Impact of screening on late-stage breast cancer in the Netherlands: a population-based cohort study (2007-2016)
Yixuan Lin1, Grigory Sidorenkov2, Jing Wang3
1Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Background:
Breast cancer (BC) screening can detect BC early to reduce mortality. This study evaluated the impact of BC screening on the incidence of late-stage BC in a population-based setting in the Netherlands.
Methods:
All Dutch women aged 50-74 years diagnosed with invasive BC or ductal carcinoma in situ (DCIS) between 2007 and 2016 (n = 108,253) were included from the Netherlands Cancer Registry. BC was classified as screen-related if diagnosed within 24 months the last screening attendance, and as screen-detected if diagnosed within 12 months after positive screening result. Late-stage BC was defined in two ways: advanced BC, including TNM stages T3, T4, or N2, N3, or M1, and metastatic BC, defined as M1 disease. Multivariable logistic regression adjusted for age and socioeconomical status was used to assess associations between screen-related and screen-detected BC and late-stage BC. Analyses were done overall and stratified by HR/HER2-defined subtypes.
Findings:
BC incidence increased between 2007 and 2013 and decreased slightly thereafter. Advanced BC incidence decreased between 2007 and 2016, while metastatic BC rates remained stable. Non-screen-related BCs were significantly more likely to be present as late disease compared with screen-related (advanced BC: aOR = 3.24, 95%CI = 3.12-3.37; metastatic BC: aOR = 6.40, 95%CI = 5.98-6.85). Similarly, non-screen-detected BCs had substantial higher odds of being late than screen-detected BCs (advanced BC: aOR = 5.54, 95%CI = 5.31-5.78; metastatic BC: aOR = 12.66, 95% CI = 11.41-14.05) than screen-detected BCs. These associations were observed across all HR/HER2-defined subtypes.
Interpretation:
Population-based screening is strongly associated with earlier-stage breast cancer at diagnosis, consistently across all immunohistochemistry subtypes.
