Aspects of Lifestyle and Symptoms in Colorectal Cancer Screening: A Population-Based Survey Study in Finland

Sanni Helander

Research output: Book/ReportDoctoral thesisCollection of Articles


An essential part of the overall evaluation of any cancer screening programme is exploring its potential psychosocial effects. Colorectal cancer (CRC) screening may cause changes in health behaviour. In 2010, the Finnish Mass Screening Registry (MSR) began a population study on the lifestyle and quality of life effects of CRC screening. This thesis examines whether there were differential developments in self- reported lifestyle or lower gastrointestinal (LGI) symptom perception at ages 59–61 among CRC screening invitees and non-contacted controls. The role of perceived LGI symptoms in CRC screening attendance and the consequences of a postal survey study on cancer screening attendance were also investigated.

In the Finnish colorectal cancer screening programme, men and women aged 60 were randomized to screening and control groups (1:1). Lifestyle and symptoms were inquired about with a self-administered postal questionnaire one year before and one year after the first-ever CRC screening at age 60 or at a corresponding time for controls. From both survey rounds, 2508 pairs of completed questionnaires were available for analysis from the screening group and 2387 from the control group. The outcome was a 2-year change in the total lifestyle index of CRC risk factors (diet, physical activity, body mass index [BMI], alcohol consumption, and smoking status) (Study I) or a symptom index of eight various LGI symptoms reported as never, occasionally or constantly (Study II). For the association of pre-screening self- reported LGI symptoms and CRC screening attendance, incidence rate ratios were used (Study II). To estimate the potential harm of studying psychosocial consequences via postal survey, we sought to determine whether administering a pre-screening questionnaire affects the subsequent attendance proportion in the first-ever CRC screening and subsequent screenings (Studies III–IV). Furthermore, we investigated whether previous exposure to a lifestyle survey and additional cancer screenings during the same calendar year affected attendance to organized breast and cervical cancer screenings (Study V).

No differences in the CRC-related lifestyle between the screening arms or screening attendance were found. The lifestyle index used in the study changed in the negative direction from the CRC point of view during the two-year follow-up. However, there was no implication that screening status affected this progression. Results show that neither invitation to nor attendance in FOBT-based CRC screening leads to a less healthy lifestyle (Study I). Similarly, the temporal changes in symptom perception were congruent in controls and screening attenders and non-attenders, meaning no effects of screening on LGI symptom perception were presented. Pre-screening symptoms increased attendance to CRC screening in men. In women, symptoms did not affect the attendance (Study II).

In the 60-year-olds who had been sent the survey, the attendance in CRC screening was lower (57%) than in those who had not received the questionnaire (60%) (Study III). The same was observed after the follow-up survey in 2012. The screening attendance rate in 2013 was 58% in the survey population and 64% in those unsurveyed. The attendance pattern created by the initial survey continued even when questionnaires were no longer being sent. On the third screening round in 2015, the attendance rate was 62% among those who had been sent the questionnaires in 2010 and 2012 and 66% in those never surveyed (P
The present study found no unfavourable changes in total lifestyle or LGI symptom perception in the studied age group due to CRC screening. Results are reassuring from the perspective of CRC screening evaluation. LGI symptoms merit attention in population education and information concerning CRC screening because perceived symptoms seem to affect screening attendance, at least among men. Exploring potential psychosocial effects must be carried out in a carefully planned and monitored manner not to harm screening attendance. Introducing a new cancer screening, i.e. CRC screening, resulted in another third cancer screening invitation during the same year for 60-year-old women, who were neither harmed nor benefited from the high attendance of breast and cervical cancer screenings.
Original languageEnglish
Place of PublicationTampere
ISBN (Electronic)978-952-03-2497-1
Publication statusPublished - 2022
Publication typeG5 Doctoral dissertation (articles)

Publication series

NameTampere University Dissertations - Tampereen yliopiston väitöskirjat
ISSN (Print)2489-9860
ISSN (Electronic)2490-0028


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