Local recurrence risk factors in women treated with BCT for early-stage breast cancer

The article by Revesz and Khan is an excellent summary of the state of our knowledge of margin width in relation to breast cancer recurrence. The importance of preventing local recurrence in women who undergo breast-conserving therapy (BCT) for early-stage breast cancer is underscored by the fact that local recurrence is associated with increased cost, psychosocial distress for the patient, and potentially worse distant disease-free and overall survival. [1] With early breast cancer, adequate local control, and more specifically, adequate surgical margins, are arguably key components of therapy. What constitutes an adequate surgical margin in breast-conserving surgery remains controversial, however. Some have advocated for margins of 10 mm or greater for ductal carcinoma in situ (DCIS), but there are no data from large randomized controlled trials to guide us as to what are safe margins for resection in BCT In National Surgical Adjuvant Breast and Bowel Project (NSABP) trials, which demonstrated the safety and efficacy of BCT, local recurrence rates were low, and a negative margin was defined as simply no tumor cells at the inked edges of the specimen. [2] Revesz and Khan note that a 2-mm margin is generally considered acceptable for DCIS, although the evidence in favor of a 2-mm margin over a 1-mm margin is primarily derived from retrospective, single-institution studies, not all of which demonstrate an advantage for greater margin width. More recently, Houssami et al performed a meta-analysis of 21 trials in which both microscopic surgical margins and recurrence rates were reported. While these were mostly retrospective analyses, the pooled data from these 14,571 women with early breast cancer treated with BCT (1026 of whom developed local recurrence) demonstrated that a positive margin or a margin less than 1 mm was associated with increased risk local recurrence, but the odds of local recurrence did not differ significantly with surgical margin widths greater than 1 mm. In other words, a 2-mm margin is not necessarily better than a 1-mm margin, and a 5-mm margin is not better than a 2-mm margin. [3] If we mandate at least 2-mm margins in BCT, however, then reexcision rates would most assuredly be greater than if a 1-mm margin is accepted as safe. Re-excision is costly from both an economic and a cosmetic standpoint, as resection of greater than 15% of the breast volume increases the risk of unacceptable cosmesis and patient dissatisfaction after BCT. [