Is Sentinel Lymph Node Dissection Warranted for Patients with a Diagnosis of Ductal Carcinoma In Situ?
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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.
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.
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).
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.
KeywordsSentinel Lymph Node Axillary Lymph Node Dissection Final Pathology Positive Sentinel Lymph Node Sentinel Lymph Node Metastasis
This work was supported by Grants from the National Institutes of Health, Cancer Center Support Grant CA016672 (Ronald DePinho) and T32 Grant CA009599 (Funda Meric-Bernstam). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health. We thank Stephanie Deming for editorial assistance.
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