Sentinel node biopsy is generally a safe procedure. But as with any surgery, it carries a risk of complications, including:

  • Bleeding
  • Pain or bruising at the biopsy site
  • Infection
  • Allergic reaction to the dye used for the procedure
  • Lymphedema — a condition in which your lymph vessels drain all the lymph fluid from an area of your body, causing fluid buildup and swelling


Although lymphedema is an unlikely complication of sentinel node biopsy, one of the main reasons sentinel node biopsy was developed was to decrease the chance of developing lymphedema, which is more likely to occur if many lymph nodes are removed from one area.

Because only a few lymph nodes are removed, the risk of lymphedema after sentinel node biopsy is small. Dozens of other lymph nodes remain in the area of your body where the sentinel node biopsy is done. In most cases, those remaining lymph nodes can effectively process the lymph fluid.