Background Negative margins are associated with reduced risk of ipsilateral breast tumor recurrence (IBTR) for women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS). However, there is no consensus about the best minimum margin width. Methods We searched the PubMed database for studies of DCIS published in English between January 1970 and July 2010 and examined the relationship between IBTR and margin status after BCS for DCIS. Women with DCIS were stratified into two groups, BCS with or without radiotherapy. We used frequentist and Bayesian approaches to estimate the odds ratios (OR) of IBTR for groups with negative margins and positive margins. We further examined specific margin thresholds using mixed treatment comparisons and meta-regression techniques. All statistical tests were two-sided. Results We identified 21 studies published in 24 articles. A total of 1066 IBTR events occurred in 7564 patients, including BCS alone (565 IBTR events in 3098 patients) and BCS with radiotherapy (501 IBTR events in 4466 patients). Compared with positive margins, negative margins were associated with reduced risk of IBTR in patients with radiotherapy (OR = 0.46, 95% credible interval [CrI] = 0.35 to 0.59), and in patients without radiotherapy (OR = 0.34, 95% CrI = 0.24 to 0.47). Compared with patients with positive margins, the risk of IBTR for patients with negative margins was smaller (negative margin >0 mm, OR = 0.45, 95% CrI = 0.38 to 0.53; >2 mm, OR = 0.38, 95% CrI = 0.28 to 0.51; >5 mm, OR = 0.55, 95% CrI = 0.15 to 1.30; and >10 mm, OR = 0.17, 95% CrI = 0.12 to 0.24). Compared with a negative margin greater than 2 mm, a negative margin of at least 10 mm was associated with a lower risk of IBTR (OR = 0.46, 95% CrI = 0.29 to 0.69). We found a probability of .96 that a negative margin threshold greater than 10 mm is the best option compared with other margin thresholds. Conclusions Negative surgical margins should be obtained for DCIS patients after BCS regardless of radiotherapy. Within cosmetic constraint, surgeons should attempt to achieve negative margins as wide as possible in their first attempt. More studies are needed to understand whether margin thresholds greater than 10 mm are warranted.

Purpose: To explore racial differences in the use and outcome of neoadjuvant chemotherapy for breast cancer. Methods: The National Cancer Data Base was queried to identify women with stage 1 to 3 breast cancer diagnosed in 2010 and 2011. Chemotherapy use and rate of pathologic complete response (pCR) was determined for various racial/ethnic groups. Results: Of 278,815 patients with known race and ethnicity, 127,417 (46%) received chemotherapy, and of 121,446 where the timing of chemotherapy was known, 27,300 (23%) received neoadjuvant chemotherapy. Chemotherapy, and neoadjuvant chemotherapy in particular, was given more frequently to black, Hispanic, and Asian women than to white women (P < 0.001). This difference was largely explained by more advanced stage, higher grade tumors, and a greater proportion of triple-negative and human epidermal growth factor receptor 2 (HER2)–positive tumors in these women. Of 17,970 patients with known outcome, 5,944 (33%) had a pCR. No differences in response rate for estrogen receptor (ER)/progesterone receptor (PR)–positive tumors were found, but compared with white women, black but not Hispanic or Asian women had a lower rate of pCR for ER/PR-negative, HER2-positive (43% v 54%, P = 0.001) and triple-negative tumors (37% v 43%, P < 0.001). This difference persisted when adjusted for age, clinical T stage, clinical N stage, histology, grade, comorbidity index, facility type, geographic region, insurance status, and census-derived median income and education for the patient’s zip code (odds ratio, 0.84; 95% CI, 0.77 to 0.93). Conclusion: Neoadjuvant chemotherapy is given more frequently to black, Hispanic, and Asian women than to white women. Black women have a lower likelihood of pCR for triple-negative and HER2-positive breast cancer. Whether this is due to biologic differences in chemosensitivity or to treatment or socioeconomic differences that could not be adjusted for is unknown.

The recent article by Welch et al.¹ in the Journal showed clearly that since the adoption of widespread screening mammography, small breast cancers have increased in incidence over three times more than large cancers have decreased. This implies that many small cancers are not destined to progress to large cancers; instead, their detection results in overdiagnosis. The purpose of our study was to characterize groups of tumors that are likely to contain a large portion of overdiagnosed cancers and to explain the mechanism that may have led to their overdiagnosis.