Outcomes of breast conserving therapy: Recurrence, imaging findings and histological correlation.

Background: Breast conserving therapy (BCT) is the mainstay therapy in patients with early breast cancer and selected patients with locally advanced breast cancer. No formal audit has been performed on BCT at our institution.

Objectives: To determine the incidence and risk factors for ipsilateral breast tumour recurrence (IBTR). Study the imaging features of IBTR. Determine adherence to the proposed annual mammographic surveillance schedule.

Method: Clinical, radiological and histopathological records of patients who underwent BCT from 01 January 2011 to 31 December 2015 were reviewed. Patients were followed up for at least 5 years.

Results: Ninety-two patients were included in the study with a mean age of 54.3 years. Eighty of the 92 (87.0%) patients were imaged within 1-year post-BCT. Ipsilateral breast tumour recurrence was 6/92 (6.5%) with mean time to IBTR of 34.4 months. One of the 92 (1.0%) patients had a contralateral metachronous recurrence with no IBTR and 11/92 (12.0%) had distant metastases only. Pathological tumour size and extent (pT2) (68.5%) and pathological lymph node (pN0) (65.2%) were the most common locoregional staging. Infiltrating ductal carcinoma was the most common histological type (88%). Age < 35 years was associated with breast cancer recurrence (p < 0.01). Imaging findings of recurrence were microcalcification (odds ratio [OR]: 4), asymmetric density (OR: 4) and skin thickening (OR: 2.5).

Conclusion: The occurrence of IBTR following BCT in our unit is acceptable and comparable to local and international units. The accuracy of assessing the post-BCT breast for IBTR is in keeping with international standards.

Contribution: Improved radiological imaging interpretation of the post-BCT breast.