Long-term effects on the incidence of second primary cancers in a randomized trial of two and five years of adjuvant tamoxifen

Figures & data

Figure 1. Cumulative incidence for contralateral breast cancer (A), endometrial cancer (B) and lung cancer (C) among patients without prior recurrences or contralateral breast cancer randomly assigned to 2 years (n = 2106) or 5 years (n = 2022) of adjuvant tamoxifen therapy.

Figure 2. Hazard ratios (5 vs. 2 years of tamoxifen) for contralateral breast cancer (A), endometrial cancer (B) and lung cancer (C) among patients without prior recurrences or contralateral breast cancer randomly assigned to 2 years (n = 2106) or 5 years (n = 2022) of adjuvant tamoxifen therapy.

Table 1. Secondary cancer incidence without prior recurrence or contralateral breast cancer according to randomized treatment (5 vs. 2 years of tamoxifen) for the entire follow-up (>2 years after start of treatment), during treatment (2–5 years) and after treatment (>5 years).

		Number of events
Cancer site/histological type	Years since start of treatment	2-year group n = 2106	5-year group n = 2022	Hazard ratio (5 vs. 2 years) (95% CI)	p Value
Contralateral breast	>2	121	92	0.73 (0.56–0.96)	0.022
cancer	2–5	29	22	0.78 (0.45–1.36)	0.38
	> 5	92	70	0.71 (0.52–0.97)	0.033
Endometrial cancer	>2	32	60	1.83 (1.19–2.81)	0.0059
	2–5	6	19	3.33 (1.33–8.34)	0.010
	> 5	26	41	1.50 (0.91–2.45)	0.11
Lung cancer	>2	41	20	0.45 (0.27–0.77)	0.0038
	2–5	6	2	0.34 (0.07–1.70)	0.19
	> 5	35	18	0.47 (0.27–0.83)	0.0096
Adenocarcinoma	>2	10	7	0.61 (0.23–1.60)	0.32
Squamous cell	>2	9	1	0.10 (0.01–0.80)	0.030
Small cell	>2	11	4	0.34 (0.11–1.08)	0.067
Undifferential and large cell	>2	8	5	0.62 (0.20–1.91)	0.41
Other specified	>2	1	1	1.05 (0.07–16.94)	0.97
Unspecified	>2	2	2	0.94 (0.13–6.66)	0.95