Micrometastasis a metastatic tumor that is too small to be identified in a scan. “studies suggest that up to 50 percent of patients with histologically normal lymph nodes have micrometastases detected by molecular techniques”

A macrometastasis was classified as “one or more tumor deposits greater than 2 mm.” A micrometastasis was classified as a tumor deposit “greater than 0.2 mm but not greater than 2.0 mm in the largest dimension.” ITC was “defined as single cells or small cluster of cells not greater than 0.2 mm in the largest dimension.”

Where do we draw the line? — Micrometastases and complete axillary lymph node dissection – Published March 2020

This study raises an interesting point that highlights the value of non-sentinel lymph node status and provokes the need for studies that utilize this information for the betterment of patient outcomes. The need to determine and treat – destroy the Cancer Cells is as critical as the primary and secondary tumors.

They have found that 14.5% of their patients with micrometastases on sentinel lymph node biopsies had non-sentinel lymph node involvement of the tumor. Although it may not seem significant, the 14.5% of patients with non-sentinel lymph node involvement may represent a quarter of patients with disease recurrence.

Defining Cancer Cells in Micrometastasis