title: Tumor characteristics and metastatic sites may predict bevacizumab efficacy in the first-line treatment of metastatic colorectal cancer.
abstract: Colorectal cancer (CRC) is among the most frequently diagnosed cancers and a major cause of cancer-related mortality worldwide. The aim of the present study was to determine whether there was an improvement in the time to disease progression (TTP) in patients with metastatic colorectal cancer (mCRC) treated with first-line bevacizumab plus chemotherapy, according to tumor characteristics and metastatic sites. Tumor characteristics and tumor burden were considered to be predictive markers of the therapeutic efficacy of bevacizumab. The medical records of 705 patients with mCRC were retrospectively reviewed in three oncology centers between January, 2005 and September, 2012. A total of 101 patients completed their first-line bevacizumab-containing treatment. The median TTP was 6.93 months [interquartile range (IQR)=4.20-9.80 months] in patients treated with irinotecan, 5-fluorouracil (5-FU) and bevacizumab vs. 7.42 months (IQR=6.08-10.68 months) in those treated with oxaliplatin, 5-FU and bevacizumab (P=0.589). When we compared patients with pulmonary metastases (median TTP, 9.9000 months) or other metastatic patients without pulmonary metastasis (median TTP, 6.9000 months), we observed a statistically significant difference (P=0.046). However, when the efficacy of bevacizumab was compared in terms of other tumor characteristics (tumor grade, size and lymph node involvement) and metastatic sites, the differences were not significant (P>0.05). We concluded that bevacizumab may be effective in all subgroups of patients with mCRC. Furthermore, bevacizumab with combination chemotherapy may be superior to combination chemotherapy only as the first-line treatment of patients with mCRC and pulmonary metastasis.
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Ege University, Bornova, Izmir;
authors.forename: Umut
authors.initials: U
authors.lastname: Varol
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Adnan Menderes University, Aydın;
authors.forename: Esin
authors.initials: E
authors.lastname: Oktay
authors.affiliation: Department of Medical Oncology, Antalya Research and Training Hospital, Antalya;
authors.forename: Mustafa
authors.initials: M
authors.lastname: Yildirim
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Ege University, Bornova, Izmir;
authors.forename: Zeki Gokhan
authors.initials: ZG
authors.lastname: Surmeli
authors.affiliation: Department of Medical Oncology, Izmir Ataturk Research and Training Hospital, Bornova, Izmir, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Dirican
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Adnan Menderes University, Aydın;
authors.forename: Nezih
authors.initials: N
authors.lastname: Meydan
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Ege University, Bornova, Izmir;
authors.forename: Burcak
authors.initials: B
authors.lastname: Karaca
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Ege University, Bornova, Izmir;
authors.forename: Bulent
authors.initials: B
authors.lastname: Karabulut
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology, Faculty of Medicine, Ege University, Bornova, Izmir;
authors.forename: Ruchan
authors.initials: R
authors.lastname: Uslu
keywords: bevacizumab; colorectal cancer; metastasis; tumor characteristics