Table 4.

Incidence of RT interruption by RT technique and type of surgery

	Mastectomy		Nonmastectomy†
RT technique	n	% with interruption	n	% with interruption
Total patients who began RT*	525	17	158	15
A: Tangents
A1: IMN <30 Gy	145	17	40	13
A2: IMN ≥30 Gy	160	13	79	15
B: Separate IMN field	137	20	31	23
C: Chest wall electrons	58	26	0	—
Other/unknown	25	0	8	0

Abbreviation: IMN = internal mammary nodes. Other abbreviations as in Table 1.

^*Excludes patients with missing data on type of surgery.

^†Lumpectomy, n = 155; axillary dissection, n = 3.