Neoadjuvant bevacizumab persistently inactivates VEGF at the time of surgery despite preoperative cessation

A prospective single-center, single-arm, open-label, phase II study of sintilimab and anlotinib combined with chemotherapy in neoadjuvant treatment of resectable esophageal cancer

BACKGROUND

Antiangiogenic treatment and immunochemotherapy effectively treat patients with advanced esophageal cancer. However, there remains a dearth of studies concerning neoadjuvant therapy for resectable esophageal cancer.

METHODS

The study focused on patients with T2-4NxM0 resectable esophageal carcinoma. Neoadjuvant treatment involved administering anlotinib (10 mg orally, once a day, 2 weeks on and 1 week off) for antiangiogenesis and sintilimab (200 mg) and chemotherapy for three cycles. Surgical treatment was performed 4-6 weeks after the last chemotherapy cycle was completed. The primary endpoints assessed were pathological complete response (pCR) and safety.

RESULTS

Out of the 34 screened patients, 17 were successfully enrolled in the study, and 14 completed the entire treatment process. The pCR was 35.3% (6/17). However, two patients experienced mortality. The occurring rate of grade 3 or higher complications after the surgery was 78.6% (11/14) according to Clavien-Dindo classification. Specifically, anastomotic leakage was observed in 57.1% (8/14) of the patients.

CONCLUSION

Compared to neoadjuvant chemotherapy, the current regimen demonstrated improved pCR. However, it did not show significant improvement compared to immunochemotherapy. It is essential to exercise caution when using this treatment approach in patients with esophageal cancer as it might increase postoperative complications, especially anastomotic leakage.

Antiangiogenic exclusion rules in glioma trials: Historical perspectives and guidance for future trial design

Background

Despite the lack of proven therapies for recurrent high-grade glioma (HGG), only 8%-11% of patients with glioblastoma participate in clinical trials, partly due to stringent eligibility criteria. Prior bevacizumab treatment is a frequent exclusion criterion, due to difficulty with response assessment and concerns for rebound edema following antiangiogenic discontinuation. There are no standardized trial eligibility rules related to prior antiangiogenic use.

Methods

We reviewed ClinicalTrials.gov listings for glioma studies starting between May 2009 and July 2022 for eligibility rules related to antiangiogenics. We also reviewed the literature pertaining to bevacizumab withdrawal.

Results

Two hundred and ninety-seven studies for patients with recurrent glioma were reviewed. Most were phase 1 (n = 145, 49%), non-randomized (n = 257, 87%), evaluated a drug-only intervention (n = 223, 75%), and had a safety and tolerability primary objective (n = 181, 61%). Fifty-one (17%) excluded participants who received any antiangiogenic, one (0.3%) excluded participants who received any non-temozolomide systemic therapy. Fifty-nine (20%) outlined washout rules for bevacizumab (range 2-24 weeks, 4-week washout n = 35, 12% most common). Seventy-eight required a systemic therapy washout (range 1-6 weeks, 4-week washout n = 34, 11% most common). Nine permitted prior bevacizumab use with limitations, 18 (6%) permitted any prior bevacizumab, 5 (2%) were for bevacizumab-refractory disease, and 76 (26%) had no rules regarding antiangiogenic use. A literature review is then presented to define standardized eligibility criteria with a 6-week washout period proposed for future trial design.

Conclusions

Interventional clinical trials for patients with HGG have substantial heterogeneity regarding eligibility criteria pertaining to bevacizumab use, demonstrating a need for standardizing clinical trial design.

Mortality of patients with metastatic colorectal cancer who received elective or emergent operation after exposure to bevacizumab: A nationwide database study

INTRODUCTION

Treatment guidelines for colorectal cancer (CRC) indicate that surgical intervention within 4 weeks or 8 weeks after bevacizumab therapy might increase the risk of postoperative complications and mortality, especially in patients who received emergent operation. Therefore, we aimed to assess the association between different surgical timings, emergent or elective surgery, and the risk of postoperative mortality.

MATERIALS AND METHODS

Using the Taiwan National Health Insurance Database and Taiwan Cancer Registry, we identified patients with metastatic colorectal cancer (mCRC) who underwent surgery within 1 year of receiving bevacizumab between January 2010 and December 2017. The primary outcomes were 30-day, 60-day, and in-hospital mortality; the secondary outcomes were hospital stay, 30-day readmission rate, and surgical complications. Multivariate analysis was used to adjust for confounders.

RESULTS

This study included 2,047 patients. In the multivariate analysis, patients who underwent emergent operation and had higher Charlson scores had a significantly higher mortality rate. Patients with a longer interval to surgery, more cycles of bevacizumab treatment, and distal metastectomy had the opposite result. In subgroup analysis, patients who received emergent operation within 28 days had the highest surgical mortality.

CONCLUSIONS

The interval to operation among mCRC patients who receive bevacizumab treatment should exceed 4 weeks to avoid additional risk of mortality whether patients receiving elective or emergent operation. Patients who received emergent operation within 28 days of bevcizumab infusion had the highest risk of mortality.

Inhibition of Vascular Endothelial Growth Factor Protects against the Development of Oxaliplatin-Induced Sinusoidal Obstruction Syndrome in Wild-Type but Not in CD39-Null Mice

(1) Background: Sinusoidal obstruction syndrome (SOS) after oxaliplatin-based chemotherapy is associated with unfavorable outcomes after partial hepatectomy for colorectal liver metastases (CLM). Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), may prevent SOS development. We investigated the impact of VEGF-inhibition on the development of SOS in a murine model. (2) Methods: Male wild-type and CD39-null mice received oxaliplatin, additional anti-VEGF (OxAV), or controls, and were sacrificed or subjected to major partial hepatectomy (MH). Specimen were used for histological analysis of SOS. Liver damage was assessed by plasma transaminases. The VEGF pathway was elucidated by quantitative PCR of liver tissue and protein analysis of plasma. (3) Results: Mice treated with oxaliplatin developed SOS. Concomitant anti-VEGF facilitated a reduced incidence of SOS, but not in CD39-null mice. SOS was associated with increased plasma VEGF-A and decreased hepatocyte growth factor (HGF). After OxAV treatment, VEGF-R2 was upregulated in wild-type but downregulated in CD39-null mice. Oxaliplatin alone was associated with higher liver damage after MH than in mice with concomitant VEGF-inhibition. (4) Conclusions: We established a murine model of oxaliplatin-induced SOS and provided novel evidence on the protective effect of VEGF-inhibition against the development of SOS that may be associated with changes in the pathway of VEGF and its receptor VEGF-R2.

Wound fluid sampling methods for proteomic studies: A scoping review

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

ELISA detection of MPO-DNA complexes in human plasma is error-prone and yields limited information on neutrophil extracellular traps formed in vivo

Over the past years, neutrophil extracellular traps (NETs) were shown to contribute to states of acute and chronic inflammatory disease. They are composed of expelled chromatin and decorated by neutrophil-derived proteins. Therefore, the analysis of DNA complexes with myeloperoxidase (MPO) by ELISA has become an attractive tool to measure NET formation in in vitro and in vivo samples. When we used a published MPO-DNA ELISA protocol and included an isotype control for the anti-MPO coating antibody, we observed high assay specificity for in vitro prepared NET samples, whereas the specificity for in vivo plasma samples was low. In addition, the assay failed to detect in vitro generated MPO-DNA complexes when spiked into plasma. Therefore, we set out to improve the specificity of the MPO-DNA ELISA for plasma samples. We found that the use of Fab fragments or immunoglobulins from different species or reversal of the antibody pair led to either a high background or a low dynamic range of detection that did not improve the specificity for plasma samples. Also, the use of higher plasma dilutions or pre-clearing of plasma immunoglobulins were ineffective. Finally, we found that a commercial reagent designed to block human anti-mouse antibodies and multivalent substances increased the detection window between the MPO antibody and isotype control for highly diluted plasma. We applied this modified ELISA protocol to analyze MPO-DNA complexes in human blood samples of acute and chronic inflammatory conditions. While markers of neutrophil activation and NET formation such as MPO, elastase and citrullinated histone H3 correlated significantly, we observed no correlation with the levels of MPO-DNA complexes. Therefore, we conclude that ELISA measurements of MPO-DNA complexes in human plasma are highly questionable regarding specificity of NET detection. In general, plasma analyses by ELISA should more frequently include isotype controls for antibodies to demonstrate target specificity.

Anti-vascular endothelial growth factor antibody monotherapy causes destructive advanced periodontitis in rice rats (Oryzomys palustris)

OBJECTIVE

Angiogenesis inhibitors (AgI) are commonly used in combination chemotherapy protocols to treat cancer, and have been linked to osteonecrosis of the jaw (ONJ). However, it is unknown if AgI therapy alone is sufficient to induce ONJ. We have previously established an ONJ model in rice rats with localized periodontitis that receive zoledronic acid (ZOL). The purpose of this study was to use this model to determine the role of anti-vascular endothelial growth factor A (anti-VEGF) antibody treatment of rice rats with localized maxillary periodontitis. We hypothesized that rice rats with localized maxillary periodontitis given anti-VEGF monotherapy will develop oral lesions that resemble ONJ, defined by exposed, necrotic alveolar bone.

METHODS

At age 4 weeks, 45 male rice rats were randomized into three groups (n = 15): 1) VEH (saline), 2) ZOL (80 μg/kg body weight, intravenously once monthly), and 3) anti-VEGF (5 mg B20-4.1.1/kg body weight, subcutaneously twice weekly). After 24 weeks, rats were euthanized, jaws were excised and a high-resolution photograph of each quadrant was taken to assign a severity grade based on gross appearance. Jaws were then fixed, scanned by MicroCT, decalcified and sectioned for histopathologic and immunohistochemical analyses.

RESULTS

40-80% of the rats in the three groups developed gross oral lesions. 50% of ZOL rats developed ONJ. In contrast, 80% of the anti-VEGF rats developed destructive advanced periodontitis that was characterized by extreme alveolar bone loss and fibrosis. Anti-VEGF rats never developed exposed, necrotic bone. Furthermore, only anti-VEGF rats developed mild to severe mandibular periodontitis. Compared to VEH rats, more T-cells were found in periodontal lesions of anti-VEGF rats and more cells of the monocyte lineage were found in ONJ lesions of ZOL rats.

CONCLUSIONS

Anti-VEGF monotherapy administered to a validated rodent model of ONJ caused a destructive advanced form of periodontitis that differed significantly from ONJ.

Bevacizumab Allows Preservation of Liver Function and its Regenerative Capacity after Major Hepatectomy

BACKGROUND

Parallel to the safety of liver resections, new chemotherapy drugs have emerged for the control of liver metastases. However, there is unclear evidence about the combination of intensive BVZ-therapy and extended resections. The main aim was to analyse the impact of Bevacizumab (BVZ) in terms of liver safety and tolerability in two experimental models: a basal-toxicity situation and after major hepatectomy.

METHODS

Eighty male-Wistar rats were grouped as toxicity analysis (sham-operated rats-OS-) and regeneration after- surgery analysis (hepatectomy rats-H-). Eight further subgroups were created according to sacrifice (6- hours-6h- or 24-hours-24h-) and dose (μg) of BVZ (none, 100, 200, 400). Several measurements were performed, including biochemical serum samples, histopathological analysis, cytokines (IL-6, TNF-α, TGF-β), oxidative-stress (GSH/GSSG, ATP), lipid-peroxidation (TBARS) and epidermal and vascular endothelium growth-factors (EGF and VEGF).

RESULTS

In the toxicity analysis, safe results with BVZ were observed, with no significant differences among the groups. A trend towards a lower oxidative status was observed in the OS 6 h-100, -200 and -400 versus the OS 6 h-none group. Similar results were observed in the hepatectomy model, with stable oxidative-stress-index and IL-6, TNF- α, and TGF- β levels. Despite higher lipid peroxidation status, overall regeneration was preserved. As expected, VEGF was almost undetectable in BVZ-treated groups after resection, but not in the non-resection group.

CONCLUSION

It was concluded that liver status was not impaired by BVZ even at the high-dose. Similarly, liver regeneration after extended hepatectomy in BVZ-treated animals was well-preserved. Extended liver resections may be encouraged in BVZ-treated patients due to its excellent tolerability and good liver regeneration status.

A Population-Based Study of Complications After Colorectal Surgery in Patients Who Have Received Bevacizumab

BACKGROUND

Patients receiving Bevacizumab, a vascular endothelial growth factor inhibitor used to treat metastatic colorectal cancer, may be at greater risk of complications after colorectal surgery because of impaired healing.

OBJECTIVE

The purpose of this study was to describe population-based rates of complications of colorectal surgery after Bevacizumab treatment and evaluate the relationship between time since last treatment and risk of complications.

DESIGN

This was a population-based retrospective cohort study using administrative and cancer registry data.

SETTINGS

The study was conducted in Ontario, Canada.

PATIENTS

Patients with metastatic colorectal cancer receiving Bevacizumab between January 2008 and December 2011 were followed for a year after treatment or until death.

MAIN OUTCOME MEASURES

Administrative data were used to identify patients who underwent colorectal surgery after initiation of Bevacizumab and to determine whether they experienced a complicated postoperative course. The relationship between time since last Bevacizumab treatment (≤28 d, 29 d to 3 mo, and >3 mo) and risk of postoperative complications was evaluated using logistic regression.

RESULTS

Of the 2759 patients who received Bevacizumab for the treatment of metastatic colorectal cancer, 265 underwent a colorectal procedure after exposure. The majority had a bowel resection or repair with no stoma (47.5%) and had emergency surgery (61.1%). Overall, 96 (36.2%) had a complicated postoperative course, including 20.4% readmission, 12.5% wound complications, and 7.9% mortality rate within 30 days of surgery. Adjusted multivariate analysis showed no difference in the likelihood of a complicated postoperative course among patients undergoing surgery within 28 days of receiving their last Bevacizumab dose compared with 29 days to 3 months (OR = 1.23 (95% CI, 0.53-2.84), or 3 to 12 months (OR = 0.98 (95% CI, 0.46-2.09) after receiving Bevacizumab.

LIMITATIONS

Reliance on administrative data to measure complications limited the scope of this study.

CONCLUSIONS

Patients with metastatic colorectal cancer requiring colorectal surgery after exposure to Bevacizumab experience substantial morbidity and mortality. The risk of complications is not detectably associated with time since exposure. See Video Abstract at http://links.lww.com/DCR/A474.

The VEGF rise in blood of bevacizumab patients is not based on tumor escape but a host-blockade of VEGF clearance

Vascular endothelial growth factor (VEGF) has become a major target in cancer treatment as it promotes tumor angiogenesis. Therapy with anti-VEGF antibody bevacizumab reportedly induces high levels of circulating VEGF which may potentially contribute to resistance. Based on animal or computational models, mechanisms of VEGF induction by bevacizumab have been proposed but not verified in the clinical setting. Hence, we evaluated sixty patients with colorectal cancer metastases for changes in plasma VEGF during neoadjuvant/conversion and adjuvant chemotherapy with or without bevacizumab. VEGF expression was assessed in tissue sections of liver metastases. The VEGF source was investigated with in vitro cultures of tumor, endothelial cells, fibroblasts and platelets, and potential protein stabilization due to anti-VEGF therapy was addressed. A VEGF rise was observed in blood of bevacizumab patients but not in chemotherapy controls, and VEGF was found to be largely complexed by the antibody. A comparable VEGF increase occurred in the presence (neoadjuvant) and absence of the tumor (adjuvant). Accordingly, VEGF expression in tumor tissue was not determined by bevacizumab treatment. Investigations with isolated cell types did not reveal VEGF production in response to bevacizumab. However, antibody addition to endothelial cultures led to a dose-dependent blockade of VEGF internalization and hence stabilized VEGF in the supernatant. In conclusion, the VEGF rise in cancer patients treated with bevacizumab is not originating from the tumor. The accumulation of primarily host-derived VEGF in circulation can be explained by antibody interference with receptor-mediated endocytosis and protein degradation. Thus, the VEGF increase in response to bevacizumab therapy should not be regarded as a tumor escape mechanism.

Peri-operative chemotherapy with or without bevacizumab in operable oesophagogastric adenocarcinoma (UK Medical Research Council ST03): primary analysis results of a multicentre, open-label, randomised phase 2-3 trial

BACKGROUND

Peri-operative chemotherapy and surgery is a standard of care for patients with resectable oesophagogastric adenocarcinoma. Bevacizumab, a monoclonal antibody against VEGF, improves the proportion of patients responding to treatment in advanced gastric cancer. We aimed to assess the safety and efficacy of adding bevacizumab to peri-operative chemotherapy in patients with resectable gastric, oesophagogastric junction, or lower oesophageal adenocarcinoma.

METHODS

In this multicentre, randomised, open-label phase 2-3 trial, we recruited patients aged 18 years and older with histologically proven, resectable oesophagogastric adenocarcinoma from 87 UK hospitals and cancer centres. We randomly assigned patients 1:1 to receive peri-operative epirubicin, cisplatin, and capecitabine chemotherapy or chemotherapy plus bevacizumab, in addition to surgery. Patients in the control group (chemotherapy alone) received three pre-operative and three post-operative cycles of epirubicin, cisplatin, and capecitabine chemotherapy: 50 mg/m2 epirubicin and 60 mg/m2 cisplatin on day 1 and 1250 mg/m2 oral capecitabine on days 1-21. Patients in the investigational group received the same treatment as the control group plus 7·5 mg/kg intravenous bevacizumab on day 1 of every cycle of chemotherapy and for six further doses once every 21 days following chemotherapy, as maintenance treatment. Randomisation was done by means of a telephone call to the Medical Research Council Clinical Trials Unit, where staff used a computer programme that implemented a minimisation algorithm with a random element to establish the allocation for the patient at the point of randomisation. Patients were stratified by chemotherapy centre, site of tumour, and tumour stage. The primary outcome for the phase 3 stage of the trial was overall survival (defined as the time from randomisation until death from any cause), analysed in the intention-to-treat population. Here, we report the primary analysis results of the trial; all patients have completed treatment and the required number of primary outcome events has been reached. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN 46020948, and with ClinicalTrials.gov, number NCT00450203.

FINDINGS

Between Oct 31, 2007, and March 25, 2014, 1063 patients were enrolled and randomly assigned to receive chemotherapy alone (n=533) or chemotherapy plus bevacizumab (n=530). At the time of analysis, 508 deaths were recorded (248 in the chemotherapy alone group and 260 in the chemotherapy plus bevacizumab group). 3-year overall survival was 50·3% (95% CI 45·5-54·9) in the chemotherapy alone group and 48·1% (43·2-52·7) in the chemotherapy plus bevacizumab group (hazard ratio [HR] 1·08, 95% CI 0·91-1·29; p=0·36). Apart from neutropenia no other toxic effects were reported at grade 3 or worse severity in more than 10% of patients in either group. Wound healing complications were more prevalent in the bevacizumab group, occurring in 53 (12%) patients in this group compared with 33 (7%) patients in the chemotherapy alone group. In patients who underwent oesophagogastrectomy, post-operative anastomotic leak rates were higher in the chemotherapy plus bevacizumab group (23 [10%] of 233 in the chemotherapy alone group vs 52 [24%] of 220 in the chemotherapy plus bevacizumab group); therefore, recruitment of patients with lower oesophageal or junctional tumours planned for an oesophagogastric resection was stopped towards the end of the trial. Serious adverse events for all patients included anastomotic leaks (30 events in chemotherapy alone group vs 69 in the chemotherapy plus bevacizumab group), and infections with normal neutrophil count (42 events vs 53).

INTERPRETATION

The results of this trial do not provide any evidence for the use of bevacizumab in combination with peri-operative epiribicin, cisplatin, and capecitabine chemotherapy for patients with resectable gastric, oesophagogastric junction, or lower oesophageal adenocarcinoma. Bevacizumab might also be associated with impaired wound healing.

FUNDING

Cancer Research UK, MRC Clinical Trials Unit at University College London, and F Hoffmann-La Roche Limited.

Liver surgery for metastatic colorectal cancer: the surgical oncologist perspective

Neoadjuvant/conversion chemotherapy has emerged as an indispensable tool to achieve resectability of initially unresectable metastatic colorectal cancer and improves oncological outcomes. In parallel, surgical strategy has adopted a more aggressive treatment approach to achieve complete tumor clearance. However, chemotherapy affects liver function and combined with extensive liver resection, morbidity has increased, thereby compromising oncological outcome. There is an imperative need for careful patient selection to optimize patient management. In this review, we discuss available evidence and indications for neoadjuvant treatment in the management of colorectal cancer liver metastases, on preoperative patient selection and identification of high-risk patients, potential treatment strategies to promote postoperative liver regeneration to avoid postoperative morbidity and potentially deleterious side effects of these therapies on tumor growth.

Pretreatment with VEGF(R)-inhibitors reduces interstitial fluid pressure, increases intraperitoneal chemotherapy drug penetration, and impedes tumor growth in a mouse colorectal carcinomatosis model

Cytoreductive surgery combined with intraperitoneal chemotherapy (IPC) is currently the standard treatment for selected patients with peritoneal carcinomatosis of colorectal cancer. However, especially after incomplete cytoreduction, disease progression is common and this is likely due to limited tissue penetration and efficacy of intraperitoneal cytotoxic drugs. Tumor microenvironment-targeting drugs, such as VEGF(R) and PDGFR inhibitors, can lower the heightened interstitial fluid pressure in tumors, a barrier to drug delivery. Here, we investigated whether tumor microenvironment-targeting drugs enhance the effectiveness of intraperitoneal chemotherapy. A mouse xenograft model with two large peritoneal implants of colorectal cancer cells was developed to study drug distribution and tumor physiology during intraperitoneal Oxaliplatin perfusion. Mice were treated for six days with either Placebo, Imatinib (anti-PDGFR, daily), Bevacizumab (anti-VEGF, twice) or Pazopanib (anti-PDGFR, -VEGFR; daily) followed by intraperitoneal oxaliplatin chemotherapy. Bevacizumab and Pazopanib significantly lowered interstitial fluid pressure, increased Oxaliplatin penetration (assessed by laser ablation inductively coupled plasma mass spectrometry) and delayed tumor growth of peritoneal implants (assessed by MRI). Our findings suggest that VEGF(R)-inhibition may improve the efficacy of IPC, particularly for patients for whom a complete cytoreduction might not be feasible.

Neoadjuvant antiangiogenic therapy reveals contrasts in primary and metastatic tumor efficacy

Thousands of cancer patients are currently in clinical trials evaluating antiangiogenic therapy in the neoadjuvant setting, which is the treatment of localized primary tumors prior to surgical intervention. The rationale is that shrinking a tumor will improve surgical outcomes and minimize growth of occult micrometastatic disease—thus delaying post-surgical recurrence and improving survival. But approved VEGF pathway inhibitors have not been tested in clinically relevant neoadjuvant models that compare pre- and post-surgical treatment effects. Using mouse models of breast, kidney, and melanoma metastasis, we demonstrate that primary tumor responses to neoadjuvant VEGFR TKI treatment do not consistently correlate with improved post-surgical survival, with survival worsened in certain settings. Similar negative effects did not extend to protein-based VEGF pathway inhibitors and could be reversed with altered dose, surgical timing, and treatment duration, or when VEGFR TKIs are combined with metronomic ‘anti-metastatic’ chemotherapy regimens. These studies represent the first attempt to recapitulate the complex clinical parameters of neoadjuvant therapy in mice and identify a novel tool to compare systemic antiangiogenic treatment effects on localized and disseminated disease.

Anti-angiogenic agents in metastatic colorectal cancer

Colorectal cancer (CRC) is a major public health concern being the third leading cause of cancer mortality in the United States. The availability of better therapeutic options has led to a decline in cancer mortality in these patients. Surgical resection should be considered in all stages of the disease. The use of conversion therapy has made surgery a potentially curative option even in patients with initially unresectable metastatic disease. In this review we discuss the role of various anti-angiogenic agents in patients with metastatic CRC (mCRC). We describe the mechanism of action of these agents, and the rationale for their use in combination with chemotherapy. We also review important clinical studies that have evaluated the safety and efficacy of these agents in mCRC patients. Despite the discovery of several promising anti-angiogenic agents, mCRC remains an incurable disease with a median overall survival of just over 2 years in patients exposed to all available treatment regimens. Further insights into tumor biology and tumor microenvironment may help improve outcomes in these patients.

Postoperative complications following neoadjuvant bevacizumab treatment for advanced colorectal cancer

PURPOSES

Attempts have been made to use bevacizumab (BEV) in an adjuvant or neoadjuvant setting. However, BEV is known to cause various adverse events, and the safety of neoadjuvant BEV has not yet been fully evaluated. This study assessed the postoperative complications in patients receiving neoadjuvant BEV for colorectal cancer.

METHODS

The data for 78 patients with resectable advanced or metastatic colorectal cancer who received neoadjuvant BEV followed by surgical resection were retrospectively analyzed.

RESULTS

The median interval between the last BEV dose and surgery was 9 weeks. The most common postoperative complication was pelvic sepsis, which occurred in 11 patients (14 %). A biliary fistula developed in four of 23 patients who underwent liver resection. Anastomotic leakage occurred in six of 24 patients with a colorectal anastomosis, four of whom required re-laparotomy. In a univariate analysis, male gender and a greater intraoperative blood loss were associated with postoperative complications of any grade. Colorectal anastomosis was a risk factor for major complications. In a multivariate analysis, intraoperative blood loss was an independent risk factor for postoperative complications of any grade (HR 6.338; P = 0.003). With regard to major postoperative complications, colorectal primary anastomosis was the only independent predictive risk factor (HR 8.285; P = 0.013).

CONCLUSIONS

In patients with colorectal cancer who underwent elective surgery after BEV treatment, the interval between BEV and surgery was not a risk factor for postoperative complications (based on a median interval of 9 weeks). Colorectal primary anastomosis was the only independent risk factor for major postoperative complications.