Delineation of target volumes and organs at risk in adjuvant radiotherapy of early breast cancer: National guidelines and contouring atlas by the Danish Breast Cancer Cooperative Group

Figures & data

Figure 1. The mammography identified a tumour at 1 o´clock 6 cm from the papillary complex in the right breast.

Figure 2. Representative examples of preconsensus and postconsensus delineations. A and B: (to the left) Preconsensus delineations. C and D: (to the right) Postconsensus delineations. CTV-breast: orange, CTV axillary LN level I: bright green, CTV axillary LN level II: blue, CTV axillary LN level III: orange, CTV interpectoral LN: yellow, CTV periclavicular LN: pink, CTV IMN: forest green.

Figure 3. Representative examples of CTVs from the consensus delineation. The full CT atlas is available online (http://www.dbcg.dk : Retningslinjer/Vejledninger). CTV- breast: orange, Tumour bed: red, CTV axillary level I: bright green, CTV axillary level II: blue, CTV axillary level III: orange, CTV interpectoral LN: yellow, CTV IMN: forest green, CTV periclavicular LN: pink, Ipsilateral lung: green.

Table I. The national guidelines for delineation of target volumes in adjuvant radiotherapy of early breast cancer.

DCBG guidelines for delineation of CTV of breast and CTVs of the regional lymph node regions
LN region	cranial	caudal	ventral	dorsal	lateral	medial
Breast Residual breast, including tumour bed	Maximal to the caudal edge of the sterno-clavicular-junction	The intermammary sulcus	5 mm below the skin	M. pectoralis major	The axillary vessels (branches from the lateral thoracic vessel)	Maximal to the ipsilateral edge of sternum
Regio mammaria (PMRT)	Equal to a CTV-breast guided by the contralateral breast
CTV-boost	Tumour bed including clips and seroma plus 5 mm's margin
Level I	1 cm below caput humeri	Free edge of m. pectoralis major including seroma	5 mm below the skin	M. latissimus dorsi, 5 mm dorsal of the axillary vessels	Maximal to 5 mm below the skin	CTV-breast, lateral border of m. pectoralis minor, m. biceps brachii
Level II	5 mm cranial to the axillary vessels	Caudal edge of m. pectoralis minor	Dorsal surface of m. pectoralis minor	Chest wall, 5 mm dorsal of the axillary vessels	Lateral border of m. pectoralis minor	Medial border of m. pectoralis minor
Level III	5 mm cranial to the axillary vessels	1 cm caudal to the axillary vessels	Dorsal surface of m. pectoralis major	Chest wall, 5 mm dorsal of the axillary and subclavian vessels	Medial border of m. pectoralis minor	Clavicle
Periclavicular	Caudal edge of cricoid cartilage	Cranial border of level II and III (lateral). Cranial edge of the sterno-clavicular-junction (medial)	Dorsal surface of m. sternomastoideus, dorsal surface of clavicle, 5 mm below skin	In front of the clavicle, behind a. carotis interna, in front of m. scalenus ant, m. scalenus med, m. omo-hyoideus and m. levator scapulae	Medial edge of m. pectoralis minor, clavicle	Medial edge of a. carotis interna and v. jugularis interna
Interpectoral	Cranial border of m. pectoralis minor	Caudal border of m. pectoralis minor	Dorsal surface of m. pectoralis major	Ventral surface of m. pectoralis minor	Lateral border of m. pectoralis minor	Medial border of m. pectoralis, if possible to the edge of sternum
IMN	Cranial edge of costa 1	Cranial edge of costa 5	Dorsal surface of m. pectoralis major, dorsal surface of sternum	Pleura	5 mm lateral of internal mammary vessels or 2 cm from the edge of sternum	The edge of sternum

Table II. Constraints for organs at risk in adjuvant radiotherapy of early breast cancer.

Organ at risk	Normofractionation 2 Gy per fraction/ 5 fractions/week
LADCA	V20Gy = 0%
Heart	V20Gy = 10%, V40Gy = 5%
Ipsilateral lung	V20Gy = 25% (exclusive periclavicular LN) V20Gy = 35% (inclusive periclavicular LN) Mean dose < 18 Gy
Spinal cord	Max. 45 Gy
Plexus brachialis	Max. 54 Gy
Maximal dose of CTV	107% = 53.5 Gy
Maximal dose outside PTV	54 Gy

CTV, clinical target volume; LADCA, left anterior descending coronary artery; LN, lymph nodes; PTV, planning tumor volume.

Table III. Mean and ranges of DSC before and after consensus.

Volume	Consensus volume (ml)	Mean DSC (range) Before consensus	Mean DSC (range) After consensus
Breast	1247	0.93 (0.89–0.96)	0.95 (0.93–0.96)
Boost	40	NA	0.75 (0.60–0.89)
Internal mammary LN	15	0.59 (0.32–0.72)	0.71 (0.63–0.81)
Axillary LN level I	108	0.65 (0.59–0.75)	0.70 (0.60–0.77)
Axillary LN level II	32	0.56 (0.35–0.69)	0.76 (0.67–0.84)
Axillary LN level III	17	0.56 (0.39–0.73)	0.74 (0.66–0.82)
Periclavicular LN	47	0.41 (0.34–0.56)	0.56 (0.43–0.73)
Interpectoral LN	33	0.54 (NA)	0.66 (0.55–0.78)
Heart	731	0.91 (0.88–0.94)	0.94 (0.90–0.96)

DSC, Dice similarity coefficient; NA, not available.