Dosimetric comparison of organs at risk in ultra-hypofractionated versus hypofractionated postoperative radiotherapy for early breast cancer: single center clinical study

Gordana Petkovska; Ivica Ratosa; Valentina Bojovska Trajanovska; Marina Iljovska; Albina Pupakovski Creslovnik; Emilija Lazareva

doi:10.2478/raon-2026-0008

$Dosimetric comparison of organs at risk in ultra-hypofractionated versus hypofractionated postoperative radiotherapy for early breast cancer: single center clinical study Cover$

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Dosimetric comparison of organs at risk in ultra-hypofractionated versus hypofractionated postoperative radiotherapy for early breast cancer: single center clinical study

Radiology and Oncology

Volume 60 (2026): Issue 1 (March 2026)

By: Gordana Petkovska, Ivica Ratosa, Valentina Bojovska Trajanovska, Marina Iljovska, Albina Pupakovski Creslovnik and Emilija Lazareva

Open Access

|Feb 2026

Figures & Tables

TABLE 1.

Patients’ characteristics

Variable	n	UHF	HF	p-level
Age (years)		mean ± SD	min-max
UHF	40	60.8 ± 7.1	50–75	t = 0.37
HF	40	61.35± 6.2	50–74	p = 0.712
Side
Right	38	22 (55)	16 (40)	X² = 1.8
Center	42	18 (45)	24 (60)	p = 0.18
Chemotherapy
No	50	24 (63.2)	26 (65)	X² = 0.029
Yes	28	14 (36.8)	14 (35)	p = 0.865
Hormonal therapy
No	8	2 (5.3)	6 (15)	X² = 1.09
Yes	70	36 (94.7)	34 (85)	p = 0.297
Target therapy
No	65	32 (84.2)	33 (82.5)	X² = 0.041
Yes	13	6 (15.8)	7 (17.5)	p = 0.839
Breast size
< 1300 cm³	68	36 (90)	32 (80)	X² = 1.57
> 1300 cm³	12	4 (10)	8 (20)	p = 0.21

1 HF = hypofractionated group; n = number; UHF = ultra-hypofractionated group

TABLE 2.

Tumor characteristics

Variable	n	UHF	HF	p-level
Tumor stage
1b	7	2 (5.26)	5 (12.5)	p = 0.185
1c	37	18 (47.37)	19 (47.5)
1mi	3	0	3 (7.5)
2	31	18 (47.37)	13 (32.5)
all	78	38	40
Tumor size
mean ± SD		20.3 ± 8.2	16.3 ± 7.9	t = 2.13 *p = 0.037
min-max		7–45	1–35
median (IQR)		19 (15–22)	15 (11.5–23)
Lymph nodes
N0	73	36 (94.74)	37 (92.5)	X² = 0.0035 p = 0.953
N1	5	2 (5.26)	3 (7.5)	X² = 0.0035 p = 0.953
Grade
G1	10	3 (8.11)	7 (17.5)	X² = 191 p = 0.384
G2	51	27 (72.97)	24 (60)
G3	16	7 (18.92)	9 (22.5)
Lymphovascular invasion
LV 0	42	21 (61.76)	21 (56.76)	X² = 0.18 p = 0.668
LV 1	29	13 (38.24)	16 (43.24)	X² = 0.18 p = 0.668
Histopathological type
NST	56	29 (72.5)	27 (67.5)	p = 0.23
lobular	11	6 (15)	5 (12.5)
mixed	4	2 (5)	2 (5)
other	7	1 (2.5)	6 (15)
Tis	2	2 (5)	0
ER/HER2
ER+ HER2+	8	4 (10.53)	4 (10)	p = 0.344
ER+ HER2-	59	31 (81.58)	28 (70)
ER-HER2+	3	0	3 (7.5)
ER-HER2-	8	3 (7.89)	5 (12.5)

1 ER = estrogen receptor; G = Grade; HER2 = human epidermal growth factor receptor 2; HF-RT = hypofractionated group; IQR = interquartile range; LV = lymphovascular invasion; N = Node; NST = non specific type; SD = standard deviation; Tis = tumor in situ; UHF-RT = ultra-hypofractionated group

TABLE 3.

Dosimetric evaluation of PTV

	PTV95%			p-level
	n	mean ± SD	min–max	p-level
UHF	40	99.3 ± 0.6	97.4 – 100	t = 4.9 ***p = 0.000006
HF	40	98.3 ± 1.2	95.2 – 99.9	t = 4.9 ***p = 0.000006

1 HF = hypofractionated group; n = number; PTV = planning target volume; UHF = ultra-hypofractionated group

TABLE 4.

Dosimetric evaluation of dose to the Heart

	HeartV(%))				p-level
	n	mean ± SD	min–max	median (IQR)	p-level
UHF	19	7.7 ±4.0	0–16.3	7.5 (5.7–9.5)	Z = 3.3 **p = 0.0011
HF	24	3.7 ± 2.9	0.03–10.0	3.1 (1.4–5.0)	Z = 3.3 **p = 0.0011

	Heart_mean (Gy)				p-level
	n	mean ± SD	min–max	median (IQR)	p-level
UHF	19	0.8 ± 0.3	0.5–1.54	0.7 (0.6–1.01)	Z = 5.2 p < 0.0001
HF	25	2.6 ± 1.3	0.9–5.4	2.4 (1.8–3.4)	Z = 5.2 p < 0.0001

	Heart mean EQD2Gy α/β (4)			p-level
	n	mean ± SD	min–max	p-level
UHF	19	1.3 ± 0.5	0.8–2.5	t = 4.9 ***p = 0.000017
HF	25	3.02 ± 1.4	1.1–6.1	t = 4.9 ***p = 0.000017

1 EQD2 = equivalent dose in 2 Gy fraction; HeartV1.5 (%) = volume of heart expressed in % that receives 1.5 Gy; HeartV20 (%) = volume of the heart expressed in % that receives 20 Gy; HF = hypofractionated group; IQR, interquartile range; UHF = ultra-hypofractionated group

TABLE 5.

Dosimetric evaluation to the Lung

	LungVGy(%)				p-level
	n	mean ± SD	min–max	median (IQR)	p-level
UHF	40	8.1 ± 4.1	0.2–15.5	7.95 (5.5–11.1)	Z = 2.59 **p = 0.0096
HF	40	11.8 ± 5.6	1.6–24.5	10.25 (7.5–16.2)	Z = 2.59 **p = 0.0096

	Lung_mean(Gy)				p-level
	n	mean ± SD	min–max	median (IQR)	p-level
UHF	40	2.5 ± 1.3	0.8–8.5	2.4 (1.8–3.1)	Z = 6.51 p < 0.0001
HF	40	5.6 ± 2.1	1.8–10.2	5.135 (3.9–7.3)	Z = 6.51 p < 0.0001

	Lung mean EQD2Gy a/β (4)				p-level
	n	mean ± SD	min–max	median (IQR)	p-level
UHF	40	3.9 ± 2.1	1.2–13.9	3.64 (2.8–4.8)	Z = 4.76 ***p = 0.000002
HF	40	6.2 ± 2.4	2.1–11.3	5.715 (4.4–8.1)	Z = 4.76 ***p = 0.000002

1 EQD2 = equivalent dose in 2Gy fraction; HF = hypofractionated group; IQR = interquartile range; LungV8(%) = volume of ipsilateral lung expressed in % that receives 8 Gy; LungV18 (%) = volume of ipsilateral lung expressed in % that receives 18Gy; UHF = ultra-hypofractionated group

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DOI: https://doi.org/10.2478/raon-2026-0008 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099

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Language: English

Page range: 124 - 131

Submitted on: Oct 14, 2025

Accepted on: Dec 1, 2025

Published on: Feb 6, 2026

Published by: Association of Radiology and Oncology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

breast cancer,

radiotherapy,

ultra-hypofractionation,

Related subjects:

© 2026 Gordana Petkovska, Ivica Ratosa, Valentina Bojovska Trajanovska, Marina Iljovska, Albina Pupakovski Creslovnik, Emilija Lazareva, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 60 (2026): Issue 1 (March 2026)