AUTHOR=Voigtländer Sven , Hakimhashemi Amir , Grundmann Nina , Rees Franziska , Meyer Martin , Algül Hana , Müller-Nordhorn Jacqueline 

TITLE=Trends of colorectal cancer incidence according to age, anatomic site, and histological subgroup in Bavaria: A registry-based study

JOURNAL=Frontiers in Oncology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.904546

DOI=10.3389/fonc.2022.904546

ISSN=2234-943X

ABSTRACT=Background:
Recent studies reported an increase in colorectal cancer incidence for adults below 50 years. There is a lack of studies distinguishing between histological subgroups, especially from Europe.
Methods:
Using data from the Bavarian Cancer Registry, we analyzed incidence trends in colorectal cancer by age (20-29, 30-39, 40-49, 50 years and above), anatomic site (colon without appendix, appendix, and rectum), and histological subgroup (adenocarcinoma, neuroendocrine neoplasms) from 2005 to 2019.We calculated three-year average annual age-standardized incidence rates for the beginning (2005-2007) and the end (2017-2019) of the study period and estimated average annual percentage change.
Results:
Data from 137,469 persons diagnosed with colorectal cancer were included. From 139,420 cases in total, 109,825 (78.8%) were adenocarcinomas (AC), 2,800 (2.0%) were neuroendocrine neoplasms (NEN), and 26,705 (19.2%) had different histology. This analysis showed a significant increase in three-year average annual age-standardized incidence rate (ASIR) of colorectal NEN in all age groups between 2005-2007 and 2017-2019 with the highest increase in the age groups 30-39 years (0.47 to 1.53 cases per 100,000 persons; +226%; p<0.05) and 20-29 years (0.52 to 1.38 cases per 100,000 persons; +165%; p<0.05). The increase was driven by appendiceal and rectal NEN but not by colonic NEN. Three-year average annual ASIR of colorectal AC did not change significantly for the age groups below 50 years. For those aged 50 years and above, three-year average annual ASIR of colorectal AC decreased significantly (132.55 to 105.95 cases per 100,000 persons; -20%; p<0.05]). The proportion of NEN increased across all age groups, especially in the younger age groups.
Conclusion:
Future studies that analyze trends in early-onset colorectal cancer need to distinguish between anatomic sites as well as histological subgroups and thus may provide useful information regarding the organization of colorectal cancer screening, which primarily helps to detect adenomas and adenocarcinomas.