Table 3. Population 1, 10-year disease-free, locoregional recurrence-free, distant metastasis-free and overall survival for different time intervals between surgery and radiation therapy in breast cancer patients, stratified for use of adjuvant systemic therapy.

	Entire cohort (n=2759)		No adjuvant treatment (n=1761)		Adjuvant treatment (n=998)
	Crude	Multivariablea	Crude	Multivariableb	Crude	Multivariablec
Time interval	HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
Primary outcome: 10-year DFS
<42 days	1	1	1	1	1	1
42–55 days	0.77 (0.64–0.93)	0.78 (0.64–0.95)	0.79 (0.63–1.01)	0.81 (0.64–1.03)	0.73 (0.53–0.99)	0.71 (0.52–0.98)
	P=0.006	P=0.011	P=0.055	P=0.086	P=0.042	P=0.035
>55 days	0.72 (0.57–0.90)	0.71 (0.56–0.90)	0.75 (0.56–0.99)	0.76 (0.57–1.02)	0.66 (0.45–0.98)	0.63 (0.41–0.95)
	P=0.004	P=0.005	P=0.044	P=0.064	P=0.041	P=0.029
Secondary outcome: 10-year LRRFS
<42 days	1	1	1	1	1	1
42–55 days	0.69 (0.48–0.97)	0.72 (0.50–1.03)	0.74 (0.49–1.13)	0.77 (0.50–1.17)	0.54 (0.27–1.05)	0.55 (0.28–1.10)
	P=0.035	P=0.072	P=0.163	P=0.221	P=0.069	P=0.092
>55 days	0.80 (0.54–1.20)	0.90 (0.59–1.37)	0.88 (0.55–1.41)	0.97 (0.60–1.57)	0.63 (0.28–1.40)	0.68 (0.29–1.57)
	P=0.282	P=0.620	P=0.605	P=0.904	P=0.255	P=0.363
Secondary outcome: 10-year DMFS
<42 days	1	1	1	1	1	1
42–55 days	0.87 (0.67–1.12)	0.89 (0.68–1.16)	1.05 (0.72–1.52)	1.08 (0.74–1.59)	0.75 (0.52–1.07)	0.69 (0.47–1.00)
	P=0.288	P=0.393	P=0.817	P=0.681	P=0.107	P=0.047
>55 days	0.66 (0.47–0.92)	0.64 (0.45–0.92)	0.69 (0.42–1.14)	0.71 (0.43–1.19)	0.67 (0.42–1.06)	0.59 (0.36–0.96)
	P=0.015	P=0.014	P=0.147	P=0.197	P=0.085	P=0.034
Secondary outcome: 10-year OS
<42 days	1	1	1	1	1	1
42–55 days	1.17 (0.97–1.41)	1.20 (0.98–1.45)	1.42 (1.10–1.82)	1.51 (1.17–1.96)	0.91 (0.68–1.21)	0.83 (0.61–1.12)
	P=0.110	P=0.071	P=0.007	P=0.002	P=0.504	P=0.219
>55 days	1.24 (1.00–1.54)	1.21 (0.96–1.52)	1.44 (1.08–1.91)	1.57 (1.17–2.11)	1.05 (0.75–1.47)	0.87 (0.61–1.25)
	P=0.051	P=0.107	P=0.013	P=0.003	P=0.777	P=0.466

Abbreviations: CI=confidence interval; DFS=disease-free survival; DMFS=distant metastasis-free survival; HR=hazards ratio; LRRFS=locoregional recurrence-free survival; OS=overall survival.

P-values depicted in bold are considered as statistically significant (P<0.05).

^aCorrected for age, hospital volume, region, histological tumour type, differentiation grade, exact tumour size (mm), exact number of positive lymph nodes, residual tumour left after the operation, adjuvant systemic therapy.

^bCorrected for hospital volume, region, histological tumour type, exact tumour size (mm), exact number of positive lymph nodes.

^cCorrected for age, region, differentiation grade, exact number of positive lymph nodes, hormone receptor status, type of adjuvant systemic therapy.