The future of targeted therapies for brain metastases

Local control and toxicity after stereotactic radiotherapy in brain metastases patients and the impact of novel systemic treatments

BACKGROUND AND PURPOSE

Treatment modalities for patients with brain metastases consist of surgery, radiotherapy, and systemic treatments such as immunotherapy and targeted therapy. Although much is known about local control of brain metastases after radiotherapy and surgery alone, more understanding is needed of the additional effect of new systemic treatments. Our study presents real-world data about the combined effects of different local and systemic treatment strategies on local response of irradiated brain metastases.

MATERIALS AND METHODS

We performed a retrospective consecutive cohort study of patients that presented with brain metastases in our institution between June 2018 and May 2020, reporting the impact of radiotherapy alone versus radiotherapy combined with systemic treatment on local control of irradiated brain metastases and toxicity. Chemotherapy and targeted therapy were temporarily discontinued around irradiation.

RESULTS

262 consecutively treated patients were included in the study. Median time to local failure of irradiated brain metastases was 18 months (IQR 9-34), median overall survival was 20 months (IQR 10-36). 211 (81 %) patients received systemic treatment. Patients with breast cancer had a worse local control (HR 2.3, 95 % CI 1.0-5.0, p = 0.038), as did patients without any systemic treatment (HR 2.1, 95 % CI 1.1-4.3, p = 0.034). Symptomatic radiation necrosis occurred in 36 (14 %) patients. A diameter > 2.5 cm was associated with a higher risk of radiation necrosis. No association was found between systemic treatment in combination with local radiotherapy and symptomatic radiation necrosis.

CONCLUSION

Patients who received any form of systemic treatment had better local control after stereotactic radiosurgery for brain metastases. We did not find an association between systemic treatment and the incidence of radiation necrosis.

Treatment modalities and relative survival in patients with brain metastasis from colorectal cancer

Standard treatment options for brain metastases (BM) from colorectal cancer (CRC) are controversial. The purpose of this study was to evaluate the efficacy of multidisciplinary treatment modalities and provide optimal therapeutic strategies for selected patients with different clinical characteristics. All eligible patients diagnosed with BM from CRC during the past two decades (1997-2016) were identified in our center. Clinical characteristics, treatment modalities and relative survival were retrospectively analyzed. Median overall survival after the identification of BM was 6 months. The 1- and 2- year survival rates were 29.40% and 5.70%, respectively. On multivariate analysis, the number of BMs, Karnofsky performance score and the treatment modalities were found to be independent prognostic factors (the p-value was 0.006, 0.001 and < 0.001, respectively). In conclusion, multidisciplinary treatment is supported to be the optimal treatment for patients with BM from CRC. For patients with single brain metastases and KPS > 70, neurosurgery combined with chemotherapy could provide an additional survival benefit. For patients with multiple brain metastases or KPS ≤ 70, radiotherapy plus chemotherapy may be appropriate.

Targeted Therapy in Brain Metastases: Ready for Primetime?

Brain metastasis is a serious complication of cancer that causes significant morbidity for patients. Over the last decade, numerous new driver somatic mutations have been recognized and targeted therapies are changing the landscape of treatment in lung cancer, breast cancer, and melanoma, which are also the three most common cancers that result in brain metastases. The common actionable mutations include the EGFR mutation and anaplastic lymphoma kinase (ALK) translocations in non-small cell lung cancer, the HER2 mutation in breast cancer, and the BRAF mutation in melanoma. However, most of the early trials with targeted agents excluded patients with brain metastases. With a better understanding of the biology, several recent trials of targeted therapy that focus on brain metastases have been reported and others are ongoing. Novel agents with better penetration across the blood-brain barrier are currently being investigated for patients with brain metastases. In this review, we discuss the current state of use and future directions of targeted therapies in brain metastases.