Risk of second primary cancer among women in the Kaiser Permanente Breast Cancer Survivors Cohort

Breast Cancer Research

Table 2 Cumulative incidence for second primary cancer according to year of first breast cancer diagnosis among 16,004 women diagnosed with a first primary unilateral invasive breast cancer^a

Year of first breast cancer diagnosis	5 years	10 years
Year of first breast cancer diagnosis	% (95% CI)	% (95% CI)
All second cancers
1990- < 2000	4.77 (4.21–5.38)	10.97 (10.09–11.90)
2000- < 2010	4.69 (4.19–5.24)	10.79 (9.92–11.70)
2010 +	4.19 (3.27–5.38)	–^b
All second non-breast cancers
1990- < 2000	3.18 (2.72–3.68)	7.14 (6.43–7.91)
2000- < 2010	3.49 (3.06–3.97)	7.87 (7.13–8.66)
2010 +	3.36 (2.54–4.35)	–^b
Contralateral breast^c
1990- < 2000	1.61 (1.29–1.99)	3.82 (3.30–4.41)
2000- < 2010	1.28 (1.02–1.60)	3.05 (2.57–3.58)
2010 +	0.98 (0.56–1.61)	–^b

^aCumulative incidence for all second primary cancers, second non-breast cancers, and contralateral breast cancer were estimated accounting for the competing risk of death and other invasive cancers (contralateral breast cancer only)
^bFollow-up time was not sufficient to report cumulative incidence at 10-years
^cWomen with bilateral mastectomies were excluded (n = 1,042)

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