Prediction of outcome after diagnosis of metachronous contralateral breast cancer

BMC Cancer

Table 3 Cox-regression analysis for distant metastasis in relation to time interval to the second breast cancer

Age at BC1	Time interval to	Cases	Metastasis	Metastasis/100.000	HR	HR*	HR**
	BC2	No	No (%)	person-years	(95% CI)	(95% CI)	(95% CI)
All	<3 years	200	74 (37)	5800	1.4 (1.1-1.9)	1.6 (1.1-2.2)	1.6 (1.1-2.3)
No = 723	≥3 years	523	136 (26)	4100	1.0	1.0	1.0
					p = 0.01	p = 0.009	p = 0.01
< 50 years	<3 years	55	34 (62)	11000	2.2 (1.4-3.4)	2.0 (1.2-3.4)	2.2 (1.2-3.8)
No = 217	≥3 years	162	60 (37)	4900	1.0	1.0	1.0
					p < 0.0001	p = 0.01	p = 0.006
≥ 50 years	<3 years	145	40 (28)	4100	1.2 (0.78-1.7)	1.5 (0.92-2.3)	1.3 (0.77-2.2)
No = 506	≥3 years	361	76 (21)	3700	1.0	1.0	1.0
					p = 0.5	p = 0.1	p = 0.3

* Adjusted for calendar period (1977-1986, 1987-1996, 1997-2007), age (under vs. over 50 years at diagnosis of BC1), mode of detection of BC2 (symptomatic vs. asymptomatic), size (mm) of BC1 and BC2, and node status (N0 vs. N+) for BC1 and BC2. Multivariate analyses in subgroups divided by age are not adjusted for age again. No = 471, 158 patients <50 years and 313 ≥50 years.
** Adjusted for factors listed under * and in addition: treatment for BC1 and BC2 (radiotherapy, chemotherapy, endocrine treatment, yes vs. no for each of the variables). Multivariate analyses in subgroups divided by age are not adjusted for age again. No = 468, 157 patients <50 years and 311 ≥50 years.
Abbreviations: BC1 first breast cancer, BC2 second breast cancer , CI confidence interval, HR hazard ratio, N+ lymph node metastases, N0 no lymph node metastases, No number, node status lymph node status.

ISSN: 1471-2407