Hypothalamic/pituitary function following high-dose conformal radiotherapy to the base of skull: demonstration of a dose-effect relationship using dose-volume histogram analysis

Could low prolactin levels after radiotherapy predict the onset of hypopituitarism?

Both local and external cranial radiotherapy (RT) can induce neurotoxicity and vascular damage of the hypothalamic-pituitary area, which can promote neuroendocrine alterations. While anterior pituitary insufficiency after RT has been extensively characterized, data on the effect of RT on prolactin (PRL) secretion are limited and heterogeneous, with different patterns of PRL behavior described in the literature. A progressive decline in PRL levels, reflecting a time-dependent, slowly evolving radiation-induced damage to the pituitary lactotroph cells has been reported. To date, the association between hypopituitarism and hypoprolactinemia in patients undergoing RT has not yet been fully investigated. The few available data suggest that lower PRL levels can predict an extent damage of the pituitary tissue and a higher degree of hypothalamic dysfunction. However, most studies on the effect of RT on pituitary function do not properly assess PRL secretion, as PRL deficiency is usually detected as part of hypopituitarism and not systematically investigated as an isolated disorder, which may lead to an underestimation of hypoprolactinemia after RT. In addition, the often-inadequate follow-up over a long period of time may contribute to the non-recognition of PRL deficiency after RT. Considering that hypoprolactinemia is associated with various metabolic complications, there is a need to define appropriate diagnostic and management criteria. Therefore, hypoprolactinemia should enter in the clinical investigation of patients at risk for hypopituitarism, mainly in those patients who underwent RT.

Molecular Mechanisms Determining Mammalian Oocyte Quality with the Treatment of Cancer Therapy

Cancer is a global public health issue and remains one of the leading causes of death in the United States (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). It is estimated in the US in 2022, about 935,000 new cases of cancer will be diagnosed in women, and the probability of developing invasive cancer is 5.8% for females younger than 50 years old (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). However, advances in screening programs, diagnostic methods, and therapeutic options have greatly increased the five-year survival rate in reproductive-age women with a variety of cancers. Given the clinical consequences of gonadotoxic cancer therapies, young, female cancer survivors may face compromised fertility, premature ovarian insufficiency, early-onset menopause, and endocrine dysregulation (Bedoschi et al. Future Oncol. 12:2333-44, 2016). Gonadotoxic side effects may include decreased oocyte quality within surviving follicles, loss of ovarian follicles, and impaired ovarian function. In reproductive-age women, oocyte quality is an important element for successful clinical pregnancies and healthy offspring as poor-quality oocytes may be a cause of infertility (McClam et al. Biol Reprod. 106:328-37, 2022; Marteil et al. Reprod Biol. 9:203-24, 2009; Krisher. J Anim Sci. 82: E14-E23, 2004). Thus, it is critical to determine the quantity and quality of surviving follicles in the ovary after cancer treatment and to assess oocyte quality within those surviving follicles as these are markers for determining the capacity for ovarian function restoration and future fertility, especially for young cancer survivors (Xu et al. Nat Med. 17:1562-3, 2011). The long-term effects of cancer therapeutics on oocyte quality are influenced by factors including, but not limited to, individual patient characteristics (e.g. age, health history, comorbidities, etc.), disease type, or treatment regimen (Marci et al. Reprod Biol Endocrinol. 16:1-112, 2018). These effects may translate clinically into an impaired production of viable oocytes and compromised fertility (Garutti et al. ESMO Open. 6:100276, 2021).

Frequency of metastases within the hypothalamic-pituitary area and the associated high-risk factors in patients with brain metastases

Objective

Brain radiotherapy often results in impairment of hypothalamic-pituitary (HT-P) function, which in turn causes secretory dysfunction of related hormones. In this paper, the frequency of metastasis in the HT-P area and its high-risk factors in patients with brain metastasis were retrospectively analyzed, and thus provide experimental evidence for protecting HT-P area during whole brain radiotherapy (WBRT).

Methods

A retrospective analysis was performed on the data of patients with brain metastasis diagnosed by cranial magnetic resonance imaging (MRI) at the First Hospital of Lanzhou University from 2017 to 2020. The anatomical positions of the hypothalamus and pituitary were delineated, followed by their expansion by 5 mm outwards, respectively, in the three-dimensional direction, and the hypothalamus +5 mm and pituitary +5 mm were obtained as the avoidance area, in which the frequency of brain metastasis was evaluated. Univariate and multivariate logistic regression models were used to analyze the high risk factors of brain metastasis in HT-P area.

Results

A total of 3,375 brain metastatic lesions from 411 patients were included in the analysis. The rates of brain metastasis in the hypothalamus +5 mm and pituitary +5 mm in the whole group of cases were 2.9% (12/411) and 1.5% (6/411) respectively; the frequency of lesions was 0.4% (13/3375) and 0.2% (6/3375) respectively. Univariate and multivariate analyses showed that the number of brain metastases (OR = 14.946; 95% CI = 4.071-54.880; p < 0.001), and the occurrence of brain metastasis in the pituitary (OR = 13.331; 95% CI = 1.511-117.620; p = 0.020) were related to brain metastasis in the hypothalamus, and that the only relevant factor for brain metastasis in the pituitary was the occurrence of that in the hypothalamus (OR = 0.069; 95% CI = 0.010-0.461; p = 0.006). There was no correlation between tumor pathological types, the maximum diameter, the total volume of brain metastatic lesions and the risk of brain metastasis in hypothalamus and pituitary.

Conclusion

The frequency of brain metastasis in the HT-P area is extremely low. The risk of brain metastases in the hypothalamus is correlated with their number. The larger the number of metastatic lesions, the higher the frequency of brain metastasis. Protection of the HT-P area during WBRT may be unlikely to compromise the tumor recurrence rate for patients with a relatively small number of brain metastases.

Comparing the Oncologic Outcomes of Proton Therapy and Intensity-Modulated Radiation Therapy for Head and Neck Squamous Cell Carcinoma

PURPOSE

To compare the oncologic outcomes between proton therapy and intensity-modulated radiation therapy (IMRT) for head and neck squamous cell carcinoma (HNSCC) patients undergoing curative radiotherapy (RT).

EXPERIMENTAL DESIGN

We studied HNSCC patients who underwent curative-intent RT from 2015 to 2019, comparing the oncologic outcomes of proton therapy and IMRT. Our national retrospective HNSCC cohort study involved three institutes with proton therapy and 17 institutes (medical center levels) with IMRT in Taiwan. We utilized the Taiwan Cancer Registry Database to collect medical data for this study. We classified patients into two groups based on treatment method: Group 1 received IMRT, while Group 2 received proton therapy. 3:1 propensity score matching was performed to minimize the impact of potential confounders. Cox proportional hazards models were used to evaluate oncologic outcomes.

RESULTS

This study of 60,485 patients with HNSCC found that proton therapy was associated with better overall and cancer-specific survival and lower locoregional recurrence rates than IMRT. After matching, 982 patients were analyzed, with well-balanced factors. Proton therapy was a significant predictor of all-cause mortality, cancer-specific death, and locoregional recurrence (LRR). Patients who received proton therapy had significantly lower risks of all-cause mortality (adjusted hazard ratio, aHR=0.43), cancer-specific death (aHR=0.44), and LRR (aHR=0.61) than those who received IMRT.

CONCLUSION

Proton therapy is associated with superior outcomes in terms of overall survival, cancer-specific survival, and locoregional recurrence rates compared to IMRT in patients with HNSCC. These results provide valuable evidence for clinicians and patients in decision-making regarding the choice of radiation therapy for HNSCC.

Evaluation of endocrinological sequelae following particle therapy performed on anterior skull base lesions in the adult population

Background

Radiotherapy has increasingly assumed a central role in the multidisciplinary treatment of skull base lesions. Unfortunately, it is often burdened by relevant radio-induced damage to the pituitary function and the surrounding structures and systems. Patients who were treated with radiotherapy around the sellar region especially have a high risk of developing radio-induced hypopituitarism. Particle therapy has the potential advantage of delivering a higher radiation dose to the target while potentially sparing the sellar region and pituitary function. The aim of this study is to evaluate the pituitary function in adult patients who have undergone hadron therapy for anterior skull base lesions involving or surrounding the pituitary gland.

Methods

This is a retrospective, observational, and noncontrolled study. We evaluated pituitary and peripheral hormone levels in all patients referring to National Center for Oncological Hadrontherapy, Pavia, Italy for anterior skull base tumors. Furthermore, we performed a magnetic resonance imaging for every follow-up to evaluate potential tumoral growth.

Results

We evaluated 32 patients with different tumoral lesions with a mean follow-up of 27.9 months. The mean hadron therapy (HT) dose was 60 ± 14 Gray, with a mean dose per fraction of 2.3 ± 2.1 Gray. Six patients were treated with carbon ions and 26 with protons. Pituitary hormone alteration of some kind was reported for six patients. No patient experienced unexpected severe adverse events related to particle therapy.

Conclusion

Particle radiotherapy performed on anterior skull base lesions has proved to cause limited damage to pituitary function in the adult population.

Effects on the Hypothalamo-Pituitary Axis in Patients with CNS or Head and Neck Tumors following Radiotherapy

BACKGROUND

Knowledge about the precise effects of radiotherapy on hypothalamo-pituitary functions is limited. Reduction of side effects is a major goal of advanced radiotherapy modalities. We assessed strategies for monitoring and replacement of hormone deficiencies in irradiated patients.

METHODS

A search strategy was systematically conducted on PubMed®. Additional articles were retrieved to describe endocrine mechanisms.

RESULTS

45 studies were evaluated from 2000 to 2022. They were predominantly retrospective and highly heterogeneous concerning patient numbers, tumor types, radiotherapy technique and follow-up. Endocrine deficiencies occurred in about 40% of patients within a median follow-up of 5.6 years without a clear difference between radiotherapy modalities. Somatotropic and thyrotropic axes were, respectively, the most and least radiosensitive.

CONCLUSIONS

Current pituitary gland dose constraints may underestimate radiation-induced endocrine deficiencies, thus impairing quality of life. Little difference might be expected between radiation techniques for PG tumors. For non-PG tumors, dose constraints should be applied more systematically.

Health-related quality of life analyses in nonfunctioning pituitary macroadenoma patients identifies at-risk populations

PURPOSE

The quality of life (QoL) impact of multidisciplinary treatment for patients with nonfunctioning pituitary macroadenomas (NFPMA) is unclear. We sought to investigate associations between patient factors, clinical data, and patient-reported QoL in patients with NFPMA.

METHODS

Patients with treated NFPMA and > 1 year of follow up after transsphenoidal surgery (TSS) and with no evidence of progressive disease were evaluated utilizing the following patient-reported outcome measures: RAND-36-Item Health Survey, Multidimensional Fatigue Inventory, Cognitive Failures Questionnaire.

RESULTS

229 eligible patients completed QoL questionnaires a median of 7.7 years after initial transsphenoidal surgery (TSS). 25% of participants received radiation therapy (RT) a median of 2.0 years (0.1-22.5) after initial TSS. Patients who received RT were younger (median age 46 v 58, p < 0.0001), had larger tumors (28 mm v 22 mm, p < 0.0001), were more likely to have visual symptoms (65% v 34%, p = 0.0002), and were more likely to have hypopituitarism (93% v 62%, p < 0.0001). Patients with hypopituitarism reported worse energy and fatigue and cognitive function (p < 0.03). Patients who received RT reported significantly worse general health, physical health, physical fatigue and cognitive functioning (p < 0.05). The largest QoL differences were in patients who experienced a financial stressor, independent of treatment type.

CONCLUSION

Hypopituitarism, radiation therapy after TSS, and financial stressors are associated with more impaired QoL in patients with NFPMA. Awareness of these factors can better guide use and timing of radiation therapy in addition to identifying patients who can benefit from multidisciplinary surveillance.

ESTRO-EANO guideline on target delineation and radiotherapy details for glioblastoma

BACKGROUND AND PURPOSE

Target delineation in glioblastoma is still a matter of extensive research and debate. This guideline aims to update the existing joint European consensus on delineation of the clinical target volume (CTV) in adult glioblastoma patients.

MATERIAL AND METHODS

The ESTRO Guidelines Committee identified 14 European experts in close interaction with the ESTRO clinical committee and EANO who discussed and analysed the body of evidence concerning contemporary glioblastoma target delineation, then took part in a two-step modified Delphi process to address open questions.

RESULTS

Several key issues were identified and are discussed including i) pre-treatment steps and immobilisation, ii) target delineation and the use of standard and novel imaging techniques, and iii) technical aspects of treatment including planning techniques and fractionation. Based on the EORTC recommendation focusing on the resection cavity and residual enhancing regions on T1-sequences with the addition of a reduced 15 mm margin, special situations are presented with corresponding potential adaptations depending on the specific clinical situation.

CONCLUSIONS

The EORTC consensus recommends a single clinical target volume definition based on postoperative contrast-enhanced T1 abnormalities, using isotropic margins without the need to cone down. A PTV margin based on the individual mask system and IGRT procedures available is advised; this should usually be no greater than 3 mm when using IGRT.

Dose-Volume Constraints fOr oRganS At risk In Radiotherapy (CORSAIR): An "All-in-One" Multicenter-Multidisciplinary Practical Summary

BACKGROUND

The safe use of radiotherapy (RT) requires compliance with dose/volume constraints (DVCs) for organs at risk (OaRs). However, the available recommendations are sometimes conflicting and scattered across a number of different documents. Therefore, the aim of this work is to provide, in a single document, practical indications on DVCs for OaRs in external beam RT available in the literature.

MATERIAL AND METHODS

A multidisciplinary team collected bibliographic information on the anatomical definition of OaRs, on the imaging methods needed for their definition, and on DVCs in general and in specific settings (curative RT of Hodgkin's lymphomas, postoperative RT of breast tumors, curative RT of pediatric cancers, stereotactic ablative RT of ventricular arrythmia). The information provided in terms of DVCs was graded based on levels of evidence.

RESULTS

Over 650 papers/documents/websites were examined. The search results, together with the levels of evidence, are presented in tabular form.

CONCLUSIONS

A working tool, based on collected guidelines on DVCs in different settings, is provided to help in daily clinical practice of RT departments. This could be a first step for further optimizations.

Proton beam therapy for the isolated recurrence of endometrial cancer in para-aortic lymph nodes: a case report

Background

Proton beam therapy penetrates tumor tissues with a highly concentrated dose. It is useful when normal structures are too proximate to the treatment target and, thus, may be damaged by surgery or conventional photon beam therapy. However, proton beam therapy has only been used to treat recurrent endometrial cancer in a few cases; therefore, its effectiveness remains unclear.

Case presentation

We herein report a case of the isolated recurrence of endometrial cancer in the para-aortic lymph nodes in a 59-year-old postmenopausal woman that was completely eradicated by proton beam therapy. The patient was diagnosed with stage IIIC2 endometrial cancer and treated with 6 courses of doxorubicin (45 mg/m²) and cisplatin (50 mg/m²) in adjuvant chemotherapy. Fifteen months after the initial therapy, the isolated recurrence of endometrial cancer was detected in the para-aortic lymph nodes. The site of recurrence was just under the left renal artery. Due to the potential risks associated with left kidney resection due to the limited surgical space between the tumor and left renal artery, proton beam therapy was administered instead of surgery or conventional photon beam therapy. Following proton beam therapy, the complete resolution of the recurrent lesion was confirmed. No serious complications occurred during or after treatment. There have been no signs of recurrence more than 7 years after treatment.

Conclusions

Proton beam therapy is a potentially effective modality for the treatment of recurrent endometrial cancer where the tumor site limits surgical interventions and the use of conventional photon beam therapy.

High prevalence of anterior pituitary deficiencies after cranial radiation therapy for skull base meningiomas

Background

Cranial irradiation represents one of the first line treatment proposed in skull base meningiomas. While cranial irradiation is associated with a high risk of secondary hypopituitarism, few studies focused on the specific location of skull base meningiomas.

Methods

Fifty-two adults receiving photon-beam therapy for skull base meningiomas between 2003 and 2014 in our Institution were included. Anterior pituitary (ACTH, FSH, GH, LH, TSH and prolactin) as well as corresponding peripheral hormones (8 am-Cortisol, IGF-1, fT3, fT4, 17βestradiol or testosterone) were biologically screened before radiotherapy (baseline), then yearly until March 2019. The pituitary gland (PG) was delineated on CT and the mean dose delivered to it was calculated.

Results

Mean age at diagnosis was 56 +/− 14 years. Median follow-up was 7 years. Up to 60% of patients developed at least ≥2 pituitary deficiencies, 10 years after radiotherapy. Gonadotroph, thyrotroph, corticotroph and somatotroph deficiencies occurred in 37, 28, 18 and 15% of patients, respectively. Hyperprolactinemia was found in 13% of patients. None patient had only one pituitary deficiency. In the multivariate analysis, a delivered dose to the PG ≥ 50 Gy or a meningioma size ≥40 mm significantly increased the risk of developing hypopituitarism.

Conclusions

Over a long-term follow-up, cranial radiation therapy used in skull base meningiomas led to a high prevalence of hypopituitarism, further pronounced in case of tumor ≥4 cm. These results advocate for an annual and prolonged follow-up of the pituitary functions in patients with irradiated skull base meningiomas.

Occurrence of pituitary hormone deficits in relation to both pituitary and hypothalamic doses after radiotherapy for skull base meningioma

CONTEXT

Little accurate information is available regarding the risk of hypopituitarism after irradiation of skull base meningiomas.

DESIGN

Retrospective study in a single centre.

PATIENTS

48 patients with a skull base meningioma and normal pituitary function at diagnosis, treated with radiotherapy (RXT) between 1998 and 2017 (median follow-up of 90 months).

MEASUREMENTS

The GH, TSH, LH/FSH and ACTH hormonal axes were evaluated yearly for the entire follow-up period. Mean doses delivered to the pituitary gland (PitD) and the hypothalamus (HypoD) were calculated, as well as the doses responsible for the development of deficits in 50% of patients after 5 years (TD50).

RESULTS

At least one hormone deficit was observed in 38% of irradiated patients and complete hypopituitarism in 13%. The GH (35%), TSH (32%) and LH/FSH axes (28%) were the most frequently affected, while ACTH secretion axis was less altered (13%). The risk of hypopituitarism was independently related to planning target volume (PTV) and to the PitD (threshold dose 45 Gy; TD50 between 50 and 54 Gy). In this series, the risk was less influenced by the HypoD, increasing steadily between doses of 15 and 70 Gy with no clear-cut dose threshold.

CONCLUSIONS

Over a median follow-up period of 7.5 years, hypopituitarism occurred in more than one third of patients irradiated for a skull base meningioma, and this prevalence was time- and dose-dependent. In this setting, the risk of developing hypopituitarism was mainly determined by the irradiated target volume and by the dose delivered to the pituitary gland.

Characteristics of growth disturbances in patients with intracranial germinomas of different origins

PURPOSE

To explore the characteristics of growth disturbance in patients with intracranial germinoma with different origins.

METHODS

Clinical data of 151 patients with single-origin germinomas were studied retrospectively. Z-score of height (ZSOH) at both diagnosis and the last follow-up was calculated using the WHO AnthroPlus software. Linear regression was used to analyse the correlation between the absolute change in ZSOH (|ZSOH _{last follow-up} - ZSOH _diagnosis|) and clinical factors.

RESULTS

The mean ZSOH decreased significantly in every origin subgroup at the last follow-up. In patients with sellar germinoma (n = 62), the mean ZSOH values at both diagnosis and the last follow-up were significantly lower than those in patients with pineal (n = 30) (p < 0.001) or basal ganglia germinomas (n = 59) (p < 0.001), respectively. In patients with basal ganglia germinoma, the mean absolute change in ZSOH decreased significantly compared to that in the patients with sellar (p = 0.006) or pineal germinomas (p = 0.04). Linear analysis revealed that sex (male vs female; p = 0.003) and age at diagnosis (≤10 years vs >10 years; p = 0.026) had negative correlations, while radiation dose at the hypothalamic-pituitary axis (HPA) (≤40 Gy vs >40 Gy; p = 0.085) had a marginally positive correlation, with absolute change in ZSOH.

CONCLUSIONS

Patients with germinoma experienced growth retardation after treatments. The growth disturbance was consistent and more severe in patients with germinoma of sellar origin, while the greatest aggravation was observed in patients with germinoma of basal ganglia origin. Decreasing radiation dose to the HPA may minimize the negative impact of radiotherapy on growth.

Identification of patient benefit from proton beam therapy in brain tumour patients based on dosimetric and NTCP analyses

BACKGROUND

The limited availability of proton beam therapy (PBT) requires individual treatment selection strategies, such as the model-based approach. In this study, we assessed the dosimetric benefit of PBT compared to photon therapy (XRT), analysed the corresponding changes in normal tissue complication probability (NTCP) on a variety of available models, and illustrated model-based patient selection in an in-silico study for patients with brain tumours.

METHODS

For 92 patients treated at two PBT centres, volumetric modulated arc therapy treatment plans were retrospectively created for comparison with the clinically applied PBT plans. Several dosimetric parameters for the brain excluding tumour and margins, cerebellum, brain stem, frontal and temporal lobes, hippocampi, cochleae, chiasm, optic nerves, lacrimal glands, lenses, pituitary gland, and skin were compared between both modalities using Wilcoxon signed-rank tests. NTCP differences (ΔNTCP) were calculated for 11 models predicting brain necrosis, delayed recall, temporal lobe injury, hearing loss, tinnitus, blindness, ocular toxicity, cataract, endocrine dysfunction, alopecia, and erythema. A patient was assumed to be selected for PBT if ΔNTCP exceeded a threshold of 10 percentage points for at least one of the side-effects.

RESULTS

PBT substantially reduced the dose in almost all investigated OARs, especially in the low and intermediate dose ranges and for contralateral organs. In general, NTCP predictions were significantly lower for PBT compared to XRT, in particular in ipsilateral organs. Considering ΔNTCP of all models, 80 patients (87.0%) would have been selected for PBT in this in-silico study, mainly due to predictions of a model on delayed recall (51 patients).

CONCLUSION

In this study, substantial dose reductions for PBT were observed, mainly in contralateral organs. However, due to the sigmoidal dose response, NTCP was particularly reduced in ipsilateral organs. This underlines that physical dose-volume parameters alone may not be sufficient to describe the clinical relevance between different treatment techniques and highlights potential benefits of NTCP models. Further NTCP models for different modern treatment techniques are mandatory and existing models have to be externally validated in order to implement the model-based approach in clinical practice for cranial radiotherapy.

Examination of the Dose-Effect Relationship of Radiation-Induced Hypopituitarism: Results of a Case-Control Study

Purpose

Previous reports have documented a dose-effect relationship for radiation-induced hypopituitarism in patients receiving therapy near or at the base of the skull. We aimed to characterize this long-term endocrinopathy further by examining the effect of dose on both the incidence and severity of toxicity, as well as exploring a possible dose threshold for this effect.

Methods and Materials

Out of an initial 346 patients who had received radiation therapy to the base of the skull, 53 patients with adequate endocrine evaluation were found. Of these, 19 patients who subsequently developed at least 1 endocrinopathy (cases) as well as 17 patients who did not (controls) were identified, for a total of 36. Patients’ charts were reviewed, and endocrinologic laboratory tests recorded. Treatment plans were reviewed and doses to the hypothalamus and pituitary gland were calculated. One-way analysis of variance was used to determine differences between cases and controls, and Pearson's correlation coefficient was used to relate mean pituitary dose to serum free thyroxine, insulin-like growth factor 1, prolactin, cortisol, and luteinizing hormone.

Results

There were 20 men and 16 women, with a median age of 58. Median follow-up was 32 months (range, 18- 85 months). Median total plan dose delivered was 54 Gy (range, 50.4-70 Gy). Independent sample t tests as well as univariate analysis showed a significantly greater dose to the hypothalamus and pituitary of the cases compared with the controls, while other factors were not significantly different between the 2 groups. There was a statistically significant negative correlation (Pearson's correlation coefficient = -0.65, P = .001) between the mean dose to the pituitary gland and the serum free thyroxine. No case of endocrine toxicity was observed at a mean dose to the pituitary below 30 Gy.

Conclusions

Our results suggest that late endocrinopathy is a true deterministic effect, with a dose threshold, and with both the incidence and severity of toxicity being related to the dose.

Recognizing Radiation-induced Changes in the Central Nervous System: Where to Look and What to Look For

Radiation therapy (RT) continues to play a central role as an effective therapeutic modality for a variety of tumors and vascular malformations in the central nervous system. Although the planning and delivery techniques of RT have evolved substantially during the past few decades, the structures surrounding the target lesion are inevitably exposed to radiation. A wide variety of radiation-induced changes may be observed at posttreatment imaging, which may be confusing when interpreting images. Histopathologically, radiation can have deleterious effects on the vascular endothelial cells as well as on neuroglial cells and their precursors. In addition, radiation induces oxidative stress and inflammation, leading to a cycle of further cellular toxic effects and tissue damage. On the basis of the time of expression, radiation-induced injury can be divided into three phases: acute, early delayed, and late delayed. Acute and early delayed injuries are usually transient and reversible, whereas late delayed injuries are generally irreversible. The authors provide a comprehensive review of the timeline and expected imaging appearances after RT, including the characteristic imaging features after RT with concomitant chemotherapy. Specific topics discussed are imaging features that help distinguish expected posttreatment changes from recurrent disease, followed by a discussion on the role of advanced imaging techniques. Knowledge of the RT plan, the amount of normal structures included, the location of the target lesion, and the amount of time elapsed since RT is highly important at follow-up imaging, and the reporting radiologist should be able to recognize the characteristic imaging features after RT and differentiate these findings from tumor recurrence. ^©RSNA, 2020.

Radiation therapy strategies for skull-base malignancies

INTRODUCTION

The management of skull base malignancies continues to evolve with improvements in surgical technique, advances in radiation delivery and novel systemic agents.

METHODS

In this review, we aim to discuss in detail the management of common skull base pathologies which typically require multimodality therapy, focusing on the radiotherapeutic aspects of care.

RESULTS

Technological advances in the administration of radiation therapy have led to a wide variety of different treatment strategies for the treatment of skull base malignances, with outcomes summarized herein.

CONCLUSION

Radiation treatment plays a key and critical role in the management of patients with skull base tumors. Recent advancements continue to improve the risk/benefit ratio for radiotherapy in this setting.

Radiotherapy of Parasellar Tumours

Parasellar tumours represent a wide group of intracranial lesions, both benign and malignant. They may arise from several structures located within the parasellar area or they may infiltrate or metastasize this region. The treatment of the tumours located in these areas is challenging because of their complex anatomical location and their heterogenous histology. It often requires a multimodal approach, including surgery, radiation therapy (RT), and medical therapy. Due to the proximity of critical structures and the risks of side effects related to the procedure, a successful surgical resection is often not achievable. Thus, RT plays a crucial role in the treatment of several parasellar tumours. Conventional fractionated RT and modern radiation techniques, like stereotactic radiosurgery and proton beam RT, have become a standard management option, in particular for cases with residual or recurrent tumours after surgery and for those cases where surgery is contraindicated. This review examines the role of RT in parasellar tumours analysing several techniques, outcomes and side effects.

Are hypothalamic- pituitary (HP) axis deficiencies after whole brain radiotherapy (WBRT) of relevance for adult cancer patients? - a systematic review of the literature

Background

Cranial radiotherapy (cRT) can induce hormonal deficiencies as a consequence of significant doses to the hypothalamic-pituitary (HP) axis. In contrast to profound endocrinological follow-up data from survivors of childhood cancer treated with cRT, little knowledge exists for adult cancer patients.

Methods

A systematic search of the literature was conducted using the PubMed database and the Cochrane library offering the basis for our debate of the relevance of HP axis impairment after cRT in adult cancer patients. Against the background of potential relevance for patients receiving whole brain radiotherapy (WBRT), a particular focus was set on the temporal onset of hypopituitarism and the radiation dose to the HP axis.

Results

Twenty-eight original papers with a total of 1728 patients met the inclusion criteria. Radiation doses to the HP area ranged from 4 to 97 Gray (Gy). Hypopituitarism incidences ranged from 20 to 93% for adult patients with nasopharyngeal cancer or non-pituitary brain tumors. No study focused particularly on hypopituitarism after WBRT. The onset of hypopituitarism occurred as early as within the first year following cRT (range: 3 months to 25.6 years). However, since most studies started follow-up evaluation only several years after cRT, early onset of hypopituitarism might have gone unnoticed.

Conclusion

Hypopituitarism occurs frequently after cRT in adult cancer patients. Despite the general conception that it develops only after several years, onset of endocrine sequelae can occur within the first year after cRT without a clear threshold. This finding is worth debating particularly in respect of treatment options for patients with brain metastases and favorable survival prognoses.

Benign Intracranial Lesions - Radiotherapy: An Overview of Treatment Options, Indications and Therapeutic Results

BACKGROUND

Radiation Therapy (RT) is an established treatment option for benign intracranial lesions. The aim of this study is to display an update on the role of RT concerning the most frequent benign brain lesions and tumors.

METHODS

Published articles about RT and meningiomas, Vestibular Schwannomas (VSs), Pituitary Adenomas (PAs), Arteriovenous Malformations (AVMs) and craniopharyngiomas were reviewed and extracted data were used.

RESULTS

In meningiomas RT is applied as an adjuvant therapy, in case of patientrefusing surgery or in unresectable tumors. The available techniques are External Beam RT (EBRT) and stereotactic ones such as Stereotactic Radiosurgery (SRS), Fractionated Stereotactic RT (FSRT), Intensity Modulated RT (IMRT) and proton-beam therapy. The same indications are considered in PAs, in which SRS and FSRT achieve excellent tumor control rate (92-100%), acceptable hormone remission rates (>50%) and decreased Adverse Radiation Effects (AREs). Upon tumor growth or neurological deterioration, RT emerges as alone or adjuvant treatment against VSs, with SRS, FSRT, EBRT or protonbeam therapy presenting excellent tumor control growth (>90%), facial nerve (84-100%), trigeminal nerve (74-99%) and hearing (>50%) preservation. SRS poses an effective treatment modality of certain AVMs, demonstrating a 3-year obliteration rate of 80%. Lastly, a combination of microsurgery and RT presents equal local control and 5-year survival rate (>90%) but improved toxicity profile compared to total resection in case of craniopharyngiomas.

CONCLUSION

RT comprises an effective treatment modality of benign brain and intracranial lesions. By minimizing its AREs with optimal use, RT projects as a potent tool against such diseases.

Surprisingly, the Result of an Unplanned Pregnancy after Cranial Radiotherapy: A Case Report (Successful Childbirth after Brain Astrocytoma)

The present study aimed to present a rare case of successful pregnancy within 6 months from cranial mass surgery and postsurgical radiotherapy. A 32-year-old female with gestational age of 19 weeks had been refereed with a past medical history of recently treated brain astrocytoma. Close obstetric monitoring had been planned; the pregnancy was complicated with severe preeclampsia at the gestational age of 36 weeks, which leads to successful delivery. Pregnancy in patients with a history of cancer has been the focus of studies today and in many cancers it is recommended to delay pregnancy for at least 2 years. The prognosis of such a patient after unplanned pregnancy conception could be more complex; and the present case report aimed to explain about it. The goal of this presentation was to emphasis on the possibility of fertility preservation in the patient with malignancy even after cranial mass surgery and radiotherapy.

Prevalence of metastases within the hypothalamic-pituitary area in patients with brain metastases

Aim

To quantify the prevalence of brain metastases involving the hypothalamic-pituitary (HT-P) area.

Introduction

Cognitive impairment and fatigue are common side effects of whole brain irradiation (WBI) comprising the quality of life (QoL) for survivors. While the former is related to radiation-induced hippocampal injury, the latter could be secondary to hormonal disbalance as a consequence of radiation of the HT-P area. Thus, sparing both regions from higher irradiation doses could reduce these sequelae.

Methods

T1 contrast medium enhanced magnetic resonance imaging (MRI) scans of 865 patients with brain metastases (4,280 metastases) were reviewed. HT-P area was individually contoured with a margin of 5 mm in order to evaluate the prevalence of brain metastases in this region.

Results

Involvement of the hypothalamic region was found in 26 patients (involvement rate of 3% for patients and 1% for metastases), involvement of the pituitary gland in 9 patients (1% for patients and < 1% for metastases). Binary logistical regression analysis revealed the presence of > 10 brain metastases as the only factor associated with hypothalamic involvement while no distinct factor was associated with an involvement of the pituitary gland.

Conclusion

The low prevalence of metastases within the HT-P area in patients with brain metastases calls for further studies examining whether sparing of this region might improve patients QoL.

Pituitary disease in pediatric brain tumor survivors

INTRODUCTION

Treatment of childhood brain tumors, including surgical resection and especially external beam radiation, often results in endocrine complications manifested by hypopituitarism, which can involve growth hormone deficiency, hypothyroidism, adrenal insufficiency, disorders of puberty, diabetes insipidus, and hypothalamic obesity.

AREAS COVERED

A comprehensive literature search was conducted on Medline (publications from the 1990s to 01/2019) including systematic reviews, meta-analyses, longitudinal controlled studies, retrospective cohort studies, and case reports. Herein, we present an up-to-date review of the current literature regarding endocrine sequellae of childhood brain tumor survivors.

EXPERT OPINION

Late endocrine sequellae can arise many years after the initial treatment of tumor, so at least annual surveillance of growth, puberty, weight, development, and endocrine status is recommended for at least 10 years after tumor therapy. This follow up should encompass childhood and adulthood among survivors. If found early, outcomes of endocrinopathies are favorable when treated appropriately. Newer tumor therapy modalities, such as proton beam radiation, offer the potential for fewer endocrine complications, but such benefit has yet to be demonstrated, and more research into short- and long-term outcomes is needed.

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.

Cancer Treatment-Related Infertility: A Critical Review of the Evidence

Cancer treatments may compromise the fertility of children, adolescents, and young adults, and treatment-related infertility represents an important survivorship issue that should be addressed at diagnosis and in follow-up to ensure optimal decision-making, including consideration of pursuing fertility preservation. Risk of infertility varies substantially with patient and treatment factors. The ability to accurately assess fertility risk for many patients is hampered by limitations of the current literature, including heterogeneity in patient populations, treatments, and outcome measures. In this article, we review and synthesize the available data to estimate fertility risks from modern cancer treatments for both children and adult cancer survivors to enable clinicians to counsel patients about future fertility.

Dose-Constraint Model to Predict Neuroendocrine Dysfunction in Young Patients With Brain Tumors: Data From a Prospective Study

PURPOSE

We report on a possible dose-constraint model to predict long-term neuroendocrine dysfunction after cranial irradiation in children and young adults with benign and low-grade brain tumors treated with stereotactic conformal radiation therapy (RT) in a prospective clinical trial.

METHODS AND MATERIALS

Patients treated with stereotactic conformal RT (54 Gy in 30 fractions) were included for analysis if their co-registered planning computed tomography and magnetic resonance imaging scans were available, along with baseline and post-RT endocrine assessment for at least 2 years. The hypothalamus-pituitary axis (HPA) was contoured on the fused computed tomography-magnetic resonance imaging data set. Worsening of endocrine function was defined biochemically as a new onset endocrine deficit or worsening of preexisting endocrine deficit. Dosimetric indices of HPA, extracted using cumulative dose-volume histograms, were correlated with worsening endocrine function using logistic regression analysis.

RESULTS

A total of 51 patients (median age: 13 years; range, 5-25 years) were included. Worsening post-RT endocrine levels were seen in 27 of 51 patients (47%). Growth hormone was the most commonly affected (70%), followed by cortisol (44%), gonadotropin (40%), and thyroxine (7%). The mean of the maximum and minimum doses to HPA was 42.1 Gy and 35.7 Gy, respectively. For patients with worsening endocrine levels, the mean maximum dose to HPA was 46.6 Gy compared with 36.5 Gy in patients with stable functions. The mean minimum dose to HPA was also higher (40.5 Gy vs 29.6 Gy) in patients with endocrine dysfunction. Logistic regression analysis identified the volume of HPA receiving 50% of the prescribed dose as the only statistically significant parameter predicting endocrine dysfunction. A dose of ≥27 Gy to any volume of HPA was associated with a 4-fold increase in risk of endocrine dysfunction (odds ratio: 4.05; 95% confidence interval, 1.07-15.62; P = .038).

CONCLUSIONS

Our prospective longitudinal study demonstrates the feasibility of HPA avoidance using modern, high-precision, conformal RT techniques and correlates HPA dosimetry with neuroendocrine dysfunction. We suggest restricting HPA doses to <27 Gy to minimize the risk of post-RT neuroendocrine deficits.

Fatigue following radiation therapy in nasopharyngeal cancer survivors: A dosimetric analysis incorporating patient report and observer rating

PURPOSE

To explore for fatigue-related regions and the radiotherapy (RT) dose-fatigue relationship in nasopharyngeal cancer (NPC) survivors.

METHODS

Eighty disease-free NPC survivors completed the MD Anderson Symptom Inventory-Head and Neck module (MDASI-HN) after RT. Fatigue was evaluated by the MDASI-HN fatigue item (MDASI-HN-F) and Common Terminology Criteria for Adverse Events v3.0 (CTC-AE), between 6 and 36 months after RT to determine the presence of chronic fatigue. Skull base MRIs and planning CT/RT dose were retrievable for 56 patients. Dosimetric data were extracted for 10 MRI-defined potential fatigue at-risk structures (FARS): brainstem (BS), pituitary gland (PG), hypothalamus (HT), basal ganglia, internal capsule, pineal gland, sub-thalamic nuclei, thalamus, substantia nigra, and hippocampus (HC). Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic fatigue.

RESULTS

56 pts formed the cohort. Thirty patients (54%) reported any fatigue per MDASI-HN-F. Thirty-three pts (59%) had any fatigue by CTC-AE. The maximum point doses (Dmax) for PG, BS, HC, and HT were numerically higher in patients with fatigue. Dmax and Dmean of the PG were significantly higher in patients with chronic fatigue, p ≤ 0.01. A dose-volume threshold of PG V52 Gy ≥16% (LogWorth 2.4, AUC 0.7) was identified on RPA, and potential sensitivity to the PG doses was observed in younger patients (<53 years-old).

CONCLUSION

A dose-fatigue relationship was identified for the pituitary gland, both patient-reported and observer ratings. We recommend limiting the Dmax of PG to <54 Gy and V52 Gy to <16%, particularly in young NPC patients, during plan optimization when achievable.

Whole-ventricular irradiation for intracranial germ cell tumors: Dosimetric comparison of pencil beam scanned protons, intensity-modulated radiotherapy and volumetric-modulated arc therapy

Background

Whole-ventricular radiotherapy (WV-RT) followed by a boost to the tumor bed (WV-RT/TB) is recommended for intracranial germ cell tumors (IGCT). As the critical brain areas are mainly in the target volume vicinity, it is unclear if protons indeed substantially spare neurofunctional organs at risk (NOAR). Therefore, a dosimetric comparison study of WV-RT/TB was conducted to assess whether proton or photon radiotherapy achieves better NOAR sparing.

Methods

Eleven children with GCT received 24 Gy(RBE) WV-RT and a boost up to 40 Gy(RBE) in 25 fractions of 1.6 Gy(RBE) with pencil beam scanning proton therapy (PBS-PT). Intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans were generated for these patients. NOAR were delineated and treatment plans were compared for target volume coverage (TVC), homogeneity index (HI), inhomogeneity coefficient (IC) and (N)OAR sparing.

Results

TVC was comparable for all three modalities. Compared to IMRT and VMAT, PBS-PT showed statistically significant optimized IC, as well as dose reduction, among others, in mean and integral dose to the: normal brain (-35.2%, -32.7%; -35.2%, -33.0%, respectively), cerebellum (-53.7%, -33.1%; -53.6%, -32.7%) and right temporal lobe (-14.5%, -31.9%; -14.7%, -29.9%). The Willis' circle was better protected with PBS-PT than IMRT (-7.1%; -7.8%). The left hippocampus sparing was higher with IMRT. Compared to VMAT, the dose to the hippocampi, amygdalae and temporal lobes was significantly decreased in the IMRT plans.

Conclusions

Dosimetric comparison of WV-RT/TB in IGCT suggests PBS-PT's advantage over photons in conformality and NOAR sparing, whereas IMRT's superiority over VMAT, thus potentially minimizing long-term sequelae.

Radiation dose constraints for organs at risk in neuro-oncology; the European Particle Therapy Network consensus

PURPOSE

For unbiased comparison of different radiation modalities and techniques, consensus on delineation of radiation sensitive organs at risk (OARs) and on their dose constraints is warranted. Following the publication of a digital, online atlas for OAR delineation in neuro-oncology by the same group, we assessed the brain OAR-dose constraints in a follow-up study.

METHODS

We performed a comprehensive search to identify the current papers on OAR dose constraints for normofractionated photon and particle therapy in PubMed, Ovid Medline, Cochrane Library, Embase and Web of Science. Moreover, the included articles' reference lists were cross-checked for potential studies that met the inclusion criteria. Consensus was reached among 20 radiation oncology experts in the field of neuro-oncology.

RESULTS

For the OARs published in the neuro-oncology literature, we summarized the available literature and recommended dose constraints associated with certain levels of normal tissue complication probability (NTCP) according to the recent ICRU recommendations. For those OARs with lacking or insufficient NTCP data, a proposal for effective and efficient data collection is given.

CONCLUSION

The use of the European Particle Therapy Network-consensus OAR dose constraints summarized in this article is recommended for the model-based approach comparing photon and proton beam irradiation as well as for prospective clinical trials including novel radiation techniques and/or modalities.

Feasibility of Intensity-Modulated Radiation Therapy in the Treatment of Advanced Cervical Chordoma

Aims and Background

Postoperative radiation is often given in cases of cervical chordoma because of the high incidence of local recurrence. The tumor mass usually surrounds the spinal cord and infiltrates vertebral bone. A combined technique using protons or electrons to boost the initial photon fields is generally applied. We evaluated the use of dynamic intensity-modulated radiation therapy as an alternative technique for treating advanced cervical chordoma.

Methods and Study Design

A female patient with incomplete resection of a vertebral chordoma surrounding C2-C3 was irradiated with a total dose of 58 Gy (ICRU point) in 2 Gy daily fractions for 29 days between December 2001 and January 2002. Beam arrangement consisted of seven 6 MV non-opposed coplanar fields. Pretreatment quality assurance included checking of the absolute dose at reference points and 2D dose map analysis. Treatment was delivered with a 120-leaf collimator in sliding window mode. To verify the daily setup, portal images at 0° and 90° were compared with the simulation images before treatment delivery (manual matching) and after treatment delivery (automatic anatomy matching).

Results and Conclusions

The mean dose to the planning target volume (PTV) was 57.6 ± 2.1 Gy covering 95% of the PTV per 95% isodose. The minimum dose to the PTV (D99) was 53.6 Gy in the overlapping area between the PTV and the spinal cord planning organ at risk volume (PRV). The maximum dose to the spinal cord was 42.2 Gy and to the spinal cord PRV (8 mm margin) 53.7 Gy. The mean dose to the parotid glands was 37.4 Gy (homolateral gland) and 19.5 Gy (contralateral gland). Average deviation in setup was -1.1 ± 2.5 mm (anterior-posterior), 2.4 ±1.3 mm (latero-lateral), 0.7 ± 0.9 mm (craniocaudal) and -0.43 ± 1° (rotation).

Conclusions

In the treatment of chordomas surrounding the spinal cord, intensity-modulated radiotherapy can provide high dose homogeneity and PTV coverage. Frequent digital portal image-based setup control is able to reduce random positioning errors for head and neck cancer patients immobilized with conventional thermoplastic masks.

MANAGEMENT OF ENDOCRINE DISEASE: Neuroendocrine surveillance and management of neurosurgical patients

Advances in the management of traumatic brain injury, subarachnoid haemorrhage and intracranial tumours have led to improved survival rates and an increased focus on quality of life of survivors. Endocrine sequelae of the acute brain insult and subsequent neurosurgery, peri-operative fluid administration and/or cranial irradiation are now well described. Unrecognised acute hypopituitarism, particularly ACTH/cortisol deficiency and diabetes insipidus, can be life threatening. Although hypopituitarism may be transient, up to 30% of survivors of TBI have chronic hypopituitarism, which can diminish quality of life and hamper rehabilitation. Patients who survive SAH may also develop hypopituitarism, though it is less common than after TBI. The growth hormone axis is most frequently affected. There is also accumulating evidence that survivors of intracranial malignancy, who have required cranial irradiation, may develop hypopituitarism. The time course of the development of hormone deficits is varied, and predictors of pituitary dysfunction are unreliable. Furthermore, diagnosis of GH and ACTH deficiency require dynamic testing that can be resource intensive. Thus the surveillance and management of neuroendocrine dysfunction in neurosurgical patients poses significant logistic challenges to endocrine services. However, diagnosis and management of pituitary dysfunction can be rewarding. Appropriate hormone replacement can improve quality of life, prevent complications such as muscle atrophy, infection and osteoporosis and improve engagement with physiotherapy and rehabilitation.

Fertility preservation in women with CNS tumors

INTRODUCTION

Fertility impairment due to treatments is a major concern for adolescents and young adult patients who survived cancer. Areas covered: Chemotherapy may determine a detrimental effect on ovary function, leading to infertility, and premature ovarian failure. Embryo and oocyte cryopreservation is a standard strategy for fertility preservation; other strategies, such as gonadal tissue cryopreservation and the use of gonadotropin - releasing hormone agonist, are still considered experimental. There are few data available regarding the effect of pregnancy on glioma, which indicates tumor progression during pregnancy in 33-45% of patients. Expert commentary: Glioma patients need to be advised about the risk of tumor progression during pregnancy, and about the possible, even if not proven, interaction between hormone stimulation and tumor growth.

RADIOTHERAPY VERSUS RADIOSURGERY IN TREATING PATIENTS WITH ACROMEGALY: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVE

When patients with acromegaly have residual disease following surgery, adjuvant radiation therapy is considered. Both stereotactic radiosurgery (SRS) and conventional fractionated radiotherapy (RT) are utilized. We conducted a systematic review and meta-analysis to synthesize the existing evidence and compare outcomes for SRS and RT in patients with acromegaly.

METHODS

We searched Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through April 2014 for studies in which SRS or RT were used in patients with acromegaly. Outcomes evaluated were serum insulin-like growth factor-I (IGF-I) and growth hormone (GH) levels, biochemical remission, all-cause mortality, hypopituitarism, headaches, and secondary malignancies. We pooled outcomes using a random-effects model.

RESULTS

The final search yielded 30 eligible studies assessing 2,464 patients. Compared to RT, SRS was associated with a nonsignificant increase in remission rate at the latest follow-up period (52% vs. 36%; P = .14) and a significantly lower follow-up IGF-I level (-409.72 μg/L vs. -102 μg/L, P = .002). SRS had a lower incidence of hypopituitarism than RT; however, the difference was not statistically significant (32% vs. 51%, respectively; P = .05).

CONCLUSION

SRS may be associated with better biochemical remission, and it had a lower risk of hypopituitarism with at least 1 deficient axis when compared with RT; however, the confidence in such evidence is very low due to the noncomparative nature of the studies, high heterogeneity, and imprecision.

Pituitary dysfunction following cranial radiotherapy for adult-onset nonpituitary brain tumours

OBJECTIVE

There are limited data concerning the evolution of radiation-induced hypopituitarism in adult-onset brain tumour (AO-BT) survivors, in part the consequence of the limited survival of many of these individuals. We aim to characterize the pituitary-related outcomes following cranial radiotherapy (cXRT) for adult-onset primary nonpituitary brain tumours.

DESIGN

We retrospectively analysed longitudinal data of patients with AO-BT who received cXRT within a tertiary cancer referral centre.

PATIENTS

A total of 107 adults (age 40·0 ± 13·1 years) followed for a median duration of 8 years following cXRT.

MEASUREMENTS

Prevalence of radiotherapy-induced hypopituitarism.

RESULTS

94·4% received fractionated photon radiotherapy (median dose 54 Gy), while the remaining patients received proton beam or stereotactic radiotherapy. 88·8% of patients developed hypopituitarism during follow-up. The frequency of GH, gonadotrophin, ACTH and TSH deficiencies was 86·9% (severe GHD 64·5%, partial GHD 22·4%), 34·6%, 23·4% and 11·2%, respectively. ACTH deficiency was clinically significant, necessitating glucocorticoid replacement, in only 10·3% of cases. Hyperprolactinaemia developed in 15% of patients, which was persistent in only 50% of cases. Multiple pituitary hormone deficiencies were present in 47·7% of patients, encountered more frequently in patients with tumours in proximity to the sella. Longitudinal data analysis revealed accumulation of hormone deficits throughout the follow-up period, with incidence of all pituitary hormone deficiencies almost doubling between years 2 and 7 of follow-up.

CONCLUSIONS

Pituitary dysfunction in AO-BT survivors following cXRT is a common, evolving, time-dependent phenomenon. It is important that deficits are identified early and replacement therapies introduced to optimize quality of life in these individuals, where prognosis is often guarded.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Skull base chondrosarcoma radiosurgery: report of the North American Gamma Knife Consortium

OBJECT

Stereotactic radiosurgery (SRS) is a potentially important option for patients with skull base chondrosarcomas. The object of this study was to analyze the outcomes of SRS for chondrosarcoma patients who underwent this treatment as a part of multimodality management.

METHODS

Seven participating centers of the North American Gamma Knife Consortium (NAGKC) identified 46 patients who underwent SRS for skull base chondrosarcomas. Thirty-six patients had previously undergone tumor resections and 5 had been treated with fractionated radiation therapy (RT). The median tumor volume was 8.0 cm3 (range 0.9-28.2 cm3), and the median margin dose was 15 Gy (range 10.5-20 Gy). Kaplan-Meier analysis was used to calculate progression-free and overall survival rates.

RESULTS

At a median follow-up of 75 months after SRS, 8 patients were dead. The actuarial overall survival after SRS was 89% at 3 years, 86% at 5 years, and 76% at 10 years. Local tumor progression occurred in 10 patients. The rate of progression-free survival (PFS) after SRS was 88% at 3 years, 85% at 5 years, and 70% at 10 years. Prior RT was significantly associated with shorter PFS. Eight patients required salvage resection, and 3 patients (7%) developed adverse radiation effects. Cranial nerve deficits improved in 22 (56%) of the 39 patients who deficits before SRS. Clinical improvement after SRS was noted in patients with abducens nerve paralysis (61%), oculomotor nerve paralysis (50%), lower cranial nerve dysfunction (50%), optic neuropathy (43%), facial neuropathy (38%), trochlear nerve paralysis (33%), trigeminal neuropathy (12%), and hearing loss (10%).

CONCLUSIONS

Stereotactic radiosurgery for skull base chondrosarcomas is an important adjuvant option for the treatment of these rare tumors, as part of a team approach that includes initial surgical removal of symptomatic larger tumors.

Radiotherapy vs. Radiosurgery in Treating Patients with Acromegaly: Systematic Review and Meta-Analysis

OBJECTIVE

When patients with acromegaly have residual disease following surgery, adjuvant radiation therapy is considered. Both stereotactic radiosurgery (SRS) and conventional fractionated radiotherapy (RT) are utilized. We conducted a systematic review and meta-analysis to synthesize the existing evidence to compare outcomes with SRS and RT in patients with acromegaly.

METHODS

We searched Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through April 2014 for studies in which SRS or RT were used in patients with acromegaly. Outcomes evaluated were serum IGF-1 and GH levels, biochemical remission, all-cause mortality, hypopituitarism, headaches and secondary malignancies. We pooled outcomes using the random-effects model.

RESULTS

The final search yielded 30 eligible studies enrolling 2464 patients. When compared to RT, SRS was associated with a non-significant increase in remission rate at the latest follow-up period (52% vs. 36%; p = 0.14), and a significantly lower follow-up IGF-1 level (decline of - 409.72 μg/1 vs. -102 μg/1; p = 0.002). SRS was associated with lower incidence of hypopituitarism than RT; however the difference was not statistically significant [(32% vs.51%, respectively; p = 0.05).

CONCLUSIONS

SRS may be associated with better biochemical remission and lower risk of hypopituitarism with at least one deficient axis when compared with RT; however, the confidence in such evidence is very low due to the non-comparative nature of the studies, high heterogeneity, and imprecision.

Organs at risk in the brain and their dose-constraints in adults and in children: a radiation oncologist's guide for delineation in everyday practice

PURPOSE

Accurate organs at risk definition is essential for radiation treatment of brain tumors. The aim of this study is to provide a stepwise and simplified contouring guide to delineate the OARs in the brain as it would be done in the everyday practice of planning radiotherapy for brain cancer treatment.

METHODS

Anatomical descriptions and neuroimaging atlases of the brain were studied. The dosimetric constraints used in literature were reviewed.

RESULTS

A Computed Tomography and Magnetic Resonance Imaging based detailed atlas was developed jointly by radiation oncologists, a neuroradiologist and a neurosurgeon. For each organ brief anatomical notion, main radiological reference points and useful considerations are provided. Recommended dose-constraints both for adult and pediatric patients were also provided.

CONCLUSIONS

This report provides guidelines for OARs delineation and their dose-constraints for the treatment planning of patients with brain tumors.

Use of gEUD for predicting ear and pituitary gland damage following proton and photon radiation therapy

OBJECTIVE

To determine the relationship between the dose to the inner ear or pituitary gland and radiation-induced late effects of skull base radiation therapy.

METHODS

140 patients treated between 2000 and 2008 were considered for this study. Hearing loss and endocrine dysfunction were retrospectively reviewed on pre- and post-radiation therapy audiometry or endocrine assessments. Two normal tissue complication probability (NTCP) models were considered (Lyman-Kutcher-Burman and log-logistic) whose parameters were fitted to patient data using receiver operating characteristics and maximum likelihood analysis. The method provided an estimation of the parameters of a generalized equivalent uniform dose (gEUD)-based NTCP after conversion of dose-volume histograms to equivalent doses.

RESULTS

All 140 patients had a minimum follow up of 26 months. 26% and 44% of patients experienced mild hearing loss and endocrine dysfunction, respectively. The fitted values for TD50 and γ50 ranged from 53.6 to 60.7 Gy and from 1.9 to 2.9 for the inner ear and were equal to 60.6 Gy and 4.9 for the pituitary gland, respectively. All models were ranked equal according to Akaike's information criterion.

CONCLUSION

Mean dose and gEUD may be used as predictive factors for late ear and pituitary gland late complications after skull base proton and photon radiation therapy.

ADVANCES IN KNOWLEDGE

In this study, we have reported mean dose effects and dose-response relationship of small organs at risk (partial volumes of the inner ear and pituitary gland), which could be useful to define optimal dose constraints resulting in an improved therapeutic ratio.

Outcomes of proton therapy for patients with functional pituitary adenomas

PURPOSE/OBJECTIVE(S)

This study evaluated the efficacy and toxicity of proton therapy for functional pituitary adenomas (FPAs).

METHODS AND MATERIALS

We analyzed 165 patients with FPAs who were treated at a single institution with proton therapy between 1992 and 2012 and had at least 6 months of follow-up. All but 3 patients underwent prior resection, and 14 received prior photon irradiation. Proton stereotactic radiosurgery was used for 92% of patients, with a median dose of 20 Gy(RBE). The remainder received fractionated stereotactic proton therapy. Time to biochemical complete response (CR, defined as ≥ 3 months of normal laboratory values with no medical treatment), local control, and adverse effects are reported.

RESULTS

With a median follow-up time of 4.3 years (range, 0.5-20.6 years) for 144 evaluable patients, the actuarial 3-year CR rate and the median time to CR were 54% and 32 months among 74 patients with Cushing disease (CD), 63% and 27 months among 8 patients with Nelson syndrome (NS), 26% and 62 months among 50 patients with acromegaly, and 22% and 60 months among 9 patients with prolactinomas, respectively. One of 3 patients with thyroid stimulating hormone-secreting tumors achieved CR. Actuarial time to CR was significantly shorter for corticotroph FPAs (CD/NS) compared with other subtypes (P=.001). At a median imaging follow-up time of 43 months, tumor control was 98% among 140 patients. The actuarial 3-year and 5-year rates of development of new hypopituitarism were 45% and 62%, and the median time to deficiency was 40 months. Larger radiosurgery target volume as a continuous variable was a significant predictor of hypopituitarism (adjusted hazard ratio 1.3, P=.004). Four patients had new-onset postradiosurgery seizures suspected to be related to generously defined target volumes. There were no radiation-induced tumors.

CONCLUSIONS

Proton irradiation is an effective treatment for FPAs, and hypopituitarism remains the primary adverse effect.

Assessment of improved organ at risk sparing for meningioma: light ion beam therapy as boost versus sole treatment option

PURPOSE

To compare photons, protons and carbon ions and their combinations for treatment of atypical and anaplastical skull base meningioma.

MATERIAL AND METHODS

Two planning target volumes (PTVinitial/PTVboost) were delineated for 10 patients (prescribed doses 50 Gy(RBE) and 10 Gy(RBE)). Plans for intensity modulated photon (IMXT), proton (IMPT) and carbon ion therapy ((12)C) were generated assuming a non-gantry scenario for particles. The following combinations were compared: IMXT+IMXT/IMPT/(12)C; IMPT+IMPT/(12)C; and (12)C+(12)C. Plan quality was evaluated by target conformity and homogeneity (CI, HI), V95%, D2% and D50% and dose-volume-histogram (DVH) parameters for organs-at-risk (OAR). If dose escalation was possible, it was performed until OAR tolerance levels were reached.

RESULTS

CI was worst for IMXT. HI<0.05±0.01 for (12)C was significantly better than for IMXT. For all treatment options dose escalation above 60 Gy(RBE) was possible for four patients, but impossible for six patients. Compared to IMXT+IMXT, ion beam therapy showed an improved sparing for most OARs, e.g. using protons and carbon ions D50% was reduced by more than 50% for the ipsilateral eye and the brainstem.

CONCLUSION

Highly conformal IMPT and (12)C plans could be generated with a non-gantry scenario. Improved OAR sparing favors both sole (12)C and/or IMPT plans.