Table 5 Prognostic indicators for breast cancers diagnosed in regular vs irregularly screeneda women, New Zealand women aged 45–69 years at year of diagnosis, 2003–2011b

From: Mammography service screening and breast cancer mortality in New Zealand: a National Cohort Study 1999–2011

 

Regularly screened

Irregularly screened

 

Prognostic indicator

n

%

n

%

Significance of difference

Grade of tumour

     

 Well differentiated

1697

30.6

2160

29.7

χ2(1)=1.38, P=0.2403

Excluding not recorded or NA (n=696)

 

32.1

 

31.6

χ2(1)=0.38, P=0.5381

 Moderately differentiated

2315

41.8

2960

40.6

 

 Poorly or undifferentiatedor anaplastic

1277

23

1724

23.7

 

 Not recorded/NA

255

4.6

441

6.1

 
 

Overall heterogeneity: χ2(3)=14.7, P=0.0021

 

Extent of disease

     

 Localised

3738

67.4

4333

59.5

χ2(1)=85.2, P<0.0001

Excluding unknown (n=847)

 

71.6

 

64.1

χ2(1)=74.1, P<0.0001

 Adjacent organ or

     

 regional lymph node

1433

25.9

2310

31.7

 

 Distant

53

1

115

1.6

 

Distant÷(distant+regional)

 

3.6

 

4.7

RR=0.75 (0.55–1.03)

 Unknown

320

5.8

527

7.2

χ2(1)=3.10, P=0.0784

 

Overall heterogeneity: χ2(3)=93, P<0.0001

 

Multiple tumours

     

 No

5475

98.8

7127

97.8

RR=0.57 (0.43–0.76)

 Yes

69

1.2

158

2.2

χ2(1)=15.5, P<0.0001

Maximum tumour size

(mm)

(mm)

   

 Mean

16.3

19.3

  

t=−12.0, P<0.0001

 Median

14

15

  

z=−10.5, P<0.0001c

  1. Abbreviation: NA=not available.
  2. aAs screened by Breastscreen Aotearoa.
  3. b2003 is the earliest year that regular and irregular screening can be established.
  4. cTwo-sample median test.