Systematic review and meta-analysis of the impact of intra-operative ultrasound guided breast-conserving surgery in early breast cancer. Background: Breast Conservation (BCS) is the standard surgical procedure for early breast cancer. It is challenging for surgeons to achieve adequate excision of the lesion with clear margins and acceptable cosmesis. A continuous Intra-Operative Ultrasound (IOUS) is used during BCS in volume precision surgery. We reviewed its effectiveness to obtain clear margins, low excision volume and better cosmetic outcome during BCS. Methods: We searched three bibliographic databases (MEDLINE, CINAHL, Cochrane Library online) for relevant published and unpublished literature from their inception until December 2019. The randomized controlled trials of the impact of IOUS on excision volume, margin status and cosmetic outcome was assessed, and meta-analysis carried out for margin status with narrative summary was done for other results. Results: This study included four articles in the systematic review. A total of 207 patients with IOUS and 192 patients with Palpation Guided (PGS) BCS was studied in this review. The standardised mean difference of excision volume for 2 trials was -0.31 (-0.62, -0.00) and -0.50 (-0.85, -0.16) with p-value of 0.048 and 0.004. There was no significant volume difference in the remaining two studies. The positive margin rate reduced significantly with IOUS guidance with the pooled OR was 0.19 (95% CI: 0.09, 0.41) with no heterogeneity among studies (p=0.72, I2= 0%). The overall cosmetic outcome favoured satisfaction in both ultrasound-guided and palpation guided BCS groups without significant difference. Conclusion: This study suggests that the use of IOUS provides a statistically significant, less positive margin without a considerable difference in excisional volume. Overall, satisfaction exceeds dissatisfaction with ultrasound-guided Breast-conserving surgery. However, there is insufficient evidence to support the better cosmetic outcome in the IOUS group.
