Brain Metastases from Colorectal Cancer: A Systematic Review of the Literature and Meta-Analysis to Establish a Guideline for Daily Treatment

Abstract

Colorectal cancer (CRC) is the third most common malignancy worldwide. Most patients with metastatic CRC develop liver or lung metastases, while a minority suffer from brain metastases. There is little information available regarding the presentation, treatment, and overall survival of brain metastases (BM) from CRC. This systematic review and meta-analysis includes data collected from three major databases (PubMed, Cochrane, and Embase) based on the key words “brain”, “metastas*”, “tumor”, “colorectal”, “cancer”, and “malignancy”. In total, 1318 articles were identified in the search and 86 studies matched the inclusion criteria. The incidence of BM varied between 0.1% and 11.5%. Most patients developed metastases at other sites prior to developing BM. Lung metastases and KRAS mutations were described as risk factors for additional BM. Patients with BM suffered from various symptoms, but up to 96.8% of BM patients were asymptomatic at the time of BM diagnosis. Median survival time ranged from 2 to 9.6 months, and overall survival (OS) increased up to 41.1 months in patients on a multimodal therapy regimen. Several factors including age, blood levels of carcinoembryonic antigen (CEA), multiple metastases sites, number of brain lesions, and presence of the KRAS mutation were predictors of OS. For BM diagnosis, MRI was considered to be state of the art. Treatment consisted of a combination of surgery, radiation, or systemic treatment.

Survival Outcome of Surgical Resection vs. Radiotherapy in Brain Metastasis From Colorectal Cancer: A Meta-Analysis

“…In a recently published systematic review ( 45 ), Müller et al included 86 articles to investigate the incidence, symptoms, diagnosis, treatment, and prognosis of CRC BM. Although it provided a comprehensive perspective regarding CRC BM, the inclusion criteria were not clearly defined in their method.…”

A rare case of colon cancer metastasis to the brain and a brief review of its treatment and prognosis

“…The vast majority of patients with brain metastases are asymptomatic at the time of diagnosis. In those with symptoms, gait disturbance, altered mental status, neurological symptoms, epileptic seizures, and signs of intracranial pressure are common symptoms [ 4 , 6 ]. Our patient experienced left upper and lower extremity neurological symptoms prior to his fall which led to the discovery of metastatic disease to his brain.…”

“…Up to 90% of patients with brain metastases have other sites of metastases at the time of diagnosis, most commonly in the liver and lungs [5] . In particular, lung and bone metastases have been shown to be independent risk factors for the development of brain metastases, both of which were present in this patient [ 4 , 7 ]. KRAS mutation, high CEA level, and cancer localized to the rectum are additional risk factors for brain metastases [4] .…”

“…Common sites of metastasis include regional lymph nodes, liver, lung, and peritoneum [3] . Brain metastases are rare, with reported incidences ranging from 0.1% to 11.5%, and an average incidence of 2.1% [4] . We present a case of a patient with a history of colon cancer who presents with a brain mass.…”

Brain Metastasis in a Young Patient: Consider the Rectum

“…The incidence of brain metastasis at the initial diagnosis of colorectal cancer is 1.38% with a median survival of four months [ 9 ]. Moreover, a recent metanalysis and systemic review of brain metastasis in colorectal cancer recommended MRI imaging of the brain if a patient with colorectal cancer had any neurological symptoms or risk factors for brain metastases such as the presence of lung metastases, KRAS mutation, high carcinoembryonic antigen (CEA) level, or rectal cancer [ 10 ]. The rising incidence of early-onset colorectal cancer, which are characterized by poorer cell differentiation, more advanced stage at diagnosis, as well as more often having a left-sided colon primary tumor [ 11 ], is one of the primary reasons the U.S. Preventative Task Force updated their recommendation to start colorectal cancer screening from age 45 [ 12 ], instead of waiting till age 50.…”