Attending the breast screening programme after breast cancer treatment: a population-based study.

Introduction: In the Netherlands, breast cancer patients are treated and followed at least 5 years after diagnosis. Furthermore, all women aged 50-74 are invited biennially for mammography by the nationwide screening programme. The relation between the outpatient follow-up (follow-up visits in the outpatient clinic for 5 years after treatment) and the screening programme is not well established and attending the screening programme as well as outpatient follow-up is considered undesirable. This study evaluates potential factors influencing women to attend the screening programme during their outpatient follow-up (overlap) and the (re-)attendance to the screening programme after 5 years of outpatient follow-up.

Methods: Data of breast cancer patients aged 50-74 years, treated for primary breast cancer between 1996 and 2007 were selected from the Netherlands Cancer Registry and linked to the National Breast Cancer Screening Programme in the Northern region. Cox regression analyses were used to study women (re-)attending the screening programme over time, possible overlap with the outpatient follow-up and factors influencing this.

Results: In total 11227 breast cancer patients were included, of whom 19% attended the screening programme after breast cancer treatment, 4.4% within 5 years and 15.4% after more than 5 years. Factors that independently influenced attendance within 5 years as well as more than 5 years after treatment were: interval tumours (HR 0.77; 95%CI 0.61-0.97 and HR 0.69; 95%CI 0.53-0.88, ref: screen-detected tumours), receiving adjuvant radiotherapy (HR 0.65; 95%CI 0.47-0.90 and HR 0.66; 95%CI 0.47-0.93; ref: none) and diagnosis of in situ tumours (HR 1.67; 95%CI 1.25-2.23 and HR 1.39; 95%CI 1.05-1.85; ref: stage I tumours). Non-screen related tumours (HR 0.41; 95%CI 0.29-0.58) and recent diagnosis (HR 0.89 per year; 95%CI 0.86-0.92) were only associated with attendance within 5 years after treatment.

Conclusion: The interrelation between outpatient follow-up and screening should be improved to avoid overlap and low attendance to the screening programme after outpatient follow-up. Breast cancer patients should be informed that attending the screening programme during the outpatient follow-up is not necessary.