Micrometastases in Breast Cancer

February 1, 2007
Oncology News International. Vol. 16 No. 2
Micrometastases are defined as lesions 0.2 to 2.0 mm and are detected by step-sectioning H—E staining, while ITCs (sub/nanomicrometastases) are less than 0.2 mm and are usually found only by immunohistochemical staining (IHC).

In another study from the John Wayne Cancer Center, 5-year disease-free survival was approximately 98% for patients with either micrometastases or IHC-negative nodes.

Why bother with this issue? he asked. "At most, with chemotherapy these patients would gain a 1% to 2% improvement in survival, and most of them receive adjuvant therapy anyway [based on other factors]," he said. Prognostic assessments might be better derived from other tools, he said, such as the 70-gene prognostic gene array (Mammaprint) developed at his institution, which can distinguish risk profiles even in patients with a single positive node.

• With micrometastases (0.2 to 2.0 mm), a lymph node dissection is generally advised. Patients with negative non-sentinel nodes should be considered node negative and treated with adjuvant therapy based on the primary tumor characteristics. Positive non-sentinel nodes are an adverse sign, and patients should be treated accordingly. Isolated tumor cells (less than 0.2 mm) have no reasonable clinical relevance, at this point, and these patients should be considered node negative, he said.

When Is There Cause for Concern?

FRANKIE ANN HOLMES, MD—"Regarding micrometastases, one of the things we are continuing to see is these delayed relapses," Dr. Holmes, co-director, Breast Cancer Research, US Oncology, Houston, told ONI. "In order to study and understand this phenomenon, I agree with Dr. Alberti [abstract 25] in that we probably need a longer time frame." She also said that it is important "to get inside these tumor cells and learn which genes are predicting relapse."

Dr. Holmes' bias regarding the significance of micrometastases and isolated tumor cells (ITCs) is this: "If the tumor has 'eloped' to another site, it tells me that this tumor means business, and we should be concerned." Fitting this picture would be a patient with micrometastases and ITCs with an ER/PR-negative grade 3 tumor. "This is a nasty tumor," she said. "Many times, you can look at the primary tumor and by its characteristics, you know that cells in the nodes are a moot point. You already know how to treat the patient."

When patients with otherwise good prognostic factors have nanometas-tases, there may be less cause for concern, she said. "To give us more information, we can use the OncotypeDx test for node-negative patients and patients with ITCs, who are technically node negative," Dr. Holmes said. "But micrometastases are classified as technically node positive, and OncotypeDx has not been tested for node-positive patients. We rely on judgment, Adjuvant!, and established guidelines, and treat them as node positive."


Netherlands study: does not recommend treatment -
Oxford Journals Medicine Annals of Oncology Volume 20, Number 1 Pp. 41-48
Prognostic value of micrometastases in sentinel lymph nodes of patients with breast carcinoma: a cohort study
P. D. Gobardhan4, S. G. Elias1, E. V. E. Madsen4, V. Bongers2, H. J. M. Ruitenberg3, C. I. Perre4 and T. van Dalen4,*
1 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht
2 Department of Nuclear Medicine, Diakonessenhuis Utrecht
3 Department of Pathology, Diakonessenhuis Utrecht, The Netherlands
4 Department of Surgery, Diakonessenhuis Utrecht

* Correspondence to: Dr T. van Dalen, Department of Surgery, Diakonessenhuis Utrecht, Bosboomstraat 1, 3582 KE Utrecht, The Netherlands. Tel: +31-30-2566225; Fax: +31-30-2566210; E-mail: tvdalen@diakhuis.nl

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interestingly - here is another take on the findings - they conclude that the recurrence rate is increased with micromets by 10% and the magazine is sponsored by Pfizer.