Surgical Management of Cerebral Metastases

[Place of surgery in brain metastases]

Surgical excision in brain metastases has been well evaluated in unique metastases. Two randomized phase III trials have shown that combined with adjuvant whole brain radiotherapy, it significantly improves overall survival. However, even in the presence of multiple brain metastases, surgery may be useful in large, symptomatic or life-threatening lesions (posterior fossa tumor with mass effect). Also, even in lesions amenable to radiosurgery, surgical resection is preferred when tumors displayed cystic or necrotic aspect with important edema or when located in highly eloquent areas or cortico-subcortically. Furthermore, surgery may have a diagnostic role, in the absence of histological documentation of the primary disease, if the radiological aspect is atypical to rule out differential diagnosis (brain abscess, lymphoma, primary tumor of the central nervous system) or in case of suspicion of progression after irradiation to differentiate radionecrosis from a genuine progression of brain disease. Finally, the issue of biological documentation of brain disease may arise in situations where a specific targeted therapy can be proposed. If the surgical indications are relatively well defined, the selection of patients who will really benefit from surgery should take into account three factors, clinical and functional status of the patient, systemic disease status and characteristics of intracranial metastases. Given the improved survival of cancer patients due to the advent of effective targeted therapies on systemic disease, a renewed interest has been given to local therapy (surgery or radiosurgery) in brain metastases. Surgical resection currently represents a valuable tool in the armamentarium of brain metastases but has also become a diagnostic and decision tool that can affect therapeutic strategies in 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.

Clinical analysis of novalis stereotactic radiosurgery for brain metastases

OBJECTIVE

The authors analyzed the effectiveness and therapeutic response of Novalis shaped beam radiosurgery for metastatic brain tumors, and the prognostic factors which influenced the outcome.

METHODS

We performed a retrospective analysis of 106 patients who underwent 159 treatments for 640 metastatic brain lesions between January 2000 and April 2008. The pathologies of the primary tumor were mainly lung (45.3%), breast (18.2%) and GI tract (13.2%). We classified the patients using Radiation Therapy Oncology Group Recursive Partitioning Analysis (RPA) and then analyzed the survival and prognostic factors according to the Kaplan Meier method and univariate analysis.

RESULTS

The overall median actuarial survival rate was 7.3 months from the time of first radiosurgery treatment while 1 and 2 year actuarial survival estimates were 31% and 14.4%, respectively. Median actuarial survival rates for RPA classes I, II, and III were 31.3 months, 7.5 months and 1.7 months, respectively. Patients' life spans, higher Karnofsky performance scores and age correlated closely with RPA classes. However, sex and the number of lesions were not found to be significantly associated with length of survival.

CONCLUSION

This result suggests that Novalis radiosurgery can be a good treatment option for treatment of the patients with brain metastases.

Surgical Therapies in Brain Metastasis

Brain metastases are the most common intracranial tumors in adults and source of the most common neurological complications of systemic cancer. The treatment approach to brain metastases differs essentially from treatment of systemic metastases due to the unique anatomical and physiological characteristics of the brain. Surgery and radiosurgery are important components in the complex treatment of brain metastases and can prolong survival and improve the quality of life (QOL). Aggressive intervention may be indicated for selected patients with well-controlled systemic cancer and good performance status in whom central nervous system (CNS) disease poses the greatest threat to functionality and survival. In this review the respective roles of surgery and radiosurgery, patient selection, general prognostic factors and tailoring of optimal surgical management strategies for cerebral metastases are discussed.

Resectable brain metastases

Brain metastases are the most common brain tumors seen in clinical practice, comprising well over half of all brain tumors. For many years, surgical resection of brain metastases was considered a form of palliative therapy only, but more recently it has been shown to have a more important role in extending survival in appropriately selected patients. Newer surgical techniques have helped to reduce the morbidity associated with tumor resection. Although randomized studies have demonstrated the need for postoperative whole-brain radiotherapy, there remains interest in the use of other surgical adjuncts to delay or eliminate the need for fractionated radiotherapy. The use of various treatment modalities, particularly image-guided surgery and stereotactic radiosurgery, allows clinicians who are focused on the treatment of brain metastases to achieve superior levels of tumor control within the brain. As a result, overall survival is much more dependent on the status of the patient's systemic disease.

Brainstem Metastases: Management Using Gamma Knife Radiosurgery

OBJECTIVE:

Brainstem metastasis is an uncommon complication of systemic cancer, generally considered to have a highly unfavorable prognosis. Surgical risks are high and standard radiation or chemotherapy have little effect. The purpose of this study is to evaluate our experience using Gamma Knife radiosurgery (GKRS) for the management of brainstem metastasis.

METHODS:

Between July 1992 and March 2001, we treated 28 patients with brainstem metastasis using GKRS. Lesions were located in the pons in 17 patients, midbrain in nine, and medulla oblongata in two. At time of the radiosurgery, eight patients presented with another supratentorial metastasis. The most frequent primary tumor site was the lung (13 cases) followed by the melanoma in four cases, the kidney in two, and other locations in six. Only six patients underwent fractionated whole-brain radiation therapy. Mean marginal radiation dose for GKRS was 19.6 Gy (range, 11–30). Mean maximum diameter was 17.2 mm (range, 10–30).

RESULTS:

No GKRS-related morbidity was observed. Local tumor control was achieved in 92% of patients. Twenty-six patients have died. Death was related to the progression of the brainstem lesion in two cases. Mean and median survival after GKRS were 10.2 and 12 months, respectively. Follow-up periods in the two surviving patients were 12 and 13 months.

CONCLUSION:

The results of this small series demonstrate that GKRS can be a valuable modality for safe and effective management of brain stem metastasis. Owing to the high risk of surgical resection and low efficacy of medical treatment, radiosurgery can be proposed upfront.

Diagnosis and management of central nervous system metastases from breast cancer

The brain, cranial nerves, leptomeninges, spinal cord, and eye compose the central nervous system (CNS) and are at risk for the development of metastases from breast cancer. Such metastases are diagnosed on the basis of clinical suspicion and substantiated by neuroimaging, resection when indicated, and sampling of cerebrospinal fluid when leptomeningeal metastasis (LM) is suspected. Treatment is aimed at palliation of symptoms and preservation of neurologic function. Historically, conventional radiation therapy has been the mainstay of palliative treatment for brain, cranial nerve, spinal cord, and ocular metastases. However, additional treatment options for brain metastases have been brought about by technological advances in surgery to resect brain metastases, and stereotactic radiosurgery (SRS) to focally irradiate metastases, both of which have been substantiated by data from randomized trials. Ongoing research is aimed at refining criteria to select which patients with brain metastases should undergo surgery and SRS and how these focal therapies should be optimally integrated with whole-brain radiotherapy. Therapy for LM must carefully balance the potential risks and perceived benefits associated with CNS-directed therapies. Despite advances in neuroimaging, surgery, and radiation therapy, novel treatments are needed to improve the effectiveness of treatments for CNS metastases, especially LM, while reducing attendant neurotoxicity.

Surgical resection of metastatic intraventricular tumors

The ventricle is a rare site of brain metastases. Renal cell carcinoma has a higher propensity to metastasize to the ventricle compared with more common metastatic tumors (e.g., lung cancer). The trigone is the predominant location for intraventricular metastases, presumably because of the high concentration of choroid plexus in this region. Surgical resection is an important component of the management of these lesions, particularly if there is only a single intraventricular lesion. Despite the deep location of these tumors within the ventricle, survival in patients undergoing surgery for them is comparable to that in patients receiving surgery for intraparenchymal metastases.

The role of tumor size in the radiosurgical management of patients with ambiguous brain metastases

OBJECTIVE

To identify a size cutoff below which it is safe to observe obscure brain lesions suspected of being metastases so that treatment of nonmetastases can be avoided.

METHODS

Medical records from patients who underwent linear accelerator-based radiosurgery from August 1991 to October 2001 were reviewed. Inclusion criteria were defined as brain metastasis tumor volume less than 5 cm(3) (diameter, thick similar 2.1 cm) treated with a dose of 20 Gy or more. One hundred thirty-five patients had 153 evaluable brain metastases with follow-up imaging that met inclusion criteria. Median age was 54 years (range, 18-79 yr). Lesion primaries were non-small-cell lung (n = 39), melanoma (n = 44), renal (n = 37), breast (n = 18), colon (n = 3), sarcoma (n = 5), other (n = 5), and unknown primary (n = 2). Median tumor volume was 0.67 cm(3) (range, 0.06-4.58 cm(3)). The minimum peripheral dose was 20 Gy (n = 132) or 21 to 24 Gy (n = 21). At the time of analysis, the median follow-up for all patients was 10 months (range, 0.2-99 mo).

RESULTS

The 1- and 2-year actuarial local control rates for all of the lesions were 69 and 46%, respectively. For lesions of 1 cm (0.5 cm(3)) or less, the corresponding local control rates were 86 and 78%, respectively, which was significantly higher than the corresponding rates of 56 and 24%, respectively, for lesions larger than 1 cm (0.5 cm(3)) (P = 0.0016).

CONCLUSION

A convincing brain metastasis measuring less than 1 cm should be pursued aggressively. If the suspected brain metastasis is ambiguous, observation is proposed up to a diameter of 1 cm. This is the first study in the literature to identify a 1-cm cutoff for radiosurgical control of small brain metastases, and validation by additional studies is required.

Image-guided craniotomy for cerebral metastases: techniques and outcomes

OBJECTIVE

The purpose of the present study was to analyze the outcomes after craniotomies for brain metastases in a modern series using image-guided technologies either in the regular operating room or in the intraoperative magnetic resonance imaging unit.

METHODS

Neurosurgical outcomes were analyzed for 49 patients who underwent 55 image-guided craniotomies for excision of brain metastases during a 5-year period. Tumors were located in critical and noncritical function regions of the brain. A total of 23 craniotomies for tumors in critical brain were performed using intravenous sedation anesthesia; craniotomies for noncritical function brain regions were completed under general anesthesia. The patients were also divided into Radiation Therapy Oncology Group recursive partitioning analysis (RPA) classes on the basis of age, Karnofsky Performance Scale scores, state of primary disease, and presence or absence of extracranial metastases.

RESULTS

There was no perioperative mortality. Gross total resection, as verified by postoperative contrast-enhanced computed tomography or magnetic resonance imaging, was achieved in 96% of patients. The median anesthesia time was 4.25 hours, and the median length of hospital stay was 3 days. In 51 symptomatic cases, there was complete resolution of symptoms in 70% (n = 36), improvement in 14% (n = 7), and no change in 12% (n = 6) postoperatively. No patient who was neurologically intact preoperatively deteriorated after surgery, and 93% of patients maintained or improved their functional status. Only two patients (3.6%) with significant preoperative deficits had increased long-term deficits postoperatively. The mean follow-up was 1 year, and the local recurrence rate was 16%. The median survival of the entire group was 16.23 months (17.5 mo in RPA Class I, 22.9 mo in RPA Class II, and 9.8 mo in RPA Class III).

CONCLUSION

Gross total resection of brain metastases, including those involving critical function areas, can be safely achieved with a low morbidity rate using contemporary image-guided systems. RPA Class I and II patients with controlled primary disease benefit from aggressive treatment by surgery and radiation.

Chemotherapy for the treatment of metastatic brain tumors

Metastatic brain tumors are the most common complication of systemic cancer and affect 20-40% of all adult cancer patients. Whole-brain radiotherapy and surgical resection of accessible, solitary lesions have been the mainstay of treatment. Recently, chemotherapy has become a more viable treatment option for metastatic brain tumors. Many different drugs and administrative approaches have been shown to be clinically active. Traditional chemotherapy given before or during irradiation can be effective with agents such as cyclophosphamide, cisplatin and etoposide. Nontraditional approaches, such as tempozolomide and intra-arterial administration of carboplatin, have demonstrated activity against recurrent metastatic disease. In early clinical trials of interstitial chemotherapy, biodegradable polymers have shown some clinical efficacy and have been well-tolerated. Molecular approaches are also under investigation in response to new information regarding the metastatic phenotype. Potential targets include growth factor receptors and other protein tyrosine kinases, internal signal transduction pathways, ras activation and matrix metalloprotease activity. New clinical trials will be needed to investigate these new molecular-based therapeutics, alone and in combination with currently available treatment options, to determine the optimal application of chemotherapy to metastatic brain tumors.

Metastatic melanoma to the brain: prognostic factors after gamma knife radiosurgery

PURPOSE

To identify important prognostic factors predictive of survival and tumor control in patients with metastatic melanoma to the brain who underwent gamma knife radiosurgery.

METHODS AND MATERIALS

A total of 122 consecutive patients with 332 intracranial melanoma metastases underwent gamma knife radiosurgery over a 5-year period. Of these, 39 (32%) also received whole-brain irradiation (WBI). The median tumor volume was 0.8 cm(3) (range: 0.02-30.20 cm(3)), and the median prescribed dose was 20 Gy (range: 14-24 Gy). Median follow-up was 6.8 months. Univariate and multivariate analyses of survival and freedom from progression were performed using the following parameters: status of systemic disease, intracranial tumor volume, number of lesions, tumor location, Karnofsky performance status, gender, age, and WBI.

RESULTS

Overall median survival was 7.0 months from time of radiosurgery and 9.1 months from the onset of brain metastasis. In multivariate analysis, improved survival was noted in patients with total intracranial tumor volume <3 cm(3) (p = 0.003) and inactive systemic disease (p = 0.0065), whereas other parameters studied were of lesser importance (tumor location, p = 0.056, and Karnofsky performance status, p = 0.086), or of no significance (number of lesions, WBI, age, and gender). Freedom from subsequent brain metastasis depended on intracranial tumor volume (p = 0.0018) and status of systemic disease (p = 0.034).

CONCLUSIONS

Stereotactic radiosurgery is an effective treatment modality for patients with intracranial metastatic melanoma. Tumor volume and status of systemic disease are good independent predictors of survival and freedom from tumor progression.

Gamma surgery for melanoma metastases in the brain

OBJECT

The aim of this study was to evaluate the usefulness and limitations of gamma surgery (GS) in the treatment of brain metastases from melanoma.

METHODS

Imaging and clinical outcomes in 45 patients treated for 92 brain metastases from melanoma between October 1989 and October 1999 were retrospectively analyzed. Follow-up imaging studies were available in 35 patients with 66 treated lesions. Twenty-four percent of the lesions disappeared, 35% shrank, 23% remained unchanged, and 18% increased in size. No undue radiation-induced changes were observed in the surrounding brain. Clinical data were available in all patients. No deaths or neurological morbidity related to GS was observed. The median survival time, calculated using the Kaplan-Meier method, was 10.4 months from the time of GS. In both univariate and multivariate Cox regression analyses, a single brain lesion and lack of visceral metastases were statistically predictive of a better prognosis. Six of eight patients with solitary metastasis (that is, a single brain metastasis with no primary visceral tumor) were still alive at the close of the study, none of them with disease progression, with a follow-up period ranging between 14 and 82 months. Sixteen patients in this series received adjunctive whole-brain radiation therapy, which had no impact on their survival time or local and distant control of the brain disease.

CONCLUSIONS

Gamma surgery is effective in treating melanoma metastases in the brain. It appears that the radiobiology of a single high dose overcomes the radioresistance barrier, yielding better results than fractionated radiation.

Surgical management of brain metastases

Metastatic brain tumors are the most common intracranial tumors in adults and the most common cause of neurologic morbidity and mortality in these patients. Recent advances in the management of the primary cancer have resulted in improved prognosis, longer survival, and thus, increased identification of the presence of brain metastases. Data suggest that aggressive treatment of the metastatic brain tumor with surgical resection increases the length of survival in these patients. New techniques, including preoperative functional imaging, stereotactic surgical resection, image-guided neurosurgery, intraoperative ultrasound, and cortical mapping, have aided neurosurgeons in surgical resection and have helped to lower the associated surgical morbidity and mortality. The respective roles of surgery, patient selection, prognostic factors, and radiotherapy are addressed in this review.

Stereotactic radiosurgery in the treatment of metastatic disease to the brain

OBJECTIVE

In recent years, stereotactic radiosurgery has been growing in popularity as a treatment modality for metastatic disease to the brain. The technique has advantages of reduced cost and low morbidity compared with open surgical treatment. Furthermore, it avoids the potential cognitive side effects of fractionated whole-brain radiotherapy. We undertook this study to determine the usefulness of adjuvant radiation therapy and to determine prognostic factors in patients treated with stereotactic radiosurgery.

METHODS

We reviewed our series of patients with metastatic tumors treated using gamma knife stereotactic radiosurgery from August 1994 to February 1999. Nonparametric methods were used to compare treatment subgroups by demographic features including age, Karnofsky Performance Scale score, diagnosis, and systemic disease status. Univariate and multivariate analyses of survival and freedom from progression were performed using Kaplan-Meier and Cox proportional hazards regression techniques.

RESULTS

This study included 190 patients harboring 431 lesions who were treated in 263 treatment sessions. The median follow-up after radiosurgery was 36 weeks for all patients. The median actuarial survival from the time of radiosurgery in all patients was 34 weeks. When patients were stratified according to tumor histology, those without melanoma had a median survival of 39 weeks, and those with melanoma had a median survival of 28 weeks. The cause of death could be determined in 122 (92%) of the patients known to have died during the data capture period. For patients harboring melanoma, death was attributable to systemic disease in 31 (47%), to central nervous system-related processes in 29 (44%), and to unknown causes in 6 (9%). For non-melanoma patients, death was attributable to systemic disease in 45 (68%), to central nervous system-related processes in 17 (26%), and to unknown causes in 4 (6%). Significantly improved survival (P = 0.002) was observed in patients with controlled systemic disease. No significant difference in survival could be ascertained for patients presenting with up to four lesions, although patients with a total tumor volume greater than 9 cc had shortened survival. No survival benefit could be demonstrated for whole-brain radiotherapy administered either concomitantly or after radiosurgery.

CONCLUSION

Factors correlated with significantly improved survival included controlled systemic disease and non-melanoma histology. We found no significant survival benefit that could be discerned from adjuvant whole-brain radiotherapy in this patient group.

Management of Cerebral Metastases: The Role of Surgery

BACKGROUND: Metastatic brain tumors represent the most common neurological complication in patients with systemic cancer. They are predominantly cerebrally located and constitute a significant source of morbidity and mortality. The overall incidence of brain metastases exceeds that of all other intracranial tumors, and as improved systemic cancer treatments have extended patients' lives, this number is rising. METHODS: The role of surgery in the management of cerebral metastases is reviewed by considering patient selection criteria, surgical approaches to metastases, intraoperative adjuncts, whole-brain irradiation as a postoperative adjuvant, resection of multiple vs single metastases, and the relative roles of stereotactic radiosurgery and conventional surgery. RESULTS: Surgical resection of single or multiple metastases can be effective management for patients with otherwise good prognoses, providing all the known metastases can be removed without producing significant neurologic deficit. Radiosurgery, an alternate approach, can be used for smaller or inaccessible tumors. CONCLUSIONS: The presence of multiple brain metastases does not automatically contraindicate surgery because in properly selected patients, resection of multiple metastases can extend survival and enhance the quality of life. An awareness of how the modalities of open craniotomy, whole-brain radiotherapy, and stereotactic radiosurgery best complement each other will result in the best outcomes.

Surgical treatment of metastatic brain tumors

Key elements in the modern surgical treatment of metastatic brain tumors are a firm grasp of criteria for selection of proper surgical candidates and a thorough grounding in the surgical approaches to, and the anatomy of, cerebral metastases. It is important to realize that the presence of multiple or recurrent brain metastases does not automatically contraindicate surgery because in properly selected patients, resection of multiple metastases or reoperation for recurrent metastases can extend survival and enhance the quality of life. Appropriate treatment of metastatic brain tumors frequently requires the judicious use of modalities such as open craniotomy, whole brain radiotherapy, and stereotactic radiosurgery. In order to assure the best outcome of patients with cerebral metastases, it is necessary to have an awareness of how these modalities can best complement one another and to apply them accordingly.