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Micrometastatic deposits in sentinel nodes may play role in treatment decisions, data show

Tuesday, December 18 2007 | Comments

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What's This? Micrometastatic deposits in the sentinel nodes may help to eventually define which patients should receive maximum adjuvant therapy (medical or surgical) and which patients could avoid additional therapy, according to results from a prospective study.

One of the most significant prognostic factors for patients with breast cancer are lymph node metastases, the researchers explained. The advent of sentinel node biopsy and the ability to evaluate multiple levels of a sentinel node has led to an increase in the detection of metastases in the sentinel node(s) both with routine hemoxylin and eosin stains and with the addition of immunohistochemical stains. The bulk of this increase is because of the identification of micrometastases.

The goal of the study was to evaluate the survival impact of micrometastases in sentinel node(s) of patients with invasive breast cancer.

A total of 790 patients underwent sentinel node biopsy and were divided into 4 groups based on the size of their sentinel node metastases. Patients with a negative result on hemoxylin and eosin stains were classified as pN0 (group 1; n=486); patients with a tumor deposit of <0.2 mm that was detected by immunohistochemical staining alone were classified as pN0(i+) (group 2; n=84); patients with a tumor deposit measuring between 0.2 mm and 2 mm were classified as pN1mic (group 3; n=54); and patients with a tumor deposit >2 mm were classified as pN1 (group 4; n=166).

Breast conserving surgery was done for the majority of patients in all 4 groups. In addition, 76.5% of patients received some form of adjuvant therapy (43.9% hormonal therapy alone, 21.2% chemotherapy alone, and 34.9% combination of both therapies).

At a median follow-up of 72.5 months, the size of sentinel node metastases was a significant predictor of 8-year disease-free survival and overall survival only for patients in group 4. No significant differences in these measures were observed among patients in the other 3 groups.

Dr. Nora Hansen, the study's lead investigator, said more trials are needed and cited an ongoing study that is investigating the issue of these micrometastatic deposits. She said researchers are waiting for these results to shed some more light on this topic.

"There was a significant decrease in 8-year disease-free survival and overall survival in patients with pN1 disease in the sentinel node(s)," the researchers concluded. "The true significance of these micrometastatic deposits is still unclear but may help to eventually better define which patients should receive maximum adjuvant therapy, medical or surgical, and in which patients additional therapy could be avoided." (Abstract 52.)

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