{'fraction_non_alphanumeric': 0.016992625841615903, 'fraction_numerical': 0.0032061558191728116, 'mean_word_length': 5.782608695652174, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Gastrointestinal oncological surgery in patients with metastatic cancer treated with angiogenesis inhibitors: safe or not?

The targeted molecular therapy agent, bevacizumab, is a recombinant humanized monoclonal antibody that selectively binds to and inhibit the activity of vascular endothelial growth factor (VEGF). This results in reduction in tumour angiogenesis and hence inhibits tumour proliferation (Fig. 1 depicts the mode of action of angiogenesis inhibitors). Following the results of its effectiveness on prolonging survival in phase III clinical trials, it is now recognized as the standard of care in the management of metastatic colorectal cancer and advanced non-small cell lung cancer. This drug has also demonstrated activity in epithelial ovarian cancer, renal cell carcinoma, oesophageal cancer, pancreatic cancer and glioblastoma multiforme, where off-label use have been in practice following early results from trials as approval from the authorities are being awaited. In Australia, this drug has recently been approved (July 2008) by the Pharmaceutical Benefits Advisory Committee for use in selected patients with metastatic colorectal cancer. Bevacizumab allows tumour downsizing and may make surgical resection a possibility. In addition, patients that respond to this drug may be good surgical candidates to undergo curative surgeries, as further use in the adjuvant setting post-operatively will allow derivation of the further benefits. However, for example, in metastatic colorectal cancer, curative surgery requires aggressive cytoreductive surgery. Gastrointestinal cytoreductive surgery often necessitates a large incision to allow adequate exposure of the abdomen and pelvis. During the surgical procedure, the exploratory process involves extensive tissue handling and adhesiolysis to facilitate access to the tumour mass. Aggressive resection often involves liver resection, multiple bowel resections, retroperitoneal lymphadenectomy or stripping of the diseased peritoneum. In patients who are nonresponders or have progressive disease, palliative surgery may be required to improve the quality of the life via bypass procedures, debulking of tumour mass and insertion of feeding tubes. All these procedures are already morbid in themselves, and the added risk of further morbidity from the toxic effects of bevacizumab in the surgical setting has not been adequately explored in the literature and needs to be considered. The overall incidence and rates of toxic complications from bevacizumab in clinical trials are similar when compared with that of current chemotherapy regimens. However, there is a greater risk of grade 3 hypertension and grade 1 or 2 proteinuria, a slightly higher occurrence of grade 3 or 4 bleeding, and impaired surgical wound healing in patients who undergo surgery during treatment with bevacizumab. In addition, potentially life-threatening events such as arterial thrombotic events and gastrointestinal perforation have occurred in a minority of patients. These serious complications of gastrointestinal perforation, wound healing complications and