Resection of Cavity Shave Margins in Stage 0-III Breast Cancer Patients Undergoing Breast Conserving Surgery: A Prospective Multicenter Randomized Controlled Trial.

OBJECTIVE: Single-center studies have demonstrated that resection of cavity shave margins (CSM) halves the rate of positive margins and re-excision in breast cancer patients undergoing partial mastectomy (PM). We sought to determine if these findings were externally generalizable across practice settings. METHODS: In this multicenter randomized controlled trial occurring in 9 centers across the United States, stage 0-III breast cancer patients undergoing PM were randomly assigned to either have resection of CSM ("shave" group) or not ("no shave" group). Randomization occurred intraoperatively, after the surgeon had completed their standard PM. Primary outcome measures were positive margin and re-excision rates. RESULTS: Between July 28, 2016 and April 13, 2018, 400 patients were enrolled in this trial. Four patients (2 in each arm) did not meet inclusion criteria after randomization, leaving 396 patients for analysis: 196 in the "shave" group and 200 to the "no shave" group. Median patient age was 65 years (range; 29-94). Groups were well matched at baseline for demographic and clinicopathologic factors. Prior to randomization, positive margin rates were similar in the "shave" and "no shave" groups (76/196 (38.8%) vs. 72/200 (36.0%), respectively, P = 0.604). After randomization, those in the "shave" group were significantly less likely than those in the "no shave" group to have positive margins (19/196 (9.7%) vs. 72/200 (36.0%), P < 0.001), and to require re-excision or mastectomy for margin clearance (17/196 (8.7%) vs. 47/200 (23.5%), P < 0.001). CONCLUSION: Resection of CSM significantly reduces positive margin and re-excision rates in patients undergoing PM.

Does Localization Technique Matter for Non-palpable Breast Cancers?

BACKGROUND: There are several techniques for localization of non-palpable breast tumors, but comparisons of these techniques in terms of margin positivity and volume of tissue resected are lacking. METHODS: Between 2011-2013 and 2016-2018, 2 randomized controlled trials involving 10 centers across the United States accrued 631 patients with stage 0-3 breast cancer, all of whom underwent breast conserving surgery. Of these, 522 had residual non-palpable tumors for which localization was required. The localization technique was left to the discretion of the individual surgeon. We compared margin positivity and volume of tissue resected between various localization techniques. RESULTS: The majority of the patients (n = 465; 89.1%) had wire localization (WL), 50 (9.6%) had radioactive seed (RS) localization, and 7 (1.3%) had Savi Scout (SS) localization. On bivariate analysis, there was no difference in terms of margin positivity (37.8% vs. 28.0% vs. 28.6%, P = .339) nor re-excision rates (13.3% vs. 12.0% vs. 14.3%, P = .961) for the WL, RS, and SS groups, respectively. Further, the volume of tissue removed was not significantly different between the 3 groups (71.9 cm3 vs. 55.8 cm3 vs. 86.6 cm3 for the WL, RS, and SS groups, respectively, P = .340). On multivariate analysis, margin status was affected by tumor size (OR = 1.336; 95% CI: 1.148-1.554, P<.001) but not by type of localization (P = .670). CONCLUSIONS: While there are a number of methods for tumor localization, choice of technique does not seem to influence volume of tissue resected nor margin status.

Are we choosing wisely? Drivers of preoperative MRI use in breast cancer patients.

INTRODUCTION: Factors contributing to the use of preoperative MRI remain poorly understood. METHODS: Data from a randomized controlled trial of stage 0-3 breast cancer patients undergoing breast conserving surgery between 2016 and 2018 were analyzed. RESULTS: Of the 396 patients in this trial, 32.6% had a preoperative MRI. Patient age, race, ethnicity, tumor histology, and use of neoadjuvant therapy were significant predictors of MRI use. On multivariate analysis, younger patients with invasive lobular tumors were more likely to have a preoperative MRI. Rates also varied significantly by individual surgeon (p < 0.001); in particular, female surgeons (39.9% vs. 24.0% for male surgeons, p = 0.001) and those in community practice (58.9% vs. 14.2% for academic, p < 0.001) were more likely to order preoperative MRI. Rates declined over the two years of the study, particularly among female surgeons. CONCLUSIONS: Preoperative MRI varies with patient age and tumor histology; however, there remains variability by individual surgeon.

Factors Affecting Time to Surgery in Breast Cancer Patients.

BACKGROUND: We sought to determine factors affecting time to surgery (TTS) to identify potential modifiable factors to improve timeliness of care. METHODS: Patients with clinical stage 0-3 breast cancer undergoing partial mastectomy in 2 clinical trials, conducted in ten centers across the US, were analyzed. No preoperative workup was mandated by the study; those receiving neoadjuvant therapy were excluded. RESULTS: The median TTS among the 583 patients in this cohort was 34 days (range: 1-289). Patient age, race, tumor palpability, and genomic subtype did not influence timeliness of care defined as TTS ≤30 days. Hispanic patients less likely to have a TTS ≤30 days (P = .001). There was significant variation in TTS by surgeon (P < .001); those practicing in an academic center more likely to have TTS ≤30 days than those in a community setting (55.1% vs 19.3%, P < .001). Patients who had a preoperative ultrasound had a similar TTS to those who did not (TTS ≤30 days 41.9% vs 51.9%, respectively, P = .109), but those who had a preoperative MRI had a significantly increased TTS (TTS ≤30 days 25.0% vs 50.9%, P < .001). On multivariate analysis, patient ethnicity was no longer significantly associated with TTS ≤30 (P = .150). Rather, use of MRI (OR: .438; 95% CI: .287-.668, P < .001) and community practice type (OR: .324; 95% CI: .194-.541, P < .001) remained independent predictors of lower likelihood of TTS ≤30 days. CONCLUSIONS: Preoperative MRI significantly increases time to surgery; surgeons should consider this in deciding on its use.

Impact of Cavity Shave Margins on Margin Status in Patients with Pure Ductal Carcinoma In Situ.

BACKGROUND: We examined the impact of cavity shave margins (CSMs) on margin status in patients with pure ductal carcinoma in situ (DCIS) undergoing partial mastectomy (PM). METHODS: One hundred and nine patients from 2 multicenter, randomized controlled trials were identified with pure DCIS (no invasive cancer). Surgeons performed their best PM, with specimen radiography and resection of selective margins per surgeon discretion. Patients were then randomized to have CSM resected or not. A positive margin was defined as <2 mm from ink. RESULTS: Median patient age was 63 years; median size of DCIS was 1.20 cm; 43.6% of patients had high-grade DCIS; and 58 (53.2%) patients were randomized to take CSM. The "shave" and "no-shave" groups were well-matched for age, race, ethnicity, palpability, grade, and size of DCIS. Although 33 (56.9%) of the patients in the shave group had a positive margin before randomization, only 12 (20.7%) had a positive margin after randomization to CSM (p < 0.001). In the no-shave group, 17 patients (33.3%) had a positive margin. Controlling for size and grade of DCIS, taking CSM resulted in a nearly 65% reduction in the positive-margin rate (odds ratio 0.366; 95% CI, 0.136 to 0.981; p = 0.046). Size of DCIS remained an independent predictor of positive margins in the model (odds ratio 1.646; 95% CI, 1.227 to 2.209; p = 0.001). CONCLUSIONS: CSM reduces positive-margin rates in patients with pure DCIS, and can be a practical solution for DCIS patients who tend to have a high rate of margin positivity.