During a sentinel node biopsy, a dye is injected in the area where your melanoma was removed.

CNN: Melanoma

To determine whether your melanoma has spread to nearby lymph nodes, your surgeon may use a procedure known as a sentinel node biopsy.

CNN: Melanoma

Sentinel node biopsy works on the principle that a few of the underarm nodes are first in line to host the spreading cancer cells.

BBC: 'One stop shop' for cancer

Professor Veronesi's research over the past decade has provided strong evidence that only a handful of spreading cancers will be missed if sentinel node biopsy is carried out instead of the full node removal.

BBC: 'One stop shop' for cancer