Radiation Oncologists’ Approach to Internal Mammary Lymph Node Radiotherapy in Breast Cancer: The Turkish Society for Radiation Oncology Breast Cancer Study Group (TROD 06-005 Survey Study)

Figures & data

Table 1 Survey Items and Results Obtained from Turkish Radiation Oncologists

a) General Information		N	%
1.Age group	< 50	121	73.3
	> 50	44	26.7
2.Participants	Specialist	110	66.7
	Associate professor	23	13.9
	Professor	22	13.3
	Resident	10	6.1
3.Years in practice	< 5	16	9.7
	5–10	40	24.2
	10–20	65	39.4
	> 20	44	26.7
4.Type of hospital	University	68	41.2
	Research hospital	65	39.4
	Private	32	19.4
5.Rates of clinical time, dedicated to breast cancer	< %5	37	22.4
	%5–25	47	28.5
	%25–75	63	38.2
	> %75	18	10.9
b) Indication		N	%
1.In which situations do you irradiate the RNI in breast cancer radiotherapy?	ALND 1–3 (+) and RF (+)	106	64.2
	ALND (-) and IMN (+) at PET-CT and CT	106	64.2
	Number of ALND-involved nodes ≥50%	98	59.4
	All ALND ≥4 (+) cases	94	57.0
	Insufficient ALND without SLND (number of nodes removed <10)	93	56.4
	All ALND 1–3 (+) cases	76	46.1
	All ALND (-) and T4 cases	67	40.6
	ALND (-) and tumor diameter ≥5 cm	34	20.6
	ALND (-) and inner quadrant/central location, tm>3 cm	33	20.0
	ALND (-) and RF (+)	26	15.8
2.In which situations do you irradiate the IMN in the inner quadrant and central tumors?	I irradiate it even if one node (+) after ALND	101	61.2
	In all the T3-T4 cases	63	38.2
	I irradiate it 1 ≥ RF (+) even if all the cases are ALND (-)	38	23.0
	I irradiate it even if all the cases are ALND (-)	18	10.9
3.In which situations do you irradiate the IMN in the non-inner quadrant and non-central tumors?	I irradiate it if ALND ≥ 4(+)	118	71.5
	All the T3-T4 cases	58	35.2
	I irradiate it even if one node (+) after ALND	41	24.8
	I irradiate it 1 ≥ RF (+) even if all the cases are ALND (-)	12	7.3
	I irradiate it even if all the cases are ALND (-)	2	1.2
4.In which situations do you irradiate the IMN?	I irradiate it if IMN (+) in PET-CT and planning CT	135	81.8
	ALND > 10 (+) or ALND involved node number > 25%	89	53.9
	ALND involved node number > 50%	86	52.1
	I irradiate it in all the clinical-pathological T4 cases	53	32.1
	I irradiate it in all the cases undergoing elective RNI	28	17.0
c) Treatment Technique and the Dose Fractionated Regimen		N	%
1. Regarding IMNRT, what are the techniques most frequently used?	3DCRT	86	52.1
	IMRT	79	47.9
2. IMN treatment field	Tangential	107	64.8
	Separate field	33	20
	Other	25	15.2
3. Irradiation of the IMN field	Photon + electron	99	60
	Only photon	57	34.5
	Only electron	9	5.5
4. Breath-hold technique	None	83	50.3
	Only for left sided breast cancer cases	68	41.2
	All cases	14	8.5
5. Hypofractionation	No	157	95.2
	Yes	8	4.8
6. What is the most frequent prescription dose?	50 Gy	107	64.8
	46 Gy	55	33.3
	40 Gy	3	1.8
7. Fractionation	2 Gy	140	84.8
	1.8 Gy	25	15.2
8. IMNRT decision for cardiac risk	No	84	50.9
	Yes	81	49.1
d) Literature Review
1. IMNRT indication after the MA20_and EORTC22922	Yes	91	55.2
	No	74	44.8
2. IMNRT CTV/PTV margin reduction after the MA20_and EORTC22922	Yes	91	55.2
	No	74	44.8

Table 2 Regional Nodal Irradiation Scenarios

	Scenario	N	%
In which situations do you irradiate the RNI in breast cancer radiotherapy?	ALND 1–3 (+) and RF (+)	106	64.2
	ALND (-) and imaging and clinical IMN (+)	106	64.2
	Number of ALND-involved nodes ≥50%	98	59.4
	All ALND ≥4 (+) cases	94	57
	Insufficient ALND without SLND (number of nodes removed <10)	93	56.4
	All ALND 1–3 (+) cases	76	46.1
	All ALND (-) and T4 cases	67	40.6
	ALND (-) and tumor diameter ≥5 cm	34	20.6
	ALND (-) and inner quadrant/central location, tm>3 cm	33	20
	ALND (-) and RF (+)	26	15.8

Notes: Tumor diameter >3 cm; the presence of LVI, grade 3, young age (premenopausal), surgical margin adjacent.

Abbreviations: ALND, axillary lymph node dissection; RF, risk factors; IMN, internal mammary lymph node; RF, aggressive biology.

Table 3 Responses Regarding RT to Regional Lymph Nodes in Breast Cancer Radiotherapy for Several Scenarios

Scenario	The Academic Practice of Participants		p
	Professor (n=22)	Residents (n=10)
ALND 1–3 (+) and RF (-)	9 (40.9%)	10 (100%)	0.011*
ALND 1–3 (+) and RF (+)	16 (72.7%)	2 (20%)	0.023*
All ALND ≥4 (+)	18 (81.8%)	5 (50%)	0.016*
	Years in practice
	> 20 years (n=44)	5–10 years (n=40)
All ALND ≥4 (+)	34 (77.3%)	16 (40%)	0.006**
Number of ALND-involved nodes ≥50%	35 (79.5%)	18 (45%)	0.009**
	Rates of clinical time, dedicated to breast cancer
	> %25 (n=81)	< %25 (n=84)
ALND 1–3 (+) and RF (+)	44 (54.3%)	32 (38.1)	0.037*
All ALND ≥4 (+)	55 (67.9%)	39(46.4%)	0.005**
ALND (-) and tumor diameter ≥5 cm	23 (28.4%)	11 (13.1%)	0.015*
All ALND (-) and T4	40 (49.4%)	27 (32.1%)	0.024*
Number of ALND-involved nodes ≥50%	55 (67.9%)	43 (51.2%)	0.029*

Notes: *p<0.05 **p<0.01. (tumor diameter >3 cm; the presence of LVI, Grade 3, young age (premenopausal), surgical margin adjacent).

Abbreviations: ALND, axillary lymph node dissection; RF, risk factors; RF, aggressive biology.

Figure 1 Responses regarding radiotherapy to the internal mammary node for several scenarios. In which situations do you irradiate the IMN?

Figure 2 Responses regarding radiotherapy to internal mammary node for number of scenarios. Tumors located in non-center or non-inner quadrant. In which situations do you irradiate the IMN in non-inner quadrant and non-central tumors?

Figure 3 Responses regarding radiotherapy to the internal mammary node for several scenarios. Tumors located in the center or inner quadrant. In which situations do you irradiate the IMN in the inner quadrant and central tumors?

Notes: Tumor, >3 cm; the presence of LVI, grade 3, young age (premenopausal), surgical margin adjacent.

Abbreviations: ALND, axillary lymph node dissection; RF, risk factors; RF, aggressive biology.