[Place of surgery in brain metastases]

Quantitative mathematical modeling of clinical brain metastasis dynamics in non-small cell lung cancer

Brain metastases (BMs) are associated with poor prognosis in non-small cell lung cancer (NSCLC), but are only visible when large enough. Therapeutic decisions such as whole brain radiation therapy would benefit from patient-specific predictions of radiologically undetectable BMs. Here, we propose a mathematical modeling approach and use it to analyze clinical data of BM from NSCLC. Primary tumor growth was best described by a gompertzian model for the pre-diagnosis history, followed by a tumor growth inhibition model during treatment. Growth parameters were estimated only from the size at diagnosis and histology, but predicted plausible individual estimates of the tumor age (2.1-5.3 years). Multiple metastatic models were further assessed from fitting either literature data of BM probability (n = 183 patients) or longitudinal measurements of visible BMs in two patients. Among the tested models, the one featuring dormancy was best able to describe the data. It predicted latency phases of 4.4-5.7 months and onset of BMs 14-19 months before diagnosis. This quantitative model paves the way for a computational tool of potential help during therapeutic management.

The role of radiosurgery in the acute management of fourth ventricle compression due to brain metastases

Background:

Approximately 20–30% of all intracranial metastases are located in the posterior fossa. The clinical evolution hinges on factors such as tumor growth dynamics, local topographic conditions, performance status, and prompt intervention. Fourth ventricle (V4) compression with secondary life-threatening obstructive hydrocephalus remains a major concern, often requiring acute surgical intervention. We have previously reported on the application of adaptive hypofractionated Gamma Knife Radiosurgery in the acute management of critically located metastases, a technique known to us as rapid rescue radiosurgery (3R). We report the results of 3R in the management of posterior fossa lesions and ensuing V4 decompression.

Case Descriptions:

Four patients with V4 compression due to posterior fossa metastases were treated with 3R by three separate gamma knife radiosurgical sessions (GKRS) over a period of seven days. Mean V4 volume was 1.02 cm³ at GKRS 1, 1.13 cm³ at GKRS 2, and 1.12 cm³ at GKRS 3. Mean tumor volume during the week of treatment was 10 cm³ at both GKRS 1 and 2 and 9 cm³ at GKRS 3. On average, we achieved a tumor volume reduction of 52% and a V4 size increase of 64% at the first follow-up (4 weeks after GKRS 3). Long-term follow-up showed continued local tumor control, stable V4 volume, and absence of hydrocephalus.

Conclusion:

For this series, 3R was effective in terms of rapid tumor ablation, V4 decompression, and limited radiation-induced toxicity. This surgical procedure may become an additional tool in the management of intractable posterior fossa metastasis with V4 compression.

Methods and results of locoregional treatment of brain metastases in patients with non-small cell lung cancer

This article presents methods and results of surgery and radiotherapy of brain metastases from non-small cell lung cancer (BMF-NSCLC). Patients with single BMF-NSCLC, with Karnofsky score ≥ 70 and controlled extracranial disease are the best candidates for surgery. Stereotactic radiosurgery (SRS) is recommended in patients with 1-3 BMF-NSCLC below 3-3.5 cm, with minor neurological symptoms, located in parts of the brain not accessible to surgery, with controlled extracranial disease. Whole brain radiotherapy (WBRT) following SRS reduces the risk of local relapse; in selected patients median survival reaches more than 10 months. Whole brain radiotherapy alone is a treatment in patients with multiple metastases, poor performance status, uncontrolled extracranial disease, disqualified from surgery or SRS with median survival 3 to 6 months. There is no doubt that there are patients with BMF-NSCLC who should receive only the best supportive care. There is a debate in the literature on how to select these patients.

[Immunohistochemical hormonal mismatch and human epidermal growth factor type 2 [HER2] phenotype of brain metastases in breast cancer carcinoma compared to primary tumors]

INTRODUCTION

Phenotype changes between primary tumor and the corresponding brain metastases are recent reported data. Breast cancer, with biological markers predicting prognosis and guiding therapeutic strategy remains an interesting model to observe and evaluate theses changes. The objective of our study was to compare molecular features (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor type 2, [HER2]) between brain metastases and its primary tumor in patients presenting with pathologically confirmed breast cancer.

MATERIAL AND METHODS

This retrospective study was based on the immunohistochemical analysis of the brain metastases paraffin embedded samples stored in our institutional tumor bank, after surgical resection. The level of expression of hormonal receptors and HER2 on brain metastases were centrally reviewed and compared to the expression status in primary breast cancer from medical records.

RESULTS

Forty-four samples of brain metastases were available for analysis. Hormonal receptor modification status was observed in 11/44 brain metastases (25%) for ER and 6/44 (13.6%) for PR. A modification of HER2 overexpression was observed in brain metastases in 6/44 (13.6%). Molecular subtype modification was shown in 17 cases (38.6%). A significant difference was demonstrated between time to develop brain metastases in cases without status modification (HER2, ER and PR) (med=49.5months [7.8-236.4]) and in cases in which brain metastases status differs from primary tumor (med=27.5months [0-197.3]), (P=0.0244, IC95=3.09-51.62, Mann and Whitney test).

CONCLUSION

the main interest of this study was to focus on the molecular feature changes between primary tumor and their brain metastases. Time to develop brain metastases was correlated to phenotypic changes in brain metastases.

[Management of brain metastases for lung cancer patients]

Brain metastases from primary lung cancer represent 40% of all brain metastases. On the other hand, 10 to 80% of primary lung cancer patients will present with synchronous or metachronous brain metastases. Management of these patients is therefore a big challenge. The management will depend on the circumstances of diagnosis (symptomatic or not), the cancer history (synchronous or metachronous brain metastases), the histology and the number of lesions.