Micrometastases in Sentinel Lymph Nodes in Breast Cancer: Clinical Implications
J Steinmetz, C Ersahin, K Rychlik, A Salhadar, PB Rajan. Chicago Medical School, North Chicago, IL; Loyola University Chicago Medical Center, Maywood, IL
Background: It remains unclear whether micrometastatic sentinel lymph node (SLN) metastases represents an adverse prognostic factor in breast cancer. Some studies have demonstrated that SLN micrometastasis has an adverse effect, whereas other studies have shown no effect on survival.
Design: All cases with SLN micrometastases were collected from our pathology files from 2003 to 2008. Small emboli of tumor cells in the lymph node sinuses and/or metastatic deposits in the lymph node parenchyma which were 0.2 mm to 2.0 mm in size were classified as micrometastases. other data collected were as follows: age, size, type and grade of primary cancer, size of SLN micrometastases, axillary node and follow-up status. Oneway Anova and Student's t tests were used for statistical analysis.
Results: There were 17 SLN micrometastases in a total of 702 SLN biopsies performed during 2003 to 2008 (2.4 %). Age of the patients ranged from 40 to 71 years (mean 53 years). 11 tumors were infiltrating ductal, 2 lobular, 2 mixed ductal and lobular, and 2 ductal carcinoma in-situ (DCIS) - 1 micropapillary and 1 comedo DCIS. Six tumors were grade 1, 6 were grade II, and 3 were grade III invasive cancers. Both DCIS showed nuclear grade III. Tumor size ranged from 0.4 to 3.9 cm (mean 1.6 cm). Lymphovascular invasion (LVI) was present in 3 of 17 cases (18%). Size of SLN metastases ranged from 0.2 mm to 2.0 mm, with multiple foci present in 1 infiltating carcinoma and in 1 DCIS (12%). Axillary dissection was performed in 14 of 17 cases. Lymph node number ranged from 7 to 30. 4 cases showed additional node micrometastases (29%) and 2 cases with additional node macrometastases (14%). Follow-up was available for 14 patients and period ranged from 4 to 60 months. All patients were alive and well. There is a statistically significant correlation between tumor size and the presence of micrometastases (p<0.05). The micrometastases did not predict additional node metastases (p>0.20).
Conclusions: The size of primary tumor is significant in predicting SLN micrometastases in this study. Age of the patient, tumor type, grade, LVI, and size and number of foci of SLN micrometastases are not predictive of micrometastases or subsequent axillary node metastases. Our results have shown that SLN micrometastases have no adverse effect on patient survival. A multi-institutional study involving a large number of patients is needed to plan appropriate management of patients with SLN micrometastases.
Tuesday, March 10, 2009 9:30 AM
Poster Session III # 73, Tuesday Morning