TABLE 2.

Local regional recurrence and development of contralateral breast cancer according to age and treatment stratification^a

Characteristic	Patient age			P
	<40 Years	40–70 Years	>70 Years	All groups	<40 versus ≥40 Years	≤70 versus >70 Years
LRR, n (%)
Total	6 (10.7)	34 (3.4)	3 (2.1)	0.016	0.005	0.390b
DCIS	6 (100.0)	20 (58.8)	1 (33.3)
Invasive	0 (0)	14 (41.2)	2 (66.7)	0.086	0.005	0.390
5 years LRR rate
Mastectomy (n = 821)	0 %	1.3 %	0 %	0.504	0.427	0.434b
BCS with radiotherapy, all patients (n = 977)	6.4 %	2.1 %	2.6 %	0.324	0.143	0.701b
BCS with radiotherapy, margins ≥2 mm (n = 877)	7.0 %	2.0 %	3.2 %	0.185	0.067	0.986b
BCS without radiotherapy (n = 239)	22.9 %	8.0 %	3.1 %	0.014	0.006	0.235b
BCS without radiotherapy or tamoxifen (n = 174)	25.9 %	9.2 %	0 %	0.005	0.003	0.095b
BCS with radiotherapy without tamoxifen (n = 521)	5.0 %	3.1 %	4.0 %	0.639	0.882	0.359b
BCS with radiotherapy with tamoxifen (n = 456)	8.3 %	1.0 %	0 %	0.002	<0.001	0.479b
Development of contralateral breast cancer, n (%)c
Total	4 (4.4)	56 (4.0)	7 (3.8)	0.995	0.926	0.988b
DCIS	4 (100.0)	24 (42.9)	4 (57.1)
Invasive	0 (0)	32 (57.1)	3 (42.9)	0.076	0.031	0.600
5 years rate of development of contralateral breast cancerc
Overall	2.2 %	3.5 %	4.0 %	0.995	0.926	0.988b
In patients receiving tamoxifen (n = 611)	4.6 %	2.9 %	2.3 %	0.540	0.808	0.273b
In patients not receiving tamoxifen (n = 1068)	1.4 %	3.9 %	5.7 %	0.931	0.788	0.772b

LRR locoregional recurrence, DCIS ductal carcinoma-in-situ, BCS breast-conserving surgery

^aP values are from the chi-square test unless otherwise indicated

^bCalculated by the Kaplan–Meier method and differences compared by the log-rank test

^cExcludes patients who had contralateral prophylactic mastectomy, bilateral breast cancer at diagnosis, and history of contralateral breast cancer