Table 3.

Overall and disease free survival in women with breast cancer over 5 years by type of surgery

	Mastectomy (n = 89)	Breast-conserving (n = 226)
Overall survival
Number of deaths	23	35
Person years	503	1,341
Crude mortality rate (per 100 person years)	4.57	2.61
Relative mortality
Crude	1.0 (ref)	0.57 (0.34–0.97)
Adjusteda	1.0 (ref)	1.00 (0.47–2.13)
Disease free survival
Number of events	30	52
Person years	485	1316
Crude event rate (per 100 person years)	6.18	3.95
Relative hazard
Crude	1.0 (ref)	0.64 (0.41–1.01)
Adjusted§	1.0 (ref)	0.91 (0.48–1.76)

^aadjusted for tumor stage, histology, age, comorbidity, chemotherapy, and hormonal therapy