Radiation therapy and CyberKnife radiosurgery in the management of craniopharyngiomas

Craniopharyngioma in Pediatrics and Adults

Craniopharyngiomas are rare malignancies of dysembryogenic origin, involving the sellar and parasellar areas. These low-grade, epithelial tumors account for two main histological patterns (adamantinomatous craniopharyngioma and papillary craniopharyngioma), which differ in epidemiology, pathogenesis, and histomorphological appearance. Adamantinomatous craniopharyngiomas typically show a bimodal age distribution (5-15 years and 45-60 years), while papillary craniopharyngiomas are limited to adult patients, especially in the fifth and sixth decades of life. Recently, craniopharyngioma histological subtypes have been demonstrated to harbor distinct biomolecular signatures. Somatic mutations in CTNNB1 gene encoding β-catenin have been exclusively detected in adamantinomatous craniopharyngiomas, which predominantly manifest as cystic lesions, while papillary craniopharyngiomas are driven by BRAF V600E mutations in up to 95% of cases and are typically solid masses. Despite the benign histological nature (grade I according to the World Health Organization classification), craniopharyngiomas may heavily affect long-term survival and quality of life, due to their growth pattern in a critical region for the presence of eloquent neurovascular structures and possible neurological sequelae following their treatment. Clinical manifestations are mostly related to the involvement of hypothalamic-pituitary axis, optic pathways, ventricular system, and major blood vessels of the circle of Willis. Symptoms and signs referable to intracranial hypertension, visual disturbance, and endocrine deficiencies should promptly raise the clinical suspicion for sellar and suprasellar pathologies, advocating further neuroimaging investigations, especially brain MRI. The optimal therapeutic management of craniopharyngiomas is still a matter of debate. Over the last decades, the surgical strategy for craniopharyngiomas, especially in younger patients, has shifted from the aggressive attempt of radical resection to a more conservative and individualized approach via a planned subtotal resection followed by adjuvant radiotherapy, aimed at preserving functional outcomes and minimizing surgery-related morbidity. Whenever gross total removal is not safely feasible, adjuvant radiotherapy (RT) and stereotactic radiosurgery (SRS) have gained an increasingly important role to manage tumor residual or recurrence. The role of intracavitary therapies, including antineoplastic drugs or sealed radioactive sources, is predominantly limited to monocystic craniopharyngiomas as secondary therapeutic option. Novel findings in genetic profiling of craniopharyngiomas have unfold new scenarios in the development of targeted therapies based on brand-new biomolecular markers, advancing the hypothesis of introducing neoadjuvant chemotherapy regimens in order to reduce tumor burden prior to resection. Indeed, the rarity of these neoplasms requires a multispecialty approach involving an expert team of endocrinologists, neurosurgeons, neuro-ophthalmologists, neuroradiologists, radiotherapists, and neuro-oncologists, in order to pursue a significant impact on postoperative outcomes and long-term prognosis.

An update on multimodal management of craniopharyngioma in children

Craniopharyngioma (CP) represent 1.2-4.6% of all intracranial tumors in children and carry a significant morbidity due to their lesional intimacy with structures involved in neurological, visual, and endocrinological functions. Variable treatment modalities being available, including surgery, radiation therapy, alternative surgeries, and intracystic therapies or combinations of them, their common goal is to reduce immediate and long-term morbidity while preserving these functions. Multiple attempts have been made to re-evaluate surgical and irradiation strategies in order to optimize their complication and morbidity profile. However, despite significant advances in "function sparing" approaches, such as limited surgery and improved technologies of radiation therapies, achieving interdisciplinary consensus on the optimal treatment algorithm remains a challenge. Furthermore, there remains a significant span of improvement given the number of specialties involved as well as the complex and chronic nature of CP disease. This perspective article aims to summarize recent changes and knowledge gains in the field of pediatric CP, outlining updated treatment recommendations, a concept of integrative interdisciplinary care and the implication of novel potential diagnostic tools. A comprehensive update on the multimodal treatment of pediatric CP is presented, focusing on "function-preserving" therapies and their implications.

Applications of Frameless Image-Guided Robotic Stereotactic Radiotherapy and Radiosurgery in Pediatric Neuro-Oncology: A Systematic Review

BACKGROUND

CyberKnife-based robotic radiosurgery (RRS) is a widely used treatment modality for various benign and malignant tumors of the central nervous system (CNS) in adults due to its high precision, favorable safety profile, and efficacy. Although RRS is emerging in pediatric neuro-oncology, scientific evidence for treatment indications, treatment parameters, and patient outcomes is scarce. This systematic review summarizes the current experience and evidence for RRS and robotic stereotactic radiotherapy (RSRT) in pediatric neuro-oncology.

METHODS

We performed a systematic review based on the databases Ovid Medline, Embase, Cochrane Library, and PubMed to identify studies and published articles reporting on RRS and RSRT treatments in pediatric neuro-oncology. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied herein. Articles were included if they described the application of RRS and RSRT in pediatric neuro-oncological patients. The quality of the articles was assessed based on their evidence level and their risk for bias using the original as well as an adapted version of the Newcastle Ottawa Quality Assessment Scale (NOS). Only articles published until 1 August 2021, were included.

RESULTS

A total of 23 articles were included after final review and removal of duplicates. Articles reported on a broad variety of CNS entities with various treatment indications. A majority of publications lacked substantial sample sizes and a prospective study design. Several reports included adult patients, thereby limiting the possibility of data extraction and analysis of pediatric patients. RRS and RSRT were mostly used in the setting of adjuvant, palliative, and salvage treatments with decent local control rates and acceptable short-to-intermediate-term toxicity. However, follow-up durations were limited. The evidence level was IV for all studies; the NOS score ranged between four and six, while the overall risk of bias was moderate to low.

CONCLUSION

Publications on RRS and RSRT and their application in pediatric neuro-oncology are rare and lack high-quality evidence with respect to entity-related treatment standards and long-term outcomes. The limited data suggest that RRS and RSRT could be efficient treatment modalities, especially for children who are unsuitable for surgical interventions, suffer from tumor recurrences, or require palliative treatments. Nevertheless, the potential short-term and long-term adverse events must be kept in mind when choosing such a treatment. Prospective studies are necessary to determine the actual utility of RRS and RSRT in pediatric neuro-oncology.

Craniopharyngiomas: Surgery and Radiotherapy

Taking into account the benign nature of craniopharyngiomas, the main method of treatment is the resection of the tumor. However, the tendency of these tumors to invade critical structures (such as optic pathways, the hypothalamic-pituitary system, the Willis circle vessels) often limits the possibility of a radical surgery.Craniopharyngiomas of the third ventricle represent the greatest challenge for surgery. After radical surgery, hypothalamic disorders often occur, including not only obesity but also cognitive, emotional, mental, and metabolic disturbances. Metabolic disorders associated with damage to the hypothalamus progress after surgery and lead to impaired functions of the internal organs. This process is irreversible and, in many cases, becomes the direct cause of mortality. The life expectancy of patients with the surgically affected hypothalamus is significantly shorter than in patients with preserved diencephalic function. The incidence of hypothalamic disorders after surgery can reach 40%.Even with macroscopically total resection, craniopharyngiomas can recur in 10-30% of cases, and in the presence of tumor remnants and with no further radiation treatment, the risk of recurrence significantly increases to up to 50-85% according to various studies. For this reason, the observation of patients with residual tumors after surgery is an incorrect strategy.Radiation therapy significantly improves progression-free survival (PFS), and the use of stereotactic irradiation techniques ensures conformity of irradiation of tumor remnants with a complicated shape and location (Iwata H et al., J Neurooncol 106(3):571-577, 2012; Aggarwal et al., Pituitary 16(1):26-33, 2013; Savateev et al., Zh Vopr Neirokhir Im N N Burdenko 81(3):94-106; 2017), which potentially reduces the risk of undesirable postradiation effects. Therefore, the quality of life in patients with craniopharyngiomas infiltrating the hypothalamus is significantly higher after non-radical operations with subsequent stereotactic radiation than after a total or subtotal removal.

Outcome After Resection of Craniopharyngiomas and the Important Role of Stereotactic Radiosurgery in Their Management

OBJECTIVE

Experience with management of craniopharyngiomas (CPH) was evaluated retrospectively.

METHODS

Between 1981 and 2012, 100 patients underwent removal of a CPH (the main surgical group), and an original tumor grading system was applied to these cases. The mean length of follow-up was 121 months. Additionally, 17 patients underwent removal of a CPH between 2012 and 2017 (the supplementary surgical group), and in 6 of them, CyberKnife radiosurgery was performed on a residual tumor (in 5 cases) or at the time of recurrence (in 1 case).

RESULTS

In the main surgical group, the gross total resection (GTR) rate was 81%. The early and late disease-specific postoperative mortality rates were 0% and 2%, respectively. Tumor recurrence was never noted after GTR. There was a statistically significant increase in the Karnofsky Performance Scale (KPS) score after surgery. The tumor surgical grade was inversely associated with both the pre- and postoperative KPS scores, and was lower in cases operated on via the transnasal transsphenoidal approach, but was unrelated to the GTR rate. In the supplementary surgical group, the GTR rate was 65%. CyberKnife radiosurgery consistently resulted in tumor shrinkage.

CONCLUSION

GTR is the preferred management option for CPH. The original surgical grading system developed at Tokyo Women's Medical University may be helpful for clinical decision-making. CyberKnife radiosurgery for residual and recurrent CPH is associated with high tumor response rates.

ESTRO ACROP guideline for target volume delineation of skull base tumors

BACKGROUND AND PURPOSE

For skull base tumors, target definition is the key to safe high-dose treatments because surrounding normal tissues are very sensitive to radiation. In the present work we established a joint ESTRO ACROP guideline for the target volume definition of skull base tumors.

MATERIAL AND METHODS

A comprehensive literature search was conducted in PubMed using various combinations of the following medical subjects headings (MeSH) and free-text words: "radiation therapy" or "stereotactic radiosurgery" or "proton therapy" or "particle beam therapy" and "skull base neoplasms" "pituitary neoplasms", "meningioma", "craniopharyngioma", "chordoma", "chondrosarcoma", "acoustic neuroma/vestibular schwannoma", "organs at risk", "gross tumor volume", "clinical tumor volume", "planning tumor volume", "target volume", "target delineation", "dose constraints". The ACROP committee identified sixteen European experts in close interaction with the ESTRO clinical committee who analyzed and discussed the body of evidence concerning target delineation.

RESULTS

All experts agree that magnetic resonance (MR) images with high three-dimensional spatial accuracy and tissue-contrast definition, both T2-weighted and volumetric T1-weighted sequences, are required to improve target delineation. In detail, several key issues were identified and discussed: i) radiation techniques and immobilization, ii) imaging techniques and target delineation, and iii) technical aspects of radiation treatments including planning techniques and dose-fractionation schedules. Specific target delineation issues with regard to different skull base tumors, including pituitary adenomas, meningiomas, craniopharyngiomas, acoustic neuromas, chordomas and chondrosarcomas are presented.

CONCLUSIONS

This ESTRO ACROP guideline achieved detailed recommendations on target volume definition for skull base tumors, as well as comprehensive advice about imaging modalities and radiation techniques.

Dosimetric and volumetric outcomes of combining cyst puncture through an Ommaya reservoir with index-optimized hypofractionated stereotactic radiotherapy in the treatment of craniopharyngioma

Large cystic craniopharyngioma management combining cyst puncture through an Ommaya reservoir with hypofractionated stereotactic radiotherapy was evaluated. The planning optimization was focused on the gradient and selectivity. Punctured and filled cyst treatment plans were compared with a retrospective analysis of volumetric and functional outcomes.

Postoperative Long-term Outcomes of Patient with Craniopharyngioma Based on CyberKnife Treatment

Objective

The results of CyberKnife treatment in patients with craniopharyngiomas are excellent, but reports of long-term follow-up are rare. Hence, considering the possibility of a long-term follow-up of five years or more, we examined the long-term prognoses of these patients.

Materials and Methods

Of 33 patients, 12 were males and 21 were females. On postoperative evaluation, three patients experienced recurrence after total resection and were treated using CyberKnife. Twenty-five patients were treated with CyberKnife after partial resection. The mean age at treatment was 47 years, and the follow-up period was 61 to 129 months.

Results

Of the cases assessed as totally resected in the postoperative evaluation, three recurred after 18 months. CyberKnife treatment was administered immediately in recurrent cases; subsequently, no recurrences were observed for 25 months or more. No recurrences were observed in any patients treated with CyberKnife on the residual site after surgical treatment. Many cases had improved pituitary function, but none had deteriorated. In addition, no case of visual function deterioration was reported. 

Conclusion

Twenty years have passed since the introduction of CyberKnife treatment; however, only a few reports have examined the long-term prognosis of patients with craniopharyngiomas who underwent this treatment. We have been aware of the efficacy of CyberKnife treatment for ten years or more; its long-term results are evident, and the good growth control and low adverse effects are impressive. We are confident that we can maintain good treatment results by combining conservative surgical resection with minimal complications and CyberKnife treatment for new patients in the future.

Benefits of image-guided stereotactic hypofractionated radiation therapy as adjuvant treatment of craniopharyngiomas. A review

PURPOSE

Craniopharyngiomas account for 5.6-13% of intracranial tumors in children. Despite being histologically benign, these tumors remain a major neurosurgical challenge because of the typical tight adherence to adjacent critical structures. The optimal therapeutic approach for this disease is controversial. Large cystic size and adherence to neurovascular, neuroendocrine, and optic structures without a clear line of cleavage make complete resection problematic and often hazardous. For these reasons, partial resection and adjuvant treatment play an important role. Post-operative radiation therapy (RT) following either complete or incomplete tumor removal is associated with significantly decreased recurrence rates. The aim of this review is to analyze the potential advantage of the most modern technical advancements for RT of craniopharyngiomas.

METHODS

This narrative review on the topic of craniopharyngiomas was based on published data available on PUBMED/Medline. All data concerning adjuvant or upfront radiation therapy treatment of craniopharyngioma were reviewed and summarized. A more detailed analysis of fractionated frameless steretactic radiosurgery of these tumors is provided as well.

RESULTS

We reviewed the possible improvement provided by intensity modulated beams, arc therapy, image guidance, proton radiation, and fractionated stereotactic radiosurgery. Many published findings on outcome and toxicity after RT involve the use of relatively outdated RT techniques. Technologic improvements in imaging, radiation planning, and delivery have improved the distribution of radiation doses to desired target volumes and reduced the dose to nearby critical normal tissues. Currently available techniques, providing image guidance and improved radiation doses distribution profile, have shown to maintain the efficacy of conventional techniques while significantly reducing the toxicity.

CONCLUSIONS

Image-guided radiosurgery holds the dose distributions and precision of frame-based techniques with the remarkable advantage of multiple-session treatments that are better tolerated by sensitive peritumoral structures, such as the optic pathway and hypothalamus. This, together with the comfort of a frameless technique, candidates frameless image-guided radiosurgery to be the first option for the adjuvant post-operative treatment of craniopharyngiomas in children and young adults when total resection cannot be achieved, in particular those with hypothalamic involvement, and when the residual tumor is mostly solid.

Stereotactic Radiosurgery for Neurosurgical Patients: A Historical Review and Current Perspectives

Today, stereotactic radiosurgery is an effective therapy for a variety of intracranial pathology that were treated solely with open neurosurgery in the past. The technique was developed from the combination of therapeutic radiation and stereotactic devices for the precise localization of intracranial targets. Although stereotactic radiosurgery was originally performed as a partnership between neurosurgeons and radiation oncologists, this partnership has weakened in recent years, with some procedures being performed without neurosurgeons. At the same time, neurosurgeons across the United States and Canada have found their stereotactic radiosurgery training during residency inadequate. Although neurosurgeons, residency directors, and department chairs agree that stereotactic radiosurgery education and exposure during neurosurgery training could be improved, a limited number of resources exist for this kind of education. This review describes the history of stereotactic radiosurgery, assesses the state of its use and education today, and provides recommendations for the improvement of neurosurgical education in stereotactic radiosurgery for the future.

A reformed surgical treatment modality for children with giant cystic craniopharyngioma

OBJECTIVE

Surgical removal plays an important role in treating children's craniopharyngioma. For a safe and minimally invasive craniotomy, a reformed surgical modality was proposed in this paper by combining the insertion of an Ommaya reservoir system (ORS) by stereotactic puncture, aspiration of cystic fluid in 2-day interval for consecutive 7-10 days, and the delayed tumor resection.

PATIENTS AND METHODS

Eleven patients (aged from 5 to 9 years old) with giant cystic craniopharyngiomas who had undergone the reformed surgical modality during November 2014 and December 2015 were collected as group A. In contrast, seven patients (aged from 5 to 11 years old) who had undergone the traditional directed operation without any prior management from January 2014 to October 2014 were collected into group B. A retrospective analysis was performed for both groups at one institution. The preoperative and postoperative clinical presentations, neuroimaging, early postoperative outcome, and the surgery-related complications of both groups were reviewed.

RESULTS

For group A, the mean value of the maximum tumor diameters shank from 52.36 to 23.82 mm after implementing aspiration of the cystic fluid in 1-day interval for consecutive 8.23 days. Eight patients (72.73%) in group A underwent a gross total resection (GTR), while two (28.57%) patients underwent GTR in group B. The postoperative electrolyte disturbance rate and endocrine disorder rate of group B were significantly higher than those of group A (42.86 vs 36.36%; 71.43 vs 45.45%). Postoperative long-term diabetes insipidus only occurred in one patient of group B, and postoperative visual deterioration occurred in two patients of group B. Besides, one patient of group B died of severe postoperative hypothalamus dysfunction. Patients with residual tumors were applied with additional adjuvant radiotherapy, and no recurrence was observed in follow-up examinations.

CONCLUSION

A favorable outcome can be achieved by combining the insertion of an ORS by stereotactic puncture, aspiration of cystic fluid in 2-day interval for continuously 7-10 days, and the delayed tumor resection. This combined treatment modality maybe an effective method to treat children with giant cystic craniopharyngiomas.

Radiosurgery for Pediatric Brain Tumors

The utility of radiosurgery for pediatric brain tumors is not well known. For children, radiosurgery may have an important role for treating unresectable tumors, residual disease, or tumors in the recurrent setting that have received prior radiotherapy. The available evidence demonstrates utility for some children with primary brain tumors resulting in good local control. Radiosurgery can be considered for limited residual disease or focal recurrences. However, the potential toxicities are unique and not insignificant. Therefore, prospective studies need to be performed to develop guidelines for indications and treatment for children and reduce toxicity in this population.

Endoscopic transnasal external fistulation in recurrent cystic subdiaphragmatic craniopharyngioma: a novel technique

The authors present a technique for the persistent external drainage of intractable subdiaphragmatic cystic recurrences with the creation of a fistula between the cyst wall epithelium and epithelium on the nasal cavity, using a pedicled nasoseptal flap as a conduit. The long-term efficacy of endoscopic transnasal external fistulation (ETEF) in controlling cystic recurrences in this patient group is addressed through a retrospective observational review of 3 male patients aged 8, 22, and 45 years with the diagnosis of recurrent cystic subdiaphragmatic craniopharyngioma who underwent the ETEF procedure between 2006 and 2009. Clinical presentation, neuroimaging, surgical interventions, and follow-up were recorded. The main outcome measure was cyst reaccumulation on MRI. Patients had a mean follow-up of 76 months (range 5-8 years) with no incidence of cystic recurrence. Follow-up imaging revealed sustained cyst involution contrary to the usual recurrent enlargement commonly seen in this patient group. Symptoms of headache and visual field defects improved post-ETEF. Long-term theoretical complications of a persistent fistula such as intracranial abscess, meningitis, or CSF leak were not observed. ETEF promotes nasalization of cystic recurrences in subdiaphragmatic craniopharyngioma. It is safe and effective, causing long-term involution of cysts and can be considered a definitive procedure.

Recurrent craniopharyngioma after conformal radiation in children and the burden of treatment

OBJECT

In this paper the authors present their experience treating children with recurrent craniopharyngioma who were initially managed with surgery followed by conformal radiation therapy (CRT).

METHODS

A departmental oncology information system was queried to identify all children (< 18 years old) who received CRT for a craniopharyngioma between 1998 and 2010 (inclusive) and specifically those who experienced tumor progression. For each patient, the authors recorded the type of recurrence (solid, cystic, or both), the time interval to first progression and each subsequent progression, the associated treatment complications, and disease status at last follow-up evaluation.

RESULTS

Among the 97 patients that met criteria for entry into this study, 18 (18.6%) experienced tumor progression (9 cystic, 3 solid, 6 cystic and solid). The median time to first recurrence was 4.62 years (range 1.81-9.11 years). The subgroup included 6 female and 12 male patients with a median age of 7.54 years (range 3.61-13.83 years). Ten patients experienced first progression within 5 years of CRT. The 5- and 10-year treatment-free survival rates for the entire cohort were 89.0% (95% confidence interval [CI] 80.5%-93.9%) and 76.2% (95% CI 64%-85%), respectively. Seven patients had a single episode of progression and 11 had more than 1. The time interval between each subsequent progression was progressively shorter. The 18 patients underwent 38 procedures. The median follow-up duration for this group was 9.32 years (range 4.04-19.0 years). Three patients died, including 1 from perioperative complications.

CONCLUSIONS

Craniopharyngioma progression after prior irradiation is exceedingly difficult to treat and local control is challenging despite repeated surgical procedures. Given our results, gross-total resection may need to be the surgical goal at the time of first recurrence, if possible. Decompressing new cyst formation alone has a low rate of long-term success.

Stereotactic radiation therapy for skull base recurrences: Is a salvage approach still possible?

AIM

A literature review was performed to analyse the role of stereotactic radiotherapy given in a single shot or in a fractionated fashion for recurrent skull base tumours in order to ascertain if it can be a real salvage approach.

BACKGROUND

The management of recurrent skull base tumours can have a curative or palliative intent and mainly includes surgery and RT.

MATERIALS AND METHODS

One-thousand-ninety-one articles were found in the search databases and the most relevant of them were analysed and briefly described.

RESULTS

Data on recurrences of meningioma, pituitary adenoma, craniopharyngioma, chordoma and chondrosarcoma, vestibular schwannoma, glomus jugulare tumours, olfactory neuroblastoma and recurrences from head and neck tumours invading the base of skull are reported highlighting the most relevant results in terms of local control, survival, side effects and complications.

CONCLUSIONS

In conclusion, it emerges that SRS and FSRT are effective and safe radiation modalities of realize real salvage treatment for recurrent skull base tumours.

Fractionated gamma knife radiosurgery for benign perioptic tumors: outcomes of 38 patients in a single institute

BACKGROUND

This study was performed to evaluate the efficacy and safety of fractionated Gamma Knife radiosurgery (GKRS) for perioptic lesions.

METHODS

Thirty-eight patients with perioptic tumors were treated at our institute from May 2004 to December 2008. All patients had a lesion in close contact with the optic apparatus. Twenty-four of these patients had undergone surgical resection before fractionated GKRS. Radiation was delivered in four sessions with 12 hours intervals between sessions. The mean target volume was 3,851 mm(3) and the median cumulative marginal dose was 20 Gy. The median follow-up was 38.2 months. Visual acuity and visual fields were analyzed according to visual impairment score using the German Ophthalmological Society guidelines.

RESULTS

Tumor control was achieved in 35 (94.6%) of the 37 patients with available follow-up images. Progressive tumor growth was observed in two craniopharyngioma patients (5.4%). Favorable visual outcomes in the postoperative period were achieved in 94.7% of cases (36/38). Sixteen patients showed visual function after fractionated GKRS, twenty cases were stationary, and two patients showed visual function deterioration after GKRS.

CONCLUSION

GKRS is a safe and effective alternative to either surgery or fractionated radiotherapy for selected benign lesions that are adjacent to the optic apparatus.

The biology of radiosurgery and its clinical applications for brain tumors

Stereotactic radiosurgery (SRS) was developed decades ago but only began to impact brain tumor care when it was coupled with high-resolution brain imaging techniques such as computed tomography and magnetic resonance imaging. The technique has played a key role in the management of virtually all forms of brain tumor. We reviewed the radiobiological principles of SRS on tissue and how they pertain to different brain tumor disorders. We reviewed the clinical outcomes on the most common indications. This review found that outcomes are well documented for safety and efficacy and show increasing long-term outcomes for benign tumors. Brain metastases SRS is common, and its clinical utility remains in evolution. The role of SRS in brain tumor care is established. Together with surgical resection, conventional radiotherapy, and medical therapies, patients have an expanding list of options for their care. Clinicians should be familiar with radiosurgical principles and expected outcomes that may pertain to different brain tumor scenarios.

Craniopharyngioma

This report is a review of findings on the diagnosis, treatment, clinical course, and prognosis of craniopharyngioma patients. Craniopharyngiomas are rare, partly cystic and calcified embryonic malformations of the sellar/parasellar region with low histological grade (WHO I°). A bimodal age distribution has been shown, with peak incidence rates in childhood-onset at 5-14 years and adult-onset craniopharyngioma at 50-74 years. Clinical manifestations are related to hypothalamic/pituitary deficiencies, visual impairment, and increased intracranial pressure. If the tumor is favorably localized, the therapy of choice is complete resection, with care taken to preserve optical and hypothalamic functions. In patients with unfavorable tumor localization (i.e., hypothalamic involvement), recommended therapy is a limited hypothalamus-sparing surgical strategy followed by local irradiation. Although overall survival rates are high (92%), recurrences and progressions are frequent. Irradiation has proven effective in reducing recurrences and progression, and timing of postsurgical irradiation in childhood-onset cases is currently under investigation in a randomized multinational trial (KRANIOPHARYNGEOM 2007). Anatomical involvement and/or surgical lesions of posterior hypothalamic areas can result in serious quality of life-compromising sequelae such as hypothalamic obesity, psychopathological symptoms, and/or cognitive problems. It is crucial that craniopharyngioma be managed as a frequently chronic disease, providing ongoing care of pediatric and adult patients' clinical and quality of life consequences by experienced multidisciplinary teams.

Craniopharyngioma

Craniopharyngiomas are partly cystic embryogenic malformations of the sellar and parasellar region. With an overall incidence of 0.5-2.0 new cases per million population per year, approximately 30-50% of all cases represent childhood craniopharyngioma. Typical manifestations at diagnosis are some combination of headache, visual impairment, polyuria/polydypsia, growth retardation, and significant weight gain. Therapy of choice in patients with favorable tumor localization is complete resection with specific focus on maintaining functions of the optic nerve and hypothalamic-pituitary axes. In patients whose unfavorable tumor localization makes maintaining hypothalamic functionality surgically challenging, a limited resection followed by local irradiation is recommended. The overall survival rates are high (92%) but occurrences of reduced quality of life are also high. Recurrences after complete resection and progressions of residual tumor after incomplete resection are frequent postsurgical events. Because irradiation is efficient in preventing tumor progression, appropriate timing of postsurgical irradiation is currently under investigation in the randomized multinational trial KRANIOPHARYNGEOM 2007 that analyzes quality of life as primary endpoint. Childhood craniopharyngioma should be recognized as a chronic disease requiring constant monitoring of the clinical and quality of life consequences in order to provide optimal care of surviving patients.

Surgical outcomes of the minimum anterior and posterior combined transpetrosal approach for resection of retrochiasmatic craniopharyngiomas with complicated conditions

OBJECT

Retrochiasmatic craniopharyngiomas are surgically challenging tumors. Retrochiasmatic craniopharyngiomas with complicated conditions such as large diameter, major calcification, or significant extension to the third ventricle or posterior fossa present surgical challenges; moreover, recurrent retrochiasmatic craniopharyngiomas are particularly formidable challenges. Although the transpetrosal approach to retrochiasmatic craniopharyngiomas published by Hakuba in 1985 can provide unique advantageous exposure of the retrochiasmatic area to allow safe neurovascular dissection and facilitate radical tumor removal, the procedure is viewed as complicated and time consuming and has a high risk of damaging hearing functions. The authors have modified Hakuba's technique to minimize petrosectomy and reduce surgical complications and have applied this modified approach to retrochiasmatic craniopharyngiomas with complicated conditions. In this study, the authors describe their technique and surgical outcomes to elucidate the role of this modified transpetrosal approach for retrochiasmatic craniopharyngiomas with complicated conditions. This is the first study to report surgical outcomes of the transpetrosal approach for retrochiasmatic craniopharyngiomas.

METHODS

Between 1999 and 2011, the minimum anterior and posterior combined (MAPC) transpetrosal approach, which is a modification of Hakuba's transpetrosal approach, was applied in 16 cases of retrochiasmatic craniopharyngiomas with complicated conditions. Eight cases were recurrent tumors, 4 had previously received radiotherapy, 11 had a large diameter, 10 had large calcification, 15 had superior extension of the tumor into the third ventricle, and 10 had a posterior extension of the tumor that compressed the midbrain and pons. In all 16 patients, more than 2 of these complicated conditions were present. The follow-up duration ranged from 0.8 to 12.5 years (mean 5.3 years). Surgical outcomes assessed were the extent of resection, surgical complications, visual function, endocrinological status, and neuropsychological function. Five-year and 10-year recurrence-free survival rates were also calculated.

RESULTS

Gross-total or near-total resection was achieved in 15 cases (93.8%). Facial nerve function was completely maintained in all 16 patients. Serviceable hearing was preserved in 15 cases (93.8%). Visual function improved in 13 out of 14 cases (92.9%) that had visual disturbance before surgery. None of the patients experienced deterioration of their visual function. Twelve cases had endocrinological deficit and received hormonal replacement before surgery. New endocrinological deficit occurred in 2 cases (12.5%). Neuropsychological function was maintained in 14 cases (87.5%) and improved in 1 case (6.3%). One case that had received previous conventional radiotherapy treatment showed a gradual decline in neuropsychological function. The 5-year and 10-year recurrence-free survival rates were both 86.5%.

CONCLUSIONS

The authors obtained good results by using the MAPC transpetrosal approach for the removal of retrochiasmatic craniopharyngiomas with complicated conditions. The MAPC transpetrosal approach should be considered as a therapeutic option for selected cases of retrochiasmatic craniopharyngiomas with complicated conditions.

Radiotherapy for craniopharyngioma

Radiotherapy remains the mainstay of multidisciplinary management of patients with incompletely resected and recurrent craniopharyngioma. Advances in imaging and radiotherapy technology offer new alternatives with the principal aim of improving the accuracy of treatment and reducing the volume of normal brain receiving significant radiation doses. We review the available technologies, their technical advantages and disadvantages and the published clinical results. Fractionated high precision conformal radiotherapy with image guidance remains the gold standard; the results of single fraction treatment are disappointing and hypofractionation should be used with caution as long term results are not available. There is insufficient data on the use of protons to assess the comparative efficacy and toxicity. The precision of treatment delivery needs to be coupled with experienced infrastructure and more intensive quality assurance to ensure best treatment outcome and this should be carried out within multidisciplinary teams experienced in the management of craniopharyngioma. The advantages of the combined skills and expertise of the team members may outweigh the largely undefined clinical gain from novel radiotherapy technologies.

[Stereotactic radiotherapy in pediatric indications]

Stereotactic radiotherapy is a very high precision procedure, which has been limited to radiosurgery for a long time. Technological improvements allowed the development of radiotherapy in stereotactic conditions, leading to a lot of innovations. Previously indicated for cerebral pathologies, this procedure is now developed for extracerebral locations. In paediatrics, stereotactic radiotherapy is still limited, delivered precociously, due to the possibility of long-term late effects that needs to be addressed. This review reports the different useful conditions, technical evolutions, and the current validated paediatric indications, with differences from adults, and future directions.

Stereotactic radiosurgery yields long-term control for benign intradural, extramedullary spinal tumors

BACKGROUND

The role of stereotactic radiosurgery in the treatment of benign intracranial lesions is well established. Although a growing body of evidence supports its role in the treatment of malignant spinal lesions, a much less extensive dataset exists for treatment of benign spinal tumors.

OBJECTIVE

To examine the safety and efficacy of stereotactic radiosurgery for treatment of benign, intradural extramedullary spinal tumors.

METHODS

From 1999 to 2008, 87 patients with 103 benign intradural extramedullary spinal tumors (32 meningiomas, 24 neurofibromas, and 47 schwannomas) were treated with stereotactic radiosurgery at Stanford University Medical Center. Forty-three males and 44 females had a median age of 53 years (range, 12-86). Twenty-five patients had neurofibromatosis. Treatment was delivered in 1 to 5 sessions (median, 2) with a mean prescription dose of 19.4 Gy (range, 14-30 Gy) to an average tumor volume of 5.24 cm (range, 0.049-54.52 cm).

RESULTS

After a mean radiographic follow-up period of 33 months (range, 6-87), including 21 lesions followed for ≥ 48 months, 59% were stable, 40% decreased in size, and a single tumor (1%) increased in size. Clinically, 91%, 67%, and 86% of meningiomas, neurofibromas, and schwannomas, respectively, were symptomatically stable to improved at last follow-up. One patient with a meningioma developed a new, transient myelopathy at 9 months, although the tumor was smaller at last follow-up.

CONCLUSION

As a viable alternative to microsurgical resection, stereotactic radiosurgery provides safe and efficacious long-term control of benign intradural, extramedullary spinal tumors with a low rate of complication.

[Therapeutic update on the treatment of craniopharyngiomas]

Craniopharyngioma is an uncommon benign neoplasm, accounting for 1%-3% of all intracranial tumors, and the most common non-neuroepithelial intracranial neoplasm in childhood. Usually, the tumor is confined to the sellar region and the third ventricle, but due to frequent infiltration and adherence to the central nervous system, it often has an unfavorable clinical behavior. Therefore, it is classified by the World Health Organization (WHO) as a tumor of low or uncertain malignant potential. Endocrine after effects, mainly hypothalamic hypopituitarism, obesity and diabetes insipidus are highlighted due to their important impact on the quality of life of patients, mostly children. Optimal treatment of this tumor is a major challenge for neurosurgeons and endocrinologists. The combination of surgery, radiation, and application of radioisotopes and intratumoral drugs, aims at maximizing the chances of cure with minimal complications. Yet, recurrence is still frequent. Choosing the best treatment modality for craniopharyngiomas is a difficult decision, and it should always be specific for each case. In order to explore the multiple therapeutic options for craniopharyngiomas, we reviewed the literature with emphasis on the therapeutic possibilities and complications inherent to the treatment of this disease.

The therapeutic efficacy of fractionated radiotherapy and gamma-knife radiosurgery for craniopharyngiomas

There is no consensus regarding the optimal timing of radiation treatment (RT) for residual or recurrent craniopharyngioma or the preferred treatment modality between fractionated radiotherapy (FRT) and gamma-knife radiosurgery (GKRS) in terms of morbidity and efficacy. This study aims to clarify the optimal timing of RT for residual or recurrent tumors by analyzing the outcomes of RT as a salvage or adjunctive treatment, and to compare the therapeutic efficacy of FRT and GKRS. Between April 1995 and November 2009, 50 of 129 patients received RT for recurrent or residual tumors. The patients were analyzed for medical data, endocrine outcome, long-term morbidity and mortality rates, recurrence rates, and responses to adjuvant RT and GKRS. Mean progression-free survival was 92.5 months (95% confidence interval, 70.9-114.1 months). Univariate analysis revealed that pre-irradiation tumor volume was closely related to better prognosis (p=0.01). We found that there was no significant difference in recurrence between patients treated with adjuvant compared to salvage RT (p>0.05). Although we found no difference in the efficacy of FRT and GKRS, five patients were newly diagnosed with hypopituitarism following RT. We concluded that RT has a very high rate of tumor control after both adjuvant or salvage RT. This study highlights the relative safety and efficacy of FRT and GKRS.

Single and hypofractionated stereotactic radiotherapy with CyberKnife for craniopharyngioma

Craniopharyngiomas are slow-growing tumors found in the suprasellar region, with especially high incidence in Japanese children. Due to the location, proximity and adhesiveness of the tumor to adjacent critical structures, these tumors remain a significant clinical challenge. The purpose of this study was to evaluate the clinical outcome of single and hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for craniopharyngioma. Forty-three patients (21 men and 22 women; median age 44 years; range 3-85 years) were treated at two institutions. Three cases were treated in a single fraction to a marginal dose of 13-16 Gy. The other 40 cases were treated in 2-5 fractions to a marginal dose of 13-25 Gy. Tumor volumes ranged from 0.09 to 20.8 cm(3) (median 2.0 cm(3)). Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period was 40 months (range 12-92 months). The 3-year overall survival and local control rates were 100 and 85%, respectively. In-field cyst enlargement was observed in 9 patients. These tumors had significantly larger volumes (mean 6.9 cm(3); 95% confidence interval, CI, 2.8-10.9 cm(3)) than the 34 controlled tumors (2.9 cm(3); CI 1.5-4.3 cm(3)) (P = 0.02). Out-field tumor regrowth was observed in 4 patients. No radiation-induced symptomatic visual disorder or brain necrosis was observed. Hypopituitarism was observed in only 1 patient. Single and hypofractionated SRT using CyberKnife produced high tumor control rates with minimal complications. Hypofractionated SRT may be useful for protecting the visual nerve and neuroendocrine function, especially for tumors located near the optic pathways and for large tumors.

Dose tolerance limits and dose volume histogram evaluation for stereotactic body radiotherapy

Almost 20 years ago, Emami et al. presented a comprehensive set of dose tolerance limits for normal tissue organs to therapeutic radiation, which has proven essential to the field of radiation oncology. The paradigm of stereotactic body radiotherapy (SBRT) has dramatically different dosing schemes but, to date, there has still been no comprehensive set of SBRT normal organ dose tolerance limits. As an initial step toward that goal, we performed an extensive review of the literature to compare dose limits utilized and reported in existing publications. The impact on dose tolerance limits of some key aspects of the methods and materials of the various authors is discussed. We have organized a table of 500 dose tolerance limits of normal structures for SBRT. We still observed several dose limits that are unknown or not validated. Data for SBRT dose tolerance limits are still preliminary and further clinical trials and validation are required. This manuscript presents an extensive collection of normal organ dose tolerance limits to facilitate both clinical application and further research.

Different approaches in radiation therapy of craniopharyngioma

Radiation therapy is a cornerstone in the therapeutic management of craniopharyngioma. The close proximity to neighboring eloquent structures pose a particular challenge to radiation therapy. Modern treatment technologies including fractionated 3-D conformal radiotherapy, intensity modulated radiation therapy, and recently proton therapy are able to precisely cover the target while preserving surrounding tissue, Tumor controls between 80 and in access of 90% can be achieved. Alternative treatments consisting of radiosurgery, intracavitary application of isotopes, and brachytherapy also offer an acceptable tumor control and might be given in selected cases. More research is needed to establish the role of each treatment modality.

Fusiform dilation of the carotid artery following radical resection of pediatric craniopharyngiomas: natural history and management

OBJECT

Fusiform dilation of the supraclinoid internal carotid artery (FDCA) is a reported occurrence following surgery for suprasellar tumors, in particular craniopharyngiomas. We report our experience of the incidence and natural history of FDCA following aggressive surgical resection of craniopharyngiomas in children.

METHODS

Between 1986 and 2006, 86 patients under the age of 21 underwent radical resection of craniopharyngiomas at our institution. Ten cases with < 1 year of follow-up imaging (6), perioperative death (3), or nonsuprasellar tumors (1) were excluded. Data were retrospectively collected on the remaining 76 patients (43 male, 33 female; mean age 9.5 years; mean tumor size 3.3 cm) to determine the risk factors for and the rate and clinical significance of FDCA.

RESULTS

Fifty patients had primary tumors and 26 patients received treatment before referral to our center. Sixty-six children (87%) had gross-total resection. At a mean follow-up time of 9.9 years, FDCA had developed in 7 patients (9.2%), all of whom had primary tumors and gross-total resection. The mean time to onset of FDCA was 6.8 months (range 3-11 months) with stabilization occurring at mean of 17.7 months (range 9-29.5 months). The mean size of the aneurysms was 9.1 mm (range 7.1-12 mm). After arrest, no lesions showed continued growth on serial imaging or produced symptoms or required treatment. There were no significant differences in age, sex, tumor size, pre- or retrochiasmatic location, extent of resection, or surgical approach (p > 0.05) between patients with and without FDCA.

CONCLUSIONS

Fusiform dilation of the supraclinoid internal carotid artery occurred in almost 10% of children following radical resection of craniopharyngiomas. In agreement with other reports, the authors concluded that FDCA probably occurs as a result of surgical manipulation of the supraclinoid carotid artery and should be managed conservatively because very few patients exhibit continued symptoms or experience growth or rupture of the lesion.

The role of radiosurgery in the treatment of craniopharyngiomas

The treatment of craniopharyngiomas is composed of an intricate balance of multiple modalities. Resection and radiotherapy have been combined to synergistically control tumor growth while preventing undue harm to crucial neurovascular structures. Although a craniopharyngioma is a benign lesion pathologically, it may induce severe neurological injury due to its location and rate of growth. More recently, the advent of targeted, fractionated radiotherapy has allowed for more aggressive tumor control while reducing the necessity for large resections. Initial studies have demonstrated significant tumor control in patients who are treated with resection combined with radiation therapy, versus surgery alone, with a lower rate of treatment-associated neurological deficits. In this review, a detailed account of the current studies evaluating the role of stereotactic radiosurgery in the management of craniopharyngiomas is presented. The authors also provide a short account of their experience to aid in defining the role of CyberKnife radiosurgery.

Radiation dose-volume effects of optic nerves and chiasm

Publications relating radiation toxicity of the optic nerves and chiasm to quantitative dose and dose-volume measures were reviewed. Few studies have adequate data for dose-volume outcome modeling. The risk of toxicity increased markedly at doses >60 Gy at approximately 1.8 Gy/fraction and at >12 Gy for single-fraction radiosurgery. The evidence is strong that radiation tolerance is increased with a reduction in the dose per fraction. Models of threshold tolerance were examined.

Ectopic recurrence of craniopharyngioma along the surgical route: case report and literature review

We present a 22-year-old woman with an ectopic recurrence of a craniopharyngioma. The patient presented first with a visual field deficit, and a craniopharyngioma was removed via an interhemispheric transcallosal approach. Magnetic resonance imaging (MRI) performed at 1 month, and then at 1 year after surgery showed complete removal of the lesion. However, at 4 years, MRI showed the presence of a small tumor in the right medial frontal lobe attached to the falx and along the previous surgical route. We present possible explanations for the ectopic recurrence and literature review.

Efficacy and safety of radical resection of primary and recurrent craniopharyngiomas in 86 children

OBJECT

Optimal treatment of primary and recurrent craniopharyngiomas remains controversial. Radical resection and limited resection plus radiation therapy yield similar rates of disease control and overall survival. The data are much less clear for recurrent tumors. The authors report their experience with radical resection of both primary and recurrent craniopharyngiomas in children and compare the outcomes between the 2 groups.

METHODS

A retrospective analysis was performed in 86 children younger than 21 years of age who underwent a total of 103 operations for craniopharyngioma between 1986 and 2008; these were performed by the senior author. The goal was resection with curative intent in all patients. Two patients were lost to follow-up and were excluded from analysis. The mean age at the time of surgery was 9.6 years, and the mean follow-up was 9.0 years.

RESULTS

All 57 children with primary tumors underwent gross-total resection (GTR). A GTR was achieved in significantly fewer children with recurrent tumors (18 [62%] of 29). There were 3 perioperative deaths (3%). Tumor recurred after GTR in 14 (20%) of 71 patients. Overall survival and progression-free survival were significantly better in patients with primary tumors at time of presentation to the authors' institution. There were no significant differences in the neurological, endocrinological, visual, or functional outcomes between patients with primary and those with recurrent tumors. Factors negatively affecting overall survival and progression-free survival include subtotal resection (recurrent tumors only), tumor size >or= 5 cm, or presence of hydrocephalus or a ventriculoperitoneal shunt. Prior radiation therapy and increasing tumor size were both risk factors for incomplete resection at reoperation.

CONCLUSIONS

In the hands of surgeons with experience with craniopharyngiomas, the authors believe that radical resection at presentation offers the best chance of disease control and potential cure with acceptable morbidity. While GTR does not preclude recurrence and is more difficult to achieve in recurrent tumors, especially large and previously irradiated tumors, radical resection is still possible in patients with recurrent craniopharyngiomas with morbidity similar to that of primary tumors.

[Stereotactical radiotherapy in pediatrics indications]

Stereotactical radiotherapy is a very high precision procedure, limited to radiosurgery since a long time. Technologic progress permitted to develop radiotherapy in stereotactical conditions, leading to a lot of innovations. Previously indicated for cerebral pathologies, this procedure is now developed for extracerebral locations. In pediatrics, stereotactical radiotherapy is still limited, delivered precociously, due to the possibility of long-term late effects that needs to be to addressed. This review reports the different useful conditions, technical evolutions, and the current validated pediatric indications, with differences from adults, and future directions. Current state of pediatric stereotactical radiotherapy used in France is presented.