Combination of Modern Radiotherapy and New Targeted Treatments for Breast Cancer Management

Background: The objective of the present study was to review the essential knowledge about the combinations of the most commonly used or under development targeted treatments and radiation therapy (RT). Methods: Preclinical and clinical studies investigating this combination were extensively reviewed. Results: Several studies showed that the combination of RT and tamoxifen increased the risk of radiation-induced pulmonary toxicity; therefore, both modalities should not be given concomitantly. The combination of HER2 inhibitors (trastuzumab, pertuzumab) and RT seems to be safe. However, trastuzumab emtansine (T-DM1) should not be administered concurrently with brain RT since this combination could increase the risk of brain radionecrosis. The combination of RT and other new target treatments such as selective estrogen receptor degradants, lapatinib, cell cycle inhibitors, immune checkpoint inhibitors, or molecules acting on DNA damage repair seems feasible but was essentially evaluated on retrospective or prospective studies with a small number of patients. Furthermore, there is considerable heterogeneity among these studies regarding the dose and fractionation of radiation, the dosage of drugs, and the sequence of treatments used. Conclusions: The combination of RT with most targeted therapies for BC appears to be well-tolerated, but these results need to be confirmed in prospective randomized studies.

Brain radionecrosis after radiation therapy for atypical meningioma

Introduction. Atypical Meningioma (AM) is at high risk of local failure. The role of radiation therapy (XRT) as an adjuvant to surgical resection is incompletely defined. The most deleterious consequence of brain-directed XRT is radiation necrosis. Brain radionecrosis (BRN) after AM has been rarely reported. The relevant literature is reviewed, highlighting its diagnostic challenges. Case Presentation. We report a 25-year-old male with a BRN after adjuvant XRT for AM, which has been misdiagnosed as a recurrent neoplastic lesion upon magnetic resonance spectroscopy (MRS) examination. Surgery and histopathological description were made and yielded a definitive diagnosis of BRN. The patient was treated by dexamethasone with concomitant hyperbaric oxygen therapy (HBO2). The patient showed a further progression of the disease. Therefore, he was elected to receive bevacizumab. However, the patient finally died for refractory brain edema. Conclusion. BRN is a relatively rare instance after XRT for AM. There is no single modality that can reliably distinguish BRN from tumour recurrence. Therefore, reaching an early prompt treatment decision is challenging.

Bevacizumab for the treatment of brain radionecrosis in cancer patients.

e19352 Background: Brain radionecrosis (BRN) occurs as a result of radiation therapy for brain tumors or metastatic brain lesions. BRN is characterized by an increase in permeability and disruption of the blood-brain barrier (BBB). There are currently no standard treatment options for BRN. While the mechanism of BRN is unknown, it is hypothesized that there is an inflammatory reaction of the local tissue to radiation which results in a continuous process involving endothelial cell dysfunction. This leads to tissue hypoxia and increased vascular endothelial growth factor (VEGF) which in turn causes capillary leakage, progressive BBB dysfunction, and cerebral edema. Bevacizumab (BEV), a humanized monoclonal antibody with action against VEGF, has recently been used in some studies for the treatment BRN. BEV essentially blocks VEGF from reaching its targets on the endothelium, thus making it an ideal treatment modality for BRN. Methods: The primary purpose of this study is to assess the effectiveness and safety of BEV for the treatment of BRN. Fifteen patients (pts), 14 diagnosed with lung cancer and one with breast cancer, that had BRN and treated with BEV between January 2014 and November 2019 were identified from Memorial Cancer Institute's database. A retrospective chart review analyzing pts's age, sex, BEV dose, dosing frequency, number of treatments received, medication-related adverse effects, and clinical benefit was conducted. Brain imaging pre-treatment and after four cycles of therapy were compared to assess the efficacy of BEV. Pts who exhibited clinical benefit (complete response (CR), partial response (PR), or stable disease (SD)) received an additional four cycles of treatment. Results: The median age was 65 years (y) (49-78y) and 10/15 (67%) of pts were female. Clinical benefit was achieved in 13/15 (87%) of pts. The most frequent dosing regimen administered was 10 mg/kg every two weeks and the median number of cycles given was eight cycles (1-12). Treatment with BEV was well tolerated with eight pts (53%) experiencing BEV-related Grade 2 or less adverse effects (AE), including hypertension (27%), proteinuria (13%), thrombocytopenia (7%), and mild nose bleeds (7%). There were no Grades 3-5 AE. Conclusions: This study demonstrates that there is a clinical benefit when administering BEV for the treatment of BRN. BEV was well tolerated and has an acceptable safety profile.