Postlumpectomy imaging: is there a role for the study of the contralateral breast?-a retrospective cohort.

Background: Some patients with breast cancer submitted to breast-conserving surgery might benefit from a postlumpectomy imaging examination previously to radiation therapy. This aims to document the complete removal of cancer and might be accomplished using mammogram with breast and axillary ultrasonography. These modalities study not only the affected side but also the contralateral side. In fact, it is well-documented that women with breast cancer have an increased risk for contralateral breast cancer. Thus, we intended to evaluate the value of postlumpectomy imaging undertaken before adjuvant radiotherapy regarding the evaluation of the contralateral breast and axilla.

Methods: In this retrospective study, medical records for patients with breast cancer submitted to breast-conserving surgery and referred to our radiotherapy unit between 2018 and 2019 were reviewed. All patients had to be submitted to bilateral mammogram with breast and axillary ultrasonography previously to radiotherapy. Patients with bilateral disease or with a history of breast cancer were excluded.

Results: One thousand two hundred forty patients were analyzed. 19 (1.5%) had suspicious findings for contralateral breast disease, and 8 (0.6%) had a re-excision positive for residual malignancy. Higher age, invasive lobular carcinoma associated or not with lobular carcinoma in situ, and presence of lobular carcinoma in situ were associated with an increased risk for residual disease.

Conclusion: Contralateral evaluation as part of postlumpectomy imaging revealed itself useful at detecting contralateral cancer, with some demographic and clinical features being associated with an increased risk for residual disease.