Is Sentinel Lymph Node Dissection Warranted for Patients with a Diagnosis of Ductal Carcinoma In Situ?

BACKGROUND: Positive sentinel lymph node (SLN) findings in ductal carcinoma in situ (DCIS) range from 1 to 22 % but have unknown biologic significance. This study sought to identify predictors of positive SLNs and to assess their clinical significance for patients with an initial diagnosis of DCIS. METHODS: The study identified 1234 patients with an initial diagnosis of DCIS who underwent SLN dissection (SLND) at our institution from 1997 through 2011. Positive SLN findings were categorized as isolated tumor cells (ITCs) (≤0.2 mm), micrometastases (>0.2-2 mm), or macrometastases (>2 mm). Predictors of positive SLNs were analyzed, and survival outcomes were examined. RESULTS: Positive SLN findings were identified in 132 patients (10.7 %): 66 patients with ITCs (5.4 %), 36 patients with micrometastases (2.9 %), and 30 patients with macrometastases (2.4 %). Upstaging to microinvasive (n = 68, 5.5 %) or invasive (n = 259, 21.0 %) cancer occurred for 327 patients (26.5 %). Factors predicting positive SLNs included diagnosis by excisional biopsy (odds ratio [OR] 1.90; P = 0.007), papillary histology (OR 1.77; P = 0.006), DCIS larger than 2 cm (OR 1.55; P = 0.030), more than three interventions before SLND (4 interventions: OR 2.04; P = 0.022; ≥5 interventions: OR 3.87; P < 0.001), and occult invasion (microinvasive: OR 3.44; P = 0.001; invasive: OR 6.21; P < 0.001). The median follow-up period was 61.7 months. Patients who had pure DCIS with and without positive SLNs had equivalent survival rates (100.0 vs 99.7 %; P = 0.679). Patients with occult invasion and positive SLNs had the worst survival rate (91.7 %; P < 0.001). CONCLUSIONS: Occult invasion and more than three total interventions were the strongest predictors of positive SLN findings in patients with an initial diagnosis of DCIS. This supports the theory of benign mechanical transport of breast epithelial cells. Except for patients at high risk for invasive disease, routine use of SLND in DCIS is not warranted.

Evaluation of a breast cancer nomogram for predicting risk of ipsilateral breast tumor recurrences in patients with ductal carcinoma in situ after local excision.

PURPOSE: Prediction 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 METHODS: We 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. RESULTS: There 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 < .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. CONCLUSION: Predictive 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.

Novel staging system for predicting disease-specific survival in patients with breast cancer treated with surgery as the first intervention: time to modify the current American Joint Committee on Cancer staging system.

PURPOSE: American Joint Committee on Cancer (AJCC) staging is used to determine breast cancer prognosis, yet patient survival within each stage shows wide variation. We hypothesized that differences in biology influence this variation and that addition of biologic markers to AJCC staging improves determination of prognosis. PATIENTS AND METHODS: We identified a cohort of 3,728 patients who underwent surgery as the first intervention between 1997 and 2006. A Cox proportional hazards model, with backward stepwise exclusion of factors and stratification on pathologic stage (PS), was used to test the significance of adding grade (G), lymphovascular invasion (L), estrogen receptor (ER) status (E), progesterone receptor (PR) status, combined ER and PR status (EP), or combined ER, PR, and human epidermal growth factor receptor 2 status (M). We assigned values of 0 to 2 to these disease-specific survival (DSS) -associated factors and assessed six different staging systems: PS, PS + G, PS + G L, PS + G E, PS + G EP, and PS + G M. We compared 5-year DSS rates, Akaike's information criterion (AIC), and Harrell's concordance index (C-index) between systems. Surveillance, Epidemiology, and End Results data were used as the external validation cohort (n = 26,711). RESULTS: Median follow-up was 6.5 years, and 5-year DSS rate was 97.4%. The PS + G E status staging system was most precise, with a low AIC (1,931.9) and the highest C-index (0.80). PS + G E status was confirmed to stratify outcomes in internal bootstrapping samples and the external validation cohort. CONCLUSION: 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.