Background: Most patients with colorectal cancer (CRC) presenting with peritoneal carcinomatosis (PC) rely on palliative systemic treatment options. However, data on the use and effect of systemic treatment strategies, including targeted agents for the palliative treatment of colorectal PC, are lacking. We conducted a nationwide population-based study with data from the period in which the targeted agent bevacizumab was introduced in the Netherlands. Patients and Methods: The present study included all patients diagnosed from 2007 to 2014 with synchronous PC from CRC treated with only palliative systemic therapy. We assessed the use of bevacizumab, the standard choice of targeted treatment, in addition to first-line chemotherapy. Multivariable logistic regression analyses were performed to calculate the predictors for the additional prescription of bevacizumab. Survival estimates were calculated, and multivariable Cox analyses were performed to estimate the hazard ratios (HRs) of death stratified by the treatment received. Results: A total of 1235 patients received palliative chemotherapy, of whom 436 also received bevacizumab (35%). Patients aged ≥ 75 years and patients with PC from colonic tumors were less likely to receive chemotherapy plus bevacizumab. The addition of bevacizumab to palliative chemotherapy was associated with an improved overall median survival of 7.5 versus 11 months in both patients with isolated PC and those with concomitant extraperitoneal metastases. The improvement remained after adjustment for patient and tumor characteristics (HR, 0.7; 95% confidence interval, 0.64-0.83). Conclusion: The results of the present nationwide population-based study support the rationale for bevacizumab in addition to palliative chemotherapy for patients with PC of CRC and underline the need for ongoing efforts to precisely determine the role of targeted therapy in the treatment of PC.

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Keywords Colorectal cancer, Palliative systemic therapy, Peritoneal metastases, Synchronous, Targeted therapy
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Journal Clinical colorectal cancer
Razenberg, L.G.E.M, van Gestel, Y.R.B.M, Lemmens, V.E.P.P, de Hingh, I.H.J.T, & Creemers, G.J.M. (2016). Bevacizumab in Addition to Palliative Chemotherapy for Patients With Peritoneal Carcinomatosis of Colorectal Origin: A Nationwide Population-Based Study. Clinical colorectal cancer, 15(2), e41–e46. doi:10.1016/j.clcc.2015.12.006