Brain metastasis in advanced colorectal cancer: Results from the South Australian metastatic colorectal cancer (SAmCRC) registry

Background

The SAmCRC registry has been enrolling patients since February 2006. Patterns of care have evolved leading to longer survival. Brain metastasis is considered rare in mCRC and surveillance imaging does not routinely include the brain. The reported rate ranges from 0.6% to 3.2%. We have analysed the SAmCRC registry to assess the frequency of brain metastasis in the SA population and the timing of presentation, which may guide the timing of appropriate surveillance assessments.

Methods

The SAmCRC registry was analysed to assess the number of patients presenting with brain metastasis during their lifetime. Patient characteristics are reported and overall survival was analysed using the K-M method.

Results

4100 patients have been entered into the registry between 2/2006 to 12/2015. The median age for all patients is 70.8 yrs (17.2-104.83), 43% female & where available 42% are KRAS exon 2 MT. Only 59 patients developed brain metastasis (1.4%). The clinical characteristics of those with brain metastasis are as follows; median age 65.3 yrs (range 37-87 yrs), 51% were female. Site of primary; 34% rectum, 36% left, 29% right, site of metastasis at presentation; 47% liver, 54% lung, 7% bone and 13.6% brain. Where KRAS was known, 55% had KRAS exon 2 MT. Prior surgery for metastatic disease: liver = 15 (25%), lung = 5 (8%), prior lines of chemotherapy (median 2, range (0-4). The median time to diagnosis of brain metastasis was 1.9 yrs (range 0-6 yrs). Thirty one (53%) had craniotomy performed and 93% had whole brain radiotherapy. The median survival from diagnosis of brain metastasis was 4.2 months (95% CI 2.9-5.5). If brain metastasis at initial diagnosis of mCRC are excluded, (n = 51) the median time to CNS metastasis is 2.05 years (range 0.3-6) and median survival is 3.8 moths (95%CI 2.0-5.7).

Conclusions

Results in a population setting confirm that brain metastasis are rare (1.4%) and the median time to development is 1.9 years. Patients with brain metastasis are younger, more likely female and KRAS MT which may allow patient selection for inclusion of CT Head imaging. Clinicians should be mindful of including imaging of brain in their surveillance protocol given the potential for surgical resection and stereotactic radiotherapy techniques.

Clinical trial identification

N/A

Legal entity responsible for the study

Flinders University

Funding

Flinders University, Haematology Oncology Unit TQEH

Disclosure

All authors have declared no conflicts of interest.