Missing First Mammogram Increases Risk for Future Breast Cancer by More Than 50%, Study Finds

Women who miss their first mammography screening at the eligible age face a significantly heightened risk of late-stage breast cancer diagnosis and mortality over the ensuing 25 years, according to a comprehensive population-based cohort study conducted in Sweden.¹

Ziyan Ma

Courtesy of Karolinska Institutet

The research tracked 432,775 women invited to attend mammography screening over nearly 3 decades and found that 32.1% did not participate in their first screening invitation. These initial nonparticipants demonstrated persistently low adherence to subsequent screenings, were more likely to have breast cancer diagnosed at advanced stages, and exhibited a 40% higher adjusted risk of breast cancer mortality compared to participants.¹

"Screening programmes remain insufficiently responsive to this high risk group, allowing persistent disengagement from preventive care and increasing the likelihood of late stage diagnoses and death. This represents a critical missed opportunity for intervention," study authors wrote in the BMJ.¹

"Skipping the first mammogram is a strong indicator of who is at risk of late detection and higher mortality. Our results show that missing the first mammogram is not just a one-time choice, but often marks the beginning of a long-term pattern of not attending check-ups," first author, Ziyan Ma, a doctoral student at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, said in a statement.²

Late-Stage Diagnoses Persist

While the science of screening, diagnosis, and treatment of breast cancer has advanced significantly, population-based research shows that up to 22% of cases are already stage III/IV disease at diagnosis.³ Mammography remains a pivotal tool for early detection and has been shown to reduce late-stage diagnoses. Ma and colleagues note that although diagnosis of advanced stage disease is more frequent among women who did not attend their most recent screening⁴ there is more to be learned about the longer-term implications of early screening. The researchers set out to clarify whether early screening behavior—specifically participation at the first invitation—can predict future screening adherence, breast cancer incidence, tumor characteristics, and mortality outcomes.

For the population-based study, the investigators tapped the Swedish Mammography Screening Register, which is tied to multiple national databases. The followed women invited to an initial breast cancer screening at ages 40 or 50 between 1991 and 2020, with follow-up through 2023 (up to 25 years). They excluded women with cancer diagnosed before their first invitation.

Ma et al defined screening participation based on attendance status at the first invitation and subsequent rounds of screening mammography, with the program inviting women biennially (every 18-24 months depending on age). Breast cancer incidence, mode of detection (screen-detected, interval, or symptom-detected after missed screening), tumor stage, and mortality were identified from national cancer and cause-of-death registries.

Findings

Breast cancer diagnoses. During the approximately 5 million person-years of observation, researchers documented 16,059 cases of breast cancer. They reported that although the overall cumulative 25-year incidence of breast cancer was similar among those who participated in first screening (7.8%) and non-participants (7.6%), the mode of detection differed substantially.¹

First screening nonparticipants were significantly more likely to present with symptom-detected cancers after missed screening episodes (2.6% vs 0.7% in participants), which tend to be diagnosed at later and more advanced stages. Adjusted analyses confirmed that non-participation at first screening correlated with increased odds of:

• invasive tumors (odds ratio [OR] 1.32)
• larger tumor size (OR 1.32 for >20 mm size)
• positive lymph node involvement (OR 1.18)
• distant metastases (OR 3.20)

For tumor stages, the odds of stage III and IV cancers were 1.53 and 3.61 times higher respectively in nonparticipants compared to first-screening attendees.¹

Mortality. Mortality analyses were conducted over 6.8 million person-years, with 1603 breast cancer deaths documented. The analyses revealed a cumulative 25-year breast cancer mortality rate of 9.9 per 1000 women among non-participants, compared with 7.0 per 1000 among participants. The adjusted hazard ratio for breast cancer death in non-participants was 1.40 (95% CI 1.26 to 1.55). This elevated risk of death was greater than that observed for non-breast cancer mortality, suggesting a disease-specific effect largely attributed to delays in diagnosis rather than differences in overall health status.¹

Screening behavior. The authors also reported that nonparticipation in first breast-cancer screening was a strong predictor of subsequent poor screening adherence. First screening nonparticipants attended an average of 4.77 screenings versus 8.74 among initial participants across 10 rounds of invitations. This persistent disengagement highlights the first screening invitation as a critical intervention point. Non-participation was not fully explained by sociodemographic factors, as adjustment for education, income, family history, and comorbidity did not eliminate the associations with worse cancer outcomes.¹

Among the study's limitations the authors acknowledged the observational design, which cannot exclude residual confounding from unmeasured behavioral factors such as health-seeking attitudes. The register excludes opportunistic screening, although results were consistent after excluding women with family cancer history. Generalizability of the findings may be limited outside organized screening settings such as Sweden's.¹

"Unlike many traditional risk factors that need specialised assessments or additional testing, information on first screening participation is already routinely captured in existing healthcare systems, making identification of this high risk group immediately available at the point of first invitation."¹ Implementing proactive and tailored strategies at the initial screening invitation stage may alter the trajectory of breast cancer outcomes and improve survival for many women, authors concluded.

References

1. Ma Z, He W, Zhang Y, et al. First mammography screening participation and breast cancer incidence and mortality in the subsequent 25 years: population based cohort study. BMJ. 2025;390:e085029. doi:10.1136/bmj-2025-085029

2. Missing first mammogram raises breast cancer death risk. News release. Karolinska Institutet. September 25, 2025. Accessed September 25, 2025. https://news.ki.se/missing-first-mammogram-raises-breast-cancer-death-risk

3. Walters S, Maringe C, Butler J, et al. Breast cancer survival and stage at diagnosis in Australia, Canada, Denmark, Norway, Sweden and the UK, 2000-2007: a population-based study. Br J Cancer. 2013;108(5):1195-208. doi:10.1038/bjc.2013.6

4. Webb ML, Cady B, Michaelson JS, et al. A failure analysis of invasive breast cancer: most deaths from disease occur in women not regularly screened. Cancer. 2014;120(18):2839-46. doi:10.1002/cncr.28199