Addition of Biological Therapies to Palliative Chemotherapy Prolongs Survival in Patients With Peritoneal Carcinomatosis of Colorectal Origin

Objectives: Combination chemotherapy regimens have shown promising results in patients with metastatic colorectal cancer. However, only very few studies have studied the effect of palliative chemotherapy in peritoneal carcinomatosis (PC) and no data are present incorporating biological therapies in the treatment of PC in colorectal cancer.

Methods: By means of merging with the regional Eindhoven Cancer Registry, all consecutive patients diagnosed with synchronous PC of colorectal origin since the year 2000 treated with palliative chemotherapy in our hospital were included. Data on chemotherapeutic agents used were collected retrospectively. The effect of biological therapies on survival was investigated.

Results: Fifty consecutive patients were included. Chemotherapeutic treatment consisted mainly of 5-fluorouracil-based chemotherapy with oxaliplatin. In 22 patients biological therapies were added. Overall survival was 12.5 months [95% confidence interval (CI), 9.2-15.5]. In patients receiving chemotherapy in combination with a biological therapy, overall survival was significantly prolonged as compared with those treated without (18.2 months, 95% CI, 9.5-27.0 vs. 10.1 mo, 95% CI, 6.2-14.1, respectively; P = 0.001). Prolongation of survival of patients receiving biological therapies in first-line treatment was even more pronounced, being 22.4 months (95% CI, 15.0-29.5). Similar effects were observed on progression-free survival.

Conclusions: Systemic chemotherapy, once regarded as futile in patients suffering from PC, resulted in an overall survival of 12 months in this unselected group of PC-patients. Addition of biological therapies in the first line of treatment prolonged overall survival to 22.4 months. Although the results of this small study should be interpreted with caution, this promising finding warrants further research.