Intraoperative ultrasound guidance in breast-conserving surgery shows superiority in oncological outcome, long-term cosmetic and patient-reported outcomes: Final outcomes of a randomized controlled trial (COBALT)

BACKGROUND: The multicenter randomized controlled COBALT trial demonstrated that ultrasound-guided breast-conserving surgery (USS) results in a significant reduction of margin involvement (3.1% vs. 13%) and excision volumes compared to palpation-guided surgery (PGS). The aim of the present study was to determine long term oncological and patient-reported outcomes including quality of life (QoL), together with their progress over time.

METHODS: 134 patients with T1-T2 breast cancer were randomized to USS (N = 65) or PGS (N = 69). Cosmetic outcomes were assessed with the Breast Cancer Conservative Treatment cosmetic results (BCCT.core) software, panel-evaluation and patient self-evaluation on a 4-point Likert-scale. QoL was measured using the EORTC QLQ-C30/-BR23 questionnaire.

RESULTS: No locoregional recurrences were reported after mean follow-up of 41 months. Seven patients (5%) developed distant metastatic disease (USS 6.3%, PGS 4.4%, p = 0.466), of whom six died of disease (95.5% overall survival). USS achieved better cosmetic outcomes compared to PGS, with poor outcomes of 11% and 21% respectively, a result mainly attributable to mastectomies due to involved margins following PGS. There was no difference after 1 and 3 years in cosmetic outcome. Dissatisfied patients included those with larger excision volumes, additional local therapies and worse QoL. Patients with poor/fair cosmetic outcomes scored significantly lower on aspects of QoL, including breast-symptoms, body image and sexual enjoyment.

CONCLUSION: By significantly reducing positive margin status and lowering resection volumes, USS improves the rate of good cosmetic outcomes and increases patient-satisfaction. Considering the large impact of cosmetic outcome on QoL, USS has great potential to improve QoL following breast-conserving therapy.