Previous studies evaluating the impact of multiple operations reveal dissatisfaction of the patient both physically and psychologically [32
]. Physically, the patient may have an unsatisfying cosmetic outcome and is subjected to the increased length of recovery associated with additional surgery. Psychologically, the patient can lose confidence in the surgeon and fear recurrence. Ideally, a patient would go to surgery only once, achieving adequate margins and not returning to the operating room. Reexcision at a second operation potentially increases the likelihood of a poor cosmetic outcome and requires the patient to assume the risks of another surgical procedure under anesthesia.
CSM is a simple technique that utilizes existing equipment to remove extra margins of tissue after the primary breast specimen has been removed. Removal of six new margins (superior, inferior, anterior, posterior, medial, and lateral) provides an extra sampling of tissue that has been shown to reduce reexcision rates in patients undergoing BCS for breast cancer [7
]. Other studies have reported on groups of women who underwent CSM and compared lumpectomy margin status to shave margin status. These studies showed that overall final margin status was histologically negative in >50% of patients with histologically positive lumpectomy margins; therefore, a reexcision was avoided in these patients () [6
]. The current study compared the reexcision rates before and after the introduction of routine CSM to primary BCS with additional margins taken at surgeon discretion. The reexcision rate fell significantly from 46.8% to 23.9% (22.9% reduction) after introduction of CSM. Other studies that also implemented CSM and compared reexcision rates to standard PM alone report similar reduction in reexcision rates from 7 to 30% () [8
]. Prior studies included patients who were undergoing excisional biopsy for diagnosis and varying approaches to what constituted an acceptable margin. In contrast, all patients in this series had a preoperative diagnosis of breast cancer via core needle biopsy, and patients were almost universally returned to the operating room for margins that were less than 2
mm. The significant reduction in reexcisions supports the use of CSM in the contemporary breast practice setting.
Comparison of various studies.
Furthermore, close (75% in CSM group compared to 44.9% in SPM group), rather than positive margins (25% in CSM group compared to 55.1% in SPM group) were the most common reason for a second operation in the CSM group. This could imply that CSM removes more cancerous tissue and thereby decreases the overall tumor burden left behind, a factor which may decrease the risk of recurrence upon long-term followup.
Another statistically significant difference was in the performance of a total mastectomy as definitive treatment; patients who underwent an SPM only were more likely to eventually choose mastectomy as a final operation (16.5% in SPM group compared to 4.5% in CSM group). This observed difference may be due to the amount of operations required to achieve adequate margins; more patients in the SPM group required >2 operations to achieve adequate margins, 10.1% in SPM group compared to 0% in CSM group. Several recent studies reveal increasing rates of prophylactic contralateral total mastectomy [35
]; the etiology of this trend continues to be unclear. In light of the current data, one of the factors that may be contributing to this increased mastectomy rate is the failure to successfully undergo BCS with one operation. As a cancer center policy, all eligible patients are offered BCT and reexcisions are routinely discussed and presented as an option to patients who fail to achieve adequate margins at the initial operation. The higher mastectomy rate in the SPM group may be a reflection of a loss of confidence in BCS as a therapeutic approach, and the patients desire to minimize the number of surgical interventions. Further investigation into the rationale for performance of the mastectomy in the SPM group as well as a potential association with contralateral prophylactic mastectomy is ongoing.
Patients with larger tumors required more reexcisions; this is possibly due to surgeons attempting to conserve more breast tissue at the initial operation, and having to go back for microscopic margins. Alternatively, this finding may be due to biological factors that lead to underestimation of larger tumors by imaging and clinical approaches, as well as growth patterns that favor occult tumor at the margins. This is also the likely explanation for the racial disparity, as AfricanAmerican and Hispanic patients typically present with larger tumors.
This study revealed that the majority of patients who required a reexcision in the CSM group and the SPM group did not have residual tumor. Although this is more evident in the CSM group (81.2% as opposed to 55.4% in the SPM group), it is still interesting to note that most of the patients in the SPM group may have been spared a second operation if CSMs were performed at the initial operation, as these patients did not have residual tumor. Given this finding, a cost analysis utilizing Current Procedural Terminology code 19301 was performed. If CSM was performed at the initial operation in those patients who underwent SPM, then 118 patients would have been spared a second operation, translating into a $183,018 surgical savings (2009, Medicare reimbursement).