We investigated the utility of regular radiological follow-up on the early detection of contralateral breast cancer(CBC) and prognosis in patients with metachronous bilateral breast cancer.

Between 1983 and 2010, 49(2.1%) metachronous bilateral breast cancer patients were identified among a total of 2,343 cases of invasive or in situ breast carcinomas. We reviewed the patients' medical records including age, stage, duration between the first and second breast cancer diagnosis, operation method, recurrence, and breast cancer-specific survival.

The mean ages at the first and second breast cancer diagnosis were 43.8 and 49.2 years, respectively. The mean duration between the first and second breast cancer diagnosis was 68.9 months (range, 7–266 months). Regular radiological follow-up with annual mammography(MMG) with or without ultrasonography was conducted in 28 patients (63.6%, Group 1), and no regular follow-up was performed in 12 patients (27.3%, Group 2). The median follow-up duration was 150 months. In a comparative analysis, Group 1 patients exhibited more stage 0 and stage 1 malignancies (82.1% vs. 25%, P =0.006) as second cancer and the same or an improved stage (71.4% vs. 33.3%, P =0.042) of second cancer compared to Group 2 patients. Breast cancer-specific survival rates between the two groups after the first cancer occurrence were higher in Group 1 patients compared to Group 2 patients, although this did not reach statistical significance.

Screening for CBC with regular radiological follow-up could result in early detection of CBC, less invasive surgical procedures, and enhanced breast cancer-specific survival outcomes.