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Breast Cancer Screening Quality and Efficiency

Key findings

Measure:  PPV: percentage of women, age 50 to 74, with an abnormal OBSP screening mammogram result and were diagnosed with breast cancer (ductal carcinoma in situ or invasive) after diagnostic work-up

 

Desired Direction:

 

An image of an arrow pointing upwards. This indicates that desired direction for this action is upwards.

 

As of this Report:

 

An image of an arrow pointing straight in a green box. This indicates that there has been no increase or decrease in performance over the previous periods identified and this action is exceeding or meeting target.

In 2016, the positive predictive value (PPV) of breast cancer screening was 6.5% in the Ontario Breast Screening Program (OBSP), Ontario’s province-wide organized cancer screening program. A PPV of 6.5% means that 3,452 of the 53,146 women age 50 to 74 who had an abnormal OBSP screening mammogram were diagnosed with breast cancer. The PPV for mammograms in Ontario has remained steady at around 6% since 2013.

Approximately 25,000 Ontario women age 50 to 72 who were screened through the OBSP in 2014 and received a 2-year screening recall recommendation had a subsequent program mammogram within 18 months (i.e., they had one too soon). This is an indicator of screening participation behaviour that falls outside recommended guidelines. Early return among women who had an OBSP mammogram with a 2-year recall recommendation increased from 4.4% in 2012 to 6% in 2015. Considerable regional variation was present for this indicator.

In 2016, approximately 7,000 women age 30 to 69 who were referred to the High Risk OBSP completed a genetic assessment (through counselling and/or testing) to determine whether they were at high risk for getting breast cancer. Of the women who completed an assessment, approximately 2,000 (nearly one-third) were determined to be at high risk for getting breast cancer, a rate that has remained steady since 2013. The proportion of women at high risk for breast cancer who were subsequently screened in the OBSP with magnetic resonance imaging (MRI) or ultrasound within 90 days of confirmation of their high risk status decreased from 61% in 2013 to 44% in 2016.

What is breast cancer screening?

  • Cancer screening is for people who may be at risk of getting cancer, but who have no symptoms and generally feel fine. It is not meant to diagnose cancer. Instead, it helps determine which people are more likely to develop cancer in the future. Ontario operates screening programs for 3 types of cancer: breast, cervical and colorectal.

Measure:  Early return: percentage of Ontario women, age 50 to 72, who were screened through the OBSP with a biennial (every 2 years) screening recall recommendation and had a subsequent program mammogram within 18 months of the previous mammogram

 

Desired Direction:

 

An image of an arrow pointing downwards. This indicates that desired direction for this action is downwards.

 

As of this Report:

 

An image of an arrow pointing upwards in a yellow box. This indicates that there has been a decrease in performance over the previous periods identified and this action is below but approaching target or has notable regional variation.

  • The purpose of breast cancer screening is to find cancer at an early stage, when it may be smaller and easier to treat.
  • A mammogram uses low-dose X-rays to produce images of the breast [1]. A breast magnetic resonance imaging (MRI) scan uses radio waves and a magnetic field to create cross-sectional images of the breast and an intravenous contrast agent (e.g., dye) is used most of the time [2]. Both tests can find breast cancers when they are small, less likely to have spread and more likely to be treated successfully.
  • Breast cancer screening with mammography is recommended every 2 years for most women age 50 to 74 [3].
  • Breast cancer screening with mammography and breast MRI (or screening breast ultrasound if MRI is not medically appropriate) is recommended every year for women ages 30 to 69 identified as being at high risk for breast cancer [1].
  • Most women with an abnormal mammogram result will not have breast cancer [1].   More tests are needed after an abnormal mammogram result to determine whether a cancer is present.
  • Diagnostic assessment includes additional radiological or surgical procedures, such as diagnostic mammography, ultrasonography, and core and/or open surgical biopsy.
  • In Ontario, breast cancer screening occurs through both OBSP and non-OBSP sites. For a map of locations, visit the Breast screening participation and retention section of this year’s Cancer Screening Quality Index (CSQI).

What is positive predictive value?

  • PPV is a quality measure that assesses the accuracy of breast cancer screening in finding breast cancer. It is influenced by the abnormal call rate (i.e., the percentage of women referred for further testing due to an abnormal screening mammogram), cancer detection rates and the underlying incidence (i.e., new cases) of breast cancer.

Figure 1. Percentage of women age 50 to 74 with an abnormal Ontario Breast Screening Program (OBSP) screening mammogram result who were diagnosed with breast cancer (ductal carcinoma in situ or invasive) after diagnostic work-up, by Local Health Integration Network (LHIN), 2013 to 2016

More information regarding the methodology is available.

Report date: December 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Figure 2. Percentage of women age 50 to 74 with an abnormal Ontario Breast Screening Program (OBSP) screening mammogram result who were diagnosed with breast cancer (ductal carcinoma in situ or invasive) after diagnostic work-up, by age group, 2013 to 2016

More information regarding the methodology is available.

Report date: December 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Figure 3. Percentage of Ontario women age 50 to 72 screened in the Ontario Breast Screening Program (OBSP) with a biennial screening recall recommendation who had a subsequent program mammogram within 18 months of the previous mammogram, by Local Health Integration Network (LHIN), 2012 to 2015

More information regarding the methodology is available.

Report date: November 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Figure 4. Percentage of Ontario women age 50 to 72 screened in the Ontario Breast Screening Program (OBSP) with a biennial screening recall recommendation who had a subsequent program mammogram within 18 months of the previous mammogram, by age group, 2012 to 2015

More information regarding the methodology is available.

Report date: November 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Figure 5. Percentage of women confirmed to be high risk by genetic assessment (counselling and/or testing), by Local Health Integration Network (LHIN), 2013 to 2016

More information regarding the methodology is available.

Report date: November 2017

Data source: ICMS, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. The High Risk Ontario Breast Screening Program began on July 1, 2011
  2. Please refer to technical documentation.

Figure 6. Percentage of women screened within 90 days of confirmation of high risk status, by Local Health Integration Network (LHIN), 2013 to 2016

More information regarding the methodology is available.

Report date: November 2017

Data source: ICMS, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. The High Risk Ontario Breast Screening Program began on July 1, 2011
  2. Please refer to technical documentation.

Data Table 1. Percentage of women age 50 to 74 with an abnormal Ontario Breast Screening Program (OBSP) screening mammogram result who were diagnosed with breast cancer (ductal carcinoma in situ or invasive) after diagnostic work-up, by Local Health Integration Network (LHIN), 2013 to 2016

LHIN Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 Rate (%) in 2016 Numerator in 2016 Denominator in 2016 Lower confidence interval in 2016 Upper confidence interval in 2016  
Ontario 5.9 2,700 45,709 5.7 6.1 6.4 3,133 49,317 6.1 6.6 6.4 3,249 51,030 6.2 6.6 6.5 3,452 53,146 6.3 6.7 ON
Erie St. Clair 8.4 164 1,962 7.1 9.6 9.1 197 2,171 7.8 10.3 7.6 205 2,698 6.6 8.6 7.2 203 2,816 6.2 8.2 1
South West 6.2 234 3,754 5.4 7.0 6.6 266 4,048 5.8 7.3 6.1 227 3,700 5.3 6.9 7.5 289 3,845 6.7 8.4 2
Waterloo Wellington 6.3 142 2,267 5.2 7.3 5.6 136 2,429 4.7 6.5 6.5 162 2,493 5.5 7.5 6.7 168 2,500 5.7 7.7 3
Hmltn-Ngr-Hldmnd-Brnt 5.8 359 6,189 5.2 6.4 6.0 395 6,544 5.5 6.6 6.0 403 6,705 5.4 6.6 6.7 439 6,539 6.1 7.3 4
Central West 5.1 99 1,927 4.1 6.1 5.7 136 2,376 4.8 6.7 5.0 143 2,868 4.2 5.8 6.1 163 2,678 5.2 7.0 5
Mississauga Halton 4.8 181 3,749 4.1 5.5 5.6 244 4,341 4.9 6.3 4.8 254 5,240 4.3 5.4 5.8 300 5,186 5.1 6.4 6
Toronto Central 6.3 181 2,883 5.4 7.2 6.2 211 3,406 5.4 7.0 6.4 223 3,499 5.5 7.2 6.4 233 3,639 5.6 7.2 7
Central 5.5 335 6,042 5.0 6.1 6.7 414 6,199 6.0 7.3 6.8 414 6,099 6.1 7.4 6.1 396 6,467 5.5 6.7 8
Central East 5.0 315 6,337 4.4 5.5 5.5 370 6,770 4.9 6.0 6.2 398 6,467 5.6 6.7 5.7 422 7,419 5.2 6.2 9
South East 7.1 155 2,198 6.0 8.1 6.9 141 2,055 5.7 8.0 7.8 164 2,105 6.6 9.0 7.7 162 2,093 6.6 8.9 10
Champlain 8.6 221 2,583 7.5 9.7 9.1 268 2,953 8.0 10.1 9.4 286 3,041 8.4 10.5 9.5 325 3,410 8.5 10.5 11
North Simcoe Muskoka 5.3 105 1,969 4.3 6.4 6.4 118 1,833 5.3 7.6 7.1 144 2,028 6.0 8.2 5.8 115 1,988 4.7 6.8 12
North East 5.2 160 3,050 4.4 6.1 5.6 186 3,294 4.8 6.5 5.4 178 3,325 4.6 6.1 4.8 171 3,542 4.1 5.5 13
North West 6.1 49 799 4.4 7.9 5.7 51 898 4.1 7.2 6.3 48 762 4.5 8.1 6.4 66 1,024 4.9 8.0 14

Report date: December 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Data Table 2. Percentage of women age 50 to 74 with an abnormal Ontario Breast Screening Program (OBSP) screening mammogram result who were diagnosed with breast cancer (ductal carcinoma in situ or invasive) after diagnostic work-up, by age group, 2013 to 2016

Age group Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 Rate (%) in 2016 Numerator in 2016 Denominator in 2016 Lower confidence interval in 2016 Upper confidence interval in 2016 p-value
50 to 74 5.9 2,700 45,709 5.7 6.1 6.4 3,133 49,317 6.1 6.6 6.4 3,249 51,030 6.2 6.6 6.5 3,452 53,146 6.3 6.7
50 to 69 5.4 2,205 41,212 5.1 5.6 5.8 2,582 44,343 5.6 6.0 5.8 2,666 46,227 5.6 6.0 5.9 2,795 47,684 5.6 6.1
50 to 54 3.2 450 14,218 2.9 3.5 3.5 548 15,742 3.2 3.8 3.3 582 17,498 3.1 3.6 3.5 601 17,219 3.2 3.8 Ref.
55 to 59 5.0 519 10,353 4.6 5.4 5.2 578 11,151 4.8 5.6 5.3 591 11,079 4.9 5.8 5.5 638 11,627 5.1 5.9 <0.001
60 to 64 6.3 570 9,024 5.8 6.8 7.4 699 9,402 6.9 8.0 7.6 715 9,403 7.1 8.1 7.6 757 9,959 7.1 8.1 <0.001
65 to 69 8.7 666 7,617 8.1 9.4 9.4 757 8,048 8.8 10.1 9.4 778 8,247 8.8 10.1 9.0 799 8,879 8.4 9.6 <0.001
70 to 74 11.0 495 4,497 10.1 11.9 11.1 551 4,974 10.2 12.0 12.1 583 4,803 11.2 13.1 12.0 657 5,462 11.2 12.9 <0.001

Report date: December 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Data Table 3. Percentage of Ontario women age 50 to 72 screened in the Ontario Breast Screening Program (OBSP) with a biennial screening recall recommendation who had a subsequent program mammogram within 18 months of the previous mammogram, by Local Health Integration Network (LHIN), 2012 to 2015

LHIN Rate (%) in 2012 Numerator in 2012 Denominator in 2012 Lower confidence interval in 2012 Upper confidence interval in 2012 Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015
Ontario 4.4 14,169 320,358 4.4 4.5 4.6 15,248 334,493 4.5 4.6 5.0 19,253 383,994 4.9 5.1 6.0 24,829 412,873 5.9 6.1
Erie St. Clair 3.5 541 15,377 3.2 3.8 3.2 492 15,471 2.9 3.5 3.6 644 18,116 3.3 3.8 6.2 1,367 22,112 5.9 6.5
South West 1.8 507 27,930 1.7 2.0 2.4 656 27,670 2.2 2.6 2.1 657 31,371 1.9 2.3 3.0 910 30,131 2.8 3.2
Waterloo Wellington 2.0 362 18,440 1.8 2.2 2.1 393 18,934 1.9 2.3 2.5 532 21,220 2.3 2.7 3.0 706 23,487 2.8 3.2
Hmltn-Ngr-Hldmnd-Brnt 1.6 653 41,744 1.4 1.7 1.5 601 41,371 1.3 1.6 2.1 962 45,553 2.0 2.2 2.7 1,314 48,069 2.6 2.9
Central West 5.1 766 15,087 4.7 5.4 5.0 775 15,472 4.7 5.4 5.7 1,091 18,974 5.4 6.1 6.3 1,468 23,304 6.0 6.6
Mississauga Halton 8.1 2,004 24,892 7.7 8.4 8.0 2,276 28,318 7.7 8.4 8.8 2,893 32,949 8.5 9.1 9.0 3,477 38,424 8.8 9.3
Toronto Central 8.5 1,570 18,366 8.1 9.0 8.8 1,803 20,373 8.5 9.2 9.1 2,107 23,045 8.8 9.5 10.6 2,907 27,399 10.2 11.0
Central 9.1 3,931 43,305 8.8 9.3 8.7 3,970 45,891 8.4 8.9 9.1 4,938 54,064 8.9 9.4 10.4 5,901 56,562 10.2 10.7
Central East 6.2 2,148 34,617 5.9 6.5 6.2 2,383 38,464 6.0 6.4 6.6 3,227 48,747 6.4 6.8 7.3 3,478 47,588 7.1 7.5
South East 1.3 208 16,316 1.1 1.5 1.3 228 17,020 1.2 1.5 1.4 262 18,772 1.2 1.6 2.3 419 18,450 2.1 2.5
Champlain 1.6 431 26,603 1.5 1.8 1.8 473 26,602 1.6 1.9 2.1 644 30,099 2.0 2.3 3.4 1,110 32,825 3.2 3.6
North Simcoe Muskoka 5.0 641 12,704 4.7 5.4 5.0 702 14,150 4.6 5.3 5.6 800 14,215 5.2 6.0 6.2 1,052 16,836 5.9 6.6
North East 1.4 252 18,505 1.2 1.5 1.7 320 18,371 1.5 1.9 1.4 267 19,655 1.2 1.5 2.2 447 20,632 2.0 2.4
North West 2.4 155 6,472 2.0 2.8 2.8 176 6,386 2.3 3.2 3.2 229 7,214 2.8 3.6 3.9 273 7,054 3.4 4.3

Report date: November 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Data Table 4. Percentage of Ontario women age 50 to 72 screened in the Ontario Breast Screening Program (OBSP) with a biennial screening recall recommendation who had a subsequent program mammogram within 18 months of the previous mammogram, by age group, 2012 to 2015

Age group Rate (%) in 2012 Numerator in 2012 Denominator in 2012 Lower confidence interval in 2012 Upper confidence interval in 2012 Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 p-value
50 to 72 4.4 14,169 320,358 4.4 4.5 4.6 15,248 334,493 4.5 4.6 5.0 19,253 383,994 4.9 5.1 6.0 24,829 412,873 5.9 6.1
50 to 54 4.8 3,816 79,619 4.6 4.9 4.9 3,972 80,351 4.8 5.1 5.4 5,076 93,528 5.3 5.6 6.2 6,367 102,053 6.1 6.4 Ref.
55 to 59 4.4 3,590 82,464 4.2 4.5 4.5 3,833 85,431 4.3 4.6 5.1 4,913 96,771 4.9 5.2 5.9 6,056 102,017 5.8 6.1 0.0042
60 to 64 4.4 3,289 74,451 4.3 4.6 4.6 3,565 77,315 4.5 4.8 4.8 4,199 87,872 4.6 4.9 5.9 5,504 93,255 5.8 6.1 0.0019
65 to 69 4.3 2,536 59,188 4.1 4.4 4.4 2,844 64,899 4.2 4.5 4.9 3,674 75,103 4.7 5.0 6.1 4,979 82,282 5.9 6.2 0.0954
70 to 72 3.8 938 24,636 3.6 4.0 3.9 1,034 26,497 3.7 4.1 4.5 1,391 30,720 4.3 4.8 5.8 1,923 33,266 5.5 6.0 0.0025

Report date: November 2017

Data source: ICMS, OHIP CHDB, OCR, RPDB, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. Please refer to technical documentation.

Data Table 5. Percentage of women confirmed to be high risk by genetic assessment (counselling and/or testing), by Local Health Integration Network (LHIN), 2013 to 2016

LHIN Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 Rate (%) in 2016 Numerator in 2016 Denominator in 2016 Lower confidence interval in 2016 Upper confidence interval in 2016  
Ontario 31.4 1,930 6,153 30.2 32.5 34.3 2,516 7,332 33.2 35.4 30.7 2,343 7,633 29.7 31.7 30.4 2,057 6,766 29.3 31.5 ON
Erie St. Clair 18.1 43 238 13.0 23.2 25.8 76 295 20.6 30.9 30.1 122 405 25.5 34.7 25.8 81 314 20.8 30.8 1
South West 30.6 123 402 26.0 35.2 34.4 147 427 29.8 39.0 30.3 121 399 25.7 35.0 34.4 114 331 29.2 39.7 2
Waterloo Wellington 26.5 76 287 21.2 31.8 36.4 127 349 31.2 41.6 31.4 74 236 25.2 37.5 32.5 82 252 26.6 38.5 3
Hmltn-Ngr-Hldmnd-Brnt 41.5 204 491 37.1 46.0 33.6 220 654 29.9 37.3 29.9 223 745 26.6 33.3 28.4 209 737 25.0 31.7 4
Central West 34.7 74 213 28.1 41.4 42.2 141 334 36.8 47.7 30.8 89 289 25.3 36.3 34.7 116 334 29.5 40.0 5
Mississauga Halton 40.8 177 434 36.0 45.5 47.3 267 565 43.1 51.5 43.0 267 621 39.0 47.0 37.3 188 504 33.0 41.6 6
Toronto Central 23.5 224 954 20.7 26.2 31.1 361 1,159 28.4 33.9 29.1 334 1,146 26.5 31.8 34.6 352 1,018 31.6 37.5 7
Central 27.9 253 906 24.9 30.9 31.0 372 1,200 28.3 33.7 26.8 367 1,370 24.4 29.2 25.2 331 1,315 22.8 27.6 8
Central East 30.9 220 712 27.4 34.4 32.3 267 827 29.0 35.5 27.6 247 896 24.6 30.5 28.4 241 848 25.3 31.5 9
South East 30.6 55 180 23.5 37.6 35.3 60 170 27.8 42.8 28.1 63 224 22.0 34.2 30.0 54 180 23.0 37.0 10
Champlain 38.4 292 761 34.8 41.9 36.4 246 676 32.7 40.1 35.8 226 632 31.9 39.6 31.2 119 382 26.4 35.9 11
North Simcoe Muskoka 39.0 90 231 32.5 45.5 38.9 91 234 32.4 45.3 38.7 101 261 32.6 44.8 34.0 83 244 27.9 40.2 12
North East 29.6 77 260 23.9 35.4 33.9 112 330 28.7 39.2 29.9 90 301 24.6 35.2 28.4 76 268 22.8 33.9 13
North West 26.2 22 84 16.2 36.2 25.9 29 112 17.3 34.5 17.6 19 108 9.9 25.2 28.2 11 39 12.8 43.6 14

Report date: November 2017

Data source: ICMS, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. The High Risk Ontario Breast Screening Program began on July 1, 2011
  2. Please refer to technical documentation.

Data Table 6. Percentage of women screened within 90 days of confirmation of high risk status, by Local Health Integration Network (LHIN), 2013 to 2016

LHIN Rate (%) in 2013 Numerator in 2013 Denominator in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Rate (%) in 2014 Numerator in 2014 Denominator in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Rate (%) in 2015 Numerator in 2015 Denominator in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 Rate (%) in 2016 Numerator in 2016 Denominator in 2016 Lower confidence interval in 2016 Upper confidence interval in 2016
Ontario 61.1 1,135 1,857 58.9 63.4 55.2 1,343 2,433 53.2 57.2 46.9 999 2,131 44.7 49.0 44.0 778 1,770 41.6 46.3
Erie St. Clair 84.6 33 39 72.0 97.2 39.7 25 63 26.8 52.6 27.4 29 106 18.4 36.3 35.6 26 73 23.9 47.3
South West 64.3 92 143 56.1 72.5 53.8 77 143 45.3 62.4 59.2 87 147 50.9 67.5 69.9 86 123 61.4 78.4
Waterloo Wellington 77.3 51 66 66.4 88.1 62.6 72 115 53.3 71.9 34.5 20 58 21.4 47.6 44.6 41 92 33.9 55.3
Hmltn-Ngr-Hldmnd-Brnt 33.6 81 241 27.4 39.8 29.7 65 219 23.4 36.0 17.7 29 164 11.5 23.8 22.6 37 164 15.9 29.3
Central West 66.7 46 69 54.8 78.5 50.0 57 114 40.4 59.6 31.2 29 93 21.2 41.1 37.3 31 83 26.3 48.4
Mississauga Halton 51.7 93 180 44.1 59.2 31.2 83 266 25.4 37.0 26.7 56 210 20.4 32.9 19.7 23 117 12.0 27.3
Toronto Central 67.6 167 247 61.6 73.6 64.0 244 381 59.1 69.0 59.8 202 338 54.4 65.1 55.3 163 295 49.4 61.1
Central 63.2 160 253 57.1 69.4 64.0 229 358 58.9 69.1 54.1 178 329 48.6 59.6 61.8 155 251 55.5 68.0
Central East 58.5 124 212 51.6 65.4 57.2 131 229 50.6 63.8 52.6 121 230 45.9 59.3 48.7 94 193 41.4 56.0
South East 60.7 17 28 40.8 80.6 63.5 40 63 50.8 76.2 70.1 47 67 58.4 81.9 58.9 33 56 45.2 72.7
Champlain 73.7 165 224 67.7 79.7 73.3 200 273 67.8 78.7 56.7 119 210 49.7 63.6 10.7 19 177 5.9 15.6
North Simcoe Muskoka 65.8 48 73 54.2 77.3 56.9 41 72 44.8 69.1 46.7 35 75 34.7 58.6 53.8 35 65 41.0 66.7
North East 87.7 57 65 78.9 96.4 63.5 66 104 53.7 73.2 49.4 43 87 38.3 60.5 43.7 31 71 31.4 55.9
North West 5.9 ≤ 5 17 -8.2 20.0 39.4 13 33 21.2 57.6 23.5 ≤ 5 17 0.4 46.6 40.0 ≤ 5 10 4.6 75.4

Report date: November 2017

Data source: ICMS, PCCF+ version 6D

Prepared by: Analytics, Cancer Screening,  P&CC

Note:

  1. The High Risk Ontario Breast Screening Program began on July 1, 2011
  2. Please refer to technical documentation.

What do the results show?

The positive predictive value of breast cancer screening in the Ontario Breast Screening Program has remained steady over time, but it varies by age group and among Local Health Integration Networks (Figures 1 and 2).

  • The overall PPV of OBSP mammograms in 2016 was 6.5%. Mammogram PPV has remained steady at approximately 6% since 2013.
  • In 2016, approximately 3,500 of the over 53,000 Ontario women age 50 to 74 who had an abnormal OBSP screening mammogram result went on to be diagnosed with breast cancer.
  • Some variation in mammogram PPV by Local Health Integration Network (LHIN) was present. The LHIN with the highest PPV in 2016 was Champlain (9.5%). The LHIN with the lowest PPV in 2016 was North East (4.8%).
  • PPV increased with age. In 2016, the PPV of OBSP mammograms was highest in women age 70 to 74 (12.0%) and lowest in women age 50 to 54 (3.5%). A similar pattern can be seen in previous years. PPV increases with subsequent screens, which is why it is higher in older age groups.
  • The PPV of a screening test depends on the underlying prevalence of disease (i.e., all people alive who currently have a specific disease) in the population being screened, which may help to explain the variation observed across LHINs and age groups.
  • PPV is reported as a single measure for first and subsequent screens in order to be consistent with Ontario’s cervical and colorectal cancer screening programs. National breast cancer screening guidelines have 2 separate PPV targets: one for first screens (≥5%) and one for subsequent screens (≥6%) [4, 5].

Considerable regional variation exists in early return among Local Health Integration Networks (Figure 3).

  • In Ontario, early return in women who had an OBSP mammogram and a 2-year screening recall recommendation increased from 4.4% in 2012 to 6% in 2015.
  • Of the approximately 413,000 women age 50 to 72 who were screened through the OBSP in 2015 and given a recommendation to re-screen in 24 months (2 years), almost 25,000 (6%) had a subsequent program mammogram within 18 months.
  • The LHINs with the lowest (i.e., better) rate of early return for women with an OBSP mammogram and 2-year recall recommendation in 2015 were South East (2.3%) and North East (2.2%). The LHINs with the highest early return for the same time period were Toronto Central (10.6%) and Central (10.4%).
  • Early return has increased in Ontario for every cohort of women with biennial screening recall recommendations since 2012. Early return also increased in every LHIN from 2014 to 2015. The LHIN with the greatest increase was Erie St. Clair (an increase of 2.6 percentage points).
  • Early return will continue to provide direction for Cancer Care Ontario in its work with its regional partners to promote adherence to risk-appropriate screening intervals across the province.

Early return for breast cancer screening varies by age group (Figure 4).

  • In 2015, the percentage of women with a biennial screening recall recommendation who returned for a subsequent program mammogram within 18 months of a previous mammogram was lowest (5.8%) in women age 70 to 72 and highest (6.2%) in the youngest age group (women age 50 to 54). A similar pattern can be seen in previous years.

Measure:  Confirmed high risk for breast cancer: percentage of Ontario women, age 30 to 69, who were referred to the High Risk OBSP and were confirmed to be at high risk for breast cancer by genetic assessment (counselling and/ or testing)

 

Desired Direction:

 

An image of an arrow pointing upwards. This indicates that desired direction for this action is upwards.

 

As of this Report:

 

An image of an arrow pointing straight in a green box. This indicates that there has been no increase or decrease in performance over the previous periods identified and this action is exceeding or meeting target.

The proportion of women referred for genetic assessment who are subsequently confirmed to be at high risk varies by region (Figure 5).

  • The proportion of women who were referred to the High Risk OBSP and were confirmed to be at high risk after referral remained steady from 2013 to 2016 (between 30% and 34%).
  • Some regional variation is present for this indicator. In 2016, the LHIN with the highest percentage of women confirmed to be at high risk for breast cancer after genetic assessment was Mississauga Halton (37%). The LHINs with the lowest percentage of women confirmed to be at high risk for breast cancer after genetic assessment were Erie St. Clair (26%) and Central (25%).
  • The High Risk OBSP has set a provincial target of 30% or greater for this indicator, meaning that approximately 1 in 3 women who are referred for genetic assessment should be confirmed to be at high risk for breast cancer [1].
  • Monitoring this indicator allows Cancer Care Ontario to see if the high risk referral criteria are interpreted correctly by primary care providers and to ensure that the criteria appropriately identify women who may be at increased risk for breast cancer.

The proportion of women screened in the High Risk Ontario Breast Screening Program within 90 days of confirmation of their high risk status has decreased since 2013 and varies considerably by region (Figure 6).

Measure:  Screened within 90 days of confirmation of high risk status: percentage of Ontario women age 30 to 69 screened through the High Risk OBSP within 90 days of confirmation of high risk status

 

Desired Direction:

 

An image of an arrow pointing upwards. This indicates that desired direction for this action is upwards.

 

As of this Report:

 

An image of an arrow pointing straight in a red box. This indicates that there has been no increase or decrease in performance over the previous periods identified and this action is well below targets.

  • In 2016, 44% of women were screened with MRI or ultrasound within 90 days of confirmation of their high risk status a decrease from 2013, when the rate was 61%.
  • The High Risk OBSP has set a provincial target of 90% or greater for this indicator, meaning that about 9 in 10 women should be screened within 90 days of confirmation of their high risk status.
  • Considerable regional variation exists for this indicator. In 2016, the LHIN with the highest percentage of women screened within 90 days of confirmation of high risk status was South West (70%). The LHIN with the lowest percentage of women screened within 90 days was Champlain (11%).
  • In 2016, the percentage of women screened within 90 days of confirmation of high risk status was similar across all age groups (data not shown).
  • The decrease in women screened within the 90-day recommendation may be partly related to increasing MRI wait times. Current wait times are available from the Ministry of Health and Long-Term Care at ontariowaittimes.com.

Why is this important to Ontarians?

Mammography is important for the early detection of breast cancer, but it is not perfect.

  • Finding breast cancer early increases the number of treatment options available, and it can lead to better treatment outcomes and survival rates [6].
  • A Canadian study on mammography effectiveness in screening programs found that mammograms are associated with a 21% reduction in breast cancer mortality in average risk women age 50 to 69 (compared to no screening) [7].
  • Women without breast cancer who receive abnormal mammogram results (false-positives) may undergo unnecessary additional imaging and biopsies. The likelihood of a false-positive result is lower for re-screens than for initial screens because previous mammograms can be used for comparison [8].
  • Even with a mammogram, some breast cancers are not found (false-negatives). Dense breast tissue and current use of hormone replacement therapy are associated with an increased risk of breast cancer being missed by screening [9].
  • Women should talk to their healthcare provider for more information about the benefits and limitations of screening with mammography.

Organized screening offers several important benefits to women and their healthcare providers.

  • The OBSP and High Risk OBSP provide high-quality screening for most women through the use of mammography, and through mammography and MRI for women at high risk (or screening breast ultrasound if MRI is not medically appropriate).
  • Quality assurance is ensured through the accreditation of all OBSP sites by the Mammography Accreditation Program (MAP) of the Canadian Association of Radiologists.
  • Communication to women and healthcare providers includes the following:
    • Women eligible for screening through the OBSP are sent invitations to get screened, along with information about breast cancer screening and details on how to find an OBSP site.
    • After their screening appointment, women with normal screening results receive letters telling them their results are normal.
    • Women screened through the OBSP receive letters reminding them when to get screened again.
    • OBSP sites follow up on abnormal screening results and send normal and abnormal results to a woman’s healthcare provider.
  • Coordination and navigation includes the following:
    • High Risk OBSP sites arrange genetic assessment (if appropriate) for women referred to the program.
    • High Risk OBSP sites book screening mammography and screening breast MRI (or screening breast ultrasound if MRI is not medically appropriate).
    • The OBSP indicates whether a woman should be screened in 1 year or 2 years based on her screening results and risk factors.
    • OBSP assessment sites help guide women with abnormal screening results through to diagnosis by coordinating follow-up tests and documenting the results of those tests.

The Ontario Breast Screening Program is continually evaluated and improved to maximize benefits and minimize limitations.

  • Women are encouraged to get screened through the OBSP. As an organized screening program, it offers important benefits, such as inviting women to participate in screening, reminding screening participants when it is time for their next screening test, informing participants of normal screening results, tracking participants throughout the screening and diagnosis processes, and measuring program quality and performance.
  • A robust quality assurance and performance monitoring framework is in place for the OBSP.
  • All OBSP screening sites are accredited by the MAP guidelines of the Canadian Association of Radiologists. The MAP guidelines cover radiologist and medical radiation technologist (MRT) qualifications, equipment, quality control, quality assurance, image quality and radiation dose [10].
  • Feedback on performance, which is then compared to national targets and quality standards, is provided annually to all OBSP and High Risk OBSP screening and assessment sites, as well as to individual radiologists.

Next steps

  • The OBSP’s quality assurance program will continue to provide performance feedback to individual OBSP sites, radiologists and MRTs. It will also work to identify opportunities for improvement (where necessary).
  • The OBSP continues to expand, with new screening sites being brought into the program in 2017 and 2018.
  • Cancer Care Ontario continues to investigate reasons for early return to the OBSP and to consider strategies for improving adherence to appropriate screening intervals.
  • Cancer Care Ontario continues to work with the Ministry of Health and Long-Term Care to identify ways to further support the High Risk OBSP so that Ontario women can continue to benefit from the program.

Notes

  1. Cancer Care Ontario. Ontario Cancer Screening Performance Report 2016. Toronto: Cancer Care Ontario; 2016.
  2. Houssami N, Miglioretti DL. Breast cancer screening: an examination of scientific evidence. Elsevier Inc.; 2016.
  3. Breast Screening Guidelines Summary [Internet]. Toronto: Cancer Care Ontario [cited 2017 Jan 26]. Available from: here.
  4. Canadian Partnership Against Cancer. Report from the evaluation indicators working group: guidelines for monitoring breast cancer screening program performance. 3rd Ed. Toronto: Canadian Partnership Against Cancer; 2013.
  5. Canadian Partnership Against Cancer. Breast cancer screening in Canada: monitoring and evaluation of quality indicators—results report, January 2011–December 2012. Toronto: Canadian Partnership Against Cancer; 2017.
  6. Nelson H, Tyne K, Naik A, Bougatsos C, Chan B, Humphrey L. Screening for breast cancer: an update for the U.S. Preventive Services Task Force. Ann Intern Med. 2009 Nov 17;151(10):727–37.
  7. Canadian Task Force on Preventive Health Care; Tonelli M, Gorber CS, Joffres M, Dickinson J, Singh H, et al. Recommendations on screening for breast cancer in average-risk women aged 40–74 years. CMAJ. 2011 Nov 22;183(17):1991–2001.
  8. Chiarelli AM, Halapy E, Nadalin V, Shumak R, O’Malley F, Mai V. Performance measures from 10 years of breast screening in the Ontario Breast Screening Program, 1990/91 to 2000. Eur J Cancer Prev. 2006 Feb;15(1):34–42.
  9. Chiarelli AM, Kirsh VA, Klar NS, Shumak R, Jong R, Fishell E, et al. Influence of patterns of hormone replacement therapy use and mammographic density on breast cancer detection. Cancer Epidemiol Biomarkers Prev. 2006 Oct;15(10):1856–62.
  10. Mammography Accreditation Program (MAP) [Internet]. Ottawa: Canadian Association of Radiologists; c2009 [cited 2015 Dec 17]. Available from: here.