||As of this Report
|Reporting of cancer stage at diagnosis for stageable breast, cervix, colorectal, lung and prostate cancers
|Reporting of cancer stage at diagnosis for all stageable cancers
| See Methodology and Approach to find out how the ratings are calculated.
The Ontario Cancer Registry is tasked with capturing population-level stage at diagnosis for several cancers. Included are capture of breast, prostate, colorectal, lung and cervix cancers. Stage capture rates are greater than 90% for all of these sites and they are within the desired range required for analytic purposes. Efforts to increase stage capture rates for diagnosis years 2010 to 2013 also were successful. Published rates for the diagnosis year 2013 increased by as much as 11% from the previous report.
Staging data obtained from Ontario’s Regional Cancer Centers supplements the capture of stage information by the registry, albeit using a non-population-based staging approach. When all the stageable types of cancer are combined, the stage capture rate for all patients diagnosed in 2014 drops to 64%. Please note that this does not mean that patients are not being staged prior to treatment by their clinicians; rather, the stage capture rate reflects whether the data has been entered into the stage capture system in the cancer registry.
In my words
Cancer diagnosis means accuracy of that diagnosis and knowing exactly what the next steps will be. There can be no doubt because as soon as those words are spoken a different journey in life begins.
What is cancer staging?
- Staging describes the extent or severity of a person’s cancer, based on the size and/or extension of the original (primary) tumour and how far it has spread in the body1.
- Almost all cancer patients begin their involvement with the cancer system through a series of diagnostic tests. These likely include imaging and, in many cases, removal of tissue or cells from the body for examination (biopsy) so that the nature and extent of the cancer can be determined.
- Stage values for invasive cancer range from stage I, which means the disease is in the early phase, to stage IV, which means the cancer has spread (or metastasized) to other organs or places in the body. An unknown stage is the result of either limited stage workup and/or limited documentation within the patient record.
Why is staging information important to patient care?
- Knowing the clinical stage of the disease helps physicians plan appropriate treatment and determine the likely outcome or course of the disease2.
- From a system performance perspective, population-based staging (staging for all newly diagnosed cancer patients by cancer registries) generates critically important information that is used for cancer surveillance, as well as healthcare planning3. Knowing the distribution of cancer stage allows cancer agencies to better evaluate the appropriateness and effectiveness of cancer treatments delivered throughout the province and to plan for future needs.
- Accurate cancer stage information can improve quality of care and decision-making in the cancer system. Linking the stage of cancer with outcome and treatment data provides valuable information, allowing the cancer system to assess the quality of cancer care and identify new ways to improve the delivery of that care.
- The value of stage capture on a population basis not only includes the evaluation of successful screening programs, but also the prioritization of resources for treatments of disease sites with a high incidence of advanced cancers3. The information is also valuable for identifying high-risk groups for education and screening.
What is the collaborative staging data collection system and how is it different from tumour, node and metastases stage data?
- CS is a standard method of collecting staging information that uses a minimum dataset of coded elements from a cancer pathology report, supplemented by clinical data found in diagnostic imaging reports, laboratory tests and physician summaries. The information can be used and shared electronically by organizations that study cancer data.
- The CS common dataset describes key cancer tumour characteristics and ensures cancer agencies around the world interpret and analyze the data in the same way.
- CS attempts to stage all cases of a specific type (e.g. breast cancer) so that meaningful inferences about that cancer can be made at the provincial level.
- Cases that contribute to the category “No Stage” include cancers that were neither diagnosed nor treated in a hospital (i.e. only contact with private labs and physician offices resulting in no Cancer Care Ontario access to patient records). “No Stage” also may include cases that have been staged but which are awaiting manual review. For 2014, approximately 7% of cases for breast, cervix, colorectal, lung and prostate cancers have no stage or 2,304 of 34,746 cases.
- Tumour, node and metastases (TNM) is a system maintained collaboratively by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC), with the most recent version being AJCC 7th Edition. The TNM system, like CS, classifies cancers by the size and extent of the primary tumour (T), involvement of regional lymph nodes (N) and the presence or absence of distant metastases (M). In recent years, this has been supplemented by non-anatomic prognostic factors (such as biomarkers).
- Unlike CS, TNM does not retain the raw data elements (e.g. the exact tumour size or number of lymph nodes involved), and it does not generate a combined stage based on both clinical and pathologic sources.
- TNM staging from the regional cancer centres is meaningful for the individual cases and the reporting facilities, but it does not capture all cancers of a single type across the province (i.e. those cases not referred to a regional cancer center during diagnosis and first course of treatment).
- Regional cancer centres submit TNM stage data to Cancer Care Ontario via Databook for sites that are not being staged using CS. This staging may be included in examining overall staging rates. Cancer centres may decide to send staging for cancer staged at CCO, and this stage may be used in instances where a collaborative stage cannot be derived.
What do the results show?
CS rates have improved for breast, colorectal, lung and prostate cancers, but the overall cases with CS have decreased (Figures, 1, 2 and 3).
- The number of stageable cases in Ontario decreased slightly from 67,326 in 2010 to 65,038 in 2014 (Figure 1).
- In the time between the 2015 Cancer System Quality Index (CSQI) report and the 2014 CSQI, the number of cases staged by the registry includes 32,531 for the most recent diagnosis year (2014) plus an additional 7,498 cases for diagnosis years 2010 to 2013. This work was completed in an effort to improve the stage capture rates for breast, colorectal, lung and prostate cancers across all diagnosis years. Thus, it is important to note that the staging rate reported here for the 2014 diagnosis year represents only 1 calendar year of staging, whereas all other years reflect more than 1 year of staging activity (Figure 2).
- As of the 2014 diagnosis year, the stage capture program at Cancer Care Ontario staged the following cancers using CS: breast, colon, appendix, rectosigmoid, rectum, lung, prostate and cervix. Breast, lung, colorectal and prostate cancers have been staged by the registry since the 2010 diagnosis year; cervical cancer had been staged since the 2011 diagnosis year.
- The scope of Cancer Care Ontario’s stage capture program in years prior to the 2014 diagnosis year included non-cervix gynecological cancers, melanoma and thyroid. Mainly as a result of this change in staging scope during 2015, the overall stage capture rate for all stageable cancers declined to 64% in the 2014 diagnosis year (from 68% in the previous year). Also, the proportion of CS-staged cases (as a percentage of all regional cancer centre- or CS-stageable cancers) declined to 50% for 2014, down from 56% in the previous year (Figure 2). These declines represent an artifact of the changes in the CS stage capture program.
- With the focus on staging breast, colorectal, lung and prostate cancers, there was an increase in the stage capture rates for those 4 sites that exceeded Cancer Care Ontario’s aim of 90% completion rate. The highest rate was for breast cancer at 94% (Figure 3).
Breast, cervical, colorectal and prostate cancers had consistent stage distribution from 2010 to 2014. The exception is lung cancer, for which stage I cases have increased over time (Figures 4, 5, 6, 7 and 8).
- The stage distribution of breast cancer has had little variation over the 5 years examined, with approximately 80% of cases diagnosed at early stage I and II (Figure 4).
- Similarly, around 75% of cases for prostate cancer were in the first 2 stages (Figure 8). This is in contrast to colorectal cancer, for which approximately 50% of cases were Stage I and II (Figure 6).
- The stage distribution of lung cancer increased in the percentage of stage I cases (from 17% in 2010 to 24% in 2014). The percentage of late stage IV cases decreased from 56% in 2010 to 47% in 2014. However, stage IV still remained the most common stage at diagnosis for Lung. (Figure 7). CCO lung cancer stage distribution rates for 2010-2014 are consistent with those of other jurisdictions and indicative of the issues preventing early detection, specifically asymptomatic disease and the lack of screening programs4.
- Cervical cancer stage distribution was fairly consistent across years, with 2014 seeing a slight decrease in the percentage of early stage I cases (from 55% in 2013 to 49% in 2014). It also saw an increase in the percentage of late stage IV cases (from 11% in 2013 to 15% in 2014) (Figure 5). For additional information, please see the Cervical Cancer page.
Accurate cancer stage information can improve quality of care and decision-making in the cancer system.
- Determining the exact location, size and spread of the cancer (i.e. the stage) is essential for selecting the best treatment for the patient2.
- Linking the stage of cancer with outcome and treatment data provides valuable information, allowing the cancer system to assess the quality of cancer care and identify new ways to improve the delivery of that care. For example, this CSQI provides performance information on the following indicators (which depend on accurate stage information):
- For many patients who are going through the cancer diagnostic journey—from when cancer is suspected, to its diagnosis and determination of stage (or to it being ruled out)—it can be a confusing and anxious time. To help transform the diagnostic phase of the cancer journey for patients, healthcare providers and the healthcare sector as a whole, Cancer Care Ontario developed Diagnostic Assessment Programs (DAPs) across the province.
Find out more
- Cancerstaging.org [Internet]. Chicago: American Joint Committee on Cancer; c2016. What is cancer staging?; [cited 2016 Mar 30]. Available from: https://cancerstaging.org/references-tools/Pages/What-is-Cancer-Staging.aspx.
- National Cancer Institute [Internet]. Bethesda (MD): National Institute of Health. Purpose of staging; [cited 2016 Mar 30]. Available from: http://training.seer.cancer.gov/staging/intro/purpose.html.
- Brierley JD, Srigley JR, Yurcan M, Li B, Rahal R, Ross J, et al. The value of collecting population-based cancer stage data to support decision-making at organizational, regional and population levels. Healthcare Quart. 2013; 16(3):27–33.
- Canadian Partnership Against Cancer. The 2015 cancer system performance report [Internet]. Toronto: Canadian Partnership against Cancer; 2015 [cited 2016 Feb 23]. Available from: http://www.cancerview.ca/idc/groups/public/documents/webcontent/the_2015_cancer_system_performance_report_en.pdf.