Outcome of Moderately Dosed Radiosurgery for Limited Brain Metastases

An overview of anti-epileptic therapy management of patients with malignant tumors of the brain undergoing radiation therapy

As our surgical, radiation, chemotherapeutic and supportive therapies for brain malignancies improve, and overall survival is prolonged, appropriate symptom management in this patient population becomes increasingly important. This review summarizes the published literature and current practice patterns regarding prophylactic and perioperative anti-epileptic drug use. As a wide range of anti-epileptic drugs is now available to providers, evidence guiding appropriate anticonvulsant choice is reviewed. A particular focus of this article is radiation therapy for brain malignancies. Toxicities and seizure risk associated with cranial irradiation will be discussed. Epilepsy management in patients undergoing radiation for gliomas, glioblastoma multiforme, and brain metastases will be addressed. An emerging but inconsistent body of evidence, reviewed here, indicates that anti-epileptic medications may increase radiosensitivity, and therefore improve clinical outcomes, specifically in glioblastoma multiforme patients.

Iodine-125 brachytherapy as upfront and salvage treatment for brain metastases : A comparative analysis

BACKGROUND

Outcome and toxicity profiles of salvage stereotactic ablative radiation strategies for recurrent pre-irradiated brain metastases are poorly defined. This study compared risk-benefit profiles of upfront and salvage iodine-125 brachytherapy (SBT) for small brain metastases. As the applied SBT treatment algorithm required histologic proof of metastatic brain disease in all patients, we additionally aimed to elucidate the value of biopsy before SBT.

PATIENTS AND METHODS

Patients with small untreated (n = 20) or pre-irradiated (n =28) suspected metastases intended for upfront or salvage SBT, respectively, were consecutively included. Temporary iodine-125 implants were used (median reference dose: 50 Gy, median dose rate: 15 cGy/h). Cumulative biologically effective doses (BED) were calculated and used for risk assessment. Treatment toxicity was classified according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria.

RESULTS

Upfront SBT was initiated in 20 patients and salvage SBT in 23. In 5 patients, salvage SBT was withheld because of proven radiation-induced lesions. Treatment groups exhibited similar epidemiologic data except for tumor size (which was slightly smaller in the salvage group). One-year local/distant tumor control rates after upfront and salvage SBT were similar (94 %/65 % vs. 87 %/57 %, p = 0.45, respectively). Grade I/II toxicity was suffered by 2 patients after salvage SBT (cumulative BED: 192.1 Gy₃ and 249.6 Gy₃). No toxicity-related risk factors were identified.

CONCLUSION

SBT combines diagnostic yield with effective treatment in selected patients. The low toxicity rate in the salvage group points to protective radiobiologic characteristics of continuous low-dose rate irradiation. Upfront and salvage SBT are similarly effective and safe. Histologic reevaluation should be reconsidered after previous radiotherapy to avoid under- or overtreatment.

Prognostic factors for survival and radiation necrosis after stereotactic radiosurgery alone or in combination with whole brain radiation therapy for 1-3 cerebral metastases

Background

In the present study factors affecting survival and toxicity in cerebral metastasized patients treated with stereotactic radiosurgery (SRS) were analyzed with special focus on radiation necrosis.

Patients and methods

340 patients with 1–3 cerebral metastases having been treated with SRS were retrospectively analyzed. Radiation necrosis was diagnosed by MRI und PET imaging. Univariate and multivariate analysis using a Cox proportional hazards regression model and log-rank test were performed to determine the prognostic value of treatment-related and individual factors for outcome and SRS-related complications.

Results

Median overall survival was 282 days and median follow-up 721 days. 44% of patients received WBRT during the course of disease. Concerning univariate analysis a significant difference in overall survival was found for Karnofsky Performance Status (KPS ≤ 70: 122 days; KPS > 70: 342 days), for RPA (recursive partitioning analysis) class (RPA class I: 1800 days; RPA class II: 281 days; RPA class III: 130 days), irradiated volume (≤2.5 ml: 354 days; > 2.5 ml: 234 days), prescribed dose (≤18 Gy: 235 days; > 18 Gy: 351 days), gender (male: 235 days; female: 327 days) and whole brain radiotherapy (+WBRT: 341 days/-WBRT: 231 days). In multivariate analysis significance was confirmed for KPS, RPA class and gender. MRI and clinical symptoms suggested radiation necrosis in 21 patients after SRS +/− whole brain radiotherapy (WBRT). In five patients clinically relevant radiation necrosis was confirmed by PET imaging.

Conclusions

SRS alone or in combination with WBRT represents a feasible option as initial treatment for patients with brain metastases; however a significant subset of patients may develop neurological complications. Performance status, RPA class and gender were identified to predict improved survival in cerebral metastasized patients.

Differentiation of local tumor recurrence from radiation-induced changes after stereotactic radiosurgery for treatment of brain metastasis: case report and review of the literature

BACKGROUND

Structural follow-up magnetic resonance imaging (MRI) after stereotactic radiosurgery (SRS) for brain metastases frequently displays local changes in the area of applied irradiation, which are often difficult to interpret (e.g., local tumor recurrence, radiation-induced changes). The use of stereotactic biopsy for histological assessment of these changes has a high diagnostic accuracy and can be considered as method of choice. In order to solve this relevant clinical problem non-invasively, advanced MRI techniques and amino acid positron-emission-tomography (PET) are increasingly used.

CASE PRESENTATION

We report the long-term follow-up of a patient who had been treated with linear accelerator based SRS for cerebral metastases of a lung cancer. Fifty-eight months after SRS, the differentiation of local recurrent brain metastasis from radiation-induced changes using structural MRI was difficult. For further differentiation, perfusion-weighted MRI (PWI), proton magnetic resonance spectroscopy (MRS), and (11)C-methyl-L-methionine (MET) PET was performed. Due to artifacts and technical limitations, PWI MRI and MRS findings were not conclusive. In contrast, MET PET findings were suggestive for radiation-induced changes. Finally, a stereotactic biopsy for histological assessment of these changes demonstrated clearly a radiation-induced necrosis and the absence of vital tumor.

CONCLUSION

The use of stereotactic biopsy for histological assessment of indistinguishable lesions on structural MRI after SRS for treatment of brain metastasis represents a highly reliable method to differentiate local tumor recurrence from radiation-induced changes. In this field, results of studies with both advanced MRI techniques and amino acid PET suggest encouraging results. However, artifacts and technical limitations (e.g., lesion size) are still a problem and comparative studies are needed to investigate the relationship, diagnostic performance, and complementary character of advanced MRI techniques and amino acid PET.

Hypofractionated stereotactic radiotherapy of limited brain metastases: a single-centre individualized treatment approach

Background

We retrospectively report treatment results of our single-centre experience with hypofractionated stereotactic radiotherapy (hfSRT) of limited brain metastases in primary and recurrence disease situations. Our aim was to find the most effective and safe dose concept.

Methods

From 04/2006 to 12/2010, 75 patients, with 108 intracranial metastases, were treated with hfSRT. 52 newly diagnosed metastases (48%), without up-front whole brain radiotherapy (WBRT), received hfSRT as a primary treatment. 56 metastases (52%) received a prior WBRT and were treated in this study in a recurrence situation. Main fractionation concepts used for primary hfSRT were 6-7x5 Gy (61.5%) and 5x6 Gy (19.2%), for recurrent hfSRT 7-10x4 Gy (33.9%) and 5-6x5 Gy (33.9%).

Results

Median overall survival (OS) of all patients summed up to 9.1 months, actuarial 6-and 12-month-OS was 59% and 35%, respectively. Median local brain control (LC) was 11.9 months, median distant brain control (DC) 3.9 months and intracranial control (IC) 3.4 months, respectively. Variables with significant influence on OS were Gross Tumour Volume (GTV) (p = 0.019), the biological eqivalent dose (calculated on a 2 Gy single dose, EQD2, α/β = 10) < and ≥ median of 39 Gy (p = 0.012), extracerebral activity of the primary tumour (p < 0.001) and the steroid uptake during hfSRT (p = 0.03). LC was significantly influenced by the EQD2, ≤ and > 35 Gy (p = 0.004) in both uni- and multivariate Cox regression analysis. Median LC was 14.9 months for EQD2 >35 Gy and 3.4 months for doses ≤35 Gy, respectively. Early treatment related side effects were usually mild. Nevertheless, patients with a EQD2 >35 Gy had higher rates of toxicity (31%) than ≤35 Gy (8.3%, p=0.026).

Conclusion

Comparing different dose concepts in hfSRT, a cumulative EQD2 of ≥35 Gy seems to be the most effective concept in patients with primary or recurrent limited brain metastases. Despite higher rates of only mild toxicity, this concept represents a safe treatment option.

Do patients with a limited number of brain metastases need whole-brain radiotherapy in addition to radiosurgery?

BACKGROUND

About 40% of patients with brain metastases have a very limited number of lesions and may be candidates for radiosurgery. Radiosurgery alone is superior to whole-brain radiotherapy (WBRT) alone for control of treated and new brain metastases. In patients with a good performance status, radiosurgery also resulted in better survival. However, the question is whether the results of radiosurgery alone can be further improved with additional WBRT.

METHODS

Information for this review was compiled by searching the PubMed and MEDLINE databases. Very important published meeting abstracts were also considered.

RESULTS

Based on both retrospective and prospective studies, the addition of WBRT to radiosurgery improved control of treated and new brain metastases but not survival. However, because a recurrence within the brain has a negative impact on neurocognitive function, it is important to achieve long-term control of brain metastases.

CONCLUSION

The addition of WBRT provides significant benefits. Further randomized studies including adequate assessment of neurocognitive function and a follow-up period of at least 2 years are needed to help customize the treatment for individual patients.

Resection plus whole-brain irradiation versus resection plus whole-brain irradiation plus boost for the treatment of single brain metastasis

BACKGROUND

The optimal treatment for patients with a single brain metastasis is controversial. This study investigated the value of a radiation boost given in addition to neurosurgerical resection and whole-brain irradiation (WBI).

PATIENTS AND METHODS

In this retrospective study, outcome data of 105 patients with a single brain metastasis receiving metastatic surgery plus WBI (S + WBI) were compared to 90 patients receiving the same treatment plus a boost to the metastatic site (S + WBI + B). The outcomes that were compared included local control of the resected metastasis (LC) and overall survival (OS). In addition to the treatment regimen, eight potential prognostic factors were evaluated including age, gender, performance status, extent of metastatic resection, primary tumor type, extracerebral metastases, recursive partitioning analysis (RPA) class, and interval from first diagnosis of cancer to metastatic surgery.

RESULTS

The LC rates at 1 year, 2 years, and 3 years were 38%, 20%, and 9%, respectively, after S + WBI, and 67%, 51%, and 33%, respectively, after S + WBI + B (p = 0.002). The OS rates at 1 year, 2 years, and 3 years were 52%, 25%, and 19%, respectively, after S + WBI, and 60%, 40%, and 26%, respectively, after S + WBI + B (p = 0.11). On multivariate analyses, improved LC was significantly associated with OP + WBI + B (p = 0.006) and total resection of the metastasis (p = 0.014). Improved OS was significantly associated with age ≤ 60 years (p = 0.028), Karnofsky Performance Score > 70 (p = 0.015), breast cancer (p = 0.041), RPA class 1 (p = 0.012), and almost with the absence of extracerebral metastases (p = 0.05).

CONCLUSION

A boost in addition to WBI significantly improved LC but not OS following resection of a single brain metastasis.

[Complete remission of multiple brain metastases of non-small cell lung cancer induced by gefitinib monotherapy]

BACKGROUND

While the activity of tyrosine kinase inhibitors as the first line treatment for primary tumors in patients with stage IV non-small cell lung cancer and a positive EGF receptor mutation is well known, little data on the efficacy in controlling cerebral metastases are available.

CASE REPORT AND RESULTS

A 43-year-old woman was diagnosed with non-small cell lung cancer with cerebral and hepatic metastases. Emergency radiation therapy was initiated at the time of diagnosis due to superior vena cava syndrome. However, after she failed to respond to this therapy and in light of a positive EGF receptor mutation, gefitinib was added at a dose of 250 mg/day while continuing radiation to the primary lesion and cervical lymph nodes. She showed a rapid clinical and radiologic response with complete remission of the cerebral metastases 6 weeks after starting gefitinib. No severe toxicity was observed.

CONCLUSION

This case demonstrates that gefitinib can be given during radiation treatment without significant toxicity. Furthermore, complete remission of cerebral metastases can be achieved with tyrosine kinase inhibitor monotherapy.

Radiosurgery for large brain metastases

PURPOSE

To determine the efficacy and safety of radiosurgery in patients with large brain metastases treated with radiosurgery.

PATIENTS AND METHODS

Eighty patients with large brain metastases (>14 cm(3)) were treated with radiosurgery between 1998 and 2009. The mean age was 59 ± 11 years, and 49 (61.3%) were men. Neurologic symptoms were identified in 77 patients (96.3%), and 30 (37.5%) exhibited a dependent functional status. The primary disease was under control in 36 patients (45.0%), and 44 (55.0%) had a single lesion. The mean tumor volume was 22.4 ± 8.8 cm(3), and the mean marginal dose prescribed was 13.8 ± 2.2 Gy.

RESULTS

The median survival time from radiosurgery was 7.9 months (95% confidence interval [CI], 5.343-10.46), and the 1-year survival rate was 39.2%. Functional improvement within 1-4 months or the maintenance of the initial independent status was observed in 48 (60.0%) and 20 (25.0%) patients after radiosurgery, respectively. Control of the primary disease, a marginal dose of ≥11 Gy, and a tumor volume ≥26 cm(3) were significantly associated with overall survival (hazard ratio, 0.479; p = .018; 95% CI, 0.261-0.880; hazard ratio, 0.350; p = .004; 95% CI, 0.171-0.718; hazard ratio, 2.307; p = .006; 95% CI, 1.274-4.180, respectively). Unacceptable radiation-related toxicities (Radiation Toxicity Oncology Group central nervous system toxicity Grade 3, 4, and 5 in 7, 6, and 2 patients, respectively) developed in 15 patients (18.8%).

CONCLUSION

Radiosurgery seems to have a comparable efficacy with surgery for large brain metastases. However, the rate of radiation-related toxicities after radiosurgery should be considered when deciding on a treatment modality.

New approach for treatment of vertebral metastases using intensity-modulated radiotherapy

PURPOSE

To perform aggressive radiotherapy for vertebral metastases. Using very steep dose gradients from intensity-modulated radiotherapy (IMRT), a protocol based on the concept of partial volume dose to the spinal cord was evaluated.

PATIENTS AND METHODS

50 patients with vertebral metastases were treated using IMRT. In previously unirradiated cases, where a prescribed dose of 80 Gy (BED10) was delivered, the constraint to the spinal cord should be less than 100 Gy (BED2). For previously irradiated cases, on the other hand, the dose is the same as in the previously unirradiated case; however, constraints for the spinal cord are a cumulative BED2 of less than 150 Gy, BED2 of less than 100 Gy in each instance, and a treatment gap of more than 6 months. There were 6 patients considered for a partial volume dose to the spinal cord. They all received higher BED2, ranging from 51-157 Gy of D1cc.

RESULTS

Among the 24 patients who survived longer than 1 year, there was 1 case of transient radiation myelitis. There were no other cases of spinal cord sequelae.

CONCLUSION

Based on the present results, we recommend a BED2 of 100 Gy or less at D1cc as a constraint for the spinal cord in previously unirradiated cases, and a cumulative BED2 of 150 Gy or less at D1cc in previously irradiated cases, when the interval was not shorter than 6 months and the BED2 for each session was 100 Gy or less. The prescribed BED10 of 80 Gy could be safely delivered to the vertebral lesions.