OBJECTIVEThe aim of this study was to analyze the clinical features and prognostic factors in patients with brain metastasis from colorectal cancer (CRC).

METHODSClinical materials of 45 colorectal cancer patients who developed brain metastasis were collected, and the data and follow-up data of those patients were retrospectively analyzed.

RESULTSMost brain metastases were from rectal cancer (64.4%), and 80.0% of the 45 cases had extracranial metastases. The most common extracranial metastatic site was the lung (57.8%), followed by the liver (35.6%). All the brain metastases in patients with liver metastases were supratentorial, while in contrast, 44.8% of the patients without liver metastasis had subtentorial metastasis, showing a significant difference between them (P<0.05). The interval time from diagnosis of CRC to the development of brain metastases in case of Dukes D stage was 12.0 months, significantly shorter than that in the cases of Dukes A stage (24.0 months), B (36.0 months) and C (29.0 months) (P<0.05). The interval time was also shorter in the patients who developed extracranial metastasis within one year than those more than one year (12.0 months vs. 38.0 months)( P<0.05). The median survival time of patients with brain metastasis from colorectal was 6.0 months, with a 1-year survival rate of 21.1% and 2-year survival rate of 3.3% only. Univariate analysis showed that the median survival of patients with a KPS score of ≥70 was 8.0 months, significantly higher than 2.0 months in those with a KPS score of <70 (P<0.05). The median survival of patients with one or two brain metastases was 8.0 months, significantly higher than 4.0 months of those with >2 brain metastases (P<0.05). The median survival time after diagnosis of brain metastasis was 4.0 months for those who received monotherapy (only steroids, only chemotherapy or only radiotherapy), significantly shorter than 10.0 months of patients who received chemoradiotherapy, and 12.0 months of those who underwent surgery (P<0.05). Comparing each two differently treated groups, the survival time of surgery combined with chemotherapy or radiotherapy group was significantly different from that of all of other groups (P<0.05). The median survival time of chemoradiotherapy group was longer than that of monotherapy, but the difference was not significant (P>0.05). Multivariate analysis showed that brain metastases >2 and treatment modality type are independent prognostic factors for survival.

CONCLUSIONSPatients initially diagnosed with a Dukes D stage primary colorectal tumor and occurrence of extracranial metastasis (especially, pulmonary metastasis) within one year are associated to an increased risk of brain metastases and have a shorter survival time. Most brain metastases in patients with liver metastases are supratentorial, while many patients without liver metastasis have subtentorial metastasis. Brain metastases >2 and the type of treatment modality are independent prognostic factors for survival. The prognosis of patients who received chemoradiotherapy is better than those treated only with chemotherapy or radiotherapy. Some subsets of patients may benefit from surgery plus chemotherapy/radiotherapy.