Optimal strategy of gamma knife radiosurgery for craniopharyngiomas

Enhanced outcomes in residual or recurrent craniopharyngioma: evaluating combined gamma knife and phosphorus-32 brachytherapy

BACKGROUND

Managing residual and recurrent craniopharyngioma effectively is crucial for improving patient outcomes. This study evaluates the combined use of gamma knife and phosphorus-32 brachytherapy, offering insights into alternative, less invasive treatment strategies.

METHODS

We conducted a retrospective analysis of 97 patients treated from 2010 to 2016 for residual and recurrent craniopharyngioma using gamma knife and phosphorus-32 brachytherapy. We classified these patients into three groups: superficial solid (Group A), simple cystic (Group B), and mixed cystic-solid (Group C). We assessed the treatment's effectiveness by the tumor control rates and evaluated safety by monitoring vision, endocrine function improvements, and complication rates.

RESULTS

The treatment achieved complete and adequate control rates of 49.5% and 87.6%, respectively. We observed improvements in vision or visual fields in 55.1% of the patients. The morbidity rate was 15.5%. The study found no significant differences in tumor control rates among the various lesion types.

CONCLUSION

The combination of gamma knife and phosphorus-32 brachytherapy presents a viable, minimally invasive alternative for treating residual and recurrent craniopharyngioma. It offers high tumor control and functional improvement rates, suggesting its potential as a preferred strategy in some instances.

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.

Effects of two different radiotherapies for craniopharyngiomas using stereotactic radiosurgery/ stereotactic radiotherapy or fractionated stereotactic radiotherapy

Background

Numerous studies have reported about good tumor control with both stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for residual and recurrent craniopharyngiomas, but no studies have reported on the appropriate use of different types of radiation modalities. This study aimed to report the outcomes of SRS/stereotactic radiotherapy (SRT) or FSRT and compare tumor control in a single center.

Methods

From 2014 when TrueBeamTM STx with Novalis was introduced in our hospital to 2021, 21 patients underwent SRS/SRT or FSRT with gamma knife surgery (GKS) and Novalis. We have selected the radiation modalities considering mainly the distance of the optic nerve and chiasm. Imaging and clinical follow-up data were sent and reviewed.

Results

The mean age was 52 years and there were 11 men. Of the 21 total patients, three experienced SRS (GKS, 50% isodose 12-15 Gy), five underwent SRT (GKS or Novalis, 19.5-24 Gy 3 fractions), and 13 patients underwent FSRT (Novalis, 54 Gy 30 fractions). The median follow-up was 32.6 (range 17-44) months after SRS/SRT and 34.0 (range 4-61) months after FSRT. In the SRS/SRT group, the mean tumor volume decreased from 1.103 to 0.131 cm³ (P < 0.01), and in the FSRT group, from 3.015 to 1.012 cm³ (P < 0.01). No radiation-induced optic neuropathy and other acute toxicity occurred.

Conclusion

Craniopharyngioma can be expected to have very good tumor control by selecting SRS/SRT or FSRT depending on the distance between the optic nerve and the tumor.

Dosimetric parameters associated with the long-term oncological outcomes of Gamma Knife surgery for sellar and parasellar tumors in pediatric patients

OBJECTIVE

The authors aimed to investigate the dosimetric parameter and the minimally required dose associated with long-term control of sellar and parasellar tumors after Gamma Knife surgery (GKS) in children.

METHODS

A retrospective analysis was performed on pediatric patients younger than 19 years of age who were diagnosed with sellar and parasellar tumors and received GKS at the authors' institution from 1998 to 2019. Cox proportional hazards regression analyses were used to investigate the dosimetric parameters associated with treatment outcome. The Kaplan-Meier method was used to analyze tumor control rates after GKS.

RESULTS

Overall, 37 patients with 40 sellar and parasellar tumors, including 22 craniopharyngiomas and 12 pituitary adenomas, had a mean follow-up of 85.8 months. The gross target volume was 0.05 cm3 to 15.28 cm3, and the mean marginal dose was 15.8 Gy (range 9.6-30.0 Gy). Ten patients experienced treatment failure at a mean of 28.0 ± 26.7 months. The actuarial 5- and 10-year tumor control rates were 79.0% and 69.8%, respectively. D98% was an independent predictive factor of tumor control (HR 0.846 [95% CI 0.749-0.956], p = 0.007), with a cutoff value of 11.5 Gy for the entire cohort and 10 Gy for the craniopharyngioma group. Visual deterioration occurred in 2 patients with the maximum point dose of 10.1 Gy and 10.6 Gy to the optic apparatus.

CONCLUSIONS

In pediatric patients, D98% was a reliable index of the minimum required dose for long-term control of sellar and parasellar tumors after GKS. The optimal D98% value for each tumor diagnosis needs to be elucidated in the future.

Craniopharyngiomas

Craniopharyngiomas are difficult to treat because of their dense adherence to surrounding structures and the frequent presence of cysts which obscure the anatomy. The introduction of endonasal endoscopic approaches has enabled microsurgery to be performed without mortality. The high recurrence rate requires other forms of treatment of which GKNS has currently been shown to be perhaps the most effective. Difficulties include poorly visualized visual pathways despite which a high degree of tumor control is achievable with surprisingly little damage to vision.

Update on management of craniopharyngiomas

PURPOSE/INTRODUCTION

Craniopharyngiomas are locally-aggressive tumors arising along the hypothalamic-pituitary axis. Treatment is nuanced as a result of their proximity and adherence to vital neurovascular structures and responsiveness to surgery, radiation and, in some cases, chemotherapy.

METHODS

We reviewed the literature discussing the current state of knowledge regarding craniopharyngioma biology and therapy.

RESULTS

Recent advances in endoscopic endonasal surgery (EEA) have made surgery a safer and more effective option. While cure may be achieved with gross total resection (GTR), when felt to be too risky, a subtotal resection followed by radiation is often a more prudent strategy, particularly in children with hypothalamic invasion. Data on long-term outcome are mostly derived from older studies in which a craniotomy, rather than EEA, was performed. Long-term EEA outcome studies are lacking. Enhanced knowledge of the biological basis of papillary CPs has led to novel medical treatments for BRAFv^600E variants that appear to be effective.

CONCLUSION

Endoscopic technology has improved surgical results for craniopharyngiomas and expanded the indications for the transsphenoidal approach. The goal of CP surgery goal is maximal safe resection to achieve cure, but subtotal resection and radiation may be equally effective. Early diagnosis of specific variants will facilitate enrollment in promising medical trials.

Stereotactic radiosurgery for craniopharyngiomas

BACKGROUND

The management of craniopharyngiomas is challenging, usually requiring multidisciplinary care. We evaluated the long-term clinical and radiologic outcomes of Gamma Knife radiosurgery (GKRS) for craniopharyngiomas.

METHODS

This retrospective study involved patients managed with GKRS for a craniopharyngioma during the period of 1989 to 2019. Patient clinical and radiologic data, tumor characteristics, and procedural details were analyzed.

RESULTS

Thirty-eight consecutive patients (24 males; mean patient age at GKRS = 30.82 years [SD ± 20.45 years]) were treated with GKRS for craniopharyngioma. Overall survival rates at 5 and 10 years were 84.1% and 80.1%, respectively. Progression-free survival at 5 years was 48.1%, and, at 10 years, it was 29.8%. Risk factors for post-GKRS clinical deterioration were increasing number of isocenters used (p = 0.04 (HR1.32, CI 1-1.73)), increasing margin dose [p = 0.02 (HR1.52, CI 1.31-1.84)], and maximum dose > 35 Gy [p = 0.002 (HR1.35, CI 1.11-1.63)].

CONCLUSION

Stereotactic radiosurgery (SRS) appears a safe and effective management option in selected craniopharyngioma patients. Increasing margin dose and maximum dose > 35 Gy are associated with an increased risk for post-SRS neurologic deficit. Further, well-designed studies are necessary to determine the optimal timing and SRS parameters and to identify which patients with craniopharyngioma will benefit the most from SRS.

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.

Optimizing stereotactic radiosurgery in patients with recurrent or residual craniopharyngiomas

PURPOSE

Stereotactic radiosurgery (SRS) is an important management strategy for residual and recurrent craniopharyngiomas. The current study evaluated the factors which affected tumor control and complications in craniopharyngioma SRS.

METHODS

This study includes 53 consecutive patients who underwent single-session SRS for recurrent or residual craniopharyngiomas. The median age was 41 years with 28 male and 25 females. The median tumor volume was 0.63 cm³ and median margin dose was 12 Gy (range 9-25 Gy).

RESULTS

The overall 3-, 5-, and 10-year survival rates were 97.8%, 92.7% and 88.5%. The overall 3-, 5-, and 10-year tumor control rates were 81.0%, 72.1%, and 53.4%. In univariate analysis, ≥ 3 mm distance from optic structures (p = 0.002), only solid or cystic tumor type (p = 0.037), and ≥ 12 Gy to ≥ 85% of the tumor (p < 0.001) were significantly associated with improved tumor control. In multivariate analysis, only solid or cystic tumor type, (p = 0.034), and ≥ 85% of the tumor receiving ≥ 12 Gy (p = 0.004) were significantly associated with better tumor control. When ≥ 85% of the tumor received ≥ 12 Gy the tumor control rates at 3-, 5-, and 10-year were 100%, 93.3%, and 93.3%. Higher conformity index was not associated with better tumor control.

CONCLUSIONS

The tumor control rates after recurrent or residual craniopharyngiomas SRS were improved by ensuring that at least 85% of the tumor received ≥ 12 Gy even when the distance between the tumor and the optic system is < 3 mm. This concept refutes the conformity theory that a high conformity index is a critical feature of effective SRS.

Evaluation of Long-Term Outcomes and Toxicity After Stereotactic Phosphorus-32-Based Intracavitary Brachytherapy in Patients With Cystic Craniopharyngioma

PURPOSE

Interstitial brachytherapy based on phosphorus-32 (P-32) has an established role as a minimally invasive treatment modality for patients with cystic craniopharyngioma. However, reporting on long-term outcomes with toxicity profiles for large cohorts is lacking in the literature. The purpose of this study is therefore to evaluate the long-term visual, endocrinal, and neurocognitive functions in what is the largest patient series having received this treatment to date.

METHODS AND MATERIALS

We retrospectively evaluated 90 patients with cystic craniopharyngiomas who were treated with stereotactic intracavitary brachytherapy between 1998 and 2010. Colloidal activity of injected radioisotope P-32 was based on an even distribution within the tumor. After treatment, patients were followed-up for a minimum of 5 years and over a mean of 121 months (60-192 months) to assess radiographic and clinical responses.

RESULTS

The 90 patients included in our study cohort underwent a total of 108 stereotactic surgical procedures for 129 craniopharyngioma-related cysts. Of the included tumors, 65 (72.2%) were associated with a single cyst, 15 (16.7%) were associated with 2 cysts, and 10 (11.1%) tumors had developed septations with 3 to 4 cysts. Stereotactic cyst puncture and content aspiration were used to drain a mean cyst fluid volume of 21.4 mL (1.0-55.0 mL). Each cyst was then instilled for interstitial brachytherapy with colloidal P-32 solution. Based on radiographic follow-up assessments, 56 cysts (43.4%) showed resolution and/or nonrecurrence, which was classified as a complete response to treatment; 47 cysts (36.4%) showed a partial response; and 5 cysts (3.9%) displayed a stable appearance. Treatment resulted in immediate and clinically significant vision improvement in 54 of 63 (86%) symptomatic patients, and this improvement was maintained. Progression-free survival rates at 5 and 10 years were 95.5% and 84.4%, respectively.

CONCLUSIONS

P-32-based interstitial brachytherapy can play an effective role in managing patients with cystic craniopharyngiomas. It can be considered a valid alternative to surgery in select patients with a favorable toxicity profile and long-term clinical outcomes.

Gliomas, germ cell tumors, and craniopharyngioma

This report summarizes the current multimodality treatment approaches for children with low- and high-grade gliomas, germinoma, and nongerminomatous germ cell tumors, and craniopharyngiomas used in the Children's Oncology Group (COG) and the International Society of Pediatric Oncology (SIOP). Treatment recommendations are provided in the context of historical approaches regarding the roles of surgery, radiation, and chemotherapy. Future research strategies for these tumors in both COG and SIOP are also discussed.

Craniopharyngiomas primarily affecting the hypothalamus

The concept of craniopharyngiomas (CPs) primarily affecting the hypothalamus, or "hypothalamic CPs" (Hy-CPs), refers, in a restrictive sense, to the subgroup of CPs originally developing within the neural tissue of the infundibulum and tuber cinereum, the components of the third ventricle floor. This subgroup, also known as infundibulo-tuberal CPs, largely occupies the third ventricle and comprises up to 40% of this pathological entity. The small subgroup of strictly intraventricular CPs (5%), lesions wholly developed within the third ventricle above an anatomically intact third ventricle floor, can also be included within the Hy-CP category. The remaining types of sellar and/or suprasellar CPs may compress or invade the hypothalamic region during their growth but will not be considered in this review. Hy-CPs predominantly affect adults, causing a wide range of symptoms derived from hypothalamic dysfunction, such as adiposogenital dystrophy (Babinski-Fröhlich's syndrome), diabetes insipidus (DI), abnormal diurnal somnolence, and a complex set of cognitive (dementia-like, Korsakoff-like), emotional (rage, apathy, depression), and behavioral (autism-like, psychotic-like) disturbances. Accordingly, Hy-CPs represent a neurobiological model of psychiatric disorders caused by a lesion restricted to the hypothalamus. The vast majority (90%) of squamous-papillary CPs belong to the Hy-CP category. Pathologically, most Hy-CPs present extensive and strong adhesions to the surrounding hypothalamus, usually formed of a thick band of gliotic tissue encircling the central portion of the tumor ("ring-like" attachment) or its entire boundary ("circumferential" attachment). CPs with these severe adhesion types associate high surgical risk, with morbidity and mortality rates three times higher than those for sellar/suprasellar CPs. Consequently, radical surgical removal of Hy-CPs cannot be generally recommended. Rather, Hy-CPs should be accurately classified according to an individualized surgery-risk stratification scheme considering patient age, CP topography, presence of hypothalamic symptoms, tumor size, and, most importantly, the CP-hypothalamus adhesion pattern.

Gamma Knife Surgery for Residual or Recurrent Craniopharyngioma After Surgical Resection: A Multi-institutional Retrospective Study in Japan

Objective

The optimal treatment for a craniopharyngioma has been controversial. Complete resection is ideal, but it has been difficult to obtain total resection in many cases because of intimate proximity to critical structures such as the optic pathway, hypothalamus, and pituitary gland. A growing number of studies have demonstrated the utility of radiosurgery in controlling residual or recurrent craniopharyngioma. However, most of them are small series. The aim of this multi-institutional study was to clarify the efficacy and safety of Gamma Knife (Elekta, Stockholm, Sweden) surgery for patients with a craniopharyngioma.

Methods

This was a multi-institutional retrospective study by 16 medical centers of the Japan Leksell Gamma Knife Society. Data on patients with craniopharyngiomas treated with Gamma Knife Surgery (GKS) between 1991 and 2013 were obtained from individual institutional review board-approved databases at each center. A total of 242 patients with craniopharyngioma were included in this study. The mean age of the patients was 41 (range, 3 to 86) years. The median follow-up time was 61.4 months (range, 3 to 180 months). The mean radiosurgery target volume was 3.1 ml (range, 0.03-22.3 ml), and the mean marginal dose was 11.4 Gy (range, 8-20.4 Gy).

Results

Two-hundred twenty patients were alive at the time of the last follow-up visit. The three-, five-, and 10-year overall survival rates after GKS were 95.4%, 92.5%, and 82.0%, respectively. The three-, five-, and 10-year progression-free survival rates after GKS were 73.1%, 62.2%, and 42.6% respectively. The rate of radiation-induced complications was 6.2%.

Conclusion

GKS is effective for controlling the tumor growth of craniopharyngiomas with an acceptable complication rate.