Factors Associated with Late Local Radiation Toxicity after Post-Operative Breast Irradiation

Table 5

Significant association between different risk factors and breast fibrosis in irradiated breast cancer patients ≥12 months after whole breast irradiation.

Author (year)	Associated risk factors	Measure of association	Strength of association
Bergom (2012)	None	NA
Bronsart (2017)	Radiotherapy dose 50 Gy vs. 30 Gy	OR	12.5 (2.73–57.13)
De santis (2016)	None	NA
Hille-betz (2016)	Ptosis grade 2/3 or C-cupsize	NR	0.02^a
	Interval to radiotherapy		0.03^a
Ishiyama (2006)^b	Time after surgery (<2 vs. >5 years)	OR	0.06 (0.005–0.83)
Kelemen (2012)	100 cm^3 increase irradiated breast volume	OR	1.07 (1.00–1.14)
	10 cm^3 increase boost volume		1.12 (1.09–1.33)
	Photon boost	NR
	Edema	NR
	PTV	NR
Joseph (2020)	Breast volume (<1032 cm^3 vs. >1032 cm^3)	OR	1.01 (1.00–1.03)
Lilla (2007)	Age		1.06 (1.01–1.11)
	Allergy		2.45 (1.11–5.51)
Meattini (2019)	Extensive intraductal component	OR	2.15 (1.17–3.98)
	Tumor grade 2 vs. 1		0.54 (0.29–0.99)
	Tumor grade 3 vs. 1		0.29 (0.11–0.74)
	Breast size >492 cc		2.64 (1.50–4.65)
	Boost dose >10 Gy		6.76 (2.04–22.45)
La rocca (2019)	Boost	OR	1.70 (1.16–2.48)

All shown variables were significantly associated with late radiation toxicity. See Supplementary material for nonsignificant variables. ^a-value ^bReported outcome is breast firmness. Abbreviations: NA not applicable; NR not reported; OR odds ratio; PTV planned target volume.