SweDCIS: Radiotherapy after sector resection for ductal carcinoma in situ of the breast. Results of a randomised trial in a population offered mammography screening

Figures & data

Table I.  Patient characteristics by study arm.

	RT^a (n = 526)	Control (n = 520)
Screening detected tumor, n (%)	415 (78.9)	408 (78.5)
Palpable tumor, n (%)	115 (21.9)	120 (23.1)
Mean size mm SD^b	17.9 (13.3)	17.8 (13.4)
Pathology margins clear, n (%)	426 (81.0)	414 (79.6)
Pathology margins unknown or missing, n (%)	48 (9.1)	46 (8.8)
Pathology margins positive, n (%)	52 (9.9)	60 (11.5)
Pathology margins given in mm, n (%)	166 (31.6)	173 (33.3)
Specimen x-ray margins clear, n (%)	388 (73.8)	394 (75.8)
Specimen x-ray margins unknown or missing, n (%)	96 (18.3)	83 (16.0)
Specimen x-ray margins positive, n (%)	28 (5.3)	25 (4.8)
Number of reexcisions, n (%)	36 (6.8)	46 (8.8)
Axillary dissection performed, n (%)	89 (16.9)	88 (16.9)
Treatment outside protocol, n (%)^c	19 (3.6)	14 (2.7)
Mean follow-up time±SD	5.5 (2.7)	5.5 (2.7)
Median follow-up time (25th Pctl, 75th Pctl)	5.1 (3.2, 7.5)	5.3 (3.4, 7.3)
Mean age±SD	56.2 (9.2)	56.7 (8.9)
Number of clinical follow-ups (mean±SD)	10.4 (6.1)	10.0 (5.5)
Number of postoperative mammographies (mean±SD)	5.0 (3.5)	5.3 (3.7)

^a Radiotherapy.

^b Size determined mammographically. A microscopically determined size was available for 30% of the patients. For these patients this measure was on average 4.1 mm smaller.

^c Tamoxifen for 2 years.

Figure 1.  Patient flow according to CONSORT recommendations [2]. After exclusions for protocol violations randomised patients were analyzed according to intention to treat.

Figure 2.  Cumulative incidence of all ipsilateral recurrences. The number of patients at risk is listed at the bottom of the figure. p < 0.0001, log-rank test.

Table II.  Number of events according to study definitions of endpoints, cumulative incidence, difference in cumulative incidences and hazard ratios with their respective 95% confidence intervals.

	Number of events	Cumulative incidence 5 years (95% CI^c)	Difference in cumulative incidence 5 years (95% CI)	Hazard ratio (95% CI)	p^b
All ipsilateral recurrence
RT^a	44	0.07 (0.05–0.10)	−0.15	0.33	<0.0001
Control	117	0.22 (0.18–0.26)	(−0.19– − 0.10)	(0.24–0.47)
All contralateral cancer
RT	26	0.033 (0.020–0.056)	−0.001	1.16	0.64
Control	22	0.032 (0.019–0.055)	(−0.026–0.024)	(0.62–2.14)
Distant metastasis or breast cancer deaths
RT	9	0.013 (0.005–0.032)	0.008	1.02	0.97
Control	9	0.005 (0.001–0.021)	(−0.006–0.021)	(0.40–2.56)

^a Radiotherapy.

^b Log-rank test stratified for health care region.

^c Confidence interval.

Table III.  Distribution within each study endpoint of events by type (in situ or invasive events, occurrences of distant metastases and breast cancer deaths).

Ipsilateral recurrence	RT^a	control
DCIS	23	69
Invasive	21	48
Sum	44	117
Contralateral cancer
DCIS	3	7
Invasive	23	15
Sum	26	22
Distant metastasis or breast cancer deaths	9	9
Distant metastasis	9	8
Breast cancer deaths without known distant metastasis	0	1
Total breast cancer deaths	7	6

^a Radiotherapy.

Figure 3.  Disease-free survival (DFS) as defined in endpoints on page 6. The number of patients is listed at the bottom of the figure. p < 0.001, log-rank test.

Moher D, Schulz KF, Altman DG. The CONSORT Statement: Revised Recommendations for Improving the Quality of Reports of Parallel-Group Randomized Trials. Lancet 2001; 357: 1191–4

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