Hypothyroidism after head-and-neck radiotherapy in children and adolescents: preliminary results of the "Registry for the Evaluation of Side Effects After Radiotherapy in Childhood and Adolescence" (RiSK)

Primary Hypothyroidism in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

From the Pediatric Normal Tissue Effects in the Clinic (PENTEC) initiative, a systematic review and meta-analysis of publications reporting on radiation dose-volume effects for risk of primary hypothyroidism after radiation therapy for pediatric malignancies was performed.

METHODS AND MATERIALS

All studies included childhood cancer survivors, diagnosed at age <21 years, whose radiation therapy fields exposed the thyroid gland and who were followed for primary hypothyroidism. Children who received pituitary-hypothalamic or total-body irradiation were excluded. PubMed and the Cochrane Library were searched for studies published from 1970 to 2017. Data on age at treatment, patient sex, radiation dose to neck or thyroid gland, specific endpoints for hypothyroidism that were used in the studies, and reported risks of hypothyroidism were collected. Radiation dose-volume effects were modeled using logistic dose response. Relative excess risk of hypothyroidism as a function of age at treatment and sex was assessed by meta-analysis of reported relative risks (RR) and odds ratios.

RESULTS

Fifteen publications (of 1709 identified) were included for systematic review. Eight studies reported data amenable for dose-response analysis. At mean thyroid doses of 10, 20, and 30 Gy, predicted rates of uncompensated (clinical) hypothyroidism were 4%, 7%, and 13%, respectively. Predicted rates of compensated (subclinical) hypothyroidism were 12%, 25%, and 44% after thyroid doses of 10, 20, and 30 Gy, respectively. Female sex (RR = 1.7, P < .0001) and age >15 years at radiation therapy (RR = 1.3, P = .005) were associated with higher risks of hypothyroidism. After a mean thyroid dose of 20 Gy, predicted risks of hypothyroidism were 13% for males <14 years of age, increasing to 29% for females >15 years of age.

CONCLUSION

A radiation dose response for risk of hypothyroidism is evident; a threshold radiation dose associated with no risk is not observed. Thyroid dose exposure should be minimized when feasible. Data on hypothyroidism after radiation therapy should be better reported to facilitate pooled analyses.

Current practices of craniospinal irradiation techniques in Turkey: a comprehensive dosimetric analysis

OBJECTIVE

This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution.

METHODS

Anonymized CT scans of adult and pediatric patients, alongside target volumes and organ-at-risk (OAR) structures, were shared with 25 local radiotherapy centers. They were tasked to develop optimal treatment plans delivering 36 Gy in 20 fractions with 95% PTV coverage, while minimizing OAR exposure. The same CT data was sent to a US proton therapy center for comparison. Various planning systems and treatment techniques (3D conformal RT, IMRT, VMAT, tomotherapy) were utilized. Elekta Proknow software was used to analyze parameters, assess dose distributions, mean doses, conformity index (CI), and homogeneity index (HI) for both target volumes and OARs. Comparisons were made against proton therapy.

RESULTS

All techniques consistently achieved excellent PTV coverage (V95 > 98%) for both adult and pediatric patients. Tomotherapy closely approached ideal Dmean doses for all PTVs, while 3D-CRT had higher Dmean for PTV_brain. Tomotherapy excelled in CI and HI for PTVs. IMRT resulted in lower pediatric heart, kidney, parotid, and eye doses, while 3D-CRT achieved the lowest adult lung doses. Tomotherapy approached proton therapy doses for adult kidneys and thyroid, while IMRT excelled for adult heart, kidney, parotid, esophagus, and eyes.

CONCLUSION

Modern radiotherapy techniques offer improved target coverage and OAR protection. However, 3D techniques are continued to be used for CSI. Notably, proton therapy stands out as the most efficient approach, closely followed by Tomotherapy in terms of achieving superior target coverage and OAR protection.

Evaluation of treatment-associated eye toxicity after irradiation in childhood and adolescence-results from the Registry of the Evaluation of Side Effects after Radiotherapy in Childhood and Adolescence (RiSK)

Purpose

The aim of the study is to evaluate treatment-related acute and late eye toxicity associated with radiation therapy in childhood and adolescence as correlated with RT (radiotherapy) doses.

Methods

From 2001 to 2016, a total of 1725 children and adolescents undergoing radiation therapy were prospectively documented in the Registry of the Evaluation of Side Effects after Radiotherapy in Childhood and Adolescence (RiSK). The RTOG/EORTC criteria were used to classify ocular acute and late effects. Uni- and multivariate analyses were carried out to evaluate the impact of patient age, pre-existing impairments, and radiation dose on ocular toxicity.

Results

Of all documented patients, 593 received dose to the eye and formed the basis of this analysis. In 435 patients, information on acute reaction was available and graded 1, 2, 3, and 4 in 49, 17, 0, and 2 patients, respectively. Information on late toxicity was available in 268 patients and graded 1, 2, 3, and 4 in 15, 11, 11, and 5 patients, respectively. The acute toxicity rate was significantly higher in children who received a maximum dose > 50 Gy to the eye (p < 0.001) and who had a pre-existing eye impairment (p < 0.001 in multivariate analysis). The development of late toxicity was significantly higher for patients experiencing acute toxicity and having received a radiation dose > 50 Gy.

Conclusion

Acute and late toxicity both correlate with high radiation dose to the eye (> 50 Gy) and acute toxicity additionally with pre-existing eye impairments.

Necessity for craniospinal irradiation of germinoma with positive cytology without spinal lesion on MR imaging-A controversy

BACKGROUND

Cerebrospinal fluid (CSF) cytology and spinal MR imaging are routinely performed for staging before treatment of intracranial germinoma. However, the interpretation of the results of CSF cytology poses 2 unresolved clinical questions: (1) Does positive CSF cytology correlate with the presence of spinal lesion before treatment? and (2) Is craniospinal irradiation (CSI) necessary for patients with positive CSF cytology in the absence of spinal lesion?

METHODS

Multicenter retrospective analyses were performed based on a questionnaire on clinical features, spinal MR imaging finding, results of CSF cytology, treatments, and outcomes which was sent to 86 neurosurgical and 35 pediatrics departments in Japan. Pretreatment frequencies of spinal lesion on MR imaging were compared between the patients with positive and negative cytology. Progression-free survival (PFS) rates were compared between patients with positive CSF cytology without spinal lesion on MR imaging treated with CSI and with whole brain or whole ventricular irradiation (non-CSI).

RESULTS

A total of 92 germinoma patients from 45 institutes were evaluated by both CSF cytology and spinal MR images, but 26 patients were excluded because of tumor markers, the timing of CSF sampling or incomplete estimation of spinal lesion. Of the remaining 66 germinoma patients, spinal lesions were equally identified in patients with negative CSF cytology and positive cytology (4.9% and 8.0%, respectively). Eleven patients treated with non-CSI had excellent PFS comparable to 11 patients treated with CSI.

CONCLUSION

CSI is unnecessary for germinoma patients with positive CSF cytology without spinal lesions on MR imaging.

Pediatric craniospinal irradiation with a short partial-arc VMAT technique for medulloblastoma tumors in dosimetric comparison

Background

This study aimed to contrast four different irradiation methods for pediatric medulloblastoma tumors in a dosimetric comparison regarding planning target volume (PTV) coverage and sparing of organs at risk (OARs).

Methods

In sum 24 treatment plans for 6 pediatric patients were realized. Besides the clinical standard of a 3D-conformal radiotherapy (3D-CRT) treatment plan taken as a reference, volumetric modulated arc therapy (VMAT) treatment plans (“VMAT_AVD” vs. “noAVD” vs. “FullArc”) were optimized and calculated for each patient. For the thoracic and abdominal region, the short partial-arc VMAT_AVD technique uses an arc setup with reduced arc-length by 100°, using posterior and lateral beam entries. The noAVD uses a half 180° (posterior to lateral directions) and the FullArc uses a full 360° arc setup arrangement. The prescription dose was set to 35.2 Gy.

Results

We identified a more conformal dose coverage for PTVs and a better sparing of OARs with used VMAT methods. For VMAT_AVD mean dose reductions in organs at risk can be realized, from 16 to 6.6 Gy, from 27.1 to 8.7 Gy and from 8.0 to 1.9 Gy for the heart, the thyroid and the gonads respectively, compared to the 3D-CRT treatment method. In addition we have found out a superiority of VMAT_AVD compared to the noAVD and FullArc trials with lower exposure to low-dose radiation to the lungs and breasts.

Conclusions

With the short partial-arc VMAT_AVD technique, dose exposures to radiosensitive OARS like the heart, the thyroid or the gonads can be reduced and therefore, maybe the occurrence of late sequelae is less likely. Furthermore the PTV conformity is increased. The advantages of the VMAT_AVD have to be weighed against the potentially risks induced by an increased low dose exposure compared to the 3D-CRT method.

Thyroid Sequelae of Pediatric Cancer Therapy

The hypothalamic-pituitary-thyroid axis is a common site of unintended, acquired disease either during or after the treatment of cancer. Children treated with external radiation therapy are at the highest risk for developing a thyroid-related late effect, but thyroid dysfunction and second primary thyroid neoplasms can also occur after treatment with radiopharmaceutical agents such as 131I-metaiodobenzylguanidine. Increasingly recognized is the development of early thyroid dysfunction as an off-target consequence of the more novel cancer therapeutics such as the tyrosine kinase inhibitors and immune checkpoint inhibitors. Thyroid sequelae resulting from irradiation may manifest only after years to decades of follow-up, and their resultant clinical symptoms may be indolent and non-specific. Therefore, lifelong monitoring of the childhood cancer survivor at risk for thyroid disease is paramount. In this comprehensive review, the myriad thyroid adverse effects resulting from pediatric cancer treatment are discussed and an overview of screening and treatment of these thyroid sequelae provided.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Lung toxicity after radiation in childhood: Results of the International Project on Prospective Analysis of Radiotoxicity in Childhood and Adolescence

BACKGROUND AND PURPOSE

This study presents the evaluation of acute and late toxicities of the lung in children and adolescents after irradiation in terms of dose-volume effects.

MATERIALS AND METHODS

Irradiated children and adolescents in Germany have prospectively been documented since 2001 in the "Registry for the Evaluation of Side-Effects after Radiotherapy in Childhood and Adolescence (RiSK)"; in Sweden since 2008 in the RADTOX registry.

RESULTS

Up to April 2012, 1,392 children were recruited from RiSK, and up to June 2013, 485 from the RADTOX-registry. Of these patients, 295 were irradiated to the lung. Information about acute toxicity was available for 228 patients. 179 patients have been documented concerning late toxicity (≥grade 1: n = 28). The acute toxicity rate was noticeably higher in children irradiated with 5-20Gy (p < 0.05). In the univariate analysis, a shorter time until late toxicity was noticeably associated with irradiation with 5-15Gy (p < 0.05).

CONCLUSION

Acute and late toxicities appear to be correlated with higher irradiation volumes and low doses. Our data indicate that similar to the situation in adult patients, V5, V10, V15 and V20 should be kept as low as possible (e.g., at least V5 < 50%, V10 and V15 < 35% and V20 < 30%) in children and adolescents to lower the risk of toxicity.

Cancer treatment induced metabolic syndrome: Improving outcome with lifestyle

Increasing numbers of long-term cancer survivors face important treatment related adverse effects. Cancer treatment induced metabolic syndrome (CTIMetS) is an especially prevalent and harmful condition. The aetiology of CTIMetS likely differs from metabolic syndrome in the general population, but effective treatment and prevention methods are probably similar. In this review, we summarize the potential mechanisms leading to the development of CTIMetS after various types of cancer treatment. Furthermore, we propose a safe and accessible method to treat or prevent CTIMetS through lifestyle change. In particular, we suggest that a lifestyle intervention and optimization of energy balance can prevent or mitigate the development of CTIMetS, which may contribute to optimal survivorship care.

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.

Screening and management of adverse endocrine outcomes in adult survivors of childhood and adolescent cancer

5 year survival for childhood and adolescent cancer in developed countries is now in excess of 80% and the number of survivors of cancer continues to increase worldwide. After completion of therapy, many of these survivors will face a lifelong risk of endocrine late effects. We summarise the available evidence related to the prevalence and risk factors for endocrine late effects among adult survivors of childhood and adolescent cancer. Present screening, surveillance, and treatment recommendations differ by country and region, so we also highlight the continued effort to harmonise the international guidelines for this population.

Hepatotoxicity after liver irradiation in children and adolescents : results from the RiSK

AIM

The aim of this study was to evaluate acute and late radiotherapy-associated hepatotoxicity in consideration of dose-volume effects and liver function in childhood and adolescence.

PATIENTS AND METHODS

Since 2001, irradiated children and adolescents in Germany have been prospectively documented in the "Register of Treatment-Associated Late Effects After Radiotherapy of Malignant Diseases in Childhood and Adolescence (RiSK)" using standardized forms. Toxicity was graded according to the Radiation Therapy Oncology Group (RTOG) criteria.

RESULTS

Until April 2012, 1,392 children and adolescents from 62 radiotherapy centers were recruited. In all, 216 patients underwent irradiation of the liver (median age 9 years, range 1-18 years, 70 patients with total-body irradiation, TBI). For 75 % of patients without TBI, information on acute toxicity of the liver was available: 24 patients had acute toxicity of grade 1-4 (grade 1, 2, and 4, in 20, 3, and 1 patient, respectively), including five patients receiving simultaneous hepatotoxic chemotherapy. Information on late toxicity was documented in 465 forms from 216 patients, with a median follow-up of 2 years. A maximum grade of toxicity of ≥ 0 occurred in 18 patients over time (with grade 1, 2, and 3 toxicity occurring in 15, 2, and 1 patient, respectively), including three patients (17 %) with TBI. One of them received simultaneous hepatotoxic chemotherapy. In multivariable analysis, volume-dose correlations showed no statistically noticeable effect on acute or chronic toxicity.

CONCLUSION

Only low hepatotoxicity developed in children after irradiation of various abdominal and thoracic tumors. Due to the low radiation doses to the liver (median liver dose = 5 Gy) and the low toxicities that were consecutively observed, dose-volume curves for liver toxicity could not be established. These findings reflect the cautious attitude of radiation oncologists in terms of attributable liver doses in the treatment of the investigated tumor entities. It offers the option of increasing these conservative doses if tumor control is necessary.

Acute and late side effects to salivary glands and oral mucosa after head and neck radiotherapy in children and adolescents. Results of the "Registry for the evaluation of side effects after radiotherapy in childhood and adolescence"

BACKGROUND

The registry for the evaluation of side effects after radiotherapy in childhood and adolescence (RiSK) was established to prospectively characterize radiation-associated side effects. The purpose of this analysis was to characterize side effects after radiotherapy to the head and neck in children and adolescents.

METHODS

Radiation doses have been collected across Germany since 2001. Acute and late side effects were characterized.

RESULTS

Until January 2010, 133 patients (median age, 12.7 years) were recruited who had received radiotherapy to the salivary glands. Toxicity evaluation was available for 114 patients (median follow-up, 2.9 years). Acute and late toxicity significantly depended on the maximum radiation dose to the salivary glands. An increase of the mean value of maximum dose of 1 Gray (Gy) to the submandibular glands resulted in an odds ratio of 1.04 (range, 1.00-1.08; p = .039) for acute toxicities of the salivary glands and 1.08 (range, 1.03-1.13; p = .001) for acute mucosal toxicities.

CONCLUSION

These data can be used for an individual risk assessment in pediatric head and neck radiotherapy.

Salivary gland malignancies in children

With an annual incidence of less than 1 per million, salivary gland malignancies in children are rare, constituting less than 10% of pediatric head and neck cancer. Although over 20 histologic types of salivary gland cancer have been reported in adults, a smaller number have been observed in the pediatric population. Mucoepidermoid carcinoma is the most common histologic type, followed by acinic cell carcinoma. Since the majority of salivary gland carcinomas are diagnosed at an early stage, the overall prognosis is often favorable with complete surgical resection. To date, no prospective or retrospective data comparing outcomes of surgery alone versus multimodality therapy in the management of salivary gland malignancies in the pediatric population exists. Consequently, management decisions are made on a case-by-base basis, taking prognosis, treatment-related morbidity, and long-term sequelae into account.

Acquired disorders of the thyroid following treatment for head and neck cancer

The multimodality management of head and neck cancer routinely utilizes radiation therapy in treatment. The hypothalamus, pituitary and thyroid gland may be included within treatment fields. The incidence of human papilloma virus-associated oropharyngeal carcinoma has seen a dramatic increase over the last 3 decades. Current guidelines for the long-term aftercare assessment advocate only for thyroid-stimulating hormone levels every 6-12 months after baseline posttreatment imaging. With a growing population of younger patients with a favorable prognosis exposed to therapeutic radiation therapy, it is anticipated that incidence of thyroid-associated complications, such as hypothyroidism and thyroid cancer, could increase significantly over time. Constructing a strategy for the long-term reassessment of these patients beyond existing guidelines may be necessary.