Temporal trends in the association between socioeconomic status and cancer survival in Ontario: a population-based retrospective study.

BACKGROUND: Cancer survival is known to be associated with socioeconomic status. The income gap between the richer and poorer segments of the population has widened over the last 20 years in Canada. The purpose of this study was to investigate temporal trends in disparities in cancer-specific survival related to socioeconomic status in Ontario. METHODS: There were 920 334 cancer cases between 1993 and 2009 in the Ontario Cancer Registry. We linked median household income from the Canadian census to the registry. We calculated 5-year cancer-specific survival rates for all cancers combined and for specific cancer sites by socioeconomic status quintile and year of diagnosis, and modelled time to death using Cox regression. RESULTS: Between 1993 and 2009, for all cancers combined, the hazard of death decreased by 3.1% (hazard ratio [HR] 0.969 [95% confidence interval (CI) 0.967-0.971]) per year in the richest quintile and by 1.2% (HR 0.988 [95% CI 0.987-0.990]) per year in the poorest quintile. The corresponding values for breast cancer were 4.3% (HR 0.957 [95% CI 0.951-0.964]) and 2.0% (HR 0.980 [95% CI 0.975-0.986]); for lung cancer, 1.4% (HR 0.986 [95% CI 0.982-0.990]) and 0.3% (HR 0.997 [95% CI 0.995-1.000]); for colorectal cancer, 3.7% (HR 0.963 [95% CI 0.958-0.968]) and 1.8% (HR 0.982 [95% CI 0.978-0.985]); and for head and neck cancer, 3.1% (HR 0.969 [95% CI 0.958-0.979]) and 1.0% (HR 0.990 [95% CI 0.983-0.996]). INTERPRETATION: Between 1993 and 2009, cancer-specific survival in Ontario improved more among patients from affluent communities than among those from poorer communities. This phenomenon cannot be explained by increased disparity in income.

Increased incidence but improved median overall survival for biliary tract cancers diagnosed in Ontario from 1994 through 2012: A population-based study.

BACKGROUND: To the authors' knowledge, the incidence of biliary tract cancer (BTC) in Canada is unknown. In the current study, the authors sought to describe the epidemiology of BTC using a large population-based cancer database from Ontario, Canada. METHODS: The current study was a population-based cohort study using the Ontario Cancer Registry. Patients with intrahepatic cholangiocarcinoma (IHCC), extrahepatic cholangiocarcinoma (EHCC), and gallbladder cancer (GBC) diagnosed between 1994 and 2012 were included. Age-standardized incidence and mortality rates were compared using incidence rate ratios (IRRs). Overall survival from the time of diagnosis was calculated for 3 eras: 1994 through 1999, 2000 through 2005, and 2006 through 2012. The number of patients receiving chemotherapy, radiotherapy, or surgery was determined using linked clinical data. RESULTS: A total of 9039 cases (1569 IHCC cases, 4337 EHCC cases, and 3133 GBC cases) were identified. The rate of BTC increased by 1.6% per year (IRR, 1.016; 95% confidence interval [95% CI], 1.008-1.024 [P<.001]). The incidence increased by 7.0% per year among cases of IHCC (IRR, 1.070; 95% CI, 1.058-1.081 [P<.001]) and 1.8% per year in cases of EHCC (IRR, 1.018; 95% CI, 1.009-1.027 [P<.001]), whereas the incidence of GBC remained unchanged (IRR, 0.991; 95% CI, 0.982-1.001 [P = .086]). The median survival for the cohort was 8.3 months, with improvement noted over the study period (6.1 months for 1994-1999 vs 8.5 months for 2000-2005 vs 10.3 months for 2006-2012 [P<.001]). The median survival was the longest for EHCC (11.3 months), followed by GBC (6.4 months) and IHCC (6.2 months). The percentage of patients receiving chemotherapy and/or radiotherapy increased over the study (P<.001), whereas the percentage of patients receiving surgery decreased (P<.001). CONCLUSIONS: An increased incidence of BTC during 1994 through 2012 was observed. Explanations for the observed temporal improvement in median survival require further exploration. Cancer 2016;122:2534-43. © 2016 American Cancer Society.

A comparison of evidence-based estimates and empirical benchmarks of the appropriate rate of use of radiation therapy in ontario.

PURPOSE: Estimates of the appropriate rate of use of radiation therapy (RT) are required for planning and monitoring access to RT. Our objective was to compare estimates of the appropriate rate of use of RT derived from mathematical models, with the rate observed in a population of patients with optimal access to RT. METHODS AND MATERIALS: The rate of use of RT within 1 year of diagnosis (RT1Y) was measured in the 134,541 cases diagnosed in Ontario between November 2009 and October 2011. The lifetime rate of use of RT (RTLIFETIME) was estimated by the multicohort utilization table method. Poisson regression was used to evaluate potential barriers to access to RT and to identify a benchmark subpopulation with unimpeded access to RT. Rates of use of RT were measured in the benchmark subpopulation and compared with published evidence-based estimates of the appropriate rates. RESULTS: The benchmark rate for RT1Y, observed under conditions of optimal access, was 33.6% (95% confidence interval [CI], 33.0%-34.1%), and the benchmark for RTLIFETIME was 41.5% (95% CI, 41.2%-42.0%). Benchmarks for RTLIFETIME for 4 of 5 selected sites and for all cancers combined were significantly lower than the corresponding evidence-based estimates. Australian and Canadian evidence-based estimates of RTLIFETIME for 5 selected sites differed widely. RTLIFETIME in the overall population of Ontario was just 7.9% short of the benchmark but 20.9% short of the Australian evidence-based estimate of the appropriate rate. CONCLUSIONS: Evidence-based estimates of the appropriate lifetime rate of use of RT may overestimate the need for RT in Ontario.

Determine the therapeutic role of radiotherapy in administrative data: a data mining approach.

BACKGROUND: Clinical data gathered for administrative purposes often lack sufficient information to separate the records of radiotherapy given for palliation from those given for cure. An absence, incompleteness, or inaccuracy of such information could hinder or bias the study of the utilization and outcome of radiotherapy. This study has three specific purposes: 1) develop a method to determine the therapeutic role of radiotherapy (TRR); 2) assess the accuracy of the method; 3) report the quality of the information on treatment "intent" recorded in the clinical data in Ontario, Canada. A general purpose is to use this study as a prototype to demonstrate and test a method to assess the quality of administrative data. METHODS: This is a population based retrospective study. A random sample was drawn from the treatment records with "intent" assigned in treating hospitals. A decision tree is grown using treatment parameters as predictors and "intent" as outcome variable to classify the treatments into curative or palliative. The tree classifier was applied to the entire dataset, and the classification results were compared with those identified by "intent". A manual audit was conducted to assess the accuracy of the classification. RESULTS: The following parameters predicted the TRR, from the strongest to the weakest: radiation dose per fraction, treated body-region, disease site, and time of treatment. When applied to the records of treatments given between 1990 and 2008 in Ontario, Canada, the classification rules correctly classified 96.1% of the records. The quality of the "intent" variable was as follows: 77.5% correctly classified, 3.7% misclassified, and 18.8% did not have an "intent" assigned. CONCLUSIONS: The classification rules derived in this study can be used to determine the TRR when such information is unavailable, incomplete, or inaccurate in administrative data. The study demonstrates that data mining approach can be used to effectively assess and improve the quality of large administrative datasets.

The impact of socioeconomic status on stage of cancer at diagnosis and survival: a population-based study in Ontario, Canada.

BACKGROUND: Lower socioeconomic status (SES) is associated with worsened cancer survival. The authors evaluate the impact of SES on stage of cancer at diagnosis and survival in Ontario, Canada. METHODS: All incident cases of breast, colon, rectal, nonsmall cell lung, cervical, and laryngeal cancer diagnosed in Ontario during the years 2003-2007 were identified by using the Ontario Cancer Registry. Stage information is captured routinely for patients seen at Ontario's 8 Regional Cancer Centers (RCCs). The Ontario population was divided into quintiles (Q1-Q5) based on community median household income reported in the 2001 census; Q1 represents the poorest communities. Overall survival (OS) and cancer-specific survival (CSS) were determined with Kaplan-Meier methodology. A Cox model was used to evaluate the association between survival and SES, stage, and age. RESULTS: Stage at diagnosis was available for 38,431 of 44,802 (85%) of cases seen at RCCs. The authors observed only very small differences in stage distribution by SES. Across all cases in Ontario, the authors found substantial gradients in 5-year OS and 3-year CSS across Q1 and Q5 for breast (7% absolute difference in OS, P < .001; 4% CSS, P < .001), colon (8% OS, P < .001; 3% CSS, P = .002), rectal (9% OS, P < .001; 4% CSS, P = .096), nonsmall cell lung (3% OS, P = .002; 2% CSS, P = .317), cervical (16% OS, P < .001; 10% CSS, P = .118), and laryngeal cancers (1% OS, P = .045; 3% CSS, P = .011). Adjustments for stage and age slightly diminished the survival gradient only among patients with breast cancer. CONCLUSIONS: Despite universal healthcare, SES remains associated with survival among patients with cancer in Ontario, Canada. Disparities in outcome were not explained by differences in stage of cancer at time of diagnosis.

Estimating the lifetime utilization rate of radiotherapy in cancer patients: the Multicohort Current Utilization Table (MCUT) method.

Extensive research has been carried out to establish the appropriate proportion of cancer patients requiring radiotherapy at some point during their illness. However, it is difficult to compare the actual rates against the appropriate rate, because calculating the actual rates requires life-long follow up of cancer patients. We have developed a method, referred to as the Multicohort Current Utilization Table (MCUT) method, to estimate the predicted lifetime utilization rates based on current medical practice. We implemented the method in SAS as a macro, and validated it by comparing the predicted and the actual utilization rates of radiotherapy in lung, breast, and prostate cancer cases diagnosed in Ontario, Canada. The MCUT method could be used to predict lifetime utilization rate of any medical services.

A population-based study of the fractionation of palliative radiotherapy for bone metastasis in Ontario.

PURPOSE: To describe the use of palliative radiotherapy (PRT) for bone metastases in Ontario between 1984 and 2001 and identify factors associated with the choice of fractionation. METHODS AND MATERIALS: Electronic RT records from the nine provincial RT centers in Ontario were linked to the Ontario Cancer Registry to identify all courses of PRT for bone metastases. RESULTS: Between 1984 and 2001, 44,884 patients received 74,432 courses of PRT for bone metastases in Ontario. The mean number of courses per patient was 1.7, and 65% of patients received only a single course of PRT for bone metastasis. The mean number of fractions per course was 3.9. The proportion of patients treated with a single fraction increased from 27.2% in 1984-1986 to 40.3% in 1987-1992 and decreased thereafter. Single fractions were used more frequently in patients with a shorter life expectancy, in older patients, and in patients who lived further from an RT center. Single fractions were used more frequently when the prevailing waiting time for RT was longer. There were wide variations in the use of single fractions among the different RT centers (intercenter range, 11.8-62.3%). Intercenter variations persisted throughout the study period and were not explained by differences in case mix. CONCLUSIONS: Despite increasing evidence of the effectiveness of single-fraction PRT for bone metastases, most patients continued to receive fractionated PRT throughout the two decades of this study. Single fractions were used more frequently when waiting times were longer. There was persistent, unexplained variation in the fractionation of PRT among different centers.

Impact of adoption of chemoradiotherapy on the outcome of cervical cancer in Ontario: results of a population-based cohort study.

PURPOSE: To describe the adoption of concurrent cisplatin-based chemoradiotherapy (C-CRT), and to evaluate its impact on the outcome of cervical cancer in Ontario. METHODS: We used a population-based cancer registry to identify the 4,069 patients with invasive carcinoma of the cervix diagnosed in Ontario between 1992 and 2001. We linked electronic records of treatment to the registry. We described time trends in the use of C-CRT, and we compared survival before and after widespread adoption of C-CRT. RESULTS: Over the study period, the proportion of patients treated with primary radical radiotherapy (RT) remained constant at approximately 42%. Between 1992 and 1998, less than 10% of RT cases received chemotherapy. Early in 1999, there was rapid adoption of C-CRT. Between 1999 and 2001, more than 60% of RT cases received C-CRT. There was a contemporaneous increase in overall 3-year survival from 71.1% in the 1995 to 1998 cohort to 75.9% in the 1999 to 2001 cohort (P = .03). There was no change in survival in patients treated with surgery alone. However, there was a significant increase in 3-year survival from 58.6% in the 1995 to 1998 cohort to 69.8% in the 1999 to 2001 cohort (P < .01) in the subpopulation of patients treated with primary RT +/- chemotherapy. CONCLUSION: The adoption of C-CRT was associated with a significant improvement in overall survival of cervical cancer at the population level. The magnitude of the benefit of C-CRT in the general population was consistent with the results of the relevant clinical trials.

Associations between socioeconomic status and cancer survival: choice of SES indicator may affect results.

PURPOSE: Two previous studies, by Gorey et al. and Boyd et al., compared associations between socioeconomic status (SES) and cancer survival in Canada and the United States. Both studies used SES information from population censuses linked to cancer registries. This study investigates why two similar studies led to apparently conflicting results. METHODS: We conducted analyses following analytic details provided by the previously published studies to describe cancer survival in Toronto, Canada, and Detroit, MI. We examined the effects of choice of census indicators and census levels on the observed SES-related gradients in cancer survival. RESULTS: Significant associations between SES and cancer survival were observed in Toronto for several major disease sites when median household income was used as an SES indicator. Associations were weaker when a poverty indicator was used. In Detroit, similar SES gradients were observed by using both income and poverty as SES indicators. When SES quintiles were represented by income ranks, SES-associated survival gradients were much steeper in Detroit than Toronto. When SES was described by the median income in each quintile, gradients were similar in the two cities. CONCLUSIONS: The apparent contradiction in results of two previous studies is related to the choice of SES indicators. Poverty may not be an indicator of choice for such an intercountry comparison.

Defining the need for radiotherapy for lung cancer in the general population: a criterion-based, benchmarking approach.

BACKGROUND: We have previously used an evidence-based, epidemiologic approach to estimate the proportion of incident cases that should be treated with radiotherapy (RT) for lung cancer. The first objective of the present study was to compare this evidence-based estimate of the appropriate rate of use of RT with the rates observed in selected "benchmark" communities where there are no barriers to the appropriate use of RT and no incentives to the unnecessary use of RT. The second objective of the study was to compare the rates of use of RT in the general populations in the United States and Canada with the estimated appropriate rate. METHODS: We established benchmark rates for the use of RT for lung cancer in Ontario, Canada, where: 1) residents make no direct payments for RT; 2) all RT is provided by site-specialized radiation oncologists in multidisciplinary cancer centers, and 3) radiation oncologists receive a salary in lieu of technical fees. Communities located close to cancer centers without long waiting lists for RT were selected to serve as benchmarks. Prospectively gathered electronic treatment records from all RT cancer centers were linked to the provincial cancer registry to describe the rate of use of RT in Ontario. The public use file of Surveillance, Epidemiology and End Results Registries (SEER) was used to describe the use of RT in the United States. RESULTS: Overall, 41.3% (95% confidence interval [CI], 39.9%, 42.7%) of incident cases of lung cancer received RT as part of their initial management in the benchmark communities compared with the evidence-based estimate of 41.6% (95% CI, 39.2%, 44.1%). The rate of use of RT in the initial management of nonsmall cell lung cancer (NSCLC) in the benchmark communities was 49.3% (95% CI, 47.5%, 51.1%) compared with the evidence-based estimate of 45.9% (95% CI, 41.6%, 50.2%). The use of RT in the initial management of small-cell lung cancer (SCLC) in the benchmark communities was 47.0% (95% CI, 43.3%, 50.7%) compared with the evidence-based estimate of 45.4% (95% CI, 42.4%, 48.4%). In many counties of Ontario, the observed rates of RT use in the initial management of lung cancer were significantly lower than either the benchmark rate or the evidence-based estimate of the appropriate rate. In contrast, rates of use of RT in most counties in the SEER regions of the United States were close to, or higher than, the estimated appropriate rate. CONCLUSIONS: The observed benchmark rate converged on the evidence-based estimate of the appropriate rate of use of RT for lung cancer, suggesting that either measure might reasonably be used as a "standard" against which to compare rates observed in similar populations elsewhere.