Delays in follow-up among women with abnormal results: a retrospective study based on population-based breast cancer screening programme in China.

Objective: Timely diagnostic follow-up subsequent to abnormal results is crucial for the efficacy of breast cancer screening programs. We aimed to identify the frequency and women-level factors of loss or delay in the follow-up for screening abnormalities in China.

Methods: This mixed-methods cohort study comprised a retrospective analysis of ultrasound based breast screening data collected from Boluo (site A), Lilin (site B), and Ordos (site C) in China from 2018 to 2021, and qualitative, semistructured interviews conducted with program leaders from the three local Maternal and Child Health (MCH) hospitals, respectively. According to the screening protocol, we assessed the follow-up of two screening results: (1) mammography after suspicious results in the ultrasound and (2) biopsy after positive results in the ultrasound or supplement mammography. The rates and timeliness of follow-up with diagnostic examinations were compared across the different sites and procedures, and logistic regression was employed to explore the women-level factors influencing failure or delay in follow-up.

Results: Of 7,939 women with abnormal screening results, 5,943 (74.86%) received final diagnostic tests, while 4,631 (58.33%) got final diagnosis timely. The follow-up rate for mammography was higher than that for biopsy. Site A performed better in follow-up, with an overall follow-up rate of 98.01%, which may be related to the provision of free biopsy services and the establishment of a robust referral system. Women aged 45 to 54 years (ref: 35-44 years; aOR = 1.18; 95% CI: 1.01, 1.38; P = 0.032) were more likely to be lost to follow-up. Women who had never attended breast screening (ref: ever screened; aOR = 1.15; 95% CI: 1.00, 1.32; P = 0.046) were at high risk for delayed follow-up. Conversely, women with a high level of education (aOR = 0.66; 95% CI: 0.59, 0.73; P < 0.001) and those with abnormal clinical breast examination results (ref: with normal results; aOR = 0.79; 95% CI: 0.69, 0.92; P = 0.002) were more likely to get timely follow-up.

Conclusions: The overall follow-up rate and quality among women with abnormal screening results showed significant regional variability, and still required to be improved. Moreover, women with higher age and lower educational levels were particularly at high risk for delayed follow-up care and deserved more attention.