Comparison of Molecular-Genetic Concordance of the Primary Tumor and Brain Metastases of Colorectal Cancer

Brain metastases (BM) from colorectal cancer (CRC) are a rare event reported in less than 3% of patients with CRC (the reported incidence ranges from 0.27 to 3%). This course is associated with a poor prognosis. Treatment of these patients remains challenging. Nevertheless, given the rarity of the event, at this time not enough is known about molecular biology of BM from colorectal cancer and its concordance with matched primary tumors.

In N.N. Blokhin National Medical Research Center of Oncology over 26 years (1998-2024) identified 108 patients with BM from CRC. Of this number, 72 patients had a history of neurosurgical resection of BM. In turn, for 32 patients access to a pair of tumor samples: from the primary tumor and from intracranial metastases. Tumor samples will be tested for mutation status of genes KRAS, NRAS, BRAF, HER2 and MSI. Analysis was limited to this pool of genes because of their clinical relevance and potential prognostic information. The molecular profile of the BM will be compared with the corresponding primary tumor with calculation of concordance rate (%).