What is the difference between a regular node biopsy and a sentinel node biopsy?

Little difference.: Think of a lymph node as a small filter. All lymph nodes act as filters. However, certain lymph nodes are the very first filters in line- they are called sentinel lymph nodes. The idea is that if the sentinel node is removed and negative, the chances of other lymph nodes further down the line being positive is small. You take out less nodes and have less complications!