Identifies the draining lymph nodes treated (if any) during the third phase of radiation therapy delivered to the patient during the first course of treatment. This data item is required for CoC-accredited facilities as of cases diagnosed 01/01/2018.

The third phase of radiation treatment commonly targets both the primary tumor (or tumor bed) and draining lymph nodes as a secondary site. This data item should be used to indicate the draining regional lymph nodes, if any, that were irradiated during the third phase of radiation.

00	No radiation treatment
01	Neck tymph node regions
02	Thoracic lymph node regions
03	Neck and thoracic lymph node regions
04	Breast/Chest wall lymph node regions
05	Abdominal lymph nodes
06	Pelvic lymph nodes
07	Abdominal and pelvic lymph nodes
08	Lymph node region, NOS
88	Not Applicable; Phase III Radiation Primary Treatment Volume is lymph nodes
99	Unknown if any radiation treatment to draining lymph nodes; Unknown if radiation treatment administered

Blanks allowed if no Phase III radiation treatment administered.