Invasive Ductal CA : Tumor Size
Tumor Size: The gross measurement of tumor size is one of the most important prognostic indicators in invasive ductal carcinoma as explained in previous slides. The tumor size measured microscopically may be different than the gross measurement. The presence of benign breast tissue with hyperplasia or reactive changes or extensive foci of DCIS may overestimate the size of the invasive component macroscopically.
For small invasive tumors that can be entirely submitted in one block, the most accurate and the preferred method (as per AJCC recommendation) is to measure the tumor size microscopically. For larger tumors that must be submitted in multiple blocks, gross measurement is preferred. If there are microscopic strands of invasive tumor extending beyond the main mass, they should be included in the measurement of tumor size. Areas of DCIS should be excluded.
If the invasive component is scattered across the entire tumor, the distance between the two furthest invasive foci is measured even if there are interspersed areas of DCIS or benign tissue. In such cases, a comment can be included in the report indicating the approximate proportion of invasive tumor in the measured area.
The image shows invasive ductal carcinoma with extensive necrosis. Image courtesy of Dr. Montemor Netto, Brazil; Used with permission.