Sentinel node micrometastases in breast cancer: clinical outcome

The sentinel lymph node biopsy has steadily replaced axillary lymph node dissection for staging clinically node-negative breast cancer. This study assesses surgical and adjuvant practice in relation to micrometastases and isolated tumor cells found on biopsy in a single surgeon cohort.

Clinicopathological characteristics were collated from 700 breast cancer patients undergoing sentinel lymph node biopsies between 1999 and 2007. The status and details of the node biopsies, continuing treatment and adverse outcomes were reported. Patient details at the time of diagnosis were entered into Adjuvant! online to look at likely prognosis. For both isolated tumor cells and micrometastases, data input was conducted twice, once as node-negative and again as node-positive, thus providing two predicted benefit data series.

A total of 665 women were eligible for inclusion, 67 with micrometastases and 20 with isolated tumor cells. Overall 33 patients developed recurrence with nine breast-cancer related deaths. Women with isolated tumor cells or micrometastases were more likely to receive adjuvant radiotherapy to the axilla compared with women with node-negative disease. Compared to those with isolated tumor cells, a higher number of women with micrometastases received systemic chemotherapy despite similar predicted benefits. Individual comparisons showed significantly higher rates of recurrence in women with isolated tumor cells than in node-negative disease (P < 0.0001).

The biological behavior of early breast cancer with isolated tumor cells on sentinel node biopsy is similar to both micrometastases and macrometastases, i.e. they behave in a node-positive fashion. This is an early indication that these patients should be treated with more aggressive adjuvant therapy.