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

Targeted Therapies, Biologics, and Immunotherapy in the Neoadjuvant and Adjuvant Settings: Perioperative Risks

Cancer therapeutics has been revolutionized by the introduction of molecularly targeted therapies and immune checkpoint inhibitors (ICIs). The paradigm of neoadjuvant therapy is commonly employed across multiple solid tumors, exhibiting significant clinical benefit as exemplified with ICIs in melanoma and non-small-cell lung cancer. However, neoadjuvant therapy can be associated with treatment-related adverse events. As the incorporation of these novel therapies in the preoperative space expands, it is crucial for surgical oncologists to understand the potential perioperative implications of these treatments. This article focuses on surgical considerations tied to these treatments, highlighting potential drug-surgery interactions and complications.

The Association of Oxaliplatin-Containing Adjuvant Chemotherapy Duration with Overall and Cancer-Specific Mortality in Individuals with Stage III Colon Cancer: A Population-Based Retrospective Cohort Study

PURPOSE

Few studies have examined the relationship between duration of oxaliplatin-containing adjuvant chemotherapy for stage III colon cancer and mortality in routine practice. We examined the association between treatment with 50% versus >85% of a maximal course of adjuvant therapy (eight cycles of CAPOX, twelve cycles of FOLFOX) and mortality in stage III colon cancer.

METHODS

Using linked databases, we identified Ontarians aged ≥18 years at diagnosis of stage III colon cancer between 2007 and 2019. In the primary comparison, we compared patients who received 50% or >85% of a maximal course of adjuvant therapy; in a secondary comparison, we evaluated a dose effect across patients who received FOLFOX in one-cycle increments from six to ten cycles against >85% (more than ten cycles) of a maximal course of FOLFOX. The main outcomes were overall and cancer-specific mortality. Follow-up began 270 days after adjuvant treatment initiation and terminated at the first of the outcome of interest, loss of eligibility for Ontario's Health Insurance Program, or study end. Overlap propensity score weights accounted for baseline between-group differences. We determined the hazard ratio, estimating the association between mortality and treatment. Non-inferiority was concluded in the primary comparison for either outcome if the upper limit of the two-sided 95% CI was ≤1.11, which is the margin used in the International Duration Evaluation of Adjuvant Chemotherapy Collaboration.

RESULTS

We included 3546 patients in the analysis of overall mortality; 486 (13.7%) received 50% and 3060 (86.3%) received >85% of a maximal course of therapy. Median follow-up was 5.4 years, and total follow-up was 20,510 person-years. There were 833 deaths. Treatment with 50% of a maximal course of adjuvant therapy was associated with a hazard ratio of 1.13 (95% CI 0.88 to 1.47) for overall mortality and a subdistribution hazard ratio of 1.31 (95% CI 0.91 to 1.87) for cancer-specific mortality versus >85% of a maximal course of therapy. In the secondary comparison, there was a trend toward higher overall mortality in patients treated with shorter durations of therapy, though confidence intervals overlapped considerably.

CONCLUSION

We could not conclude that treatment with 50% of a maximal course is non-inferior to >85% of a maximal course of adjuvant therapy for mortality in stage III colon cancer. Clinicians and patients engaging in decision-making around treatment duration in this context should carefully consider the trade-off between treatment effectiveness and adverse effects of treatment.

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.

Association Between Preoperative Patient-Reported Symptoms and Postoperative Outcomes in Rectal Cancer Patients: A Retrospective Cohort Study

BACKGROUND

Rectal cancer patients undergoing preoperative radiotherapy experience a significant symptom burden. However, it is unknown whether symptoms during radiotherapy may portend adverse postoperative outcomes and healthcare utilization.

METHODS

A retrospective cohort study was performed of rectal cancer patients undergoing neoadjuvant radiotherapy and proctectomy in Ontario from 2007 to 2014. The primary outcome was a complicated postoperative course-a dichotomous variable created as a composite of postoperative mortality, major morbidity, or hospital readmission. Patient-reported Edmonton Symptom Assessment System (ESAS) scores, collected routinely at outpatient provincial cancer center visits, were linked to administrative healthcare databases. The receiver-operating characteristic analysis was used to compare ESAS scoring approaches and to stratify patients into low versus high symptom score groups. Multivariable regression models were constructed to evaluate associations between preoperative symptom scores and postoperative outcomes.

RESULTS

1455 rectal cancer patients underwent sequential radiotherapy and proctectomy during the study period and recorded symptom assessments. Patients with high preoperative symptom scores were significantly more likely to experience a complicated postoperative course (OR 1.55, 95% CI 1.23-1.95). High preoperative ESAS scores were also associated with the secondary outcomes of emergency department visits (OR 1.34, 95% CI 1.08-1.66) and longer length of stay (IRR 1.23, 95% CI 1.04-1.45).

CONCLUSIONS

Rectal cancer patients reporting elevated symptom scores during neoadjuvant radiotherapy have increased odds of experiencing a complicated postoperative course. Preoperative patient-reported outcome screening may be a useful tool to identify at-risk patients and to efficiently direct perioperative supportive care.

Does the presence of an intact primary increase the risk of nonelective colorectal surgery in patients treated with bevacizumab?

AIM

In patients with incurable metastatic colorectal cancer (mCRC), resection of the primary tumour is debated; however, patients with intact primaries may be at a higher risk of complications requiring surgery when receiving treatment with bevacizumab. Our aim was to estimate the risk of nonelective colorectal surgery in patients undergoing bevacizumab therapy for mCRC and evaluate the association between intact primary tumours and risk of nonelective surgery.

METHOD

We designed a population-based, retrospective cohort study using administrative and cancer registry data in Ontario, Canada. We included patients with mCRC who received bevacizumab from 1 January 2008 to 31 December 2014. The primary outcome was nonelective colorectal surgery after initiation of bevacizumab. We determined the cumulative incidence of nonelective colorectal surgery among patients with previously resected and unresected primaries, accounting for the competing risk of death. We explored the relationship between previous resection of the primary and need for nonelective surgery using a cause-specific hazards model, controlling for patient, tumour and treatment factors.

RESULTS

We identified 1840 (32.7%) patients with intact primaries and 3784 (67.3%) patients with prior resection. The cumulative incidence of nonelective surgery 1 year after initiating bevacizumab for all patients was 3.9% (95% CI 3.4-4.5%). One-year cumulative incidence was higher in those with intact primaries than in those with resected primaries (6.1% vs 2.9%, P < 0.0001). After adjustment, an intact primary remained strongly associated with nonelective colorectal surgery (hazard ratio = 2.89, 95% CI 2.32-3.61; P < 0.0001).

CONCLUSION

Bevacizumab is associated with a low but meaningful risk for serious gastrointestinal complications, necessitating vigilance, particularly among patients with an intact primary tumour.

Morbidity and mortality after major large bowel resection of non-malignant polyp among participants in a population-based screening program

Background and aims

Colonoscopy following positive fecal occult blood screening may detect non-malignant polyps deemed to require major large bowel resection. We aimed to estimate the major inpatient morbidity and mortality associated with major resection of non-malignant polyps detected at colonoscopy following positive guaiac fecal occult blood screening in Ontario's population-based colorectal screening program.

Methods

We identified those without a diagnosis of colorectal cancer in the Ontario Cancer Registry ≤24 months following the date of colonoscopy prompted by positive fecal occult blood screening between 2008 and 2017, who underwent a major large bowel resection ≤24 months after the colonoscopy, with a diagnosis code for non-malignant polyp, in the absence of a code for any other large bowel diagnosis. We extracted records of major inpatient complications and readmissions ≤30 days following resection. We computed mortality within 90 days following resection.

Results

For those undergoing colonoscopy ≤6 months following positive guaiac fecal occult blood screening, 420/127,872 (0.03%) underwent major large bowel resection for a non-malignant polyp. In 50/420 (11.9%), the resection included one or more rectosigmoid or rectal polyps, with or without a colonic polyp. There were one or more major inpatient complications or readmissions within 30 days in 117/420 (27.9%). Death occurred within 90 days in 6/420 (1.4%).

Conclusions

Serious inpatient complications and readmissions following major large bowel resection for non-malignant colorectal polyps are common, but mortality ≤90 days following resection is low. These outcomes should be considered as unintended adverse consequences of population-based colorectal screening programs.

Morbidity and mortality following major large bowel resection for colorectal cancer detected by a population-based screening program

BACKGROUND AND AIMS

In 2008, Ontario initiated a population-based colorectal screening program using guaiac fecal occult blood testing. This work was undertaken to fill a major gap in knowledge by estimating serious post-operative complications and mortality following major large bowel resection of colorectal cancer detected by a population-based screening program.

METHODS

We identified persons with a first positive fecal occult blood result between 2008 and 2016, at the age of 50-74 years, who underwent a colonoscopy within 6 months, and proceeded to major large bowel resection for colon cancer within 6 months or rectosigmoid/rectal cancer within 12 months, and identified an unscreened cohort of resected cases diagnosed during the same years at the age of 50-74 years. We identified serious postoperative complications and readmissions ≤30 days following resection, and postoperative mortality ≤30 days, and between 31 and 90 days among the screen-detected and the unscreened cohorts.

RESULTS

Serious post-operative complications or readmissions within 30 days were observed among 1476/4999 (29.5%) cases in the screen-detected cohort, and among 3060/8848 (34.6%) unscreened cases. Mortality within 30 days was 43/4999 (0.9%) among the screen-detected cohort, and 208/8848 (2.4%) among the unscreened cohort. Among 30 day survivors, mortality between 31 and 90 days was 28/4956 (0.6%) and 111/8640 (1.3%), respectively.

CONCLUSION

Serious post-operative complications, readmissions, and mortality may be more common following major large bowel resection for colorectal cancer between the ages of 50 and 74 among unscreened compared to screen-detected cases.

Gene therapy knockdown of VEGFR2 in retinal endothelial cells to treat retinopathy

Inhibition of vascular endothelial growth factor (VEGF) in retinopathy of prematurity (ROP) raises concerns for premature infants because VEGF is essential for retinovascular development as well as neuronal and glial health. This study tested the hypothesis that endothelial cell-specific knockdown of VEGF receptor 2 (VEGFR2), or downstream STAT3, would inhibit VEGF-induced retinopathy without delaying physiologic retinal vascular development. We developed an endothelial cell-specific lentiviral vector that delivered shRNAs to VEGFR2 or STAT3 and a green fluorescent protein reporter under control of the VE-cadherin promoter. The specificity and efficacy of the lentiviral vector-driven shRNAs were validated in vitro and in vivo. In the rat oxygen-induced retinopathy model highly representative of human ROP, the effects of endothelial cell knockdown of VEGFR2 or STAT3 were determined on intravitreal neovascularization (IVNV), physiologic retinal vascular development [assessed as area of peripheral avascular/total retina (AVA)], retinal structure, and retinal function. Targeted knockdown of VEGFR2 or STAT3 specifically in retinal endothelial cells by subretinal injection of lentiviral vectors into postnatal day 8 rat pup eyes efficiently inhibited IVNV, and knockdown of VEGFR2 also reduced AVA and increased retinal thickness without altering retinal function. Taken together, our results support specific knockdown of VEGFR2 in retinal endothelial cells as a novel therapeutic method to treat retinopathy.