Impact of Whole Cranium Radiotherapy on Survival in Patients with Brain Metastasis of Different Cancers: Descriptive Study

Abstract

Brain metastases (BMs) are the most common intracranial brain tumor and a common complication of systemic cancer. The incidence ranges from 20% - 40% of all patients diagnosed with cancer. The most common primary site is the lung followed by breast. Metastatic brain tumors outnumber primary brain tumors by a factor of 10 - 1, The prognosis of BMs is poor and the impact on the patient’s quality of life is important as a result of the functional neurologic deficits associated. The mainstay of treatment for BMs has been corticosteroids and whole brain radiotherapy. The aim of the study is to determine the impact of whole cranium irradiation gray (Gy) (2000 cGy) on median and mean survival of BMs and to analyze prognostic factors affecting survival of patients receiving whole brain irradiation. This study retrospectively reviewed the records of 80 patients with BMs who were not eligible for surgical resection and who underwent whole-brain radiation (WBRT) in Baghdad oncology teaching hospital between 1st of July 2015 and 1st of January 2017. About 47 patients were diagnosed as primary breast cancer, 20 patients as primary lung cancer and 13 patients from other site of body. All patients were treated with conventional external beam radiotherapy with a total dose of 20 Gy in five fractions over 1 week for all patients. Breast cancer represented the most common primary cancer type 47 patients (58.8%), followed by lung cancer 20 patients (25%), other types of primary care represent 13 patients (16.3%), The median survival for the total population who were receiving WBRT was 7 months, and mean survival was 9.8 months. For breast cancer the median survival time was 8 months, for lung cancer patients it was 6 months and for primary metastasis from other sites of body was 6 months. In general, the result is that patients with breast cancer had better survival than patients with other primary cancers. In regard of time to develop to BMs, median time for breast cancer, lung cancer and for other sites (22, 5, and 12 months) respectively. Breast cancer has the longest time before BMs. According to the stage of primary breast tumor. The highest frequency was seen among patients with T3A followed by T2B and T3B respectively, while the lowest frequency with T1B. Our study reported a strong correlation between the tumor stage and time to BMs with significant (p = 0.033). In regards of primary breast cancer metastasis, the results showed that human epidermal growth factor receptor 2 (HER2) overexpressed was 19 patients (40.4%), Triple negative were 10 patients (21.3%), luminal A-like were 9 patients (19.1%) and luminal B-like were 9 patients (19.1%). The highest frequency was seen among patients with HER2 overexpressed followed by triple negative. Our results showed a negative correlation between the molecular subtypes and time to develop of BMs with p value = 0.482 which was statistically not significant. WBRT is generally the treatment of choice, demonstrated an increase in median overall survival (OS) from 1 month with no treatment to 5 - 8 months following WBRT, primary breast cancer patients represent best OS 8 months compare to lung 6 months and other types 6 months, metastases to the brain and survivals depending on biological subtype, median survival is shortest among patients with triple-negative breast cancer. Although patients with HER2-positive tumors have higher rates of BMs.