Patients with tumors that are ER-positive 1%-9% have clinical and pathologic characteristics different from those with tumors that are ER-positive ≥10%. Similar to patients with ER-negative tumors, those with ER-positive 1%-9% disease do not appear to benefit from endocrine therapy; further study of its clinical benefit in this group is warranted. Also, there is a need to better define which patients of this group belong to basal or luminal subtypes.

Our results validate an improved breast cancer staging system that incorporates grade and ER status. We recommend that biologic markers be incorporated into revised versions of the AJCC staging system.

Background Positive sentinel lymph node (SLN) findings in DCIS range from 1–22% but have unknown biologic significance. We sought to identify predictors of positive SLNs and to assess their clinical significance in patients initially diagnosed with DCIS. Methods We identified 1234 patients with an initial diagnosis of DCIS who underwent SLN dissection (SLND) at our institution (1997–2011). Positive SLN findings were categorized as isolated tumor cells (ITCs) (≤0.2mm), micrometastases (>0.2–2mm), or macrometastases (>2mm). Predictors of positive SLNs were analyzed, and survival outcomes examined. Results Positive SLN findings were identified in 132 patients (10.7%): ITCs 66 (5.4%), micrometastases 36 (2.9%), and macrometastases 30 (2.4%). Upstaging to microinvasive (n=68 [5.5%]) or invasive (n=259 [21.0%]) cancer occurred in 327 patients (26.5%). Factors predicting positive SLNs included diagnosis by excisional biopsy (OR 1.90, P=.007), papillary histology (OR 1.77, P=.006), DCIS >2cm (OR 1.55, P=.030), >3 interventions before SLND (OR 2.04, P=.022 [4 interventions]; OR 3.87, P<.001 [≥5 interventions]), and occult invasion (OR 3.44, P=.001 [microinvasive]; OR 6.21, P<.001 [invasive]). Median follow-up was 61.7 months. Patients with pure DCIS with and without positive SLNs had equivalent survival (100.0% vs 99.7%, P=.679). Patients with occult invasion and positive SLNs had the worst survival (91.7%, P<.001). Conclusions Occult invasion and more than 3 total interventions were the strongest predictors of positive SLN findings in patients initially diagnosed with DCIS. This supports the theory of benign mechanical transport of breast epithelial cells. Other than patients at high risk for invasive disease, routine use of SLND in DCIS is not warranted.

A B S T R A C T PurposePrediction of patients at highest risk for ipsilateral breast tumor recurrence (IBTR) after local excision of ductal carcinoma in situ (DCIS) remains a clinical concern. The aim of our study was to evaluate a published nomogram from Memorial Sloan-Kettering Cancer Center to predict for risk of IBTR in patients with DCIS from our institution. Patients and MethodsWe retrospectively identified 794 patients with a diagnosis of DCIS who had undergone local excision from 1990 through 2007 at the MD Anderson Cancer Center (MDACC). Clinicopathologic factors and the performance of the Memorial Sloan-Kettering Cancer Center nomogram for prediction of IBTR were assessed for 734 patients who had complete data. ResultsThere was a marked difference with respect to tumor grade, prevalence of necrosis, initial presentation, final margins, and receipt of endocrine therapy between the two cohorts. The biggest difference was that more patients received radiation in the MDACC cohort (75% at MDACC v 49% at MSKCC; P Ͻ .001). Follow-up time in the MDACC cohort was longer than in the MSKCC cohort (median 7.1 years v 5.6 years), and the recurrence rate was lower in the MDACC cohort (7.9% v 11%). The median 5-year probability of recurrence was 5%, and the median 10-year probability of recurrence was 7%. The nomogram for prediction of 5-and 10-year IBTR probabilities demonstrated imperfect calibration and discrimination, with a concordance index of 0.63. ConclusionPredictive models for IBTR in patients with DCIS who were treated with local excision are imperfect. Our current ability to accurately predict recurrence on the basis of clinical parameters alone is limited.