Hypertension as a predictor of advanced colorectal cancer outcome and cetuximab treatment response

Background: Adrenergic receptor stimulation is involved in the development of hypertension (htn) and has been implicated in cancer progression and dissemination of metastases in various tumours, including colon cancer. Adrenergic antagonists such as beta-blockers (bbs) demonstrate inhibition of invasion and migration in colon cancer cell lines and have been associated with decreased mortality in colorectal cancer (crc). We examined the association of baseline htn and bb use with overall (os) and progression-free survival (pfs) in patients with pretreated, chemotherapy refractory, metastatic crc (mcrc). We also examined baseline htn as a predictor of cetuximab efficacy. Methods: Using data from the Canadian Cancer Trials Group co.17 study [cetuximab vs. best supportive care (bsc)], we coded baseline htn and use of anti-htn medications, including bbs, for 572 patients. The chi-square test was used to assess the associations between those variables and baseline characteristics. Cox regression models were used for univariate and multivariate analyses of os and pfs by htn diagnosis and bb use. Results: Baseline htn, bb use, and anti-htn medication use were not found to be prognostic for improved os. Baseline htn and bb use were not significant predictors of cetuximab benefit. Conclusions: In chemorefractory mcrc, neither baseline htn nor bb use is a significant prognostic factor. Baseline htn and bb use are not predictive of cetuximab benefit. Further investigation to determine whether baseline htn or bb use have a similarly insignificant impact on prognosis in patients receiving earlier lines of treatment remains warranted.