The association between smoking and breast cancer characteristics and outcome

BMC Cancer

Table 5 Adjusted Five-year disease free survival, breast cancer specific survival and overall survival^a

Population^b (num)	5-y DFS HR 95% CI	p	5-y BCSS HR 95% CI	p	5-y OS HR 95% CI	p
Hx smoking^c
Yes (178)	0.65	0.418	0.66	0.632	1.14	0.852
No (443)	(0.23–1.83)	0.418	(0.12–3.58)	0.632	(0.28–4.71)	0.852
Current Smoking³
Yes (104)	0.46	0.33	NA	NA	NA	NA
No (513)	(0.10–2.18)	0.33	NA	NA	NA	NA
Number of pack years (PY)
PY³ 0–29 (523)	0.69	0.616	1.02	0.984	2.15	0.344
PY > =30 (67)	(0.16–2.96)	0.616	(0.12–8.40)	0.984	(0.44–10.49)	0.344

^aMultivariate adjustment included the following covariates: age, menopausal status, ethnicity, tumor size, nodal involvement and grade
^bSample size: DFS: Smoking history n = 439, smoking status n = 437, pack years n = 423, BCSS: Smoking history n = 443, smoking status n = 441, pack years n = 425, OS: Smoking history n = 444 smoking status n = 442, pack years n = 426
^cData regarding smoking was retrieved during the first visit at the oncologist clinic. Current smokers were defined as patients who actively smoked at the time of breast cancer diagnosis. Patients with history of smoking were defined as ever smoker
- Abbreviations: BCSS breast cancer specific survival, DFS disease free survival, NA not applicable, OS overall survival
- Cohort included patients with ER positive, HER2 negative disease

ISSN: 1471-2407