management is explained, and clinical studies of applications in areas such as the pelvis, abdomen and breast are reviewed. A companion review paper (O'Shea et al 2015 Phys. Med. Biol. submitted) will extensively discuss the use of US imaging for intra-fraction motion quantification and novel applications of US technology to RT.

Ultrasound surveillance for thyroid malignancies in survivors of childhood cancer following radiotherapy: a single institutional experience

BACKGROUND

Survivors of childhood cancer (SCC) who have received radiotherapy to the head, neck, and upper thorax are at higher risk of developing subsequent thyroid malignancies. As part of the post treatment long-term follow-up protocol, the current Children's Oncology Group guideline recommends surveillance by annual palpation; however, thyroid nodules are difficult to detect by physical examinations alone, and potentially malignancy-harboring nodules may be undetected. Since thyroid ultrasound is a sensitive and noninvasive procedure, it was incorporated in our institutional follow-up protocol. The aim of this study was to examine the outcome of ultrasound screening in this high-risk population. The following describes our experience from 2007 to 2013.

METHODS

A retrospective chart review was conducted on survivors enrolled in our follow-up program. SCC who have received direct or scattered radiation to the thyroid gland, and who were ≥10 years from the diagnosis of primary childhood cancer were considered to be at-risk.

RESULTS

Seventy-eight survivors met the inclusion criteria and were screened. Thyroid ultrasound detected thyroid nodule(s) in 46 patients (59%), 17 of which had nodule(s) between 5 and 10 mm (22%), and 15 patients had nodules ≥10 mm (19%). Fourteen patients (18%) underwent fine-needle aspiration biopsy. Six patients (8%) underwent surgery, and 5 (6%) had confirmed papillary carcinoma. At the time of the first ultrasound, thyroid nodules of various sizes were found. However, over time, these nodules demonstrated slow growth rates.

CONCLUSIONS

Incorporation of thyroid ultrasound into routine follow-up of high-risk SCC may aid in the detection of thyroid malignancies that are not clinically apparent. The use of ultrasound allows detailed characterization of the thyroid nodule and reliable monitoring of nodule progression. In SCC without suspicious nodule(s), it may be reasonable to perform screening ultrasounds less frequently due to the slow growth rate of thyroid nodules. However, in those with suspicious features, surgical work-up resulted in the removal of a high number of malignancies, with few unnecessary surgeries and complications.

Thyroid nodules

According to the literature, thyroid nodules (TNs) are quite rare in the first two decades of life and are predominantly non-cancerous, although cancerous TNs are more common in the first two decades of life than in adults. Therefore, it is important for clinicians to distinguish benign from malignant lesions preoperatively because the latter require a total thyroidectomy with or without neck lymph node dissection. A careful work-up and a fine-needle aspiration biopsy (FNAB) are mandatory to improve the preoperative diagnosis. High-resolution thyroid ultrasound and real-time elastosonography are adjuvant presurgical tools in selecting patients for surgery, particularly those with indeterminate or non-diagnostic cytology. Elevated thyroid-stimulating hormone (TSH) level in a patient with a thyroid nodule is a new laboratory predictor of thyroid cancer risk. The majority of thyroid carcinomas derive from the follicular cell, whereas medullary thyroid carcinoma (MTC) derives from calcitonin-producing cells. Patients with MTC are screened for germ-line RET mutations to detect carriers and identify family members for prophylactic or therapeutic thyroidectomy.

Update on endocrine and metabolic therapy-related late effects observed in survivors of childhood neoplasia

PURPOSE OF REVIEW

To provide a summary of the most recent research pertaining to the endocrine and metabolic complications observed in childhood cancer survivors.

RECENT FINDINGS

Data on prevalence and risk associations are increasingly available from large cohorts of childhood cancer survivors. New directions in research include novel risk-prediction strategies and the study of genetic predisposition.

SUMMARY

Endocrine complications are observed in more than 50% of adult childhood cancer survivors. Some continue to develop decades following cancer treatment exposures. The present review provides a summary of the most recent outcomes research pertaining to growth, thyroid, gonadal-reproductive, bone and body composition with emphasis on new directions and challenges in each area.