Appendiceal neoplasm incidence and mortality rates are on the rise in Australia

Incidence of occult appendiceal neoplasm in patients over 40 years with acute appendicitis: A single-institution review

OBJECTIVE

To investigate the incidence of occult appendiceal neoplasm in patients aged 40 years and over who underwent appendicectomy for appendicitis.

METHODS

The clinical coding electronic database was used to identify patients aged 40 years and over who were diagnosed with appendicitis from September 2010 to September 2022. Patients were included if they were managed operatively.

DESIGN

Retrospective cohort study.

SETTING

Modified Monash category 3 (large rural town).

PARTICIPANTS

Patients aged 40 years and over undergoing appendicectomy for appendicitis.

MAIN OUTCOME MEASURES

Incidence of appendiceal neoplasm within appendicectomy specimen.

RESULTS

A total of 279 patients aged 40 years and over underwent appendicectomy, with a median age of 53 years (range 40-95). Nineteen patients (7%) were found to have a primary neoplastic lesion within the appendix: seven neuroendocrine neoplasms (37%), six sessile serrated lesions (32%), two colonic-type adenocarcinoma (11%), two goblet cell adenocarcinoma (11%) and two appendiceal mucinous neoplasms (11%). Additionally, one patient had a metastatic adenocarcinoma of pancreaticobiliary aetiology.

CONCLUSIONS

Occult appendiceal neoplasm was higher than reported in the literature in our cohort. This would support appendicectomy as the treatment of choice for patients aged 40 years and over with acute appendicitis and caution against nonoperative management in this demographic.

Incidence rate and histology of appendiceal neoplasms in complicated versus uncomplicated appendicitis: A meta-analysis and systematic review

INTRODUCTION

Studies evaluating the rate and histology of appendiceal neoplasms between complicated and uncomplicated appendicitis include a small number of patients. Therefore, we sought a meta-analysis and systematic review comparing the rates and types of appendiceal neoplasm between complicated and uncomplicated appendicitis.

METHODS

We included articles published from the time of inception of the datasets to September 30, 2022. The electronic databases included English publications in Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, and Scopus.

RESULTS

A total of 4962 patients with appendicitis enrolled in 4 comparative studies were included. The mean age was 43.55 years (16- 94), and half were male (51%). Based on intra-operative findings, 1394 (38%) had complicated appendicitis, and 3558 (62%) had uncomplicated appendicitis. The overall incidence rate of neoplasm was 1.98%. No significant difference was found in the incidence rate of appendiceal neoplasm between complicated (3.29%) and uncomplicated (1.49%) appendicitis (OR 0.44, 95% CI 0.16- 1.23; p < 0.087; I2 = 54.9%). The most common appendiceal neoplasms were Neuroendocrine Tumors (NET) (49.21%), Nonmucinous Adenocarcinoma (24.24%), Mixed Adeno-Neuroendocrine Tumor (MANEC) (11.40%), Mucinous Adenocarcinoma (4.44%). There was a significant difference between complicated and uncomplicated appendicitis in rates of adenocarcinoma (50% vs. 13%), NET (31% vs. 74%), MANEC (19% vs. 13%) (P < 0.001).

CONCLUSION

While there was no significant difference in the overall neoplasm rate between complicated and uncomplicated appendicitis, the NET rate was significantly higher in uncomplicated appendicitis. In comparison, the Adenocarcinoma rate was considerably higher in Complicated appendicitis. These findings emphasize the importance of evaluating risk factors for neoplasm when considering appendectomy in patients with appendicitis.

Epidemiological trends of gallbladder cancer in Australia between 1982 to 2018: A population-based study utilizing the Australian Cancer Database

Backgrounds/Aims

Gallbladder cancer (GBC) is a rare neoplasm. The epidemiology of GBC has not been updated in Australia for over five decades.

Methods

Data of all Australian patients diagnosed with GBC at any age from 1982 to 2018 were identified from the Australian Cancer Database. Age-standardized rates were calculated and joinpoint analysis was performed to ascertain the trends of incidence and mortality of GBC.

Results

Between 1982 and 2018, there were 22,745 cases of GBC and 11,054 GBC-related deaths in Australia. There were three distinct periods showing changed incidence. Period 1 (1982–1995) was stable. Period 2 (1996–2006) showed reduced incidence in females (3.6 to 2.8/100,000; p < 0.01) and all Australians (3.7 to 2.8/100,000, p < 0.01). Period 3 (2006–2017) demonstrated significantly increased incidence in all groups (males: 2.7 to 4.0/100,000, p < 0.01; females: 2.8 to 3.5/100,000, p < 0.01; all Australians: 2.8 to 3.7/100,000, p < 0.01). Incidence between females and males had declined from 1.10 : 1 in 1982 to 0.87 : 1 in 2017. There was a 71% reduction in mortality (3.1 to 0.9/100,000; p < 0.01). Median age at diagnosis increased from 69.7 to 74.3 years for females and from 67.2 to 73.3 years for males. Increasing incidence in the 6th to 8th decade of life in males, compared to previous years, was noted.

Conclusions

Incidence, mortality, sex, and age of GBC have significantly changed in Australia since 1982. Rising incidence of GBC in Australia warrants further investigation.

Incidentally found mucinous epithelial tumors of the appendix with or without pseudomyxoma peritonei: diagnostic and therapeutic algorithms based on current evidence

Mucinous appendiceal tumors with or without the pseudomyxoma peritonei (PMP) syndrome are rare, but often present as an incidental finding. The confusing histology and lack of large prospective trials result in a considerable diagnostic and therapeutic challenge in these patients. We propose treatment algorithms in patients with incidentally found mucinous epithelial appendiceal tumors, with or without PMP, based on the currently available evidence. The therapeutic approach should take into account the histology and grade of the primary appendix tumor, as well as those of the associated peritoneal disease.

Immunohistochemistry features and molecular pathology of appendiceal neoplasms

Primary appendiceal neoplasms (ANs) comprise a heterogeneous group of tumors. The pathology and classification of ANs have been controversial, and thus, a new classification of these neoplasms was published in the World Health Organization (WHO) classification of tumors (5th edition, 2019). However, immunohistochemistry (IHC) features of epithelial ANs are not explained in this edition and the limited data on the molecular pathology of these tumors shows inconsistent findings in various studies. It would be useful to identify biomarkers appropriate for each subtype to better aid in treatment selection. Therefore, we reviewed the literature to investigate what is known of the molecular pathology and IHC features of the most frequently diagnosed pathological subtypes of epithelial ANs based on the recent classification. The inconsistencies in research findings regarding the IHC features and molecular pathology of ANs could be due to differences in the number of samples and their collection and preparation as well as to the lack of a universally accepted classification system for these neoplasms. However, the literature shows that epithelial ANs typically stain positive for MUC2, CK20, and CDX2 and that the expression of SATB2 protein could be used as a biomarker for appendix tumor origin. Low-grade appendiceal mucinous neoplasms tend to have mutations in KRAS and GNAS but are usually wild-type for BRAF, APC, and P53. Conversely, appendiceal adenocarcinomas are frequently found with mutations in KRAS, GNAS, P53, PIK3CA, and APC, and have significant nuclear expression of β-catenin, loss of nuclear or nuclear and cytoplasmic expression of SMAD4, and loss of cytoplasmic membranous expression of E-cadherin. Goblet cell carcinomas (GCCs) typically stain positive for keratin and mucin markers and are frequently mutated in P53 and chromatin-modifier genes, but they tend to be wild-type for KRAS, GNAS, APC, and PIK3CA. The expression of CK7 and SATB2 proteins is usually negative in appendiceal neuroendocrine neoplasms and they lack the mutations in common cancer-associated genes including APC, BRAF, SMAD4, and PIK3C. The available data suggest that GCCs have distinct molecular and immunohistochemical features and that they have characteristics more in common with adenocarcinoma than classical neuroendocrine tumors. In addition, MSI does not seem to have a role in the pathogenesis of epithelial ANs because they are rarely detected in these tumors. Finally, hereditary predisposition may have a role in the development of ANs because heterozygous CTNNβ1, NOTCH1, and NOTCH4 germline mutations have recently been identified in low and high grades ANs.