Objective: The purpose of this study was to determine the performance and added value of bilateral mammography in identifying cancers distant from sites of presenting breast symptoms in women 30-39 years old.
Materials and methods: A search identified consecutively registered women 30-39 years old who underwent mammography and ultrasound to evaluate focal breast symptoms between June 2006 and August 2016. Outcomes were determined by imaging and pathologic analysis through linkage with a tumor registry. Medical records were reviewed to determine the presence of breast cancer risk factors. Lifetime breast cancer risk was calculated with the International Breast Cancer Intervention Study model.
Results: The study included 4426 diagnostic examinations of 3997 women 30-39 years old. Sixty-eight breast cancers were diagnosed (cancer detection rate, 15.4 per 1000 examinations). Sixty examinations led to biopsy of a finding distant from the presenting symptom site, yielding nine incidental malignancies (positive predictive value, 15.0%; incidental cancer detection rate, 2.0 per 1000 examinations [9/4426]). Among the other 59 cancers diagnosed in the symptomatic area, bilateral mammography depicted multicentric or contra-lateral disease in seven (11.9%). Average lifetime risk of breast cancer among the 68 women with cancer was significantly higher than that among age-matched control subjects (22.8% vs 13.1%, p < 0.001); 45 of these 68 women (66.2%) had identifiable risk factors. Lifetime risk among the nine women with incidental cancers was higher than that of age-matched control subjects, although without statistical significance (24.9% vs 13.2%, p = 0.07).
Conclusion: Bilateral mammographic evaluation of women 30-39 years old presenting with breast symptoms yielded an additional 2.0 incidental cancers per 1000 examinations. The low added cancer yield may support the judicious rather than routine use of mammography in this patient cohort.
Keywords: breast cancer risk; breast symptoms; breast ultrasound; mammography.