Early-onset colorectal cancer incidence in Norway: a national registry-based study (1993-2022) - analyzing subsite and morphology trends

Q: What is the main purpose of the study on early-onset colorectal cancer in Norway?

To provide up-to-date incidence patterns of EOCRC, emphasizing age-specific differences in tumor site and morphology, using a largely screening-naive population.

Q: Which age group and tumor types drove the increase in EOCRC incidence?

EOCRC in ages 20–49 increased, mainly caused by left-sided colon and rectal cancers.

Q: How did incidence trends differ between older age groups compared with EOCRC?

Ages 50–74 showed stable overall incidence, while ages 75 and above had an increased incidence largely associated with right-sided colon cancer, with changes over time.

Sep 21, 2026

Uploaded by Ophelia

Nationwide registry data quantify how early-onset colorectal cancer (EOCRC) incidence evolved in Norway from 1993–2022, with attention to age-specific differences in tumor site and morphology. Cancer Registry of Norway records were analyzed with age-standardized incidence rates and joinpoint regression to estimate annual and average annual percentage change. Results show a sustained rise in EOCRC (20–49 years), driven largely by left-sided colon and rectal cancers, while incidence in older groups remained stable or increased more recently.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Background

Materials and methods

Results

Conclusions

Introduction

Epidemiology of colorectal cancer in Norway

Prognostic and molecular relevance of subsite

Rationale for studying neuroendocrine neoplasms and screening

ORIGINAL ARTICLE Early-onset colorectal cancer incidence in Norway: a national registry-based study (1993-2022) analyzing subsite and morphology trends M. F. Ystgaard1, T. Å . Myklebust2 , 3, J. Smeby1, I. K. Larsen2, T. K. Guren1, E. H. Kure4, K. M. Tveit5, B. Glimelius6, M. G. Guren1 , 5 􀀁 & J. Hamfjord1, 4, 7 1Department of Oncology, Oslo University Hospital, Oslo; 2Department of Registration, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo; 3Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund; 4Department of Cancer Genetics, Institute for Cancer Research, Oslo University Hospital, Oslo; 5Division of Cancer Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; 6Department of Immunology, Genetics and Pathology, Uppsala university, Uppsala, Sweden; 7Lovisenberg Diaconal University College, Oslo, Norway Available online 2 August 2024 Background: The overall incidence of colorectal cancer (CRC) has decreased or stabilized in most high-income countries, but an increase is observed in adults <50 years of age, termed early-onset colorectal cancer (EOCRC) . Materials and methods: We conducted a nationwide registry-based study to provide up-to-date incidence patterns of EOCRC, with an emphasis on age-speciﬁc differences in tumor site and morphology. We extracted data from the Cancer Registry of Norway, with completeness estimated to be >99% . We calculated age-standardized incidence rates and used joinpoint regression to provide annual percentage change (APC) and average annual percentage change (AAPC) . National screening started in Norway in 2022; hence, this study is on a largely screening-naive population. Results: There were 107 523 cases of CRC diagnosed between 1993 and 2022 eligible for analysis. The incidence of EOCRC (20-49 years) increased by 66%(AAPC 1 .3), caused by left-sided colon and rectal cancers. The age group 50- 74 years had a stable overall incidence (AAPC e0 . 2) . In the age group 􀀃75 years, an increased incidence (AAPC 0 .8) was observed, mainly by right-sided colon cancer, which increased until 2016 (APC 2.5), followed by a decrease (APC e0 .9) . EOCRC adenocarcinomas increased by 77%(AAPC 1 .4) . Neuroendocrine neoplasms were rare (1 .4%), but increased in all age groups (AAPC 4 . 2) . EOCRC showed a signiﬁcantly higher proportion of distant metastases at time of diagnosis compared with the age group 􀀃75 years (28 .6% versus 18 . 2%, P < 0.001) . Conclusions: We observed a sustained increase in EOCRC, caused by left-sided colon and rectal cancers. Unlike countries with established screening programs, the incidence of the age group >50 years remained stable or increased, but declined in recent years. Key words: early-onset, incidence, colorectal cancer, primary tumor location, neuroendocrine, adenocarcinoma INTRODUCTION Colorectal cancer (CRC) is one of the most common malignancies worldwide and is the second leading cause of cancer death.1 Norway has a high incidence of CRC, which has been increasing until the past two decades, when it has subsequently leveled out.2,3 The incidence in most high-income countries has been either stable or decreasing, but there have been several reports of increasing incidence rates in younger adults( <50years old), termed early-onset colorectal cancer (EOCRC) .4,5 *Correspondence to: Prof. Marianne G. Guren, Department of Oncology, Oslo University Hospital, P.O. Box 4956 Nydalen, Oslo N-0424, Norway. Tel: þ47 22 93 40 00 [E-mail:](E-mail: marianne.gronlie.guren@ous-hf.no)[ marianne.gronlie.guren@ous-hf.no](E-mail: marianne.gronlie.guren@ous-hf.no) (M. G. Guren). 2949-8198/© 2024 The Authors. Published by Elsevier Ltd on behalf of European Society for Medical Oncology. This is an open access article under the CC BY license ([http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/)). Compared with late-onset CRC (LOCRC, a

FAQs

What is the main purpose of the study on early-onset colorectal cancer in Norway?

To provide up-to-date incidence patterns of EOCRC, emphasizing age-specific differences in tumor site and morphology, using a largely screening-naive population.

Which age group and tumor types drove the increase in EOCRC incidence?

EOCRC in ages 20–49 increased, mainly caused by left-sided colon and rectal cancers.

How did incidence trends differ between older age groups compared with EOCRC?

Ages 50–74 showed stable overall incidence, while ages 75 and above had an increased incidence largely associated with right-sided colon cancer, with changes over time.

Sep 21, 2026

Uploaded by Ophelia