This study reports that 1 in 5 women who have breast conserving surgery need further surgery and that reoperation rates vary significantly from one centre to another. As the authors note controversy surrounds what defines complete excision and therefore when re-excision is required. There has been until recently no consensus on what constitutes an adequate distance between the edge of the cancer and the edge of the specimen. A major problem in the published literature is that there are large numbers of single centre studies and in surveys there has been no margin width that more than 50% of surgeons or oncologists agree on [1,2].

The first major review of surgical margins was published in 2002 [3] and established that leaving disease at margins was unacceptable but showed that wider margins did not reduce local recurrence rates. A more recent comprehensive review with meta-analysis of 21 studies including 14,571 patients with breast cancer published in 2010 [4] demonstrated significantly increased local recurrence rates with involved or close margins relative to negative margins in invasive breast cancer; however, it found no statistical difference in the risk of local recurrence with margin widths ≥2mm and ≥5mm relative to a narrower width (1mm) when the results were adjusted for follow-up time and the proportion of women who received a radiation boost or endocrine therapy. The conclusion of this meta-analysis is that a 1mm negative margin is as good as a wider margin if patients receive optimal adjuvant therapy.

In Edinburgh we have used a 1mm margin for the last decade and our local recurrence rates are as good as any reported in the literature being1.7% at 5 years [5]. Margin width is important as a demand for wider margins removes more normal breast tissue and results in a poorer cosmetic outcome. This is because the volume of tissue excised is the single most important factor influencing the cosmetic result [5]. How the breast looks after surgery is so important because of the correlation between cosmetic outcome and the patients’ anxiety and depression score, body image, sexuality and self esteem [6].

The problem in breast conserving surgery is not so much the variation in re excision rates highlighted in the BMJ report but the inconsistency in applying the current knowledge base on margin width. As stated by the authors interpreting re excision rates without knowledge of local protocols as indicators of quality cannot be justified, yet that is the message that percolated to the media. As Morrow and colleagues so eloquently argue in their recent article titled ‘Surgical Margins in Lumpectomy for Breast Cancer – Bigger is not Better’ surgeons need to abandon local protocols as suggested by the Association of Breast Surgeons and follow the evidence. [7]

REFERENCES
1.Vallasiadou K, Young OE, Dixon JM. Current practices in breast conservation surgery: results of a questionnaire. Br J Surg 2003; 90:44.

2.Azu M, Abrahamse P, Katz SJ et al. What is an adequate margin for breast conserving surgery? Surgeon attitudes and correlates. Ann Surg Oncol. 2010; 17:558-63

3.Singletary SE. Surgical margins in patients with early-stage breast cancer treated with breast conservation therapy. Am J Surg. 2002 Nov;184(5):383-93

4.Houssami N, Macaskill P, Marinovich ML, et al. Meta-analysis of the impact of surgical margins on local recurrence in women with early-stage invasive breast cancer treated with breast-conserving therapy. Eur J Cancer 2010;46:3219-3232

5.Dixon JM. Breast-conserving surgery: the balance between good cosmesis and local control. In: A Companion to Specialist Surgical Practice: Breast Surgery. Ed. Dixon JM. Elsevier, Edinburgh, 2009, pp. 49-65.

6. Sharif K, Al-Ghazal SK, Blamey RW. Cosmetic assessment of breast-conserving surgery for primary breast cancer. Breast 1999; 8:162–8

7. Morrow M, Harris JR, Schnitt SJ. Surgical Margins in Lumpectomy for Breast Cancer – Bigger is not Better. N Engl J Med 2012 Jul 5;367(1):79-82

J Michael Dixon
Professor of Breast Surgery and Consultant Surgeon
Western General Hospital, Edinburgh, UK

Nehmat Houssami
Associate Professor, Screening & Test Evaluation Program
Sydney Medical School, University of Sydney, Australia

Competing interests: None declared