Management of newly diagnosed single brain metastasis using resection and permanent iodine-125 seeds without initial whole-brain radiotherapy: a two institution experience

Innovations in intraoperative therapies in neurosurgical oncology: a narrative review

PURPOSE

High-grade gliomas (HGG) represent the most aggressive primary brain tumors in adults, characterized by high recurrence rates due to incomplete resection. This review explores the effectiveness of emerging intraoperative therapies that may extend survival by targeting residual tumor cells. The main research question addressed is: What recent intraoperative techniques show promise for complementing surgical resection in HGG treatment?

METHODS

A comprehensive literature review was conducted, examining recent studies on intraoperative therapeutic modalities that support surgical resection of HGG. Techniques reviewed include laser interstitial thermal therapy (LITT), intraoperative brachytherapy, photodynamic therapy (PDT), sonodynamic therapy (SDT), and focused ultrasound (FUS). Each modality was evaluated based on clinical application, evidence of effectiveness, and potential for integration into standard HGG treatment protocols.

RESULTS

Findings indicate that these therapies offer distinct mechanisms to target residual tumor cells: LITT provides localized thermal ablation; intraoperative brachytherapy delivers sustained radiation; PDT and SDT activate cytotoxic agents in tumor cells; and FUS enables precise energy delivery. Each method has shown varying levels of clinical success, with PDT and LITT currently more widely implemented, while SDT and FUS are promising but under investigation.

CONCLUSION

Intraoperative therapies hold potential to improve surgical outcomes for HGG by reducing residual tumor burden. While further clinical studies are needed to optimize these techniques, early evidence supports their potential to enhance the effectiveness of surgical resection and improve patient survival in HGG management.

Surgically targeted radiation therapy versus stereotactic radiation therapy: A dosimetric comparison for brain metastasis resection cavities

PURPOSE

Surgically targeted radiation therapy (STaRT) with Cesium-131 seeds embedded in a collagen tile is a promising treatment for recurrent brain metastasis. In this study, the biological effective doses (BED) for normal and target tissues from STaRT plans were compared with those of external beam radiotherapy (EBRT) modalities.

METHODS

Nine patients (n = 9) with 12 resection cavities (RCs) who underwent STaRT (cumulative physical dose of 60 Gy to a depth of 5 mm from the RC edge) were replanned with CyberKnifeⓇ (CK), Gamma KnifeⓇ (GK), and intensity modulated proton therapy (IMPT) using an SRT approach (30 Gy in 5 fractions). Statistical significance comparing D95% and D90% in BED10Gy (BED10Gy95% and BED10Gy90%) and to RC + 0 to + 5 mm expansion margins, and parameters associated with radiation necrosis risk (V83Gy, V103Gy, V123Gy and V243Gy) to the normal brain were evaluated by a Wilcoxon-signed rank test.

RESULTS

For RC + 0 mm, median BED10Gy 90% for STaRT (90.1 Gy10, range: 64.1-140.9 Gy10) was significantly higher than CK (74.3 Gy10, range:59.3-80.4 Gy10, p = 0.04), GK (69.4 Gy10, range: 59.8-77.1 Gy10, p = 0.005), and IMPT (49.3 Gy10, range: 49.0-49.7 Gy10, p = 0.003), respectively. However, for the RC + 5 mm, the median BED10Gy 90% for STaRT (34.1 Gy10, range: 22.2-59.7 Gy10) was significantly lower than CK (44.3 Gy10, range: 37.8-52.4 Gy10), and IMPT (46.6 Gy10, range: 45.1-48.5 Gy10), respectively, but not significantly different from GK (34.1 Gy10, range: 22.8-47.0 Gy10). The median V243Gy was significantly higher in CK (11.7 cc, range: 4.7-20.1 cc), GK(6.2 cc, range: 2.3-11.9 cc) and IMPT (19.9 cc, range: 11.1-36.6 cc) compared to STaRT (1.1 cc, range: 0.0-7.8 cc) (p < 0.01).

CONCLUSIONS

This comparative analysis suggests a STaRT approach may treat recurrent brain tumors effectively via delivery of higher radiation doses with equivalent or greater BED up to at least 3 mm from the RC edge as compared to EBRT approaches.

Brachytherapy in Brain Metastasis Treatment: A Scoping Review of Advances in Techniques and Clinical Outcomes

Brain metastases pose a significant therapeutic challenge in the field of oncology, necessitating treatments that effectively control disease progression while preserving neurological and cognitive functions. Among various interventions, brachytherapy, which involves the direct placement of radioactive sources into or near tumors or into the resected cavity, can play an important role in treatment. Current literature describes brachytherapy's capacity to deliver targeted, high-dose radiation while minimizing damage to adjacent healthy tissues-a crucial consideration in the choice of treatment modality. Furthermore, advancements in implantation techniques as well as in the development of different isotopes have expanded its efficacy and safety profile. This review delineates the contemporary applications of brachytherapy in managing brain metastases, examining its advantages, constraints, and associated clinical outcomes, and provides a comprehensive understanding of advances in the use of brachytherapy for brain metastasis treatment, with implications for improved patient outcomes and enhanced quality of life.

Dosimetric Impact of Source Displacement in GammaTile Surgically Targeted Radiation Therapy for Gliomas

Background This study aims to evaluate dosimetric changes that happened during the first month after GammaTile surgically targeted radiation therapy (STaRT) for gliomas due to Cesium-131 (Cs-131) seed displacement caused by cavity shrinkage in brain brachytherapy. Methodology In this study, 10 glioma patients had 4-11 GammaTiles placed along the resection bed after maximal safe resection during craniotomy. Each GammaTile is composed of four Cs-131 seeds embedded in a biodegradable collagen sponge to minimize seed movement and maintain seed-to-cavity surface distance. The Cs-131 seed positions were identified using VariSeed on day one. On day 30, post-implant computed tomography (CT) images and dosimetry parameters were calculated. An iterative closest point (ICP) algorithm was used to compute rigid transformation between the day one and day 30 seed clouds. The seed displacement was calculated after registration. The volume receiving 100% of the prescription dose (V100), the dose received by 90% of the planning target volume (D90_PTV), the planning target volume receiving 100% of the prescription dose (V100_PTV), and the dose to organs at risk (OARs) were calculated for both CT images to determine the dosimetric changes from any seed displacement. Results The mean seed displacement of 1.8 ± 1.0 mm for all patients was observed between day one and day 30. The maximum seed displacement for each patient ranged from 2.3 mm to 7.3 mm. The mean V100 difference between day one and day 30 was 2.5 cc (range = 0.5-6.5 cc). The mean D90_PTVs were 95.5% (range = 69.0%-131.0%) and 98.1% (range = 19.9%-149.0%) on day one and day 30, respectively. The mean V100_PTVs were 88.4% (range = 81.3%-99.1%) and 87.9% (range = 47.0%-99.7%) on day one and day 30, respectively. On day one, the brainstem dose was 63.5 Gy for one case and 28.1 Gy for another case; while on day 30, the brainstem dose was 55.8 Gy and 20.6 Gy for the same patients, contributing to 7.7 Gy (12.8%) and 7.5 Gy (12.5%) dose reductions to brainstem for these patients, respectively. Only two patients received a dose to the optic nerves (34.1 Gy and 5.2 Gy). There were small changes (1.8 Gy and 0.5 Gy, respectively) in the dose to optic nerves when comparing the dose calculated on day one and the dose calculated on day 30 CT images. The same two patients received 30.4 Gy and 6.8 Gy to the chiasm, respectively. Small changes in the dose to the chiasm (≤1.1 Gy) were noted between day one and day 30. Conclusions A maximum seed displacement of up to 7.3 mm and a mean seed displacement of 1.8 mm caused by cavity shrinkage were observed during the first month after GammaTile STaRT for gliomas. There were noticeable changes in dosimetry parameters. Changes in the doses to OARs, particularly the brainstem, were large (up to 12.8% of the prescription dose). These changes in dosimetry should be considered when evaluating treatment outcomes and planning future GammaTile treatments.

Surgical resection and orbital iodine-125 brachytherapy for orbital malignancy: a novel treatment for orbital lymphoma

OBJECTIVES

Orbital lymphoma is one of the most common adult orbital malignancies, accounting for approximately 10% of all orbital tumors. This study aimed to analyze the effects of surgical resection and orbital iodine-125 brachytherapy implantation for orbital lymphoma.

PATIENTS AND METHODS

This was a retrospective study. Clinical data of 10 patients were collected from October 2016 to November 2018 and followed up to March 2022. Patients underwent the primary surgery for maximal safe removal of the tumor. After a pathologic diagnosis of a primary orbital lymphoma was established, iodine-125 seed tubes were designed based on the tumor size and invasion range, and direct vision was placed into the nasolacrimal canal or/and under the orbital periosteum around the resection cavity during the secondary surgery. Then, follow-up data, including the general situation, ocular condition, and tumor recurrence, were recorded.

RESULTS

Of the 10 patients, the pathologic diagnoses included extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (6 cases), small lymphocytic lymphoma (1 case), mantle cell lymphoma (2 cases), and diffuse large B-cell lymphoma (1 case). The number of seeds implanted ranged from 16 to 40. The follow-up period ranged between 40 and 65 months. All patients in this study were alive and well had tumors that were completely controlled. No tumor recurrences or metastases occurred. Three patients had dry eye syndrome and two patients had abnormal facial sensation. No patient had radiodermatitis involving the skin around the eye, and no patient had radiation-related ophthalmopathy.

CONCLUSIONS

Based on preliminary observations, iodine-125 brachytherapy implantation appeared to be a reasonable alternative to external irradiation for orbital lymphoma.

Low-Energy X-Ray Intraoperative Radiation Therapy (Lex-IORT) for Resected Brain Metastases: A Single-Institution Experience

BACKGROUND

Resection followed by local radiation therapy (RT) is the standard of care for symptomatic brain metastases. However, the optimal technique, fractionation scheme and dose are still being debated. Lately, low-energy X-ray intraoperative RT (lex-IORT) has been of increasing interest.

METHOD

Eighteen consecutive patients undergoing BM resection followed by immediate lex-IORT with 16-30 Gy applied to the spherical applicator were retrospectively analyzed. Demographic, RT-specific, radiographic and clinical data were reviewed to evaluate the effectiveness and safety of IORT for BM. Descriptive statistics and Kaplan-Meyer analysis were applied.

RESULTS

The mean follow-up time was 10.8 months (range, 0-39 months). The estimated local control (LC), distant brain control (DBC) and overall survival (OS) at 12 months post IORT were 92.9% (95%-CI 79.3-100%), 71.4% (95%-CI 50.2-92.6%) and 58.0% (95%-CI 34.1-81.9%), respectively. Two patients developed radiation necrosis (11.1%) and wound infection (CTCAE grade III); both had additional adjuvant treatment after IORT. For five patients (27.8%), the time to the start or continuation of systemic treatment was ≤15 days and hence shorter than wound healing and adjuvant RT would have required.

CONCLUSION

In accordance with previous series, this study demonstrates the effectiveness and safety of IORT in the management of brain metastases despite the small cohort and the retrospective characteristic of this analysis.

Salvage brachytherapy for multiply recurrent metastatic brain tumors: a matched-case analysis

Background

Patients with recurrent brain metastases who have exhausted external radiation options pose a treatment challenge in the setting of advances in systemic disease control which have improved quality of life and survival. Brachytherapy holds promise as salvage therapy given its ability to enforce surgical cytoreduction and minimize regional toxicity. This study investigates the role of salvage brachytherapy in maintaining local control for recurrent metastatic lesions.

Methods

We retrospectively reviewed our institution’s experience with brachytherapy in patients with multiply recurrent cerebral metastases who have exhausted external radiation treatment options (14 cases). The primary outcome of the study was freedom from local recurrence (FFLR). To capture the nuances of tumor biology, we compared FFLR achieved by brachytherapy to the preceding treatment for each patient. We further compared the response to brachytherapy in patients with lung cancer (8 cases) against a matched cohort of maximally radiated lung brain metastases (10 cases).

Results

Brachytherapy treatment conferred significantly longer FFLR compared to prior treatments (median 7.39 vs 5.51 months, P = .011) for multiply recurrent brain metastases. Compared to an independent matched cohort, brachytherapy demonstrated superior FFLR (median 8.49 vs 1.61 months, P = .004) and longer median overall survival (11.07 vs 5.93 months, P = .055), with comparable side effects.

Conclusion

Brachytherapy used as salvage treatment for select patients with a multiply recurrent oligometastatic brain metastasis in the setting of well-controlled systemic disease holds promise for improving local control in this challenging patient population.

Dosimetric Impacts of Source Migration, Radioisotope Type, and Decay with Permanent Implantable Collagen Tile Brachytherapy for Brain Tumors

Introduction: Brachytherapy using permanently implantable collagen tiles containing cesium-131 (Cs-131) is indicated for treatment of malignant intracranial neoplasms. We quantified Cs-131 source migration and modeled the resulting dosimetric impact for Cs-131, iodine-125 (I-125), and palladium-103 (Pd-103). Methods and Materials: This was a retrospective analysis of a subgroup of patients enrolled in a prospective, single-center, nonrandomized, clinical trial (NCT03088579) of Cs-131 collagen tile brachytherapy. Postimplant Cs-131 plans and hypothetical I-125 and Pd-103 calculations were compared for 20 glioblastoma patients for a set seed geometry. Dosimetric impact of decay and seed migration was calculated for 2 hypothetical scenarios: Scenario 1, assuming seed positions on a given image set were unchanged until acquisition of the subsequent set; Scenario 2, assuming any change in seed positions occurred the day following acquisition of the prior images. Seed migration over time was quantified for a subset of 7 patients who underwent subsequent image-guided radiotherapy. Results: Mean seed migration was 1.7 mm (range: 0.7-3.1); maximum seed migration was 4.3 mm. Mean dose to the 60 Gy volume differed by 0.4 Gy (0.6%, range 0.1-1.0) and 0.9 Gy (1.5%, range 0.2-1.7) for Cs-131, 1.2 Gy (2.0%, range 0.1-2.1) and 1.6 Gy (2.6%, range 1.2-2.6) for I-125, and 0.8 Gy (1.3%, range 0.2-1.5) and 1.4 Gy (2.3%, range 0.3-1.9) for Pd-103, for Scenarios 1 and 2, respectively, compared with the postimplant plan. For a set seed geometry mean implant dose was higher for Pd-103 (1.3 times) and I-125 (1.1 times) versus Cs-131. Dose fall-off was steepest for Pd-103: gradient index 1.88 versus 2.23 (I-125) and 2.40 (Cs-131). Conclusions: Dose differences due to source migration were relatively small, suggesting robust prevention of seed migration from Cs-131-containing collagen tiles. Intratarget heterogeneity was greater with Pd-103 and I-125 than Cs-131. Dose fall-off was fastest with Pd-103 followed by I-125 and then Cs-131.

Time to administration of stereotactic radiosurgery to the cavity after surgery for brain metastases: a real-world analysis

OBJECTIVE

Publications on adjuvant stereotactic radiosurgery (SRS) are largely limited to patients completing SRS within a specified time frame. The authors assessed real-world local recurrence (LR) for all brain metastasis (BM) patients referred for SRS and identified predictors of SRS timing.

METHODS

The authors retrospectively identified BM patients undergoing resection and referred for SRS between 2012 and 2018. Patients were categorized by time to SRS, as follows: 1) ≤ 4 weeks, 2) > 4-8 weeks, 3) > 8 weeks, and 4) never completed. The relationships between timing of SRS and LR, LR-free survival (LRFS), and survival were investigated, as well as predictors of and reasons for specific SRS timing.

RESULTS

In a cohort of 159 patients, the median age at resection was 64.0 years, 56.5% of patients were female, and 57.2% were in recursive partitioning analysis (RPA) class II. The median preoperative tumor diameter was 2.9 cm, and gross-total resection was achieved in 83.0% of patients. All patients were referred for SRS, but 20 (12.6%) did not receive it. The LR rate was 22.6%, and the time to SRS was correlated with the LR rate: 2.3% for patients receiving SRS at ≤ 4 weeks postoperatively, 14.5% for SRS at > 4-8 weeks (p = 0.03), and 48.5% for SRS at > 8 weeks (p < 0.001). No LR difference was seen between patients whose SRS was delayed by > 8 weeks and those who never completed SRS (48.5% vs 50.0%; p = 0.91). A similar relationship emerged between time to SRS and LRFS (p < 0.01). Non-small cell lung cancer pathology (p = 0.04), earlier year of treatment (p < 0.01), and interval from brain MRI to SRS (p < 0.01) were associated with longer intervals to SRS. The rates of receipt of systemic therapy also differed significantly between patients by category of time to SRS (p = 0.02). The most common reasons for intervals of > 4-8 weeks were logistic, whereas longer delays or no SRS were caused by management of systemic disease or comorbidities.

CONCLUSIONS

Available data on LR rates after adjuvant SRS are often obtained from carefully preselected patients receiving timely treatment, whereas significantly less information is available on the efficacy of adjuvant SRS in patients treated under "real-world" conditions. Management of these patients may merit reconsideration, particularly when SRS is not delivered within ≤ 4 weeks of resection. The results of this study indicate that a substantial number of patients referred for SRS either never receive it or are treated > 8 weeks postoperatively, at which time the SRS-treated patients have an LR risk equivalent to that of patients who never received SRS. Increased attention to the reasons for prolonged intervals from surgery to SRS and strategies for reducing them is needed to optimize treatment. For patients likely to experience delays, other radiotherapy techniques may be considered.

Dosimetric differences between cesium-131 and iodine-125 brachytherapy for the treatment of resected brain metastases

Purpose

To compare treatment plans and evaluate dosimetric characteristics of permanent cesium-131 (¹³¹Cs) vs. iodine-125 (¹²⁵I) implants used in brain brachytherapy.

Material and methods

Twenty-four patients with ¹³¹Cs implants from a prospective phase I/II trial were re-planned with ¹²⁵I implants. In order to evaluate the volume of brain tissue exposed to radiation therapy (RT), the dose volume histogram was generated for both radioisotopes. To evaluate the dosimetric differences of the two radioisotopes we compared homogeneity (HI) and conformity indices (CI), and dose covering 100% (D₁₀₀), 90% (D₉₀), 80% (D₈₀), and 50% (D₅₀) of the clinical target volume (CTV).

Results

At the 100%, 90%, 80%, and 50% isodose lines, the ¹³¹Cs plans exposed less mean volume of brain tissue than the ¹²⁵I plans (p < 0.001). The D₁₀₀, D₉₀, D₈₀, and D₅₀ were smaller for ¹³¹Cs (p < 0.001). The HI and CI for ¹³¹Cs vs. ¹²⁵I were 19.71 vs. 29.04 and 1.31 vs. 1.92, respectively (p < 0.001).

Conclusions

Compared to ¹²⁵I, ¹³¹Cs exposed smaller volumes of brain tissue to equivalent doses of radiation and delivered lower radiation doses to equivalent volumes of the CTV. ¹³¹Cs exhibited a higher HI, indicating increased uniformity of doses within the CTV. Lastly, ¹³¹Cs presented a CI closer to 1, indicating that the total volume receiving the prescription dose was closer to the desired CTV volume. These results suggest that ¹³¹Cs is dosimetrically superior to ¹²⁵I and may explain the reason for the 0% incidence of radiation necrosis (RN) in our previously published prospective study using ¹³¹Cs.

The role of brachytherapy in the management of brain metastases: a systematic review

Purpose

Brain metastases have a highly variable prognosis depending on the primary tumor and associated prognostic factors. Standard of care for patients with these tumors includes craniotomy, stereotactic radiosurgery (SRS), or whole brain radiotherapy (WBRT) for patients with brain metastases. Brachytherapy shows great promise as a therapy for brain metastases, but its role has not been sufficiently explored in the current literature.

Material and methods

The PubMed, Cochrane, and Scopus databases were searched using a combination of search terms and synonyms for brachytherapy, brain neoplasms, and brain metastases, for articles published between January 1^st, 1990 and January 1^st, 2018. Of the 596 articles initially identified, 37 met the inclusion criteria, of which 14 were review articles, while the remaining 23 papers with detailing individual studies were fully analyzed.

Results

Most data focused on ¹²⁵I and suggested that it offers rates of local control and overall survival comparable to standard of care modalities such as SRS. However, radiation necrosis and regional recurrence were often high with this isotope. Studies using photon radiosurgery modality of brachytherapy have also been completed, resulting superior regional control as compared to SRS, but worse local control and higher rates of radiation necrosis than ¹²⁵I. More recently, studies using the ¹³¹Cs for brachytherapy offered similar local control and survival benefits to ¹²⁵I, with low rates of radiation necrosis.

Conclusions

For a variety of reasons including absence of physician expertise in brachytherapy, lack of published data on treatment outcomes, and rates of radiation necrosis, brachytherapy is not presently a part of standard paradigm for brain metastases. However, our review indicates brachytherapy as a modality that offers excellent local control and quality of life, and suggested that its use should be further studied.

Placement of 131Cs permanent brachytherapy seeds in a large combined cavity of two resected brain metastases in one setting: case report and technical note

Large brain metastases are presently treated with surgical resection and adjuvant radiotherapy. However, local control (LC) for large tumors decreases from over 90% to as low as 40% as the tumor/cavity increases. Intraoperative brachytherapy is one of the focal radiotherapy techniques, which offers a convenient option of starting radiation therapy immediately after resection of the tumor and shows at least an equivalent LC to external techniques. Our center has pioneered this treatment with a novel FDA-cleared cesium-131 (¹³¹Cs) radioisotope for the resected brain metastases, and published promising results of our prospective trial showing superior results from ¹³¹Cs application to the large tumors (90%). We report a 57-year-old male patient, with metastatic hypopharyngeal brain cancer. The patient presented with two metastases in the right frontal and right parietal lobes. Post-resection of these lesions resulted in a large total combined cavity diameter of 5.3 cm, which was implanted with ¹³¹Cs seeds. The patient tolerated the procedure well, with 100% local control and 0% radiation necrosis. This case is unique in demonstrating that the ¹³¹Cs isotope was not only a convenient option of treating two resected brain metastases in one setting, but also that this treatment option offered excellent long-term LC and minimal toxicity rates.

Intraoperative brachytherapy for resected brain metastases

Brain metastases are the most common intracranial malignancies in adults. Surgical resection is the preferred treatment approach when a pathological diagnosis is required, for symptomatic patients who are refractory to steroids, and to decompress lesions causing mass effect. Radiotherapy is administered to improve local control rates after surgical resection. After a brief review of the literature describing the treatment of brain metastases using whole-brain radiotherapy, postoperative stereotactic radiosurgery, preoperative radiosurgery, and brachytherapy, we compare patient-related, technical, practical, and radiobiological considerations of each technique. Finally, we focus our discussion on intraoperative brachytherapy, with an emphasis on the technical aspects, benefits, efficacy, and outcomes of studies utilizing permanent Cs-131 implants.

Surgical Resection and Interstitial Iodine-125 Brachytherapy for High-Grade Meningiomas: A 25-Year Series

BACKGROUND

Atypical and malignant meningiomas can recur despite resection and radiation.

OBJECTIVE

To determine outcomes of patients with recurrent atypical or malignant meningioma treated with repeat resection and permanent iodine-125 ( 125 I) brachy-therapy.

METHODS

Charts of patients who underwent surgical resection and 125 I brachyther-apy implantation for atypical and malignant meningiomas between 1988 and 2013 were retrospectively reviewed. The Kaplan-Meier actuarial method was used to calculate progression-free and overall survival. The log-rank test was used to compare groups. Significance was set at P < .05.

RESULTS

Forty-two patients underwent 50 resections with 125 I brachytherapy im-plantations. All patients had undergone previous resections and 85% had previously undergone radiation. Median follow-up was 7.5 years after diagnosis and 2.3 years after brachytherapy. Median time to progression after resection with 125 I brachytherapy was 20.9 months for atypical meningioma, 11.4 months for malignant meningioma, and 11.4 months for the combined groups. Median survival after re-resection and 125 I brachytherapy was 3.5 years for atypical meningioma, 2.3 years for malignant menin-gioma, and 3.3 years for all subjects. Median overall survival after diagnosis was 11.1 years for atypical meningioma, 9.1 years for malignant meningioma, and 9.4 years for all subjects. Complications occurred in 17 patients and included radiation necrosis (n = 8, 16%), wound breakdown (n = 6, 12%), hydrocephalus (n = 4, 8%), infection (n = 3, 6%), and a pseudomeningocele (n = 2, 5%).

CONCLUSION

This is the largest experience with adjuvant 125 I brachytherapy for recurrent high-grade meningiomas. The outcomes support the use of adjuvant brachytherapy as an option for these aggressive tumors.

[Delineation of the surgical bed of operated brain metastases treated with adjuvant stereotactic irradiation: A review]

Stereotactic radiotherapy of the surgical bed of brain metastases is a technique that comes supplant indications of adjuvant whole brain radiotherapy after surgery. After a growing number of retrospective studies, a phase III trial has been presented and validated this indication. However, several criteria such as the dose, the fractionation, the use of a margin and definition of volumes remain to be defined. Our study consisted in making a literature review in order to provide a guideline of delineation of surgical beds of brain metastases, as well as the different modalities of their implementation process.

Resection and brain brachytherapy with permanent iodine-125 sources for brain metastasis

OBJECTIVE Stereotactic radiosurgery (SRS) with or without whole-brain radiotherapy can be used to achieve local control (> 90%) for small brain metastases after resection. However, many brain metastases are unsuitable for SRS because of their size or previous treatment, and whole-brain radiotherapy is associated with significant neurocognitive morbidity. The purpose of this study was to investigate the efficacy and toxicity of surgery and iodine-125 (¹²⁵I) brachytherapy for brain metastases. METHODS A total of 95 consecutive patients treated for 105 brain metastases at a single institution between September 1997 and July 2013 were identified for this analysis retrospectively. Each patient underwent MRI followed by craniotomy with resection of metastasis and placement of ¹²⁵I sources as permanent implants. The patients were followed with serial surveillance MRIs. The relationships among local control, overall survival, and necrosis were estimated by using the Kaplan-Meier method and compared with results of log-rank tests and multivariate regression models. RESULTS The median age at surgery was 59 years (range 29.9-81.6 years), 53% of the lesions had been treated previously, and the median preoperative metastasis volume was 13.5 cm³ (range 0.21-76.2 cm³). Gross-total resection was achieved in 81% of the cases. The median number of ¹²⁵I sources implanted per cavity was 28 (range 4-93), and the median activity was 0.73 mCi (range 0.34-1.3 mCi) per source. A total of 476 brain MRIs were analyzed (median MRIs per patient 3; range 0-22). Metastasis size was the strongest predictor of cavity volume and shrinkage (p < 0.0001). Multivariable regression modeling failed to predict the likelihood of local progression or necrosis according to metastasis volume, cavity volume, or the rate of cavity remodeling regardless of source activity or previous SRS. The median clinical follow-up time in living patients was 14.4 months (range 0.02-13.6 years), and crude local control was 90%. Median overall survival extended from 2.1 months in the shortest quartile to 62.3 months in the longest quartile (p < 0.0001). The overall risk of necrosis was 15% and increased significantly for lesions with a history of previous SRS (p < 0.05). CONCLUSIONS Therapeutic options for patients with large or recurrent brain metastases are limited. Data from this study suggest that resection with permanent ¹²⁵I brachytherapy is an effective strategy for achieving local control of brain metastasis. Although metastasis volume significantly influences resection cavity size and remodeling, volumetric parameters do not seem to influence local control or necrosis. With careful patient selection, this treatment regimen is associated with minimal toxicity and can result in long-term survival for some patients. ▪ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: retrospective case series; evidence: Class IV.

Cesium-131 brachytherapy for recurrent brain metastases: durable salvage treatment for previously irradiated metastatic disease

OBJECTIVE Managing patients whose intraparenchymal brain metastases recur after radiotherapy remains a challenge. Intraoperative cesium-131 (Cs-131) brachytherapy performed at the time of neurosurgical resection may represent an excellent salvage treatment option. The authors evaluated the outcomes of this novel treatment with permanent intraoperative Cs-131 brachytherapy. METHODS Thirteen patients with 15 metastases to the brain that recurred after stereotactic radiosurgery and/or whole brain radiotherapy were treated between 2010 and 2015. Stranded Cs-131 seeds were placed as a permanent volume implant. Prescription dose was 80 Gy at 5-mm depth from the resection cavity surface. The primary end point was resection cavity freedom from progression (FFP). Resection cavity freedom from progression (FFP), regional FFP, distant FFP, median survival, overall survival (OS), and toxicity were assessed. RESULTS The median duration of follow-up after salvage treatment was 5 months (range 0.5-18 months). The patients' median age was 64 years (range 51-74 years). The median resected tumor diameter was 2.9 cm (range 1.0-5.6 cm). The median number of seeds implanted was 19 (range 10-40), with a median activity per seed of 2.25 U (range 1.98-3.01 U) and median total activity of 39.6 U (range 20.0-95.2 U). The 1-year actuarial local FFP was 83.3%. The median OS was 7 months, and 1-year OS was 24.7%. Complications included infection (3), pseudomeningocele (1), seizure (1), and asymptomatic radionecrosis (RN) (1). CONCLUSIONS After failure of prior irradiation of brain metastases, re-irradiation with intraoperative Cs-131 brachytherapy implants provides durable local control and limits the risk of RN. The authors' initial experience demonstrates that this treatment approach is well tolerated and safe for patients with previously irradiated tumors after failure of more than 1 radiotherapy regimen and that it results in excellent response rates and minimal toxicity.

Feasibility and Clinical Value of CT-guided (125)I Brachytherapy for Bilateral Lung Recurrences from Colorectal Carcinoma

PURPOSE

To prospectively evaluate the feasibility and clinical value of computed tomography (CT)-guided iodine 125 ((125)I) brachytherapy to treat bilateral lung recurrences from colorectal carcinoma.

MATERIALS AND METHODS

This study was approved by Sun Yat-sen University Cancer Center Institutional Review Board and all patients provided informed written consent. Seventy-two patients with bilateral lung recurrences from colorectal carcinoma were enrolled and randomly divided into two groups. Thirty-three were percutaneously treated with CT-guided (125)I brachytherapy (group A) and the other 39 were only given symptomatic and supportive treatments (group B). Follow-up contrast agent-enhanced CT scans were reviewed and efficacy of treatment was evaluated. (125)I brachytherapy was considered a success if it achieved the computerized treatment planning system criteria 1 month after procedure. Analyses included Kaplan-Meier, Mantel-Cox log-rank test, and Cox proportional hazards regression.

RESULTS

In group A, 37 (125)I brachytherapy procedures were performed in 33 patients with 126 lung metastatic lesions and the success rate was 87.9% (29 of 33 patients). The local control rate of 3, 6, 12, 24, and 36 months was 75.8%, 51.5%, 33.3%, 24.2%, and 9.1%, respectively. A small amount of pulmonary hematoma occurred in five patients, and six patients presented with pneumothorax with pulmonary compression of 30%-40%. No massive bleeding or radiation pneumonitis occurred. The mean overall survival (OS) of group A was significantly longer than that of group B, and (125)I brachytherapy was an independent factor that affected the OS (group A, 18.8 months; group B, 8.6 months; hazard ratio, 0.391 [95% confidence interval: 0.196, 0.779]; P = .008).

CONCLUSION

CT-guided (125)I brachytherapy is feasible and safe for the treatment of bilateral lung recurrences from colorectal carcinoma.

Surgical Technique and Clinically Relevant Resection Cavity Dynamics Following Implantation of Cesium-131 (Cs-131) Brachytherapy in Patients With Brain Metastases

BACKGROUND

Cesium-131 (Cs-131) brachytherapy is used to reduce local recurrence of resected brain metastases. In order to ensure dose homogeneity and reduce risk of radiation necrosis, inter-seed distance and cavity volume must remain stable during delivery.

OBJECTIVE

To investigate the efficacy of the "seeds-on-a-string" technique with intracavitary fibrin glue in achieving cavity volume stability.

METHODS

We placed intra-operative Cs-131 brachytherapy in 30 cavities post-resection of brain metastases. Seeds-on-a-string were placed like barrel staves within the cavity with fibrin glue. Serial MRI imaging occurred post-operatively. Pre-operative tumor volumes were compared with post-operative cavity volumes to evaluate volume stability. Thirty patients who underwent post-resective stereotactic radiosurgery (SRS) were used as a control group for volumetric comparison.

RESULTS

Cs-131 and SRS patients exhibited consistent cavity shrinkage over the median 110-day follow-up (p<.001), with total median shrinkage of 56.5% (Cs-131) and 84.8% (SRS). During the first month when ~88% of Cs-131 dosage is delivered, however, there was non-significant volume decrease in the Cs-131 group (median 22.0%; p=.063), while SRS patients showed significantly more shrinkage (46.7%; p=.042). No events of radiation necrosis occurred in either group.

CONCLUSION

Cs-131 patients exhibited significantly less cavity shrinkage than SRS patients during the first critical month with 88% Cs-131 dose delivery. This significant difference in shrinkage suggests that the intracavitary seeds-on-a-string technique facilitates increased cavity stability, promoting more homogenous dose delivery.

Phase I/II study of resection and intraoperative cesium-131 radioisotope brachytherapy in patients with newly diagnosed brain metastases

OBJECT

Resected brain metastases have a high rate of local recurrence without adjuvant therapy. Adjuvant whole-brain radiotherapy (WBRT) remains the standard of care with a local control rate > 90%. However, WBRT is delivered over 10-15 days, which can delay other therapy and is associated with acute and long-term toxicities. Permanent cesium-131 ((131)Cs) implants can be used at the time of metastatic resection, thereby avoiding the need for any additional therapy. The authors evaluated the safety, feasibility, and efficacy of a novel therapeutic approach with permanent (131)Cs brachytherapy at the resection for brain metastases.

METHODS

After institutional review board approval was obtained, 24 patients with a newly diagnosed metastasis to the brain were accrued to a prospective protocol between 2010 and 2012. There were 10 frontal, 7 parietal, 4 cerebellar, 2 occipital, and 1 temporal metastases. Histology included lung cancer (16), breast cancer (2), kidney cancer (2), melanoma (2), colon cancer (1), and cervical cancer (1). Stranded (131)Cs seeds were placed as permanent volume implants. The prescription dose was 80 Gy at a 5-mm depth from the resection cavity surface. Distant metastases were treated with stereotactic radiosurgery (SRS) or WBRT, depending on the number of lesions. The primary end point was local (resection cavity) freedom from progression (FFP). Secondary end points included regional FFP, distant FFP, median survival, overall survival (OS), and toxicity.

RESULTS

The median follow-up was 19.3 months (range 12.89-29.57 months). The median age was 65 years (range 45-84 years). The median size of resected tumor was 2.7 cm (range 1.5-5.5 cm), and the median volume of resected tumor was 10.31 cm(3) (range 1.77-87.11 cm(3)). The median number of seeds used was 12 (range 4-35), with a median activity of 3.82 mCi per seed (range 3.31-4.83 mCi) and total activity of 46.91 mCi (range 15.31-130.70 mCi). Local FFP was 100%. There was 1 adjacent leptomeningeal recurrence, resulting in a 1-year regional FFP of 93.8% (95% CI 63.2%-99.1%). One-year distant FFP was 48.4% (95% CI 26.3%-67.4%). Median OS was 9.9 months (95% CI 4.8 months, upper limit not estimated) and 1-year OS was 50.0% (95% CI 29.1%-67.8%). Complications included CSF leak (1), seizure (1), and infection (1). There was no radiation necrosis.

CONCLUSIONS

The use of postresection permanent (131)Cs brachytherapy implants resulted in no local recurrences and no radiation necrosis. This treatment was safe, well tolerated, and convenient for patients, resulting in a short radiation treatment course, high response rate, and minimal toxicity. These findings merit further study with a multicenter trial.

Survival after surgery and stereotactic radiosurgery for patients with multiple intracranial metastases: results of a single-center retrospective study

OBJECTIVES

Patients with systemic cancer and a single brain metastasis who undergo treatment with resection plus radiotherapy live longer and have a better quality of life than those treated with radiotherapy alone. Historically, whole-brain radiotherapy (WBRT) has been the mainstay of radiation therapy; however, it is associated with significant delayed neurocognitive sequelae. In this study, the authors looked at survival in patients with single and multiple intracranial metastases who had undergone surgery and adjuvant stereotactic radiosurgery (SRS) to the tumor bed and synchronous lesions.

METHODS

The authors retrospectively reviewed the records from an 8-year period at a single institution for consecutive patients with brain metastases treated via complete resection of dominant lesions and adjuvant radiosurgery. The cohort was analyzed for time to local progression, synchronous lesion progression, new intracranial lesion development, systemic progression, and overall survival. The Kaplan-Meier method (stratified by age, sex, tumor histology, and number of intracranial lesions prior to surgery) was used to calculate both progression-free and overall survival. A Cox proportional-hazards regression model was also fitted with the number of intracranial lesions as the predictor and survival as the outcome controlling for disease severity, age, sex, and primary histology.

RESULTS

The median overall follow-up among the 150-person cohort eligible for analysis was 17 months. Patients had an average age of 46.2 years (range 16-82 years), and 62.7% were female. The mean (± standard deviation) number of intracranial lesions per patient was 2.5 ± 2.3. The mean time between surgery and stereotactic radiosurgery (SRS) was 3.2 ± 4.1 weeks. Primary cancers included lung cancer (43.3%), breast cancer (21.3%), melanoma (10.0%), renal cell carcinoma (6.7%), and colon cancer (6.7%). The average number of isocenters per treated lesion was 7.6 ± 6.6, and the average treatment dose was 17.8 ± 2.8 Gy. One-year survival for patients in this cohort was 52%, and the 1-year local control rate was 77%. The median (±standard error) overall survival was 13.2 ± 1.9 months. There was no difference in survival between patients with a single lesion and those with multiple lesions (p = 0.319) after controlling for age, sex, and histology of primary tumor. Patients with primary breast histology had the greatest overall median survival (22.9 ± 6.2 months); patients with colorectal cancer had the shortest overall median survival (5.3 ± 1.8 months). The most common cause of death in this series was systemic progression (79%).

CONCLUSIONS

These results confirm that 1-year survival for patients with multiple intracranial metastases treated with resection followed by SRS to both the tumor bed and synchronous lesions is similar to established outcomes for patients with a single intracranial metastasis.

Surgery for brain metastases

The use of surgery in the treatment of brain metastases is controversial. Patients who present certain clinical characteristics may experience prolonged survival with resection compared with radiation therapy. Thus, for patients with a single metastatic lesion in the setting of well-controlled systemic cancer, surgery is highly indicated. Stereotactic radiosurgery (SRS) alone can provide a similar survival advantage, but when used as postoperative adjuvant therapy, patients experience extended survival times. Furthermore, surgery remains the only treatment option for patients with life-threatening neurological symptoms, who require immediate tumor debulking. Treatment of brain metastases requires a careful clinical assessment of individual patients, as different prognostic factors may indicate various modes or combinations of therapy. Since surgery is an effective method for achieving tumor management in particular cases, it remains an important consideration in the treatment algorithm for brain metastases.

Current advances in understanding and managing secondary brain metastasis

Metastatic brain tumors are the number one cause of intracranial neoplasms in adults and are associated with higher morbidity and mortality. The frequency of metastatic brain tumors is increasing because of improved survival in cancer patients. The molecular mechanism of brain metastasis is complex and not completely known. Vasogenic edema produced by tumor-derived VEGF is responsible for clinical symptoms. Dexamethasone remains the mainstay of medical management with not completely known mechanisms of action. Surgery and radiation are the main treatment modalities for metastatic brain tumors. Systemic chemotherapy has a very limited role in treatment of these tumors. Leptomeningeal metastasis is associated with extremely poor outcome.

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.

125I radioactive seed interstitial brachytherapy for liver metastases

AIM: To detect the efficacy of ¹²⁵I radioactive seed interstitial brachytherapy for liver metastases.

METHODS: Thirty-two tumors in 24 patients with liver metastases were treated by ¹²⁵I radioactivity seed interstitial brachytherapy. The tumor diameter ranged from 4.5 to 12.8 cm, with an average value of 7.8 cm. The treatment response, local control rate and survival rate were evaluated and adverse events observed.

RESULTS: Complete remission (CR) was achieved in 7 tumors, and partial remission (PR) was achieved in 16 tumors. Five tumors had no remission (NR), and 4 tumors had progressive deterioration (PD). The response rate was 71.9%. The patients were followed up for 7 to 22months (median 16 mo). The local control rate was 65.9%, and total survival rate 70.1%. No serious side effects were observed.

CONCLUSION: Radioactive seed interstitial brachytherapy is an effective form of treatment for patients with liver metastases.

Stereotactic 125Iodine Brachytherapy for the Treatment of Singular Brain Metastases: Closing a Gap?

BACKGROUND:

Brain metastases represent the most common intracranial tumors and are associated with very poor prognosis.

OBJECTIVE:

To investigate the feasibility, survival, and cerebral disease control of patients with singular brain metastases treated with stereotactic 125iodine brachytherapy (SBT), to identify prognostic factors, and to compare results with other local treatment methods.

METHODS:

Complications, survival (overall and separated by recursive partitioning analysis [RPA] classes), and local and distant disease control were evaluated retrospectively in 90 patients. Prognostic factors were identified by forming subgroups of patients based on age, Karnofsky Performance Status, status of extracranial disease, interval since initial diagnosis, absence/presence of prior whole-brain radiation therapy, localization, morphology, and tumor volume.

RESULTS:

There was no treatment-related mortality, and morbidity was transient and low (3.3%). Median survival was 8.5 months overall and 18.1 months for RPA class 1 patients. After 1 year, the actuarial incidence of local and distant cerebral relapse was 5.4% and 46.4%, respectively. Karnofsky Performance Status ≥ 70 (P &lt; .002), stable systemic disease (P &lt; .02), RPA class 1 (P &lt; .02), and a prolonged (&gt; 12 month) interval between initial diagnosis and SBT (P &lt; .05) significantly improved survival. No significant influence of previous whole-brain radiation therapy on survival or cerebral disease relapse was found.

CONCLUSION:

SBT represents a safe, minimally invasive, and, compared with SRS and microsurgery, a similarly effective local treatment option in terms of survival and cerebral disease control. It allows histological (re-)evaluation and treatment within 1 stereotactic operation. Because it is less restricted by tumor localization or size, it greatly advances local treatment options, and on the basis of its favorable biological irradiation effect, SBT does not limit additional irradiation treatment in the event of disease relapse.

Investigational therapies for brain metastases

Contrary to the incidence of primary cancers, the incidence of brain metastasis has been increasing. This increase is likely because of the effects of an aging population, improved neuroimaging surveillance, and better control of systemic cancer, allowing time for brain metastasis to occur. Unlike systemic cancers, for which chemotherapy is the mainstay of treatment, the therapeutic strategies available to treat brain metastasis have traditionally been limited to surgical resection, whole brain radiation therapy, or stereotactic radiosurgery, either individually or in combination. It is important to put the treatment in the context of the prognosis for patients with brain metastases.

Clinical and pathological characteristics of brain metastasis resected after failed radiosurgery

OBJECTIVE

This study evaluates the tumor histopathology and clinical characteristics of patients who underwent resection of their brain metastasis after failed gamma knife radiosurgery.

METHODS

This study was a retrospective review from a prospective database. A total of 1200 brain metastases in 912 patients were treated by gamma knife radiosurgery during a 7-year period. Fifteen patients (1.6% of patients, 1.2% of all brain metastases) underwent resective surgery for either presumed tumor progression (6 patients) or worsening neurological symptoms associated with increased mass effect (9 patients). Radiographic imaging, radiosurgical and surgical treatment parameters, histopathological findings, and long-term outcomes were reviewed for all patients.

RESULTS

The mean age at the time of radiosurgery was 57 years (age range, 32-65 years). Initial pathological diagnoses included metastatic non-small cell lung carcinoma in 8 patients (53%), melanoma in 4 patients (27%), renal cell carcinoma in 2 patients (13%), and squamous cell carcinoma of the tongue in 1 patient (7%). The mean time interval between radiosurgery and surgical extirpation was 8.5 months (range, 3 weeks to 34 months). The mean treatment volume for the resected lesion at the time of radiosurgery was 4.4 cm(3) (range, 0.6-8.4 cm(3)). The mean dose to the tumor margin was 21Gy (range, 18-24 Gy). In addition to the 15 tumors that were eventually resected, a total of 32 other metastases were treated synchronously, with a 78% control rate. The mean volume immediately before surgery for the 15 resected lesions was 7.5 cm(3) (range, 3.8-10.2 cm(3)). Histological findings after radiosurgery varied from case to case and included viable tumor, necrotic tumor, vascular hyalinization, hemosiderin-laden macrophages, reactive gliosis in surrounding brain tissue, and an elevated MIB-1 proliferation index in cases with viable tumor. The mean survival for patients in whom viable tumor was identified (9.4 months) was significantly lower than that of patients in whom only necrosis was seen (15.1 months; Fisher's exact test, P < 0.05).

CONCLUSION

Radiation necrosis and tumor radioresistance are the most common causes precipitating a need for surgical resection after radiosurgery in patients with brain metastasis.

Controversies concerning the application of brachytherapy in central nervous system tumors

INTRODUCTION

Brachytherapy (BRT) is defined as a therapy technique where a radioactive source is placed a short distance from or within the tumor being treated. Much expectation has been placed on its efficacy to improve the outcome for patients with central nervous system (CNS) tumors due to the initial promising results from single institution retrospective studies. However, these optimistic findings have been highly debated since the selection criteria itself is preferable to other therapeutic modalities. The fact that BRT demonstrated no significant survival advantage in two prospective studies, together with the emerging role of stereotactic convergence therapy as a promising alternative, has further decreased the enthusiasm for BRT. Despite all the negative aspects, BRT continues to be conducted for the management of CNS tumors including gliomas, meningiomas and brain metastases.

MATERIAL AND METHODS

As many controversies have been aroused concerning the experience and future application of BRT, this article reviews the existing heterogeneities in terms of implants choice, optimal dose rate, targeting volume, timing of BRT, patients selection, substantial efficacy, BRT in comparison with stereotactic convergence therapy techniques and BRT in combination with other treatment modalities (data were identified by Pubmed searches).

RESULTS AND CONCLUSION

Though it is inconvincible to argue for the routine use of BRT, BRT may provide a choice for patients with large recurrent or inoperable deep-seated tumors, especially with the Glia-site technique. Radiotherapies including BRT may hold more promise if biologic mechanisms of radiation could be better understand and biologic modifications could be added in clinical trials.

The role of emerging and investigational therapies for metastatic brain tumors: a systematic review and evidence-based clinical practice guideline of selected topics

QUESTION

What evidence is available regarding the emerging and investigational therapies for the treatment of metastatic brain tumors?

TARGET POPULATION

These recommendations apply to adults with brain metastases.

RECOMMENDATIONS

New radiation sensitizers Level 2 A subgroup analysis of a large prospective randomized controlled trial (RCT) suggested a prolongation of time to neurological progression with the early use of motexafin-gadolinium (MGd). Nonetheless this was not borne out in the overall study population and therefore an unequivocal recommendation to use the currently available radiation sensitizers, motexafin-gadolinium and efaproxiral (RSR 13) cannot be provided. Interstitial modalities There is no evidence to support the routine use of new or existing interstitial radiation, interstitial chemotherapy and or other interstitial modalities outside of approved clinical trials. New chemotherapeutic agents Level 2 Treatment of melanoma brain metastases with whole brain radiation therapy and temozolomide is reasonable based on one class II study. Level 3 Depending on individual circumstances there may be patients who benefit from the use of temozolomide or fotemustine in the therapy of their brain metastases. Molecular targeted agents Level 3 The use of epidermal growth factor receptor inhibitors may be of use in the management of brain metastases from non-small cell lung carcinoma.

Fluorescence-guided surgery of metastatic brain tumors using fluorescein sodium

We aimed to demonstrate the effectiveness of fluorescence-guided surgery of metastatic brain tumors using fluorescein sodium. The study comprised 38 patients with metastatic brain tumors who underwent tumor resection after intravenous injection of fluorescein sodium. The local recurrence rate was investigated in 36 of the 38 patients, and compared for patients who had undergone surgery only and surgery plus whole-brain radiotherapy (WBRT). In 31 of 36 patients, the tumors had been completely resected using fluorescence-guided surgery. Postoperative WBRT was not performed in 20 of the 31 patients who underwent gross total resection. Although the recurrence rate for these 20 patients was 20%, compared to 9.1% for the 11 patients who also underwent postoperative WBRT, the difference was not statistically significant. Use of fluorescein sodium in metastatic brain tumor surgery may reduce the rate of local recurrence, and thus help improve the quality of life for these patients.

Gamma Knife radiosurgery to the surgical cavity following resection of brain metastases

OBJECT

This study evaluated the efficacy of postoperative Gamma Knife surgery (GKS) to the tumor cavity following gross-total resection of a brain metastasis.

METHODS

A retrospective review was conducted of 700 patients who were treated for brain metastases using GKS. Forty-seven patients with pathologically confirmed metastatic disease underwent GKS to the postoperative resection cavity following gross-total resection of the tumor. Patients who underwent subtotal resection or who had visible tumor in the resection cavity on the postresection neuroimaging study (either CT or MR imaging with and without contrast administration) were excluded. Radiographic and clinical follow-up was assessed using clinic visits and MR imaging. The radiographic end point was defined as tumor growth control (no tumor growth regarding the resection cavity, and stable or decreasing tumor size for the other metastatic targets). Clinical end points were defined as functional status (assessed prospectively using the Karnofsky Performance Scale) and survival. Primary tumor pathology was consistent with lung cancer in 19 cases (40%), melanoma in 10 cases (21%), renal cell carcinoma in 7 cases (15%), breast cancer in 7 cases (15%), and gastrointestinal malignancies in 4 cases (9%). The mean duration between resection and radiosurgery was 15 days (range 2-115 days). The mean volume of the treated cavity was 10.5 cm3 (range 1.75-35.45 cm3), and the mean dose to the cavity margin was 19 Gy. In addition to the resection cavity, 34 patients (72%) underwent GKS for 116 synchronous metastases observed at the time of the initial radiosurgery.

RESULTS

The mean radiographic follow-up duration was 14 months (median 10 months, range 4-37 months). Local tumor control at the site of the surgical cavity was achieved in 44 patients (94%), and tumor recurrence at the surgical site was statistically related to the volume of the surgical cavity (p=0.04). During follow-up, 34 patients (72%) underwent additional radiosurgery for 140 new (metachronous) metastases. At the most recent follow-up evaluation, 11 patients (23%) were alive, whereas 36 patients had died (mean duration until death 12 months, median 10 months). Patients who showed good systemic control of their primary tumor tended to have longer survival durations than those who did not (p=0.004). At the last clinical follow-up evaluation, the mean Karnofsky Performance Scale score for the overall group was 78 (median 80, range 40-100).

CONCLUSION

Radiosurgery appears to be effective in terms of providing local tumor control at the resection cavity following resection of a brain metastasis, and in the treatment of synchronous and metachronous tumors. These data suggest that radiosurgery can be used to prevent recurrence following gross-total resection of a brain metastasis.

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.

Brain metastases: current management and new developments

PURPOSE OF REVIEW

To review the state-of-the-art and new developments in the management of patients with brain metastases.

RECENT FINDINGS

Treatment decisions are based on prognostic factors to maximize neurologic function and survival, while avoiding unnecessary therapies. Whole-brain radiotherapy (WBRT) is the treatment of choice for patients with unfavorable prognostic factors. Stereotactic radiosurgery (SRS) or surgery is indicated for patients with favorable prognostic factors and limited brain disease. In single brain metastasis, the addition of either stereotactic radiosurgery or surgery to WBRT improves survival. The omission of WBRT after surgery or radiosurgery results in a worse local and distant control, though it does not affect survival. The incidence of neurocognitive deficits in long-term survivors after WBRT remains to be defined. New approaches to avoid cognitive deficits following WBRT are being investigated. The role of chemotherapy is limited. Molecularly targeted therapies are increasingly employed. Prophylaxis with WBRT is the standard in small-cell lung cancer.

SUMMARY

Many questions need future trials: the usefulness of new radiosensitizers; the role of local treatments after surgery; and the impact of molecularly targeted therapies on subgroups of patients with specific molecular profiles. Quality of life and cognitive functions are recognized as major endpoints in clinical trials.

Surgical resection and permanent iodine-125 brachytherapy for brain metastases

PURPOSE

To evaluate the efficacy and toxicity of surgical resection and permanent iodine-125 brachytherapy without adjuvant whole brain radiation therapy (WBRT) for brain metastases.

METHODS AND MATERIALS

Forty patients were treated with permanent iodine-125 brachytherapy at the time of resection of brain metastases from 1997 to 2003. Actuarial freedom from progression (FFP) and survival were measured from the date of surgery and estimated using the Kaplan-Meier method, with censoring at last imaging for FFP endpoints.

RESULTS

The median survival was 11.3 months overall, 12.0 months in 19 patients with newly diagnosed brain metastases and 7.3 months in 21 patients with recurrent brain metastases. Twenty-two patients (55%) remained free of progression of brain metastases, three failed at the resection cavity (including one with leptomeningeal dissemination), two failed with leptomeningeal spread only, and 13 failed elsewhere in the brain including two who also had leptomeningeal disease. The 1-year resection cavity FFP probabilities were 92%, 86% and 88%; and brain FFP probabilities were 29%, 43% and 37% for the newly diagnosed, recurrent and all patients, respectively. Symptomatic necrosis developed 7.4-40.0 months (median, 19.5 months) after brachytherapy in 9 patients (23%), confirmed by resection in 6 patients.

CONCLUSIONS

Excellent local control was achieved using permanent iodine-125 brachytherapy for brain metastasis resection cavities, although there is a high risk of radiation necrosis over time. These data support consideration of permanent brachytherapy without adjuvant WBRT as a treatment option in patients with symptomatic or large newly diagnosed or recurrent brain metastases.

Combined surgical resection and stereotactic radiosurgery for treatment of cerebral metastases

BACKGROUND

Patients with limited intracranial metastatic disease traditionally have been treated with surgery followed by WBRT. However, there is growing concern for the debilitating cognitive effects after WBRT in long-term survivors. We present a series of patients treated with surgery followed by SRS, while reserving WBRT as a salvage therapy for disease progression.

METHODS

Medical records from 15 patients with 1 to 2 cerebral metastases who underwent both resection and SRS were reviewed. Outcome measures included overall survival, survival by RPA class, EOR, local tumor control, progression of intracranial disease, need for WBRT salvage therapy, and COD.

RESULTS

Fifteen patients with cerebral metastases were treated with the combined surgery-SRS paradigm. Eight of the 15 patients (53.3%) were designated RPA class 1, with 6 of 15 (40.0%) in class 2 and 1 of 15 (6.7%) in class 3. Gross total resection was achieved in 12 cases (80.0%). Overall median survival was 20.0 months, with values of 22.0 and 13.0 months for RPA classes 1 and 2, respectively. Local recurrence occurred in 16.7% of those patients with GTR. Six patients (40.0%) went on to receive WBRT at a median of 8.0 months from initial presentation. Twelve patients (80.0%) had died at the completion of the study, and the COD was CNS progression in 33.3%.

CONCLUSIONS

Surgical resection combined with SRS is an effective treatment for selected patients with limited cerebral metastatic disease. Survival using this combined treatment was equivalent to or greater than that reported by other studies using surgery + WBRT or SRS + WBRT.