Table 1 Suggested CTV delineation for breast, chest wall, and lymph node regions

Breast CTV

(CTV_B)

Upper border of palpable/visible breast tissue; maximally up to the caudal edge of the sterno-clavicular joint

Most caudal CT slice with visible breast

5 mm under skin surface (3 mm for small breast)

Major pectoral muscle or costae and intercostal muscles where no muscle

Lateral to the medial perforating mammarian vessels; maximally to the edge of the sternal bone

Lateral breast fold; anterior to the lateral thoracic artery

Chest wall CTV

(CTV_CW)

Guided by palpable/visible signs; if appropriate guided by the contralateral breast; maximally up to the caudal edge of the sterno-clavicular joint

Guided by palpable/visible signs; if appropriate guided by the contralateral breast

Skin

Major pectoral muscle or costae and intercostal muscles where no muscle

(For T4a/T4c cases, the major pectoral muscle and ribs should be included)

Guided by palpable/visible signs; if appropriate guided by the contralateral breast

Guided by palpable/visible signs; if appropriate guided by the contralateral breast. Usually anterior to the mid-axillary line

Supraclavicular CTV

Medial supraclavicular CTV (CTV_M_SCL)

Caudal to the cricoid cartilage

Includes the subclavian vein with 5 mm margin, thus connecting to the cranial border of CTVn_IMN

Sternocleidomastoid muscle, dorsal edge of the clavicle

Anterior aspect of the scalene muscle

Including the jugular vein without margin; excluding the thyroid gland and the common carotid artery

Cranial: Sternocleidomastoid muscle

Caudal: junction of 1st rib and clavicle

Entire supraclavicular CTV (CTV_E_SCL)

Same as above

Same as above

Same as above

Trapezius muscle

The same as CTV_M_SCL anteriorly, avoids the scalene and elevator scapulae muscles posteriorly

Sternocleidomastoid muscle, clavicle, and connecting to axillary level III

Internal mammary node CTV

(CTV_IMN)

Caudal limit of CTV_SCL

Cranial side of the 4th rib

(in selected cases 5-6th rib)

Ventral limit of the vascular area

Pleura

5 mm from the internal mammary vein (artery in cranial part down to and including first intercostal space)

5 mm from the internal mammary artery

Undissected axillary CTV

(CTV_udALN)

Undissected Axillary level 2

Includes the cranial extent of the axillary artery (i.e. 5 mm cranial of axillary vein)

The caudal border of the minor pectoral muscle, but should exclude the extent of the dissection

Minor pectoral muscle

Up to 5 mm dorsal of axillary vein or to costae and intercostal muscles

Medial edge of minor pectoral muscle

Lateral edge of minor pectoral muscle, but should exclude the extent of the dissection

Axillary level 3

Includes the cranial extent of the subclavian artery (i.e. 5 mm cranial of subclavian vein)

5 mm caudal to the subclavian vein

Major pectoral muscle

Same as level 2

Junction of subclavian and internal jugular veins, connects to CTV_SCN

Medial side of the minor pectoral muscle

Interpectoral nodes

Includes the cranial extent of the axillary artery (i.e. 5 mm cranial of axillary vein)

The caudal border of the minor pectoral muscle

Major pectoral muscle

Minor pectoral muscle

Medial edge of minor pectoral muscle

Lateral edge of minor pectoral muscle