Comparative effectiveness of primary tumor resection versus chemotherapy in patients with asymptomatic unresectable metastatic colorectal cancer: a retrospective cohort study using the target trial emulation framework.

Patients who undergo primary tumor resection (PTR) reportedly have significantly higher overall survival (OS) than those who do not undergo this procedure. However, this result is only evident in past retrospective studies, and clinical trial results did not show the same trend. Thus, it remains unclear whether primary tumor resection effectively increases survival in patients with metastatic colorectal cancer (mCRC) across different study designs. We compared the OS of patients with asymptomatic unresectable mCRC who underwent PTR with that of those who did not. This retrospective cohort study was designed to be a target trial emulation of a randomized controlled trial (RCT) that would have compared the effectiveness of PTR versus non-PTR in patients with asymptomatic unresectable mCRC from 2009 to 2017. A systematic review and meta-analysis were conducted to compare the efficacy of PTR and non-PTR in patients with mCRC, and corresponding results were compared. This cohort included 1,132 patients for a per-protocol analysis. The PTR group had non-significantly longer survival (adjusted hazard ratio: 0.70, 95% confidence interval: 0.62-1.01) than the non-PTR group in our cohort. A meta-analysis including five RCTs (1,016 patients) and our cohort found that the PTR group did not have a significantly lower mortality rate than the non-PTR group. The results of this cohort study and previous RCTs suggest that PTR is not associated with improved survival compared to systemic chemotherapy combined with targeted therapy among asymptomatic unresectable mCRC patients. Therefore, routine PTR is not recommended in these patients.

Explanatory Role of Conversion Surgery as a Mediator of the Mortality Risk Difference Between Patients With Unresectable Metastatic Colorectal Cancer Treated With First-Line Anti-EGFR Agents Versus Bevacizumab.

INTRODUCTION: Bevacizumab and antiepidermal growth factor receptor-blocking (anti-EGFR) agents plus chemotherapy are first-line therapies for metastatic colorectal cancer (mCRC). Conversion surgery may improve outcomes; however, the extent to which it explains the difference in mortality rates among treatments is unclear. Herein, we aimed to assess the effects of conversion surgery on survival outcomes of patients with unresectable mCRC treated with bevacizumab and anti-EGFR agents. MATERIALS AND METHODS: This retrospective cohort study included patients with mCRC treated with bevacizumab and anti-EGFR agents as first-line therapy. We estimated the direct and indirect effects of treatments by comparing the mortality risk associated with targeted therapy type. Hazard ratios (HR) and the corresponding confidence intervals (CI) were estimated. Mediation analysis was used to estimate hazard ratio differences, and the proportion mediated. RESULTS: A total of 5,106 patients were included. The natural indirect effect of conversion surgery reduced mortality risk (HR: 0.95; 95% CI, 0.93-0.97), with a mediated proportion of 42% after propensity score adjustment. In subgroup analyses, KRAS wild-type (HR: 0.94; 95% CI: 0.91-0.97), left tumor sidedness (HR: 0.94; 95% CI, 0.91-0.96), and liver resection (HR: 0.95; 95% CI, 0.93-0.98) were associated with reduced risks of mortality. The controlled and total direct effects of targeted therapy were associated with reduced mortality risk in the anti-EGFR-treated group compared to those in the bevacizumab-treated group; however, this effect was not statistically significant. CONCLUSION: Conversion surgery may account for the difference in survival outcomes between users of the anti-EGFR agents and bevacizumab.

Assessing the effectiveness of targeted agents in adjuvant therapy for patients with metastatic colorectal cancer undergoing surgical resection: a retrospective cohort study.

Background: Primary tumor resection and metastasectomy may be beneficial for many patients with metastatic colorectal cancer (mCRC). Objective: To assess the differences in postoperative survival outcomes between adjuvant therapy with chemotherapy alone and chemotherapy plus targeted agents (TAs). Design: Retrospective cohort study. Methods: Patients with mCRC who underwent surgical resection for primary colorectal tumor and distant metastases and received adjuvant therapy from 1 January 2010 to 31 December 2017 were enrolled in the Taiwan Cancer Registry. We analyzed the overall survival of patients with resectable or initially unresectable mCRC who received adjuvant chemotherapy alone and chemotherapy plus TAs. Results: We enrolled 1124 and 542 patients with resectable and initially unresectable mCRC, respectively. Adjuvant chemotherapy plus TAs and chemotherapy alone resulted in similar mortality rates among patients with resectable mCRC [adjusted hazard ratio (aHR) = 1.13; 95% confidence interval (CI), 0.93-1.36]; however, it marginally reduced the mortality rate among patients with initially unresectable mCRC who underwent conversion surgery after neoadjuvant therapy (aHR = 0.81; 95% CI, 0.62-1.06). The subgroup analysis of patients who received more than nine cycles of TAs preoperatively and anti-epidermal growth factor receptor agents revealed aHRs of 0.48 (95% CI, 0.27-0.87) and 0.33 (95% CI, 0.18-0.60), respectively. Conclusion: Adjuvant chemotherapy plus TAs may improve survival in patients with initially unresectable tumors who underwent conversion surgery following neoadjuvant therapy with TAs, especially in those who respond well to the targeted therapy. Our study underscores the importance of stratifying patients with mCRC based on tumor resectability when selecting the adjuvant therapy regimen.

Comparative Effectiveness of Adjuvant Therapy on Survival in Patients With Metastatic Colorectal Cancer.

BACKGROUND/AIM: Postoperative survival outcomes are crucial in treatment decision making. This study aimed to compare the efficacy of adjuvant chemotherapy (AC)-alone with that of chemotherapy + targeted agents (CTA) in patients with metastatic colorectal cancer (mCRC) and to investigate the association between neoadjuvant therapy and survival. PATIENTS AND METHODS: Patients who underwent primary tumor excision and metastasectomy were identified in the Taiwan Cancer Registry from 2010 to 2019. The analysis assessed the influence of adjuvant therapy on survival and examined the interactions between adjuvant therapy types (AC-alone and CTA) and patient characteristics with respect to overall survival. RESULTS: Overall, 1,728 and 757 patients received AC alone and CTA, respectively. Compared to AC alone, adjuvant CTA yielded similar mortality after surgery [hazard ratio (HR)=1.03; 95% confidence interval (CI)=0.91-1.17] but resulted in marginally reduced mortality among patients treated with neoadjuvant therapy with targeted agents (HR=0.6; 95%CI=0.34-1.05) after propensity score matching. In patients with mCRC, those who received targeted agents preoperatively and postoperatively in combination with AC had the highest mortality rate (HR=1.75; 95%CI=1.33-2.32). CONCLUSION: Overall survival is comparable between adjuvant CTA and AC alone, but adjuvant CTA may be more beneficial in patients with mCRC who undergo neoadjuvant therapy with targeted agents.

Comparative Effectiveness of Cetuximab Versus Panitumumab in Patients With Metastatic Colorectal Cancer: A Nationwide Database Study.

BACKGROUND/AIM: The study aimed to determine the effectiveness of cetuximab and panitumumab on the survival of patients with metastatic colorectal cancer or those who had undergone conversion surgery and to identify their prognostic factors. PATIENTS AND METHODS: This retrospective cohort study used data from patients with metastatic colorectal cancer who received cetuximab or panitumumab as first-line targeted agent-based therapy. Overall survival and conversion surgery rates were evaluated, and the prognostic factors were determined. RESULTS: A total of 1,749 and 318 patients received cetuximab or panitumumab with chemotherapy, respectively. Overall survival and conversion surgery rates were similar between the cetuximab [hazard ratio (HR)=0.96] and panitumumab groups (HR=1.00). The prognostic factors associated with metastasectomy significantly lowered mortality among patients with metastatic colorectal cancer (HR=0.61). Older age (≥70 years), tumor stage 4B and 4C, right-sided tumors, mucinous adenocarcinoma, primary tumor resection, and the number of positive lymph nodes were associated with higher mortality and lower conversion surgery rates. CONCLUSION: Though panitumumab- and cetuximab-based therapies showed no differences, several factors, such as age over 70 years old, tumor stage 4B and 4C, undifferentiated carcinoma, mucinous carcinoma, right-sided tumor, number of positive lymph nodes, obstruction, and primary tumor resection increased the mortality risk of patients. This study underscores the importance of metastasectomy in current treatment guidelines and future clinical trials.

Efficacy and Safety of a Parenteral Nutrition Program for Patients with RAS Wild-Type Metastatic Colorectal Cancer Administered First-Line Cetuximab Plus Chemotherapy: A Propensity Score Matching Study.

Malnutrition is a common problem in patients with metastatic colorectal cancer (mCRC) receiving targeted therapy plus chemotherapy, resulting in severe toxicity and decreased survival rates. This retrospective study employing propensity score matching (PSM) examined the efficacy and safety of a supplemental home parenteral nutrition (HPN) program for patients with RAS wild-type mCRC receiving cetuximab plus chemotherapy. This retrospective nationwide registry study included data from 14 medical centers/hospitals across Taiwan, and the data period ranged from November 2016 to December 2020. Patients with RAS wild-type mCRC receiving cetuximab plus chemotherapy as their first-line therapy were included and divided into HPN and non-HPN program groups. HPN was initiated based on patient-specific factors, such as baseline nutritional status, treatment-related toxicities, and comorbidities. Clinical outcomes were evaluated using response to therapy, duration of response (DoR), progression-free survival (PFS), and overall survival (OS). This study recruited 758 patients, of whom 110 and 648 were included in the HPN and non-HPN program groups, respectively. After 1:3 PSM, the data of 109 and 327 patients from the HPN and non-HPN program groups were analyzed, respectively. The HPN program group had a higher metastasectomy rate (33.9% vs. 20.2%, p = 0.005), and longer duration of treatment and DoR than the non-HPN program group (13.6 vs. 10.3 and 13.6 vs. 9.9 months, p = 0.001 and < 0.001, respectively). The HPN program group tended to have a longer median PFS (18.2 vs. 13.9 months, p = 0.102). Moreover, we noted a significant improvement in the median OS in the same group (53.4 vs. 34.6 months, p = 0.002). Supplemental HPN programs may be recommended for select patients with mCRC receiving targeted therapy plus chemotherapy to improve oncological outcomes.

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.

Survival benefit of metastasectomy in first-line cetuximab therapy in patients with RAS wild-type metastatic colorectal cancer: a nationwide registry.

This multicenter study aimed to explore the survival benefit of metastasectomy by first-line cetuximab-based chemotherapy in real-world patients with RAS wild-type metastatic colorectal cancer (mCRC). The primary endpoints were overall survival (OS) and progression-free survival (PFS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), and metastasectomy rate. The exploratory endpoint was the optimal treatment cycle for better OS and PFS. Receiver operating characteristic curve with the area under curve (AUC) was used to identify the optimal cut-off cycle for survival outcomes. A total of 758 mCRC patients were enrolled in this study, with a median OS of 35.1 months, median PFS of 14.6 months, and metastasectomy rate of 21.4%. Left-sided mCRC had a significantly higher DCR (88.9% vs. 73.1%, P<0.001) and better OS (36.4 vs. 19.6 months, P<0.001). There were no significant differences in PFS and metastasectomy rate between left-sided and right-sided mCRC. However, mCRC patients who underwent metastasectomy over the course of treatment had better OS (54.9 vs. 28.6 months, P<0.001) and PFS (21.0 vs. 13.1 months, P<0.001) than those who did not. Notably, right-sided mCRC who benefited from first-line cetuximab-based chemotherapy to underwent metastasectomy also had favorable outcomes, on a par with left-sided mCRC. The optimal treatment cycle was 14 cycles (AUC: 0.779, P<0.001). Patients who received ≥14 cycles had higher metastasectomy rates (27.5% vs. 13.5%, P<0.001), favorable OS (42.6 vs. 23.4 months, P<0.001) and PFS (18.1 vs. 8.6 months, P<0.001), and, importantly, had comparable adverse events compared with patients who received <14 cycles of treatment. Patients who underwent metastasectomy after or during first-line cetuximab therapy have an improved OS in both left-sided and right-sided mCRC. Furthermore, patients receive ≥14 cycles of treatment whenever possible to achieve a higher likelihood of metastasectomy was associated with favorable survival outcomes.

Diving, lifting, and horizontal dissection followed by loop-clip traction (DLH+T) can facilitate mucosal flap creation during colorectal ESD.

BACKGROUND: Colorectal ESD is difficult because of the poor maneuverability and difficulty of mucosal flap creation. Diving, Lifting and Horizontal (DLH) dissection technique and loop-clip traction are two different methods to facilitate mucosal trimming and adequate mucosal flap creation. We combined the advantages of these two techniques (DLH+T) in our daily practice colorectal ESD since July 2020. OBJECTIVE: The purpose of this study was to examine the outcomes of DLH+T dissection compared with the conventional dissection. METHODS: We retrospectively reviewed the clinical using DLH+T dissection compared with the conventional dissection since January 2018 at a single tertiary care institution. Postoperative short-term outcomes were investigated after the procedure including mucosal flap creation time, dissection time, dissection speed, en bloc resection rate, and perioperative complications. RESULTS: 28 lesions were in DLH+T dissection group and 39 lesions in the conventional dissection group. The outcomes including en bloc resection rate, dissection speed, and complication between the two groups were similar. The mean mucosal flap creation time (p = 0.035) and the mean dissection speed (p = 0.041) of the DLH+T dissection group was significantly shorter and faster. CONCLUSION: DLH dissection followed by loop-clip traction (DLH+T) technique is a useful technique for safe, efficient, and adequate mucosal flap creation, which can increase the dissection speed and may prevent complication, especially in biopsy-related submucosal fibrosis.

Comparative Effectiveness of Bevacizumab versus Cetuximab in Metastatic Colorectal Cancer Patients without Primary Tumor Resection.

Primary tumor resection may be unfeasible in metastatic colorectal cancer. We determined the effects of bevacizumab and cetuximab therapies on survival or conversion surgery in patients with metastatic colorectal cancer who did not undergo primary tumor resection. This retrospective cohort study enrolled 8466 patients who underwent first-line bevacizumab- or cetuximab-based therapy. We analyzed the data of both therapies in patients who did not undergo primary tumor resection. Overall survival after targeted therapy plus chemotherapy was assessed. The groups were matched using propensity score matching and weighting. Cetuximab resulted in lower mortality than bevacizumab (hazard ratio (HR) = 0.75); however, it did not have the same effect in patients that underwent primary tumor resection (HR = 0.95) after propensity score weighting. Among patients treated with targeted agents, primary tumor resection was associated with lower mortality among those who received both bevacizumab (HR = 0.60) and cetuximab (HR = 0.75). Among patients that did not undergo primary tumor resection, multivariable analysis for conversion surgery showed that the cetuximab group (HR = 1.82) had a significantly higher metastasectomy rate. In these patients, cetuximab-based therapy was associated with significantly better survival compared with bevacizumab-based therapy. Cetuximab also yielded a higher conversion surgery rate. These findings demonstrate the importance of stratification by primary tumor resection in the application of current treatment guidelines and initiation of future clinical trials.

Shared decision-making and patient decision aids in choosing first-line targeted therapy for metastatic colorectal cancer in Taiwan.

INTRODUCTION: In Taiwan, given the discrepancy between current treatment guidelines and reimbursement options, patients might require a tool to support their decision-making process when selecting a regimen for metastatic colorectal cancer, especially therapeutic strategies, and subsequent costs, along with efficacy and safety outcomes. Therefore, we developed a patient decision aid (PDA) to support patients in choosing between treatment options recommended based on the current evidence and those reimbursed by the Taiwanese National Health Insurance. METHODS: By carefully reviewing the updated data and then interpreting the clinical tool, we conducted a needs assessment using a serial questionnaire to test for a step-by-step adjustment of the PDA. RESULTS: Patients, their relatives, and medical team members were most concerned about outcomes, such as overall survival, progression-free survival, objective response rate, tumor shrinkage to resectable status, total medical cost, severe gastrointestinal perforation, and severe skin reaction. After a serial alpha test for quality, we performed quantitative evaluation and beta tests, revealing average scores of more than 4 points (on a scale of 1-5) for both perceptibility and utility. CONCLUSIONS: The present findings suggest that PDAs are useful and supplement the shared decision-making practice, helping patients make decisions about preferences and consider the pros and cons of treatment regimens, along with insurance reimbursement options.

Optimal Sequence and Second-Line Systemic Treatment of Patients with RAS Wild-Type Metastatic Colorectal Cancer: A Meta-Analysis.

Although several sequential therapy options are available for treating patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC), the optimal sequence of these therapies is not well established. A systematic review and meta-analysis of 13 randomized controlled trials and 4 observational studies were performed, resulting from a search of the Cochrane Library, PubMed, and Embase databases. Overall survival (OS) did not differ significantly in patients with RAS-WT failure who were administered a second-line regimen of changed chemotherapy (CT) plus anti-epidermal growth factor receptor (EGFR) versus only changed CT, changed CT plus bevacizumab versus changed CT plus anti-EGFR, or changed CT versus maintaining CT plus anti-EGFR after first-line therapy with CT, plus bevacizumab. However, OS was significantly different with a second-line regimen that included changed CT plus bevacizumab, versus only changing CT. Analysis of first-line therapy with CT plus anti-EGFR for treatment of RAS-WT mCRC indicated that second-line therapy of changed CT plus an anti-EGFR agent resulted in better outcomes than changing CT without targeted agents. The pooled data study demonstrated that the optimal choice of second-line treatment for improved OS was an altered CT regimen with retention of bevacizumab after first-line bevacizumab failure. The best sequence for first-to-second-line therapy of patients with RAS-WT mCRC was cetuximab-based therapy, followed by a bevacizumab-based regimen.

Snare Tip Is an Alternative Tool for Colorectal Endoscopic Submucosal Dissection.

BACKGROUND: Colorectal endoscopic submucosal dissection is typically performed by specialized knife, such as a dual knife. However, it is not covered by Taiwan's National Health Insurance. In the literature review, using a traditional snare tip for endoscopic submucosal dissection has been reported for stomach lesions only. OBJECTIVE: The purpose of this study was to evaluate the outcomes of colorectal endoscopic submucosal dissection using a snare tip. DESIGN: We retrospectively reviewed the clinical using of a snare tip compared with a dual knife for colorectal endoscopic submucosal dissection. Postoperative short- and long-term outcomes were investigated after the procedure. SETTINGS: This study was conducted at a single tertiary care institution. PATIENTS: Patients who could not afford the expense of a specialized knife were included. MAIN OUTCOME MEASURES: Dissection time, dissection speed, and perioperative complications were used for short-term outcome measurement. Recurrence-free rate was used for long-term outcome measurement. RESULTS: Twenty-one lesions were in the snare tip group and 57 lesions in the dual knife group. The outcomes, including rate of en bloc resection, complication, local recurrence, and recurrence-free interval, between the 2 groups were similar. The mean resected specimen diameter in the dual knife group is larger than the snare tip group (p = 0.041). The dissection time of the snare tip group was shorter than the dual knife group (p = 0.025). However, the dissection speed was significantly slower in the snare tip group than in the dual knife group (p = 0.008). LIMITATIONS: This study was a retrospective and single doctor chart review in nature with a limited patient number. CONCLUSIONS: The snare tip is an alternative tool for colorectal endoscopic submucosal dissection in a selected population without the support of specialized knives, such as the dual knife. Although the dissection speed is slower using a snare tip, it is still a recommended technique for developing country or low-income patients.

Loading dose and efficacy of continuous or extended infusion of beta-lactams compared with intermittent administration in patients with critical illnesses: A subgroup meta-analysis and meta-regression analysis.

WHAT IS KNOWN AND OBJECTIVE: The role of continuous/extended beta-lactam infusions (CEIs) in improving clinical outcomes among critically ill patients remains controversial. Therefore, we aimed to compare the clinical efficacy of CEI versus intermittent administration (IA) of beta-lactams by performing a systematic review and meta-analysis. METHODS: PubMed, the Cochrane Library and Embase were searched from inception until December 2018 for studies comparing clinical outcomes of CEI versus IA in critically ill patients. The meta-analysis included 18 randomized controlled trials (RCTs) and 13 non-RCTs. RESULTS AND DISCUSSION: For CEI versus IA, the summary relative risk (RR) for overall mortality and clinical cure was 0.82 (95% confidence interval [CI]: 0.72-0.94) and 1.31 (95% CI: 1.15-1.49), respectively. Subgroup and meta-regression analyses of the loading dose revealed a significantly increased clinical cure rate in the loading-dose group (RR: 1.44, 95% CI: 1.22-1.69), which remained significant after adjustments for beta-lactam type, and association between clinical cure and loading dose for clinical cure (RR: 1.47, 95% CI: 1.20-1.80; p = .001). Subgroup analysis of administration type indicated that both groups had low mortality and high clinical cure rates; however, the heterogeneity analysis did not support an association across continuous infusion and extended infusion groups. Subgroup analysis of the Acute Physiology and Chronic Health Evaluation (APACHE) score was conducted; according to APACHE scores ≥ 16, overall mortality and clinical cure significantly differed between CEI and IA. WHAT IS NEW AND CONCLUSION: CEIs with loading-dose treatment may significantly improve the clinical outcomes in critically ill sepsis or septic shock patients.

Endoscope rotating technique is useful for difficult colorectal endoscopic submucosal dissection.

BACKGROUND: Conventional lesion-up colorectal ESD has the potential risk of iatrogenic perforation due to the knife's direction toward the muscular layer of the bowel wall. If we rotate the endoscope to the proper position, the mucosal flap is easy to be lifted down by tip attachment and the knife is easy to approach the proper dissection plane, which may prevent the perforation and facilitate difficult ESD. METHODS: We aimed to retrospectively assess the safety and efficacy of this rotating technique compared with the conventional lesion-up dissection regardless of shape, location, or size of the tumor, and investigated in short- and long-term outcomes following the ESD procedure. RESULTS: 41 lesions were enrolled into rotating technique group and 37 lesions in lesion-up group. The dissection speed was significantly faster in the rotating technique group (p = 0.023). R0 resection rate was significantly higher in rotating technique group (p = 0.008). The rate of perioperative complication was significantly higher in lesion-up method group (p = 0.003). Local recurrence was higher in lesion-up group (p = 0.001). Recurrence-free rate was higher in rotating technique group (p = 0.018). CONCLUSION: The endoscope rotating is a useful technique for difficult colorectal ESD due to easy approaching the proper dissection plane. This technique also increases the rate of en bloc resections, R0 resections regardless of size, shape, and location and improves dissection speed without increasing the incidence of adverse events.

Tumor sidedness and efficacy of first-line therapy in patients with RAS/BRAF wild-type metastatic colorectal cancer: A network meta-analysis.

We conducted a systemic search of several databases for randomized controlled trials (RCTs) that reported efficacy and safety outcomes of drugs for left-sided and right-sided metastatic colorectal cancer (mCRC), to identify the best available treatment. A network meta-analysis with mixed comparisons was created to interpret the best treatment option using the surface under the cumulative ranking curve. In the left-sided rat sarcoma (RAS) wild-type (WT) mCRC patients, bevacizumab, panitumumab, or cetuximab with chemotherapy groups showed a significantly better objective response rate than the chemotherapy alone group. The progression-free survival (PFS) and overall survival were better with panitumumab or cetuximab with chemotherapy than with chemotherapy alone. In the right-sided RAS WT mCRC patients, PFS for bevacizumab with chemotherapy was significantly better than that for cetuximab with chemotherapy. Cetuximab, closely followed by panitumumab, is the most effective treatment in left-sided RAS WT mCRC. Bevacizumab is more effective in right-sided mCRC.

Incidence and Clinical Outcomes of Gonadal Artery Injury during Colorectal Surgery in Male Patients.

BACKGROUND: Gonadal artery is susceptible to accidental injury due to their anatomical proximity to the colon and rectum. There are few literature reviews focusing on this injury during colorectal surgery. We conduct a retrospective study to evaluate the incidence and the clinical significance of these injuries in terms of testicular size and testicular enhancement on the contrast CT scan. METHODS: Patients' characteristic data included age, body mass index (BMI), diagnosis, operation type, cause of gonadal artery injury, side of injury, level of injury, method of vessel ligation, and follow-up period. We measured the testicular sizes before and after gonadal artery injury and measured the enhancement level by recording the mean attenuation value on the injury side and non-injury side of the testis on the CT scan. RESULTS: The incidence of gonadal artery injury was 3.61% and 15 male patients with this injury were enrolled. There were 5 patients with iatrogenic injury and 10 patients with non-iatrogenic injury due to advanced tumor or inflammation. No patients had any complaints of testicular discomforts or atrophy after the surgery. The testicular sizes before and after the surgery showed no significant difference (p = 0.877). The mean attenuation values of the injury side and non-injury side of the testis also showed no significant difference (p = 0.79). CONCLUSIONS: Gonadal artery injury during colorectal surgery is not a rare complication. To prevent this injury, knowledge of the anatomy and staying in the proper plane of dissection are the key points. In patients with gonadal artery injury during colorectal surgery, sacrifice of the gonadal artery is safe without clinical significance in terms of testicular size and testicular enhancement on the contrast CT scan.