Chemotherapy and targeted molecular therapies for brain metastases

Saturated Fatty Acid Emulsions Open the Blood-Brain Barrier and Promote Drug Delivery in Rat Brains

We performed this study to evaluate whether saturated fatty acid (SFA) emulsions affect the BBB and determine the duration of BBB opening, thereby promoting drug delivery to the brain. Butyric, valeric, caproic, enanthic, and caprylic acid emulsions were infused into the carotid artery of the rat model. We evaluated the BBB opening and drug delivery over time. The trypan blue and doxorubicin delivery studies were repeated from 30 min to 6 h. In the 1 h rats in each group, transmission electron microscopy (TEM) was performed to morphologically evaluate tight junctions, and the delivery of temozolomide was assessed by desorption electrospray ionization mass spectrometry. The ipsilateral hemisphere was positive for trypan blue staining in all the five SFA emulsion groups. In the valeric, enanthic, and caprylic acid emulsion groups, RGB ratios were significantly higher at 30 min and decreased thereafter. Doxorubicin delivery increased in all emulsion groups at all time points. Tight junctions were observed to be open in all groups. TMZ delivery was significantly higher in the ipsilateral hemisphere. In conclusion, intra-arterially infused SFA emulsions opened the BBB and promoted drug delivery within 30 min, which decreased thereafter. Therefore, SFA emulsions may aid BBB research and promote drug delivery to the brain.

Intraoperative radiotherapy to treat newly diagnosed solitary brain metastasis: initial experience and long-term outcomes

OBJECT

The authors assessed the feasibility of intraoperative radiotherapy (IORT) using a portable radiation source to treat newly diagnosed, surgically resected, solitary brain metastasis (BrM).

METHODS

In a nonrandomized prospective study, 23 patients with histologically confirmed BrM were treated with an Intrabeam device that delivered 14 Gy to a 2-mm depth to the resection cavity during surgery.

RESULTS

In a 5-year minimum follow-up period, progression-free survival from the time of surgery with simultaneous IORT averaged (± SD) 22 ± 33 months (range 1-96 months), with survival from the time of BrM treatment with surgery+IORT of 30 ± 32 months (range 1-96 months) and overall survival from the time of first cancer diagnosis of 71 ± 64 months (range 4-197 months). For the Graded Prognostic Assessment (GPA), patients with a score of 1.5-2.0 (n = 12) had an average posttreatment survival of 21 ± 26 months (range 1-96 months), those with a score of 2.5-3.0 (n = 7) had an average posttreatment survival of 52 ± 40 months (range 5-94 months), and those with a score of 3.5-4.0 (n = 4) had an average posttreatment survival of 17 ± 12 months (range 4-28 months). A BrM at the treatment site recurred in 7 patients 9 ± 6 months posttreatment, and 5 patients had new but distant BrM 17 ± 3 months after surgery+IORT. Six patients later received whole-brain radiation therapy, 7 patients received radiosurgery, and 2 patients received both treatments. The median Karnofsky Performance Scale scores before and 1 and 3 months after surgery were 80, 90, and 90, respectively; at the time of this writing, 3 patients remain alive with a CNS progression-free survival of > 90 months without additional BrM treatment.

CONCLUSIONS

The results of this study demonstrate the feasibility of resection combined with IORT at a dose of 14 Gy to a 2-mm peripheral margin to treat a solitary BrM. Local control, distant control, and long-term survival were comparable to those of other commonly used modalities. Surgery combined with IORT seems to be a potential adjunct to patient treatment for CNS involvement by systemic cancer.

The minimum percentage of triolein emulsion for studying cerebral vascular permeability with least brain edema

Background:

Triolein emulsion infusion into the brain produces transiently increased vascular permeability.

Objectives:

The purpose of this study was to find the minimum percentage of triolein emulsion required for studying vascular permeability with minimal brain edema.

Materials and Methods:

Sixty healthy cats were divided into six groups according to the concentration of emulsified triolein infused into the carotid artery: group 1, 0.125% (n = 10); group 2, 0.25% (n = 10); group 3, 0.5% (n = 10); group 4, 1% (n = 10); group 5, 2% (n = 10); and group 6, saline infusion (control group, n = 10). T2-, T1- and contrast enhanced T1-weighted MR images were obtained 2 hours after infusing triolein emulsion. Contrast enhancement ratios (CERs) and signal intensity ratios (SIRs) versus contralateral hemispheres were calculated. Statistical analysis was performed by analysis of variance followed by Tukey’s test. P values of ≤ 0.05 were considered significant.

Results:

The lesion hemispheres showed mild hyperintensity due to edema on T2-weighted images, and contrast enhancement on post-contrast T1-weighted images in cats of group 1-5. CERs showed statistically significant differences between the control group and group 3 (P = 0.006), group 4 (P = 0.003), and group 5 (P < 0.001). However, SIRs were significantly different between the control group and group 5 only (P < 0.001).

Conclusion:

The minimum concentration of triolein emulsion required to increase vascular permeability adequately with minimal brain edema in a cat model was 0.5%.

Burden of breast cancer with brain metastasis: a French national hospital database analysis

OBJECTIVE

Incidence of breast cancer with brain metastases (BCBM) is increasing, especially among patients over-expressing HER2. Epidemiology on this sub-type of cancer is scarce, since cancer registries carry no information on the HER2 status. A retrospective database analysis was conducted to estimate the burden of BCBM, especially among HER2-positive patients in a secondary objective.

METHODS

Patients with a new diagnosis of BCBM carried out between January and December 2008 were identified from the national hospital database using the International Disease Classification. Patients receiving a targeted anti-HER2 therapy were identified from the national pharmacy database. Hospital and pharmacy claims were linked to estimate the burden of HER2-positive patients. Data on hospitalizations were extracted to describe treatment patterns and healthcare costs during a 1-year follow-up. Predictors of treatment cost were analyzed through multi-linear regression analysis.

RESULTS

Two thousand and ninety-nine BCBM patients were identified (mean age (SD) = 57.8 (13.6)), of whom 12.2% received a targeted anti-HER2 therapy; 79% of patients had brain metastases associated with extracranial metastases, and the attrition rate reached 82%. Patients received mostly palliative care (47.4%), general medical care (40.6%), and chemotherapy (35.0%). The total annual hospital cost of treatment was 8,426,392€, representing a mean cost of 22,591€ (±14,726) per patient, mainly influenced by extracranial metastases, surgical acts, and HER2-overexpression (p < 0.0001).

CONCLUSIONS

The database linkage of hospital and pharmacy claims is a relevant approach to identify sub-type of cancer. Chemotherapy was widely used as a systemic treatment for breast cancer rather than for local treatment of brain metastases whose morbi-mortality remains high. The variability of treatment costs suggests clinical heterogeneity and, thus, extensive individualization of protocols.

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.

Reactive glia are recruited by highly proliferative brain metastases of breast cancer and promote tumor cell colonization

Interactions between tumor cells and the microenvironment are crucial to tumor formation and metastasis. The central nervous system serves as a "sanctuary" site for metastasis, resulting in poor prognosis in diagnosed patients. The incidence of brain metastasis is increasing; however, little is known about interactions between the brain and metastatic cells. Brain pathology was examined in an experimental model system of brain metastasis, using a subline of MDA-MB-231 human breast cancer cells. The results were compared with an analysis of sixteen resected human brain metastases of breast cancer. Experimental metastases formed preferentially in specific brain regions, with a distribution similar to clinical cases. In both the 231-BR model, and in human specimens, Ki67 expression indicated that metastases were highly proliferative (approximately 50%). Little apoptosis was observed in either set of tumors. In the model system, metastases elicited a brain inflammatory response, with extensive reactive gliosis surrounding metastases. Similarly, large numbers of glial cells were found within the inner tumor mass of human brain metastases. In vitro co-cultures demonstrated that glia induced a approximately 5-fold increase in metastatic cell proliferation (P<0.001), suggesting that brain tissue secretes factors conducive to tumor cell growth. Molecules used to signal between tumor cells and the surrounding glia could provide a new avenue of therapeutic targets for brain metastases.

Chemotherapy and cerebral metastases: misperception or reality?

Cerebral metastases remain a common complication among patients with cancer. Surgery and radiotherapy remain the principal therapeutic interventions. In contrast, the benefit of chemotherapy has long been viewed with skepticism. Nonetheless, as survival in cancer patients improves and the incidence of cerebral metastases increases, so does the demand for effective therapies. It is now recognized that the blood-brain barrier within metastases is permeable and thus allows entry of otherwise excluded drugs. Limited data have suggested that cerebral metastases have modest sensitivity to chemotherapy. Furthermore, novel agents and delivery strategies have been developed to facilitate central nervous system penetration. Nonetheless, data are limited by methodological flaws, including heterogeneous inclusion criteria, small sample sizes, lack of randomization, and inconsistencies in defined end points and response assessment criteria. Well-designed clinical trials are needed to address the effect of chemotherapy. Acceptable control arms must be established to measure the effect of chemotherapies. Standardized response criteria and disease-specific studies are essential.