Interstitial iodine-125 radiosurgery alone or in combination with microsurgery for pediatric patients with eloquently located low-grade glioma: a pilot study

125 I interstitial brachytherapy in management of pediatric skull base tumors

BACKGROUND

The purpose of this study was to present our preliminary assessment of the safety and efficacy of ¹²⁵ I interstitial brachytherapy (IBT) in the management of pediatric skull base tumors.

METHODS

Thirty pediatric patients with skull base tumors treated with ¹²⁵ I IBT from April 2007 to May 2017 were included in this study. The probabilities of local control (LC) and overall survival (OS) were calculated by the Kaplan-Meier method.

RESULTS

The one- and two-year LC rates were 96.7% and 74.8%, respectively. The one- and two-year OS rates were 93.3% and 72.2%, respectively. No severe acute toxicity was observed. Severe late toxicities were observed in one (3.33%) of 30 patients.

CONCLUSION

¹²⁵ I IBT is effective and safe in the management of pediatric skull base tumors, with satisfactory cosmetic and functional outcomes.

Early treatment of complex located pediatric low-grade gliomas using iodine-125 brachytherapy alone or in combination with microsurgery

To analyze efficacy, functional outcome, and treatment toxicity of low-dose rate I-125 brachytherapy (SBT) alone or in combination with best safe resection (in case of larger tumor volumes) as first-line treatment for pediatric low-grade gliomas (PLGGs) not suitable for complete resection. Consecutively treated (2000-2014) complex located circumscribed WHO grade I/II PLGGs were included. For small tumors (≤4 cm in diameter) SBT alone was performed; for larger tumors best safe resection and subsequent SBT was chosen. Temporary Iodine-125 seeds were used (median reference dose: 54 Gy). Treatment response was estimated with the modified MacDonald criteria. Analysis of functional outcome included ophthalmological, endocrinological and neurological evaluation. Survival was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from proportional hazards models. Toxicity was categorized according to the Common Terminology Criteria for Adverse Events. Fifty-eight patients were included treated either with SBT alone (n = 39) or with SBT plus microsurgery (n = 19). Five-year progression-free survival was 87%. Two patients had died due to tumor progression. Among survivors, improvement/stabilization/deterioration of functional deficits was seen in 20/14/5 patients, respectively. Complete/partial response had beneficial impact on functional scores (P = 0.02). The 5-year estimated risk to receive adjuvant radiotherapy/chemotherapy was 5.2%. The overall early (delayed) toxicity rate was 8.6% (10.3%), respectively. No permanent morbidity occurred. In complex located PLGGs, early SBT alone or combined with best safe resection preserves/improves functional scores and results in tumor control rates usually achieved with complete resection. Long-term analysis is necessary for confirmation of these results.

Comparison of Iodine-125 seeds implantation and afterloading radiotherapy in murine models of human cervical cancer

OBJECTIVE

To compare the efficacies and side effects of Iodine-125 (125I) seeds implantation with afterloading radiotherapy on tumor xenografts derived from Hela cells.

METHODS

Mice bearing Hela cells were randomly divided into three groups: two therapeutic groups receiving four 125I seeds implantation and afterloading therapy, respectively, and the one control group without any intervention. Comparisons were evaluated in aspects of curative efficacies (tumor volume, tumor inhibition rate and metastasis) and side effects (body weight, ovarian endocrine functions, skin lesion surrounding the tumor).

RESULTS

The xenografts tumor volume of therapeutic groups were significantly smaller than that of controls(p < 0.05),both of the 125I seeds implantation and afterloading therapy showed excellent tumor inhibition rate. Furthermore, 125I seeds implantation had milder side effects on skin, weight loss, ovarian endocrine functions.

CONCLUSIONS

(125)I seed implantation may be an alternative minimally invasive therapy for cervical cancer.

Stereotactic iodine-125 brachytherapy for the treatment of WHO grades II and III gliomas located in the central sulcus region

BACKGROUND

Resection of gliomas located in eloquent brain areas remains a neurosurgical challenge. The reported incidence of transient or permanent neurological deficits after microsurgery in eloquent brain ranges 20%-100%, or 0%-47% among contemporary neurosurgical series. The aim of this study was to assess the feasibility of stereotactic brachytherapy (SBT) as a local treatment alternative to microsurgical resection for patients with gliomas in highly eloquent areas, located in the central sulcus region (CSR).

METHOD

Between 1997 and 2010, 60 patients with World Health Organization (WHO) grades II and III gliomas located in the CSR were treated with SBT (iodine-125 seeds; cumulative therapeutic dose, 50-65 Gy). Following SBT, WHO grade III glioma patients additionally received percutaneous radiotherapy (median boost dose, 25.2 Gy). We evaluated procedure-related complications, clinical outcome, and progression-free survival.

RESULTS

Procedure-related mortality was zero. Within 30 days of SBT, 3 patients (5%) had transient neurological deficits, and 8 patients (13%) had temporarily increased seizure activity. One patient (1.6%) deteriorated permanently. Space-occupying cysts (6 patients) and radiation necrosis (1 patient) developed after a median of 38 months and required surgical intervention. Seizure activity, rated 12 months following SBT, decreased in 82% of patients (Engel classes I-III). Median progression-free survivals were 62.2 ± 19.7 months (grade II gliomas) and 26.1 ± 17.9 months (grade III gliomas).

CONCLUSIONS

Compared with microsurgical resection, SBT harbors a low risk of procedural complications, is minimally invasive, and seems to be an effective local treatment option for patients with inoperable, eloquent WHO grade II and III gliomas in the CSR. However, the value of SBT for treating gliomas still needs to be determined in prospective, randomized studies.

Long-term follow-up of the multicenter, multidisciplinary treatment study HIT-LGG-1996 for low-grade glioma in children and adolescents of the German Speaking Society of Pediatric Oncology and Hematology

The Hirntumorstudien (HIT)-LGG-1996 protocol offered a comprehensive treatment strategy for pediatric patients with low-grade glioma (LGG), ie, observation, surgery, adjuvant radiotherapy, and chemotherapy to defer the start of irradiation in young children. In this current study, we sought to determine clinical factors for progression and survival. Between October 1, 1996 and March 31, 2004, 1031 patients were prospectively recruited into an observation arm (n = 668) and a nonsurgical arm stratifying 12 months of vincristine-carboplatin chemotherapy (n = 216) and conventional radiotherapy/brachytherapy (n = 147) in an age-dependent manner. Median patient age was 6.9 years; 28 patients had diencephalic syndrome, 44 had dissemination, and 108 had neurofibromatosis type 1(NF-1). Main tumor location was the supratentorial midline (40.4%), and the main histology was pilocytic astrocytoma (67.9%). Following a median observation of 9.3 years, 10-year overall survival (OS) was 0.94 and 10-year event-free survival (EFS) was 0.47. Ten-year progression-free survival was 0.62 following radiotherapy and 0.44 following chemotherapy. Sixty-one of 216 chemotherapy patients received radiotherapy 0.3-8.7 years after initial diagnosis. By multivariate analysis, diencephalic syndrome and incomplete resection were found to be unfavorable factors for OS and EFS, age ≥11 years for OS, and supratentorial midline location for EFS. Dissemination, age <1 year, and nonpilocytic histology were unfavorable factors for progression following radiotherapy (138 patients); and diencephalic syndrome, dissemination, and age ≥11 years were unfavorable factors following chemotherapy (210 patients). NF-1 patients and boys experienced prolonged tumor stabilization with chemotherapy. A nationwide multimodal treatment strategy is feasible for pediatric LGG. Extended follow-up yielded results comparable to single-institution series for the treatment groups. Three-quarters of surviving chemotherapy patients have not yet received radiation therapy. Infants with or without diencephalic syndrome and dissemination bear the highest risk for death and progression following diagnosis or treatment.

Stereotactic iodine-125 brachytherapy for brain tumors: temporary versus permanent implantation

Stereotactic brachytherapy (SBT) has been described in several publications as an effective, minimal invasive and safe highly focal treatment option in selected patients with well circumscribed brain tumors <4 cm. However, a still ongoing discussion about indications and technique is hindering the definition of a clear legitimation of SBT in modern brain tumor treatment. These controversies encompass the question of how intense the irradiation should be delivered into the target volume (dose rate). For instance, reports about the use of high does rate (HDR) implantation schemes (>40 cGy/h) in combination with adjuvant external beam radiation and/or chemotherapy for the treatment of malignant gliomas and metastases resulted in increased rates of radiation induced adverse tissue changes requiring surgical intervention. Vice versa, such effects have been only minimally observed in numerous studies applying low dose rate (LDR) regiments (3-8 cGy/h) for low grade gliomas, metastases and other rare indications. Besides these observations, there are, however, no data available directly comparing the long term incidences of tissue changes after HDR and LDR and there is, furthermore, no evidence regarding a difference between temporary or permanent LDR implantation schemes. Thus, recommendations for effective and safe implantation schemes have to be investigated and compared in future studies.

Stereotactic iodine-125 brachytherapy for treatment of inoperable focal brainstem gliomas of WHO grades I and II: feasibility and long-term outcome

Microsurgical resection is the most frequently suggested treatment option for accessible focal brainstem gliomas (F-BSG) of World Health Organization (WHO) grades I and II. Because of their location in the highly eloquent brain, however, resection is associated with permanent postoperative morbidity, ranging from 12 to 33 %. Only a few reports have suggested stereotactic brachytherapy (SBT) with implantation of iodine-125 seeds as a local treatment alternative. Between 1993 and 2010, 47 patients were treated with SBT (iodine-125 seeds; cumulative surface dose 50-65 Gy) for inoperable F-BSG, WHO grades I and II, in one of the largest reported patient series. We evaluated procedure-related complications, clinical outcome, and progression-free and overall survival (PFS, OS). Median follow-up was 81.6 months. Procedure-related mortality was zero. Within 30 days of seed implantation six patients (12.8 %) had transient neurological deficits. Two patients (4.3 %) deteriorated permanently. Space-occupying cysts occurred in six patients (12.8 %) after a median of 28.5 months, and required surgical intervention. Nine patients (19.1 %) presented with tumor relapse after a median of 56.6 months (range 7.9-118.0 months). For the remaining 38 patients complete response was observed for 23.4 %, partial response for 29.8 %, and stable disease for 27.7 %. Actuarial PFS was 97.7 ± 2.2, 92.8 ± 4.0, 81.2 ± 6.5, and 62.0 ± 10.4 % after 1, 2, 5, and 10 years, respectively. Corresponding OS was 100 ± 0.0 % (1 and 2 years), 97.4 ± 2.6 % (5 years), and 87.6 ± 7.0 % (10 years). SBT is a comparatively safe, minimally invasive, and highly effective local treatment option for patients with inoperable F-BSG WHO grades I and II; it merits further evaluation in prospective randomized trials.

Iodine-125 brachytherapy for brain tumours--a review

Iodine-125 brachytherapy has been applied to brain tumours since 1979. Even though the physical and biological characteristics make these implants particularly attractive for minimal invasive treatment, the place for stereotactic brachytherapy is still poorly defined.An extensive review of the literature has been performed, especially concerning indications, results and complications. Iodine-125 seeds have been implanted in astrocytomas I-III, glioblastomas, metastases and several other tumour entities. Outcome data given in the literature are summarized. Complications are rare in carefully selected patients.All in all, for highly selected patients with newly diagnosed or recurrent primary or metastatic tumours, this method provides encouraging survival rates with relatively low complication rates and a good quality of life.

Stereotactic brachytherapy with iodine-125 seeds for the treatment of inoperable low-grade gliomas in children: long-term outcome

PURPOSE

Resection is generally considered the gold standard for treatment of low-grade (WHO grades I and II) gliomas (LGGs) in childhood. However, approximately 30% to 50% of these tumors are inoperable because of their localization in highly eloquent brain areas. A few reports have suggested stereotactic brachytherapy (SBT) with implantation of iodine-125 ((125)I) seeds as a safe and effective local treatment alternative. This single-center study provides a summary of the long-term outcome after SBT in one of the largest reported patient series.

PATIENTS AND METHODS

All pediatric patients treated with SBT ((125)I seeds; cumulative therapeutic dose 50-65 Gy within 9 months) by our group for LGG with follow-up of more than 6 months were included. Clinical and radiologic outcome, time to progression, and overall survival were evaluated. Prognostic factors (age, sex, Karnofsky performance score, tumor volume, and histology) for survival and disease progression were investigated.

RESULTS

In all, 147 of 160 pediatric patients treated with SBT (from 1982 through 2009) were analyzed in detail. Procedure-related mortality was zero, and the 30-day morbidity was transient and low (5.4%). Survival rates at 5 and 10 years were 93%, and 82%, respectively, with no significant difference between WHO grades I and II tumors (median follow-up, 67.1 ± 57.7 months). Twenty-one (14.8%) of 147 patients presented with tumor relapse. The remaining 126 patients revealed complete response in 24.6%, partial response in 31.0%, and stable disease in 29.6%. Neurologic status improved (57.8%) or remained stable (23.0%). None of the evaluated factors had significant impact on the study's end points except tumor volume more than 15 mL, which caused significantly higher rates of tumor recurrence (P < .05).

CONCLUSION

We demonstrate that SBT represents a safe, minimally invasive, and highly effective local treatment option for pediatric patients with inoperable LGG WHO grades I and II.

The place of interstitial brachytherapy and radiosurgery for low-grade gliomas

Even though stereotactic brachytherapy has been used for treatment of complex located low-grade glioma for many years, its place within modern treatment concepts is still debated and only a few centers have gained experience with this complex treatment modality. The current article reviews selection criteria, treatment protocols, radiobiology, treatment effects, risk models and side effects of stereotactic brachytherapy. Potentially alternative techniques such as radiosurgery were also reviewed under consideration of radiobiological similarities and differences.

Surgical resection plus stereotactic 125I brachytherapy in adult patients with eloquently located supratentorial WHO grade II glioma - feasibility and outcome of a combined local treatment concept

OBJECTIVE

The current pilot study analyzed feasibility, risk and effectiveness of 1) microsurgery plus stereotactic iodine-125 ((125)I) brachytherapy (SBT) for large (diameter > 4 cm), circumscribed, and complex located WHO grade II glioma and 2) SBT alone for small (diameter < 4 cm), and complex located recurrences.

METHODS

Lowactivity temporary (125)I seeds were used. The applied reference dose was 54 Gy and the dose rate was low (median, 10 cGy/h). Time to progression and time to additional external beam radiation (EBR) and/or chemotherapy were estimated with the Kaplan-Meier method. Any adverse sequel potentially attributable to treatment was classified as morbidity. Treatment effects of SBT were estimated according to the modified MacDonald criteria.

RESULTS

Thirtyone patients (de novo group: n = 18, recurrence group: n = 13) were included. The median tumor volume before surgery was 66 ml. A planned partial tumor resection achieved eligibility for SBT in all patients. Transient morbidity of microsurgery and SBT was 27.8 % and 6.4 %, respectively. There was no permanent morbidity. Radiogenic complications did not occur. Complete response, partial response, and stable disease were seen in 8, 9, and 14 patients, respectively. Ten patients exhibited tumor progression (overall 5-year progression- free survival > 60 %). The 5-year probability to receive chemotherapy and/or EBR was 18 %.

CONCLUSION

A planned partial tumor resection of large and complex located WHO grade II glioma is safe. SBT of small and complex located residual of recurrent tumors is safe and minimally invasive. Combined treatment may provide the possibility to withhold EBR and/or chemotherapy for a considerable number of patients and deserves further prospective evaluation.