Hospital volume and prognosis among Norwegian breast cancer patients enrolled in adjuvant trials

Figures & data

Table I. Number of eligible patients included in three multicenter randomized adjuvant trials of breast cancer in Norway 1984–1994.

		Number of included patients by operating volumes (1990)			Number of evaluable patients by type of adjuvant therapy
NBCG Study [ref]	Period of inclusion	1-50	>50	Total	Control	Tam	LHRH	Cyclic Tam/MA	No. of hospitals
1 [14]	01.1984–02.1988	147	203	350	170	180			32
2 [15]	01.1989–06.1994	159	158	317		159	158		35
3 [16]	03.1989–12.1994	295	169	464		229		235	36
	Total included, n	601	530	1131	170	568	158	235	50
	Total included, %	53	47	100

TAM, Tamoxifen; LHRH, luteinizing hormone-releasing hormone agonist; MA, megestrol acetate; NBCG, Norwegian Breast Cancer Group.

Table II. Patient and tumour characteristics of evaluable patients randomized into adjuvant trials of breast cancer in Norway 1984–1994.

	Annual operation volumes			Hospital function
	1–50 patients	>50 patients	p	University	Non-University	p	Total
Evaluable patients, n	601	530		483	648		1131
Hospitals, n	44	6		5	45		50
Age, years
median	58.0	54.0	<0.001	55.0	57.0	<0.01	56.0
range	23–75	22–75		22–75	23–75		22–75
Tumour size, cm
median	2.2	2.2		2.2	2.3		2.2
pT1, %	47	47	0.95	48	47	0.46	47
pT2, %	53	53		51	53		53
Axillary lymph nodes no. of examined
median	8.0	10.5	<0.001	10.0	8.0	<0.01	9.0
range	1–34	1–36		2–36	1–32		1–36
no. with metastases
median	2.0	2.0	0.25	2.0	2.0	0.11	2.0
range	1–30	1–32		1–32	1–25		1–32
1–3 pos. LN, %	73	67	0.03	66	74	0.01	70
>4 pos. LN, %	27	33		34	26		30
ER, fmol/mg protein
median	76	48	0.02	48	67	0.10	58
range	10–1772	10–1871		10–1871	10–1626		10–1871
Hormone receptor status
ER + and/or PgR+, %	76	90	<0.001	85	85	0.44	85
Type of operation, %
Mastectomy	92	84	<0.001	84	92	<0.01	89
Breast Conservation	8	16		16	8		11

ER, oestrogen receptor; PgR, progesteron receptor.

Table III. Survival data per operating volume (patients, pts) and hospital function category for patients randomised into adjuvant trials of breast cancer in Norway 1984–1994, with number of patients (n) in each category.

	Category	Overall results	1–50 pts n = 601	>50 pts n = 530	25% high quartile n = 324	25% low quartile n = 282	University n = 483	Non-University n = 648
RFS	Median	7.0	7.1	6.9	6.6	7.0	6.9	7.0
	CI 95%	6.3; 7.7	6.3; 7.9	5.7; 8.2	4.8; 8.4	5.9; 8.0	5.9; 8.0	6.1; 8.0
	5 year, %	59	60	58	55	60	59	59
	10 year, %	39	37	41	40	37	40	39
OS	Median	10.1	9.8	10.4	10.3	9.9	10.3	10.1
	CI 95%	9.4; 10.9	8.9; 10.8	9.2; 11.5	NA	8.7; 11.2	9.2; 11.5	9.2; 10.0

OS, overall survival; RFS, relapse-free survival; NA, not assessable.

Figure 1. Recurrence-free survival for high volume surgical units (> 50 patients/year, black line) versus low volume surgical units (1–50 patients/year, grey line). The number of patients still at risk is provided below the figure (p = 0.8).

Figure 2. Overall survival for high volume surgical units (> 50 patients/year, black line) versus low volume surgical units (1–50 patients/year, grey line). The number of patients still at risk is provided below the figure (p = 0.2).

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