TY - JOUR

T1 - Cohort Profile

T2 - The Danish SEQUEL cohort

AU - Levinsen, Anne Katrine Graudal

AU - Dalton, Susanne Oksbjerg

AU - Thygesen, Lau Caspar

AU - Jakobsen, Erik

AU - Gögenur, Ismail

AU - Borre, Michael

AU - Zachariae, Robert

AU - Christiansen, Peer

AU - Laurberg, Søren

AU - Christensen, Peter

AU - Hölmich, Lisbet Rosenkrantz

AU - de Nully Brown, Peter

AU - Johansen, Christoffer

AU - Kjær, Susanne K.

AU - van de Poll-Franse, Lonneke

AU - Kjaer, Trille Kristina

N1 - Funding Information: This work was supported by the Novo Nordisk Foundation [grant number NNF18OC0052543]; the Danish Cancer Society Scientific Committee [grant number R269-A15811]; and Helsefonden [grant number 20-B-0434]. We thank all the cancer survivors who participated in the questionnaire study. We would also like to thank the Danish National Clinical Quality Cancer Databases for access to their data: the Danish Breast Cancer Cooperative Group Database, the Danish Prostate Cancer Database, the Danish Lung Cancer Registry, the Danish Colorectal Cancer Group Database, the Danish Melanoma Database and the Danish National Lymphoma Registry. Funding Information: This work was supported by the Novo Nordisk Foundation [grant number NNF18OC0052543]; the Danish Cancer Society Scientific Committee [grant number R269-A15811]; and Helsefonden [grant number 20-B-0434]. Acknowledgements

PY - 2024

Y1 - 2024

N2 - Why was the cohort set up?The number of cancer survivors is increasing worldwide, largely due to ageing populations, advances in early detection and cancer treatment.1 The 5-year prevalences of cancer survivors in Denmark have increased by almost 200% from 2000 to 2020, and close to 6% of the Danish population have been diagnosed with cancer.2 Extensive research has established that globally, but also in countries with equal and free access to health care, there is social inequality in stage at cancer diagnosis, treatment provided and survival.3 Since the introduction of cancer treatment by surgery, then radiation and later systemic chemotherapy, late effects have been a part of the aftermath accompanying survival. Late effects are defined as physiological and psychological symptoms or disorders which occur during or after end of treatment and which may become long-term or chronic.1 Little is known about social inequality in late effects.A Danish national study of 458 646 adult cancer survivors showed a significantly increased risk of other diseases in all but one of 11 major diagnostic groups, such as diseases in the nervous system and endocrine, cardiovascular, metabolic and respiratory disorders, for cancer survivors across cancer types up to 17 years after treatment compared with cancer-free individuals. This cohort study included only cancer survivors free of the diseases in the diagnostic group prior to the date of the cancer diagnosis.4 A prospective cohort from the USA of more than 12 000 people observed a 37% higher risk of cardiovascular disease and up to 52% higher risk of heart failure in adult cancer survivors compared with cancer-free individuals, depending on cancer type and treatment.5 Additionally, systematic reviews and meta-analyses found that up to 49% of cancer survivors suffer from fatigue6 and 47% suffer from pain.7 A Danish nationwide study reported that 57% have impaired sex life.8 Furthermore, a systematic review of 20 studies of psychological symptoms among long-term cancer survivors showed that 21% reported having depression,9 and another systematic review of 43 studies on mood disorders among long-term cancer survivors found a prevalence of anxiety of 18%.10 An American population-based cohort study found that 20% of breast cancer survivors have lymphoedema 2 years after diagnosis.11 Late effects comprise several other conditions, including sleep problems, peripheral neuropathy, cognitive impairments, physical limitations, problems with body image, psychological issues and reduced quality of life, as well as familial, financial and employment problems.12,13 Thus, physical, psychological and social complications after cancer and cancer treatment should be considered. Not all late effects can be measured objectively, which makes it crucial to include the patient’s perspective.

AB - Why was the cohort set up?The number of cancer survivors is increasing worldwide, largely due to ageing populations, advances in early detection and cancer treatment.1 The 5-year prevalences of cancer survivors in Denmark have increased by almost 200% from 2000 to 2020, and close to 6% of the Danish population have been diagnosed with cancer.2 Extensive research has established that globally, but also in countries with equal and free access to health care, there is social inequality in stage at cancer diagnosis, treatment provided and survival.3 Since the introduction of cancer treatment by surgery, then radiation and later systemic chemotherapy, late effects have been a part of the aftermath accompanying survival. Late effects are defined as physiological and psychological symptoms or disorders which occur during or after end of treatment and which may become long-term or chronic.1 Little is known about social inequality in late effects.A Danish national study of 458 646 adult cancer survivors showed a significantly increased risk of other diseases in all but one of 11 major diagnostic groups, such as diseases in the nervous system and endocrine, cardiovascular, metabolic and respiratory disorders, for cancer survivors across cancer types up to 17 years after treatment compared with cancer-free individuals. This cohort study included only cancer survivors free of the diseases in the diagnostic group prior to the date of the cancer diagnosis.4 A prospective cohort from the USA of more than 12 000 people observed a 37% higher risk of cardiovascular disease and up to 52% higher risk of heart failure in adult cancer survivors compared with cancer-free individuals, depending on cancer type and treatment.5 Additionally, systematic reviews and meta-analyses found that up to 49% of cancer survivors suffer from fatigue6 and 47% suffer from pain.7 A Danish nationwide study reported that 57% have impaired sex life.8 Furthermore, a systematic review of 20 studies of psychological symptoms among long-term cancer survivors showed that 21% reported having depression,9 and another systematic review of 43 studies on mood disorders among long-term cancer survivors found a prevalence of anxiety of 18%.10 An American population-based cohort study found that 20% of breast cancer survivors have lymphoedema 2 years after diagnosis.11 Late effects comprise several other conditions, including sleep problems, peripheral neuropathy, cognitive impairments, physical limitations, problems with body image, psychological issues and reduced quality of life, as well as familial, financial and employment problems.12,13 Thus, physical, psychological and social complications after cancer and cancer treatment should be considered. Not all late effects can be measured objectively, which makes it crucial to include the patient’s perspective.

KW - cancer survivors

KW - inequality in cancer

KW - Survivorship

U2 - 10.1093/ije/dyad189

DO - 10.1093/ije/dyad189

M3 - Journal article

C2 - 38205845

AN - SCOPUS:85184788101

VL - 53

JO - International Journal of Epidemiology

JF - International Journal of Epidemiology

SN - 0300-5771

IS - 1

M1 - dyad189

ER -