Surveillance Outcomes by Imaging Methods in the First 5 Years After Breast Cancer Surgery.

Objective: To compare the outcomes of imaging methods (mammography alone, ultrasound [US] alone, mammography combined with US, and magnetic resonance imaging [MRI]-based examination) for surveillance during the first 5 years after breast cancer surgery.

Materials and methods: This retrospective cohort study analyzed the medical records of patients who underwent breast cancer surgery at a single institution between January 2011 and December 2015. Imaging surveillance was performed at 6-month or 1-year intervals during the first 5 years.

Results: A total of 6371 women (median age, 49 years; age range, 20-90 years) underwent 28199 mammograms, 42759 US, and 2619 MRI examinations. Of 172 second breast cancer diagnoses, 19 (11.0%) were interval cancers. Mammography combined with US demonstrated higher cancer detection rate (CDR) compared to mammography alone (odds ratios [OR] = 3.31, 95% confidence interval [CI]: 1.52-8.96, P = 0.009) and US alone (OR = 2.80, 95% CI: 1.71-4.65, P < 0.001), whereas there was no statistical significance when compared with MRI-based examinations (OR = 0.89, 95% CI: 0.49-1.74, P > 0.999). A statistically significant interaction was observed between the mammographic breast density (MBD) and CDR of the imaging methods (P for interaction = 0.003).

Conclusion: The CDR of surveillance mammography combined with US was comparable with that of MRI-based examinations in an intensive surveillance setting. Considering the significant interaction between MBD and the CDR, a tailored approach for surveillance based on breast density is warranted.