Risk of colorectal cancer after appendectomy: A systematic review and meta-analysis

Feasibility and effectiveness of endoscopic retrograde appendicitis therapy for uncomplicated acute appendicitis: a systematic review and meta-analysis

BACKGROUND

Acute appendicitis is a prevalent abdominal emergency, with appendectomy and antibiotic therapy being the conventional mainstays of treatment. Recently, endoscopic retrograde appendicitis therapy (ERAT) has emerged as a promising minimally invasive alternative. This study aims to evaluate the feasibility and effectiveness of ERAT in the management of uncomplicated acute appendicitis.

METHODS

A systematic review of the literature was performed by searching the PubMed, Embase, Web of Science, and Cochrane Library databases, covering records from inception to January 2025. Meta-analyses were conducted using Review Manager 5.4, employing a random-effects model when applicable.

RESULTS

A total of 8 studies were included, consisting of three randomized controlled trials and five retrospective studies, with a combined sample size of 2005 participants. When compared with the laparoscopic appendectomy (LA) group, the ERAT group demonstrated a significantly lower treatment success rate (odds ratio [OR] 0.15, 95% confidence interval [CI] 0.04-0.57, P = 0.005) and a significantly higher recurrence rate (OR 7.68, 95% CI 2.32-25.46, P = 0.0009). In contrast, compared with the antibiotic therapy group, the ERAT group exhibited a higher treatment success rate (OR 2.10, 95% CI 0.95-4.64, P = 0.07) and a lower recurrence rate (OR 0.31, 95% CI 0.09-1.07, P = 0.06), although these differences did not reach statistical significance. Additionally, the overall incidence of adverse events associated with ERAT was significantly lower than that observed with antibiotic therapy (OR 0.09, 95% CI 0.02-0.50, P = 0.005).

CONCLUSION

ERAT is a promising but not yet definitive alternative for uncomplicated acute appendicitis, with advantages in organ preservation and fewer adverse events compared to antibiotics. However, relatively low success rate and high recurrence rate of ERAT currently prevent it from completely replacing appendectomy. Further high-quality studies are needed to better define its role in clinical practice.

Exploring the Immunological Role of the Microbial Composition of the Appendix and the Associated Risks of Appendectomies

The appendix, an integral part of the large intestine, may serve two purposes. First of all, it is a concentration of lymphoid tissue that resembles Peyer's patches. It is also the main location in the body for the creation of immunoglobulin A (IgA), which is essential for controlling intestinal flora's density and quality. Second, the appendix constitutes a special place for commensal bacteria in the body because of its location and form. Inflammation of the appendix, brought on by a variety of infectious agents, including bacteria, viruses, or parasites, is known as appendicitis. According to a number of studies, the consequences of appendectomies may be more subtle, and may relate to the emergence of heart disease, inflammatory bowel disease (IBD), and Parkinson's disease (PD), among other unexpected illnesses. A poorer prognosis for recurrent Clostridium difficile infection is also predicted by the absence of an appendix. Appendectomies result in gut dysbiosis, which consequently causes different disease outcomes. In this review, we compared the compositional differences between the appendix and gut microbiome, the immunological role of appendix and appendix microbiome (AM), and discussed how appendectomy is linked to different disease consequences.

Appendectomy, acute appendicitis, and gastrointestinal diseases: A Mendelian randomization study

BACKGROUND

Appendectomy is the standard treatment for acute appendicitis. However, the effects of appendectomy and acute appendicitis on gastrointestinal diseases are not fully understood.

METHODS

Genetic variants associated with appendectomy and acute appendicitis at a genome-wide significance level (P ​< ​5.0E-08) were selected as instrumental variables. Two-sample univariate and multivariate Mendelian randomization (MR) analyses were performed to examine the independent effects of appendectomy and acute appendicitis on related gastrointestinal diseases.

RESULTS

Appendectomy was linked to an increased risk of colon cancer (odds ratio [OR], 1.54; 95 ​% confidence interval [CI], 1.15-2.07; P ​= ​0.004; FDR-corrected P ​= ​0.016) and a decreased risk of primary sclerosing cholangitis (OR, 0.57; 95 ​% CI, 0.38-0.84; P ​= ​0.004; FDR-corrected P ​= ​0.016). Acute appendicitis was associated with a higher risk of cholelithiasis (OR, 1.16; 95 ​% CI, 1.06-1.27; P ​= ​0.002; FDR-corrected P ​= ​0.016).

CONCLUSION

This study suggested that appendectomy and acute appendicitis might affect the risk of several gastrointestinal diseases in European populations.

Risk of colorectal cancer and adenoma after an appendectomy: results from three large prospective cohort studies and meta-analysis

PURPOSE

The relationship between appendectomy and subsequent colorectal cancer risk remains unclear, and no study has examined its association with colorectal adenoma.

METHODS

We used data from three prospective cohorts: Health Professionals Follow-up Study, Nurses' Health Study (NHS), and NHSII. Appendectomy history was self-reported at baseline. Colorectal cancer risk was analyzed with Cox proportional hazard models among 224,109 participants followed up to 32 years. Colorectal adenoma risk was evaluated among 157,490 participants with at least one lower gastrointestinal endoscopy during follow-up with logistic regression models accounting for repeated observations. We also performed a meta-analysis of cohort studies that examined association between appendectomy and colorectal cancer risk.

RESULTS

We documented 3,384 colorectal cancers, 13,006 conventional adenomas, and 11,519 serrated polyps during the follow-up period. Compared to participants without appendectomy, those who reported appendectomy history were not at higher risk of colorectal (HR [95% CI], 0.92 [0.84-1.00]), colon (0.92 [0.83-1.01]), or rectal (0.85 [0.70-1.03]) cancer. Similarly, appendectomy history was not associated with higher risk of conventional adenoma (OR [95% CI], 1.00 [0.97-1.02]), serrated polyp (0.97 [0.94-1.00]), or high-risk adenoma (0.96 [0.92-1.01]). The meta-analysis showed appendectomy was associated with a higher risk of colorectal cancer within a short time after the procedure (1.68 [1.01-2.81]), while the long-term risk was slightly inverse (0.94 [0.90-0.97]).

CONCLUSION

We found no evidence of an association between appendectomy history and long-term risk of colorectal cancer or its precursors. The observed higher risk of colorectal cancer right after appendectomy in the first few years is likely due to reverse causation.

No genetic causality between appendectomy and gastrointestinal cancers: a Mendelian randomization study and meta-analysis in European population

The impact of appendectomy on the risk of gastrointestinal cancers remains unknown. We aimed to systematically estimate the causal relationship between appendectomy and gastrointestinal cancers in the European population using two-sample Mendelian randomization (TSMR) study methods and meta-analysis. As part of the discovery cohort analysis, we identified independent genetic variants strongly associated with appendectomy from the UK Biobank (50,105 cases) to serve as instrumental variables (IVs). Summary-level data for gastrointestinal cancers were obtained from the FinnGen study. As the replication cohort, IVs associated with appendectomy were extracted in the FinnGen study (28,601 cases). The data for gastrointestinal cancers were obtained from the UK Biobank. Finally, meta-analyses were conducted to evaluate the combined causal effects of the MR results. We found no causal relationship between appendectomy and gastrointestinal cancers in both the discovery and replication cohorts. Finally, the meta-analysis revealed no causal association between appendectomy and gastrointestinal cancers. Our findings suggest no causal relationship exists between appendectomy and gastrointestinal cancers in the European population. This genetic evidence supports the conclusion from other observational studies that appendectomy does not affect the risk of gastrointestinal cancers in the European population.

Endoscopic retrograde appendicitis therapy

Endoscopic retrograde appendicitis therapy (ERAT) is a novel and minimally invasive technological alternative for the management of acute or chronic appendicitis. Through endoscopic appendiceal intubation, obstructions such as appendiceal feces and parasites within the appendiceal lumen can be effectively eliminated, leading to patient recovery. Additionally, in cases where the orifices are swollen or complicated appendicitis is present, a stent may be inserted following appendiceal flushing. Due to the utilization of endoscopy for accessing the orifices of the appendix in order to alleviate appendiceal obstruction, patients were able to avoid undergoing appendectomy and experienced a reduced likelihood of recurrence when compared to antibiotic therapy. Additionally, the ERAT provided alternative options for individuals with appendicitis and comorbidities. Recent advancements in techniques, such as the "mother-baby" endoscopic system and the use of microbubble contrast agents, have expanded the range of indications and the eligible patient populations. The objective of this review is to present a comprehensive overview of the development, procedural aspects, therapeutic principles, treatment efficacy, therapeutic applications, and potential complications associated with ERAT.

Modified endoscopic retrograde appendicitis therapy vs. laparoscopic appendectomy for uncomplicated acute appendicitis in children

OBJECTIVES

Modified endoscopic retrograde appendicitis therapy (mERAT) has been proposed as an alternative to laparoscopic appendectomy for the treatment of appendicitis. However, data from children in large samples are lacking. The aim of this article is to evaluate the efficacy between mERAT and laparoscopic appendectomy (LA) in children with uncomplicated appendicitis.

METHOD

We retrospectively analyzed 594 patients with suspected uncomplicated appendicitis from October 2018 to May 2021. A pool of 294 consecutive patients who met the inclusion criteria were ultimately enrolled in this study (228 and 66 patients in mERAT and LA, respectively). Given the differences in baseline clinical data (gender, age), the regression equation including differences in clinical baseline, grouping factor, and white blood cell count was established to address the influence of potential confounding factors.

RESULT

The initial success rate of mERAT management was 96.9%, and the recurrence rate was 6.9% in the mERAT group and 1.7% in the LA group within 1 year, which was no significant difference. But the mERAT group had a lower rate of adverse events. Finally, those results indicated that the treatment modalities, LA or mERAT, had no significant effect on initial success rate (P = 0.99) or recurrence rate (P = 0.17) within 1 year, but a significant effect on the adverse events rate during hospitalization (P = 0.01) in the multivariate regression analysis.

CONCLUSION

Among children with uncomplicated appendicitis, an initial mERAT management strategy had a success rate of 96.9%, which was similar to the LA group at 1 year. This follow-up supports the feasibility of mERAT alone as an alternative to surgery for uncomplicated appendicitis.

Is appendoscope a new option for the treatment of acute appendicitis?

Acute appendicitis is a common surgical emergency. It is commonly caused by obstruction of the appendiceal lumen due to fecaliths, tumors, or lymphoid hyperplasia. For over a century, appendectomy has been the primary treatment for acute appendicitis. Abraham Groves performed the first open appendectomy in 1883. In 1983, Kurt Semm completed the first laparoscopic appendectomy, heralding a new era in appendectomy. However, appendectomy is associated with certain complications and a rate of negative appendectomies. Studies have suggested controversy over the impact of appendectomy on the development of inflammatory bowel disease and Parkinson's disease, but an increasing number of studies indicate a possible positive correlation between appendectomy and colorectal cancer, gallstones, and cardiovascular disease. With the recognition that the appendix is not a vestigial organ and the advancement of endoscopic te-chnology, Liu proposed the endoscopic retrograde appendicitis therapy. It is an effective minimally invasive alternative for treating uncomplicated acute appendicitis. Our team has developed an appendoscope with a disposable digital imaging system operated through the biopsy channel of a colonoscope and successfully applied it in the treatment of appendicitis. This article provides an overview of the progress in endoscopic treatment for acute appendicitis and offers a new perspective on the future direction of appendiceal disease treatment.

Appendectomy and appendicitis do not increase colorectal cancer risk: evidence from Mendelian randomization

Background

Acute appendicitis (AA) is one of the most prevalent acute abdominal diseases and appendectomy is the definitive treatment of appendicitis. However, whether appendicitis and appendectomy cause colorectal cancer (CRC) is controversial. The results of observational studies are contradictory, but randomized controlled trials (RCT) cannot be conducted.

Methods

Data of appendectomy, AA, and CRC were obtained from the IEU Open GWAS project. We selected several Genome-wide association studies (GWAS) summary statistics for CRC: statistics for colon cancer (CC) were obtained from MRC-IEU and Neale lab, respectively; statistics for rectum cancer (RC) were obtained from MRC-IEU and FinnGen, respectively; statistics for CRC were provided by Sakaue S et al. Mendelian randomization (MR) was used to evaluate the causal relationships between exposure and outcomes. Inverse variance weighting (IVW) was the most important analysis method. Meta-analysis was used to summarize the results of IVW to increase the reliability and sensitivity analysis was used to evaluate the robustness of the results.

Results

According to the results of IVW, appendectomy did not increase risk of CC: MRC-IEU (OR:1.009, 95%CI:0.984-1.035, P=0.494), Neale lab (OR:1.016, 95%CI:0.993-1.040, P=0.174); Appendectomy also did not increase risk of RC: MRC-IEU(OR:0.994, 95%CI:0.974-1.014, P=0.538), FinnGen(OR:2.791, 95%CI:0.013-580.763, P=0.706); Appendectomy also did not increase risk of CRC: Sakaue S(OR:1.382, 95%CI:0.301-6.352, P=0.678). Appendicitis did not increase risk of CC: MRC-IEU(OR:1.000, 95%CI:0.999-1.001, P=0.641), Neale lab(OR:1.000, 95%CI:1.000-1.001, P=0.319); Appendicitis also did not increase risk of RC: MRC-IEU(OR:1.000, 95%CI:0.999-1.000, P=0.361), FinnGen(OR:0.903, 95%CI:0.737-1.105, P=0.321); Appendicitis also did not increase risk of CRC: Sakaue S (OR:1.018, 95%CI:0.950-1.091, P=0.609). The results of Meta-analysis also showed appendectomy (P=0.459) and appendicitis (P=0.999) did not increase the risk of CRC.

Conclusions

Appendectomy and appendicitis do not increase the risk of colorectal cancer. More clinical trials are needed in the future to verify the causal relationships.

Epidemiological insights into colorectal cancer in northwestern Algeria

Objectives

The incidence of colorectal cancer (CRC) has exhibited regional variability in North Africa and the Middle East, with a steady increase in Algeria. Despite this trend, limited data exist on the epidemiology of CRC in northwestern Algeria. Our study aimed to investigate the epidemiological characteristics of CRC in this region.

Methods

We conducted a retrospective study examining 255 confirmed CRC cases through medical records from patients at the Sidi Bel Abbes anti-cancer centre.

Results

The mean age of the study participants was 59 ± 13 years. The results showed a higher incidence in males (57%) than in females, and colon (62%) than rectal cancer. Within this cohort, 47% had a pre-existing medical condition, while 39% had a family history of cancer. Adenocarcinomas were the prevailing histological subtype in 94% of CRC cases. Compared with colon cancer, rectal cancer was less often diagnosed at stage IV of the disease (OR = 0.75; 95% CI = 0.09, 4.86; p = 0.8) and more likely in early-onset patients (OR = 2.27; 95% CI = 1.25, 4.17; p = 0.007). Men were at a higher risk of being diagnosed with metastatic CRC primarily hepatic metastases (OR = 2.03; 95% CI = 1.07, 3.99; p = 0.033) and pulmonary metastases (OR = 2.50; 95% CI = 1.07, 6.59; p = 0.045).

Conclusion

This study may provide a comprehensive glimpse into CRC epidemiology in northwest Algeria. Understanding regional differences is the key to implementing specific preventive and interventional strategies.

Increased risk of colon cancer after acute appendicitis: a nationwide, population-based study

Background

Acute appendicitis is the most common digestive disease requiring emergency surgery. Colorectal cancer is the third most common cancer in France. An increased risk of colorectal cancer after acute appendicitis has been suggested. We aimed to assess the frequency of hospitalization for colon cancer after appendicitis in a nationwide analysis.

Methods

Using the French Hospital Discharge Database (PMSI), we included all patients aged 18-59 years presenting with acute appendicitis between 2010 and 2015. Univariate and multivariate analyses were performed to compare colon cancer occurrence in these patients vs a control-matched population with a hospital stay for trauma in the same period. Patients presenting strong risk factors for colorectal cancer were excluded.

Findings

A total of 230,349 patients with acute appendicitis (exposed group) were included. We used a propensity score to match each exposed patient with two unexposed patients (controls) to ensure the comparability of the groups, resulting in a control group of 460,698 patients. Univariate analysis found significantly more colon cancer in the appendicitis group, especially during the first year after appendicitis (5 per 10,000 vs 1 per 10,000, p < 0.000, this corresponds to 111 patients in the appendicitis group), namely within the first 6 months. Survival analysis confirmed patients treated for appendicitis present a 4 times higher risk of being diagnosed with colon cancer than control patients during the first year of follow-up (sHR = 4.67 (95% CI: 3.51-6.21), and 8 times higher during the first 6 months (sHR = 8.39; 95% CI: 5.41-12.99). The association was even more marked for right-sided colon cancer (sHR = 8.25; 95% CI: 5.03-13.54 during the 1st year). While the risk of diagnosis of colon cancer was also significant for patients over 40 years, it was even greater in patients under 40 years, who had between a 6-fold and 12-fold increase in risk.

Interpretation

In this population-based study, we found that acute appendicitis seems to be a warning sign for colon cancer (reverse causality) in both middle-aged and younger adults. The risk of presenting with cancer colon was higher during the first six months after acute appendicitis. This raises the issue of routine diagnostic work-up in adults presenting with acute appendicitis.

Funding

Regional Council of Burgundy.