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Quality and Efficiency of Staging Tests in Breast Cancer

Key findings

The majority of Ontario women with early stage breast cancer undergo imaging for staging to detect metastases. Practice guidelines, however, do not recommend routine imaging to detect metastatic disease in patients with no symptoms. We have seen a small decline in the number of early stage breast cancer patients receiving these tests in the past few years. Efforts should continue to focus on improving awareness among physicians and patients and knowledge translation to increase guideline adherence.

Measure:  Percentage of stage I breast cancer patients who received imaging tests to detect distant metastasis

 

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 downwards in a yellow box. This indicates that there has been an increase in performance over the previous years identified and this action is below but approaching target or has notable regional variation.

What type of tests are used for metastatic staging in breast cancer?

  • Most women with a new diagnosis of breast cancer present with early stage disease (stages I and II) [1]. In early stage breast cancer, the disease is confined to the breast tissue. This is in contrast to late stage breast cancer, where the disease has spread to other organs and tissues. These tumour deposits are known as metastases.  
  • Baseline imaging tests to detect metastases include bone scanning, liver ultrasonography, chest radiography (X-ray) and computed tomography (CT) [2, 3].
  • The likelihood of tests detecting metastases in stage I or II breast cancer patients with no symptoms of spread are 0.2% and 1.2% respectively [4]. For this reason, most guidelines (both national and international) do not recommend imaging for early stage breast cancer patients who have no symptoms of metastatic disease [2, 3].
  • Imaging tests in patients without symptoms may identify findings unrelated to breast cancer that are of no clinical significance. This, in turn, may result in unnecessary further testing and needless patient anxiety.
  • A disease pathway map for the screening and diagnosis of breast cancer outlines evidence-based best practices for when these and other tests should be ordered.
  • Imaging equipment and resources to run the technologies are expensive and should be used appropriately whenever possible.
  • In 2012, the American Board of Internal Medicine launched the Choosing Wisely® campaign with a goal of improving the dialogue around avoiding unnecessary or harmful medical tests, treatments and procedures. Choosing Wisely Canada (CWC) was promoted by a team of leading Canadian physicians in partnership with the Canadian Medical Association (CMA). CWC has endorsed the Choosing Wisely® recommendations and investigated additional opportunities to use resources more efficiently and effectively. For more information on CWC, visit http://www.choosingwiselycanada.org.
  • In particular, Choosing Wisely® suggests the following:
    • “Imaging with PET, CT or radionuclide bone scans can be useful in the staging of specific cancer types. However, these tests are often used in the staging evaluation of low-risk cancers, despite a lack of evidence suggesting they improve detection of metastatic disease or survival.”
    • “In breast cancer, for example, there is a lack of evidence demonstrating a benefit for the use of PET, CT or radionuclide bone scans in asymptomatic individuals with newly identified ductal carcinoma in situ (DCIS), or clinical stage I or II disease.”
    • “Unnecessary imaging can lead to harm through unnecessary invasive procedures, over-treatment, unnecessary radiation exposure and misdiagnosis.”

What is efficiency?

  • Efficiency is a dimension of health service quality that tracks whether we are making the best use of our existing resources (such as types of treatment, machines, staff and hospital beds) to achieve desired outcomes.
  • The results tell us about the proportion of patients being treated according to guidelines. They also help us consider the utilization of these unique technologies in order to identify whether they are being used to their maximum potential—or whether there is opportunity to better use the capacity of a limited resource for those patients who need it most.

Figure 1. Percentage of breast cancer patients receiving at least 1 imaging test for staging, Ontario, by stage, 2012 to 2016

More information regarding the methodology is available.

Report date: February 2018

Data source: OCR, RPDB, CIHI-DAD, CIHI-NACRS, OHIP

Prepared by: Analytics and Informatics, Cancer Care Ontario

Note:

  1. See technical notes for detailed methodology and inclusions/exclusions

Figure 2. Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging, by Local Health Integration Network (LHIN), 2012 to 2016

More information regarding the methodology is available.

Report date: February 2018

Data source: OCR, RPDB, CIHI-DAD, CIHI-NACRS, OHIP

Prepared by: Analytics and Informatics, Cancer Care Ontario

Note:

  1. See technical notes for detailed methodology and inclusions/exclusions

Data Table 1. Percentage of breast cancer patients receiving at least 1 imaging test for staging, Ontario, by stage, 2012 to 2016

Year Stage I Number of stage 1 patients imaged Number of stage 1 patients diagnosed Stage II Number of stage 2 patients imaged Number of stage 2 patients diagnosed Stage I + II
2012 63.6 1,567 2,465 87.8 1,923 2,191 75.0
2013 58.7 1,494 2,544 86.2 1,925 2,232 71.6
2014 56.5 1,552 2,748 85.8 2,035 2,373 70.0
2015 50.7 1,402 2,764 82.8 1,953 2,359 65.5
2016 46.6 1,329 2,850 80.1 1,830 2,284 61.5

Report date: February 2018

Data source: OCR, RPDB, CIHI-DAD, CIHI-NACRS, OHIP

Prepared by: Analytics and Informatics, Cancer Care Ontario

Note:

  1. See technical notes for detailed methodology and inclusions/exclusions

Data Table 2. Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging, by Local Health Integration Network (LHIN), 2012 to 2016

LHIN Acronym Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging in 2012 Number of stage 1 patients imaged in 2012 Number of stage 1 patients diagnosed in 2012 Lower confidence interval in 2012 Upper confidence interval in 2012 Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging in 2013 Number of stage 1 patients imaged in 2013 Number of stage 1 patients diagnosed in 2013 Lower confidence interval in 2013 Upper confidence interval in 2013 Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging in 2014 Number of stage 1 patients imaged in 2014 Number of stage 1 patients diagnosed in 2014 Lower confidence interval in 2014 Upper confidence interval in 2014 Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging in 2015 Number of stage 1 patients imaged in 2015 Number of stage 1 patients diagnosed in 2015 Lower confidence interval in 2015 Upper confidence interval in 2015 Percentage of stage I breast cancer patients receiving at least 1 imaging test for staging in 2016 Number of stage 1 patients imaged in 2016 Number of stage 1 patients diagnosed in 2016 Lower confidence interval in 2016 Upper confidence interval in 2016
Ontario ON 63.6 1,567 2,465 61.7 65.5 58.7 1,494 2,544 56.8 60.7 56.5 1,552 2,748 54.6 58.4 50.7 1,402 2,764 48.8 52.6 46.6 1,329 2,850 44.8 48.5
Erie St. Clair ESC 78.2 115 147 71.2 85.2 73.3 107 146 65.8 80.8 65.7 94 143 57.6 73.9 54.7 93 170 46.9 62.5 47.3 69 146 38.8 55.7
South West SW 49.1 105 214 42.1 56.0 53.6 112 209 46.6 60.6 50.5 106 210 43.5 57.5 48.3 83 172 40.5 56.0 49.6 114 230 42.9 56.2
Waterloo Wellington WW 62.9 73 116 53.7 72.2 52.4 77 147 44.0 60.8 55.6 84 151 47.4 63.9 41.2 47 114 31.8 50.7 43.4 62 143 34.9 51.8
Hmltn-Ngr-Hldmnd-Brnt HNHB 56.0 167 298 50.2 61.8 51.7 148 286 45.8 57.7 49.0 143 292 43.1 54.9 46.5 134 288 40.6 52.5 42.8 122 285 36.9 48.7
Central West CW 52.4 55 105 42.4 62.4 61.2 71 116 51.9 70.5 47.4 64 135 38.6 56.2 48.0 59 123 38.7 57.2 44.4 64 144 36.0 52.9
Mississauga Halton MH 56.3 121 215 49.4 63.1 50.8 97 191 43.4 58.1 48.2 110 228 41.5 55.0 39.8 90 226 33.2 46.4 35.6 80 225 29.1 42.0
Toronto Central TC 59.6 99 166 51.9 67.4 55.8 110 197 48.7 63.0 44.5 105 236 37.9 51.0 45.8 114 249 39.4 52.2 39.3 94 239 32.9 45.7
Central Cen 75.7 218 288 70.6 80.8 68.1 228 335 62.9 73.2 65.3 222 340 60.1 70.5 54.4 196 360 49.2 59.7 51.1 182 356 45.8 56.5
Central East CE 61.0 172 282 55.1 66.9 54.9 161 293 49.1 60.8 59.8 204 341 54.5 65.2 55.2 181 328 49.7 60.7 52.3 173 331 46.7 57.8
South East SE 59.8 76 127 50.9 68.8 49.5 55 111 39.8 59.3 57.4 70 122 48.2 66.6 46.9 67 143 38.3 55.4 42.4 59 139 33.9 51.0
Champlain Ch 83.8 181 216 78.7 88.9 78.5 179 228 73.0 84.1 64.7 167 258 58.7 70.8 64.7 194 300 59.1 70.2 60.5 182 301 54.8 66.2
North Simcoe Muskoka NSM 67.0 75 112 57.8 76.1 55.6 69 124 46.5 64.8 67.8 61 90 57.6 78.0 45.6 52 114 36.0 55.2 41.9 49 117 32.5 51.3
North East NE 59.2 74 125 50.2 68.2 50.5 55 109 40.6 60.3 62.0 88 142 53.6 70.3 51.8 73 141 43.2 60.4 45.7 64 140 37.1 54.3
North West NW 81.8 36 44 69.3 94.4 55.6 25 45 39.9 71.2 73.9 34 46 60.1 87.7 61.3 19 31 42.5 80.1 34.9 15 43 19.5 50.3

Report date: February 2018

Data source: OCR, RPDB, CIHI-DAD, CIHI-NACRS, OHIP

Prepared by: Analytics and Informatics, Cancer Care Ontario

Note:

  1. See technical notes for detailed methodology and inclusions/exclusions

What do the results show?

The number of patients receiving unnecessary tests (as defined by guidelines) is higher than expected and includes regional variation (Figures 1 and 2).

  • Figure 1 shows that the majority of women diagnosed with early stage breast cancer may be receiving unnecessary imaging tests for staging. The average number of stage I patients receiving these tests has decreased slightly each year since 2012, the year Choosing Wisely® was launched.
  • Women with stage II breast cancer are undergoing more tests than women with stage I breast cancer. This may partly be due to variations in guideline recommendations: the current Cancer Care Ontario guidance document indicates bone scanning for stage II patients [3], but Choosing Wisely® does not recommend this test [2].
  • Modalities included in this analysis are ultrasound, CT, X-Ray, and bone scan.  These tests were performed on any of the following: skeleton, thorax (excluding pre-operative chest X-ray) abdomen, and pelvis.
  • Some early stage breast cancer patients will present with symptoms and comorbidities that require staging tests. Clinical consensus and recent evidence says that these patients only account for 5% to 10% of the early stage breast cancer population [7], yet in 2016, 47% of stage I patients received imaging tests for staging. Of the 3,957 distinct tests performed on stage I patients in 2016 (data not shown), 3,561 (90%) may have been unnecessary.
  • Figure 2 shows that in 2016, the proportion of stage I breast cancer patients who had staging tests for metastatic disease showed some regional variation (from 35% to 60%). A similar range was seen in the previous two years: 2015 (from 40% to 65%) and 2014 (from 44% to 74%). However, the regional rankings vary between the years and there is no clear region with best or worst practices.
  • The reasons for a discrepancy between guideline recommendations and practice are likely a combination of patient-related and physician-related factors. Patients have reported that additional testing gives them peace of mind and that they would be uncomfortable if their doctor, in concordance with the local Cancer Care Ontario guidelines, did not perform imaging for metastatic disease [3, 5]. Physicians, however, have reported that clinical findings or suspicious clinical history is what prompts referral for staging tests (as opposed to patient preference) [6].
  • The cost of each scan depends on the modality, and it includes a physician fee, technician fee and facility overhead costs. A CT scan of the abdomen, for example, costs around $219 ($108.30 (X126: CT abdomen, with or without IV contrast) [8]; $18.50 (NOC 3215: medical radiation technologists median wage $37.00; assume 0.5hour for CT [9]); $92.54 (institutional internal overhead cost) to the system[8, 9]. A recent study published in the journal Current Oncology found that the cost of all imaging on early stage breast cancer patients in Ontario ranged from $4.4 million to $6.8 million over a 5-year period, depending on guideline recommendations (figures are cumulative and in Canadian dollars)[10].
  • These tests have downstream implications on the system because they may lead to follow-up examinations and (in the case of false positive tests) unnecessary treatment. If unnecessary tests were eliminated, it might increase test availability for other patients.
  • As of December 2017, the median adult wait times in Ontario for patients with known or suspected invasive cancer (non-aggressive, non-emergency) were 13 days for CT scans and 13 days for MRI scans. 63% of patients were scanned within the target time of 10 days [11].

Why is this important for patient care?

Appropriate testing is a quality issue and a limited system resource issue.

  • One of the main purposes of staging is to rule out metastasis. Staging may occur before surgery, but it is more commonly performed after surgery at the hospital where primary therapy is given [4].
  • Staging tests are time-consuming and anxiety-provoking. Occasionally, false-positive results lead to other expensive tests. Unnecessary imaging can lead to harm through unnecessary invasive procedures, over-treatment, unnecessary radiation exposure and misdiagnosis [2].
  • Each test is associated with a wait time. Unnecessary testing delays definitive treatment (surgery or systemic) and is not likely to provide benefit to the patient.
  • Imaging is a limited resource. Increases in use of diagnostic imaging in Canada have far exceeded population growth: from 1993 to 2004 there was a 3-fold increase in the number of CT scans and a 7-fold increase in the number of MRI scans [12]. The high demand for these services contributes to longer wait times. When patients who do not need a test are removed from the queue, there is more timely capacity for those patients who do need the tests.

How does Ontario compare?

  • An Ontario study, published in the Canadian Medical Association Journal in 2015, demonstrated similar results presented here [13]. Overall, there was a higher imaging utilization rate (86%) for early stage breast cancer patients (stage I and II) than those presented in this section (62% of stage I and II patients). The lower numbers reported in the Cancer System Quality Index (CSQI) may be attributed to the exclusion of pre-operative chest X-ray from these data (as per the CWC anesthesiology recommendations) [14]. The Ontario study in the Canadian Medical Association Journal also assessed data from 2007 to 2012, prior to any effects that the Choosing Wisely® recommendations would have had on diagnostic testing. The CSQI data analysis took a conservative approach by including only the most common forms of breast cancer, and excluding those unusual pathologic subtypes that could be associated with a higher risk of distant metastases.
  • A study from the United States demonstrated that only 15% of early stage breast cancer patients from 2 separate facilities had at least 1 imaging test during the staging window. Investigators conducted chart-level audits and found that approximately half of the imaging tests were ordered in response to a sign or symptom [7].
  • A Canadian study assessed the consistency of radiological staging for breast cancer in an academic oncology setting and found that 59% of stage I patients and 58% of stage II patients were over-investigated. The study estimated that the cost of non-adherence is in the range of $78 (Canadian dollars) for every new early stage breast cancer patient who is seen at the centre [15].

Find out more

For more information on Cancer Care Ontario’s Disease Pathway Map for patients with breast cancer, visit Cancer Care Ontario’s website: https://www.cancercareontario.ca/en/pathway-maps.

For more information on the Imaging Program, visit Cancer Care Ontario’s website: https://www.cancercareontario.ca/en/cancer-care-ontario/programs/clinical-services/cancer-imaging.

For more information on Choosing Wisely®, visit: http://www.choosingwisely.org/ .

For more information on the Choosing Wisely Canada initiative, visit: http://www.choosingwiselycanada.org/ .

Notes

  1. Cancer Care Ontario. Ontario breast screening program: 2011 report [Internet]. Toronto: Cancer Care Ontario: 2011 [cited 2018 Feb 14]. Available from: here.
  2. Schnipper LE, et al. American Society of Clinical Oncology identifies five key opportunities to improve care and reduce costs: the top five list for oncology. J Clin Oncol. 2012; 14(30):1715–1724.
  3. Cancer Care Ontario. Baseline staging tests in primary breast cancer [Internet]. Toronto: Cancer Care Ontario; 2011 [cited 2018 Feb 14]. Available from: here.
  4. Brennan ME, Houssami N. Evaluation of the evidence on staging imaging for detection of asymptomatic distant metastasis in newly diagnosed breast cancer. Breast. 2012; 21(2):112–23.
  5. Simos et al. Patient perceptions and expectations regarding imaging for metastatic disease in early stage breast cancer. SpringerPlus. 2014; 3:176.
  6. Simos D, Hutton B, Graham ID, Arnaout A, Caudrelier JM, Clemons M. Imaging for metastatic disease in patients with newly diagnosed breast cancer: are doctor's perceptions in keeping with the guidelines? J Eval Clin Pract. 2015; 21:67–73.
  7. Hahn EE, Tang T, Lee JS, Munoz-Plaza C, Adesina JO, Shen E, et al. Use of imaging for staging of early stage breast cancer in two integrated health care systems: adherence with a choosing wisely recommendation. J Oncol Pract. 2015; 11(3):320–328.
  8. Ministry of Health and Long-Term Care (MOHLTC). Schedule of benefits: physician services under the Health Insurance Act [Internet]. Toronto: MOHLTC [cited 2018 Feb 14]. Available from: here.
  9. Jobbank.ca [Internet]. Ottawa: Government of Canada. Explore careers—wage report; 2015 Oct 23 [cited 2018 Feb 14]. Available from: here.
  10. Thavorn K, Wang Z, Fergusson D, van Katwyk S, Arnaout A, Clemons M. Cost implications of unwarranted imaging for distant metastasis in women with early stage breast cancer in Ontario. Curr Oncol. 2016; 23(Suppl 1):s52–55.
  11. Health Quality Ontario. Wait times for diagnostic imaging [Internet]. Toronto: Health Quality Ontario; 2017 Dec [cited 2018 Feb 14]. Available from: here.
  12. Tu JV, Pinfold PS, McColgan P, Laupacis A, editors. Access to health services in Ontario, ICES Atlas. 2nd edition [Internet].Toronto: ICES; May 2006 [cited 2018 Feb 14]. Available from: here.
  13. Simos D, Catley C, van Walraven C, Arnaout A, Booth CM, McInnes M, et al. Imaging for distant metastases in women with early stage breast cancer: a population-based cohort study. CMAJ. 2015. doi: 0.1503/cmaj.150003
  14. Choosing Wisely Canada [Internet]. Anesthesiology: five things physicians and patients should question; 2015 Sept 17 [cited 2018 Feb 14]. Available from: here.
  15. Han D, Hogeveen S, Goldstein MS, George R, Brezden-Masley C, Hoch J, et al. Is knowledge translation adequate? A quality assurance study of staging investigations in early stage breast cancer patients. Breast Cancer Res Tr. 2012; 132(1):1–7.