Abstract 101P
Background
Although the survival outcome of metastatic colorectal cancer (mCRC) has been improved by the development of new chemotherapies, identification of biomarkers, and availability of less invasive surgical procedures, metastasis to the brain and bone remains difficult to treatment, as these lesions are refractory to treatment. We aimed to identify the predictive and prognostic factors of bone and brain metastases in mCRC.
Methods
Patients who presented with bone or brain metastases of colorectal cancer at our hospital between 2010 and 2022 were retrospectively assessed. The risk factors for bone and brain metastasis and prognostic factors were analyzed using multivariate analysis. Biomarkers (RAS, BRAF, MSI), treatment interventions, the primary tumor histology, and number and symptoms of metastases were included as variables.
Results
Among 372 eligible patients with mCRC, 49 (13.2%) and 12 (3.2%) had bone and brain metastases, respectively. Of these, 19 bone metastases (38.8%) and 9 brain metastases (8.2%) were symptomatic. The median durations between the initial diagnosis of stage IV/recurrence and the detection of bone and brain metastases were 11.8 and 23.8 months, respectively. The median overall survival (OS) of patients with bone and brain metastases were 11.0 (95% confidence interval [CI] = 7.77–14.67) and 3.5 months (95% CI = 2.56–13.1). Multivariable analysis identified a rectal tumor location (vs. colon: odds ratio = 0.44, 95% CI = 0.21–0.92, p = 0.0297) as a risk factor for bone metastasis. Among patients with bone metastasis, the only identified poor prognostic factor for OS on multivariate analysis was multiple bone metastasis (hazard ratio = 3.2, 95% CI = 1.42–7.23, p = 0.0028). Meanwhile, no significant predictive or prognostic factors for brain metastases was detected, likely because of the small sample size. No examine biomarkers (RAS, BRAF, and MSI-H) were associated with prognosis in patients with brain or bone metastasis of mCRC.
Conclusions
Despite recent progress in multidisciplinary treatment for mCRC, the prognosis of mCRC with bone and brain metastases is still dismal. Further treatment development is warranted.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
K. Kataoka: Financial Interests, Personal, Invited Speaker: Merck Biopharma, Eli Lilly. All other authors have declared no conflicts of interest.