133 Background: Ductal carcinoma in situ of the breast (DCIS) is considered a precancerous condition. Nevertheless, 6 to 13% of cases will present cancerous cells in the sentinel lymph node biopsy (SNB) when analyzed using immunohistochemistry (IHC). Current guidelines do not specify if patients with isolated tumor cells (ITC, staged as N0[i+] for clusters <0.2mm) or with micrometastases (micromets, staged as N1mic for clusters between 0.2mm and 2 mm) would benefit from radiation or systemic therapy. We compared the clinical outcomes of patients diagnosed with DCIS and found to have ITC or micromets on SNB to those of patients diagnosed with DCIS without SNB analysis. Methods: Retrospective study. Medical records from patients diagnosed with DCIS at the Cancer Center of AEMC between 01/01/97 and 12/31/08 were reviewed and the SNB status assessed. Other pertinent data (receptor status, type of recurrence and time to recurrence) was collected. The primary outcomes were recurrence/distant metastasis rate (RR) confirmed by biopsy and the time to recurrence (TTR). Descriptive statistics, chi-square and Mann-Whitney U tests were used to analyze the data. Results: Of the patients diagnosed with DCIS between 1997 and 2008 (N=743), 145 were lost to follow up; 598 charts were analyzed. Only 22% of patients had a SNB. Those that underwent the SNB showed a higher RR as compared to those w/o a SNB (9.2% vs 3.6%, p=0.018). The average TTR between groups showed a wide distribution and no statistically significant difference (SNB mean= 2163 days, S.D=1664; w/o SNB mean= 1300 days, S.D. =819, p=0.180). Subgroup analysis in the SNB group showed that patients w/o IHC exam showed the highest rate of recurrence (6 cases, 13.6%), as compared to those with negative findings (5 cases, 7.6%), those with isolated tumor cells (1 case, 5.9%) and those with micromets (0 cases) (p=0.597). Conclusions: Patients with SNB had a higher RR when compared to those w/o SNB. Among patients with SNB, those w/o IHC had a higher RR as compared to those with SNB and IHC (although p > 0.05), possibly due to unidentified ITC/micromets. These results are limited due to the small number of cases with SNB and short follow up interval for patients with SNB and performed IHC.
Locoregional treatment of early breast cancer with isolated tumor cells or micrometastases on sentinel lymph node biopsy
