Breast conservation: factors predictive of residual disease following reoperation for narrow surgical margins.

Abstract

#5152 Introduction:
 Ensuring pathologically tumor free surgical margins reduces local recurrence rates following breast conserving surgery for breast cancer or DCIS. There is no general agreement regarding the definition of a clear margin but units with an agreed policy report reduced local recurrence rates. In our unit all patients with a surgical clearance of <5mm are offered further surgery either by mastectomy or by re-excision. We have examined factors that may predict residual disease in re-excised tissues.
 Method:
 All attempted breast conserving operations between 01/01/2004 to 31/09/2007 were identified from a dedicated database. Patient age, presentation (symptomatic or screening), surgeon (any of 4 surgeons), weight of tissue removed, tumour size, grade, presence of lymphovascular invasion (LVI) and the closest radial margin (categorised as involved, <2mm, 2-5mm) were examined.
 Results:
 Breast conservation was attempted in 605 women (mean age 60; 297 symptomatic, 308 screening). Further surgery was performed in 166 (27.4%) women, including 89 (14.7%) mastectomies. Median tumour size was 20mm (range 0-109). Residual disease was found in 83(50%) of re excisions (66/111 with involved margins, 16/40 for non involved margins up to 2mm, and 1/15 for margins over 2mm). On univariate analysis excision margin (OR=0.33, p=0.000) and total tumor size (OR=4.0 p=0.045 for the smallest size quartile versus the largest) were associated with residual disease. On multivariate analysis only tumor margin remained predictive (OR for <2mm vs involved: 0.46, p=0.043; OR for 2-5mm vs involved: 0.05, p=0.004).
 Conclusion:
 In a unit with an aggressive re-excision policy, involved or close surgical margins predict the presence of residual disease in re-excision specimens. A margin of greater than 2mm reduces the risk of residual disease to 1/20 of that seen with microscopically involved margins. This study supports a 2mm minimum radial margin policy when attempting breast conservation for breast malignancy. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5152.

Breast Cancer Local Therapy: What Is Its Effect on Mortality?

“…Thus Pittinger and colleagues found residual disease in 44% of cases with involved margins, 24% of cases with free margins of B3 mm, and no further tumour in wider excision/mastectomy specimens when the free margin exceeded 3 mm [62]. An analysis of data from the authors' unit has shown that residual disease is found in 60% of patients with involved margins, 40% of those with negative margins up to 2 mm, and only 6% for patients with a margin of 2-5 mm (OR: 2-5 mm margin versus involved margin = 0.05; p = 0.004) [63]. Other investigators have similarly reported a low probability of finding residual disease upon further resection when the margin of clearance is at least 2 mm (2.3%), compared with one third of cases where the clearance is between 0.1 and 0.9 mm [56].…”

“…These loco-regional effects of systemic treatments will tend to reduce the impact of surgery and radiotherapy on mortality; the chance of any persistent or recurrent disease in the breast and regional nodes acting as a source of distant disease will be minimized, and patients will be more likely to succumb Fig. 12 Relationship of local recurrence to margin status (defined as ''positive'' and ''negative'') [63] World J Surg (2012) 36:1460-1474 1471 from competing risks of pre-existent distant metastases. Techniques of gene profiling can potentially characterize the biology of individual tumors and provide a molecular ''portrait,'' which can guide treatment strategies.…”