Demographic trends in the incidence of malignant appendiceal tumours in England between 1995 and 2016: Population-based analysis

Abstract

Aims Recent data suggest that the incidence of malignant appendiceal tumours is increasing. This study aimed to determine temporal trends in the incidence of malignant appendiceal tumours within England and a possible influence by demographic factors. Methods All incident cases of appendiceal tumours in patients aged 20 years and above were identified from the National Cancer Registration and Analysis Service database between 1995 and 2016 using ICD-9/10 codes. Cancers were categorized according to histology. Joinpoint regression analysis was used to investigate changes in age-standardized incidence rates by age, sex, histological subtype and index of multiple deprivation quintiles, based on socioeconomic domains (income, employment, education, health, crime, barriers to housing and services and living environment). Average annual per cent changes (AAPCs) were estimated by performing Monte-Carlo permutation analysis. Results A total of 7333 tumours were diagnosed and 7056 patients were analysed, comprising 3850 (54.6 per cent) neuroendocrine tumours (NETs), 1892 (26.8 per cent) mucinous adenocarcinomas and 1314 (18.6 per cent) adenocarcinoma (not otherwise specified). The overall incidence of appendiceal tumours increased from 0.3 per 100 000 to 1.6 per 100 000 over the study interval. Incidence rate increases of comparable magnitude were observed across all age groups, but the AAPC was highest among patients aged 20–29 years (15.6 per cent, 95 per cent c.i 12.7–18.6 per cent) and 30–39 years (14.2 per cent, 12.2–16.2 per cent) and lowest among those aged 70–79 years (6.8 per cent, 5.7–8.0 per cent). Similar incidence rate increases were reported across all socioeconomic deprivation quintiles and in both sexes. Analysis by grade of NET showed that grade 1 tumours accounted for 63 per cent between 2010 and 2013, compared with 2 per cent between 2000 and 2003. Conclusions The incidence rate of malignant appendiceal tumours has increased significantly since 1995 and is mainly attributed to an increase in NETs. The increased diagnosis of low-grade NETs may in part be due to changes in pathological classification systems.

The other colon cancer: a population‐based cohort study of appendix tumour trends and prognosis

“…In a recent publication from the UK, Orchard et al similarly examined time trends in appendiceal tumours [19]. The authors determined that the main increase in cases was seen in low-grade NET and argue that this may either be associated with the overall rate of appendectomy or rather the handling of the appendix specimen.…”

“…In several studies older patients appear to be more at risk for a missed diagnosis when treated for a presumed appendicitis or during an interval appendectomy [17, 18]. In a recent publication from the UK, Orchard et al similarly examined time trends in appendiceal tumours [19]. The authors determined that the main increase in cases was seen in low‐grade NET and argue that this may either be associated with the overall rate of appendectomy or rather the handling of the appendix specimen.…”

Appendiceal neoplasms—A practical guide

“…2 However, the incidence has been increasing with numerous articles from both North America and Europe documenting a significantly increased incidence of appendiceal neoplasms (ANs) in recent decades, as high as 0.97 per 100 000 persons in the United States. [3][4][5] While most of the increased incidence may be attributed to a subset of pathologies, namely neuroendocrine histologies, the contemporary incidence of ANs establishes this pathology as a much less rare phenomenon, one that the average surgeon will likely encounter in the course of their practice. Of the more than 500 000 appendectomies performed yearly, approximately 0.9%-1.4% of these specimens will include AN.…”

“…Historically, these tumors have been considered extremely rare, with a reported incidence of 0.12 per million person‐years in the United States 2 . However, the incidence has been increasing with numerous articles from both North America and Europe documenting a significantly increased incidence of appendiceal neoplasms (ANs) in recent decades, as high as 0.97 per 100 000 persons in the United States 3–5 . While most of the increased incidence may be attributed to a subset of pathologies, namely neuroendocrine histologies, the contemporary incidence of ANs establishes this pathology as a much less rare phenomenon, one that the average surgeon will likely encounter in the course of their practice.…”

Survival outcomes used to validate version 9 of the American Joint Committee on Cancer staging system for appendiceal cancer

“…Although primary carcinomas of the appendix are rare malignancies, with approximately one to two cases per 100,000 people in the United States annually, [1][2][3] the incidence of appendiceal cancer has consistently increased over the past 3 decades, rising by 54%-232%. [2][3][4] Unfortunately, few clinical advances were made over the preceding decade because of the rare and heterogeneous nature of this disease. In addition, histologic subtype, as well as tumor grade and stage, is increasingly acknowledged as being strongly associated with variations in survival outcomes.…”