The Registry Partners October 2019 CTR Coding Break discusses Sentinel Lymph Node Biopsy and Regional Lymph Node Dissection. The presentation will review the Commission on Cancer’s 6 new data items relating to the sentinel lymph node biopsy and regional lymph node dissection, providing examples on how each data item is coded. The date item, date of sentinel lymph node biopsy is required for breast and melanoma cases only. Scenarios show how to determine the date of sentinel lymph node biopsy if there is a separate sentinel lymph node procedure and a subsequent regional lymph node dissection procedure performed or if the sentinel lymph node biopsy is performed during the same procedure. The date fields Sentinel Lymph Nodes Examined and Sentinel Lymph Nodes Positive are examined with examples. The coding break concludes with a review of the data field Date Regional Lymph Node Dissection tying together the breast and melanoma case instructions with sentinel lymph node biopsy.