Canadian Journal of Surgery Journal Canadien De Chirurgie, Aug 1, 2006
BackgroundThere is a lack of information from Canadian hospitals on the role of hospital characte... more BackgroundThere is a lack of information from Canadian hospitals on the role of hospital characteristics such as procedure volume and teaching status on the survival of patients who undergo major cancer resection. Therefore, we chose to study these relationships using data from patients treated in Ontario hospitals.MethodsWe used the Ontario Cancer Registry from calendar years 1990–2000 to obtain data on patients who underwent surgery for breast, colon, lung or esophageal cancer or who underwent major liver surgery related to a cancer diagnosis between 1990 and 1995 in order to assess the influence of volume of procedures and teaching status of hospitals on in-hospital death rate and long-term survival. For each disease site and before observing patient outcomes data, volume cut-off points were selected to create volume groups with similar numbers of patients. Teaching hospitals were those directly affiliated with a medical school. Logistic regression and proportional hazards models were used to consider the clustering of data at the hospital level and to assess operative death and long-term survival. We also used 4 measures to gauge the degree of procedure regionalization across the province including (1) the number of hospitals performing a procedure; (2) the percentage of patients treated in teaching hospitals; (3) the percentage of rural patients treated in higher volume procedure hospitals; and (4) median distances travelled by patients to receive care.ResultsThe number of patients in our cohorts who underwent resection of the breast, colon, lung, esophagus or liver was 14 346, 8398, 2698, 629 and 362, respectively. Surgery in a high-volume versus a low-volume hospital did not have a statistically significant influence on the odds of operative death for patients who underwent colon, liver, lung or esophageal cancer resection. The risk of long-term death was increased in low-volume versus high-volume hospitals for patients who underwent resection of the breast (hazard ratio [HR] 1.2, 95% confidence interval [95% CI] 1.0–1.4, p < 0.05), lung (HR 1.3, 95% CI 1.1–1.6, p < 0.01) and liver (HR 1.7, 95% CI 1.0–2.7, p = 0.04). There were no significant differences in the odds of operative (in-hospital) death or risk of long-term death among patients treated in teaching compared with nonteaching hospitals. There was more regionalization of liver, lung and esophageal operations versus breast and colon operations.ConclusionsIncreased hospital procedure volume correlated with improved long-term survival for patients in Ontario who underwent some, but not all, cancer resections, whereas hospital teaching status had no significant impact on patient outcomes. Across the province, further regionalization of care may help improve the quality of some cancer procedures.
A population-based cohort study of soft tissue sarcoma of the extremities (STSE) in Ontario, Cana... more A population-based cohort study of soft tissue sarcoma of the extremities (STSE) in Ontario, Canada was conducted using linked administrative databases. Electronic administrative databases were linked from the Ontario Cancer Registry, the Canadian Institute for Health Information, and Radiation Oncology Research Unit database of radiation therapy (RT) records. The definitive surgery was amputation for 6.0%, resection for 60.9%, biopsy for 7.5%; the remainder had no surgical record. Adjuvant RT was administered to 40.2% of cases. Among cases initially treated by surgical resection, 2.0% later underwent amputation and 9.5% underwent further resection during follow-up. The adjusted odds ratio (OR) for amputation as definitive surgery was 2.3 (1.19, 4.45) in eastern Ontario relative to Toronto. The likelihood of adjuvant RT among those not registered at a cancer centre within 3 months of diagnosis was decreased (OR = 0.20 (95% CI (0.13, 0.30)) relative to those registered. The adjusted relative risk of amputation at any time following diagnosis was 3.48 (95% CI (1.63, 7.46)) among cases not attending a cancer centre. The adjusted relative risk of death was 1.4; 95% CI (1.1, 1.7) among those not attending a cancer centre. Cases not seen at a multidisciplinary cancer centre within 3 months following diagnosis of STSE have an increased relative risk for amputation at any time, and for death due to any cause. Many hypotheses for further study are suggested by the results of this analysis.
Canadian journal of public health. Revue canadienne de santé publique
A case-control study of the etiology of lung cancer in women was conducted in the Niagara Region ... more A case-control study of the etiology of lung cancer in women was conducted in the Niagara Region of Ontario, because of local concerns about a high incidence of lung cancer. 51 female patients with lung cancer and 45 matched controls were interviewed. Information was collected about active and passive smoking, occupation and residential history. There was a strong association between active cigarette smoking and lung cancer (ever/never odds ratio 10.0; p less than .001) and 85% of the cases of lung cancer were attributed to active cigarette smoking. No other factors were significantly associated with lung cancer; there was weak evidence of an association between urban environment during childhood and lung cancer (p = 0.07). Associations between lung cancer and air pollution, and residential history, were not demonstrated, contrary to public perception. Thus, a previously reported excess of lung cancer in Niagara females is most likely attributable to cigarette smoking.
It is known that the socioeconomic status (SES) of the patient is associated with cancer survival... more It is known that the socioeconomic status (SES) of the patient is associated with cancer survival in the United States. The purpose of this study was to determine whether the association between SES and survival is also present in Canada, a society with a comprehensive, universal, health insurance program. A population-based cancer registry was used to identify the 357,530 cases of invasive cancer diagnosed in the Canadian province of Ontario between 1982 and 1991. Information from the 1986 Canadian census was linked to the registry and used to describe the SES of the area in which each patient resided. Cox regression was used to describe the association between median household income and survival while controlling for age, sex, and the region in which the patient resided. The Cox model was fitted in a competing risk framework to assess the association between income and the probability of specific causes of death. Lung cancer and cancers of the head and neck region were relatively more common in poor-income communities, and cancers of the breast, CNS, and testis were relatively more common in richer communities. A strong and statistically significant association between community income and survival was observed in cancers of the head and neck region, cervix, uterus, breast, prostate, bladder, and esophagus. Smaller, but significant associations were seen in cancers of the lung and rectum. No significant association between community income and survival was observed in cancers of the stomach, colon, pancreas, or ovary. Analysis of the cause of death showed that community income is associated both with the probability of death from cancer and with the probability of death from other causes. Although Canada&#39;s health care system was designed to provide equitable access to equivalent standards of care, it does not prevent a difference in cancer survival between rich and poor communities.
To analyse the extent of variation by county and hospital in the use of breast-conserving surgery... more To analyse the extent of variation by county and hospital in the use of breast-conserving surgery in the initial management of breast cancer and to assess some factors that might explain the observed variation. Population-based retrospective cohort study. Ontario. All women with breast cancer newly diagnosed from Jan. 1, 1989, to Dec. 31, 1991. Proportion of women undergoing unilateral breast cancer surgery who had breast-conserving surgery in each hospital and county. Of the 14,570 women with newly diagnosed breast cancer 12,815 (88.0%) underwent unilateral breast cancer surgery. The mean proportion of breast-conserving procedures by county was 52% and ranged from 11% to 84%. The proportion of breast-conserving procedures in individual hospitals with one or more cases of breast cancer per month ranged from 6% to 84%. The variations in the rates between hospitals was greater than that expected by chance alone (p < 0.0001). There was marked variation at the hospital and county lev...
Objectives. We examined health insurance mediation of Mexican American (MA) non-Hispanic white (N... more Objectives. We examined health insurance mediation of Mexican American (MA) non-Hispanic white (NHW) disparities on breast cancer care and survival. Based on social capital and barrio advantage theories, we hypothesized a 3-way ethnicity by poverty by health insurance interaction, that is, that 2-way poverty by health insurance interaction effects would differ between ethnic groups. Methods. We analyzed registry data for 303 MA and 3,611 NHW women diagnosed between 1996 and 2000 and followed until 2011. Socioeconomic data were obtained from the 2000 census to categorize neighborhood poverty: high (> 30% poor), middle and low (< 5% poor). Barrios were neighborhoods where 50% or more of the residents were MA. Primary health insurers were Medicaid, Medicare, private or none. Results. MA-NHW diagnostic, treatment and survival disparities were completely mediated by the main and interacting effects of health insurance. Advantages of health insurance were largest in low poverty neig...
Cancer prevention & control: CPC = Prévention & contrôle en cancérologie: PCC
To observe the association between socioeconomic status (SES) and cancer incidence in a cohort of... more To observe the association between socioeconomic status (SES) and cancer incidence in a cohort of Canadians. Cases of primary malignant cancer (83,666) that arose in metropolitan Toronto, Ont., from 1986 to 1993 were ascertained by the Ontario Cancer Registry and linked by residence at the time of diagnosis to a census-based measure of SES. Socioeconomic quintile areas were then compared by cancer incidence. Significant associations between SES and cancer incidence in the hypothesized direction--greater incidence in low-income areas--were observed for 15 of 23 cancer sites. These findings, together with the recently observed consistent pattern of significant associations between SES and cancer survival in the United States and the equally consistent pattern of nonsignificant associations in Canada, support the notion that differences in cancer incidence alone explain the observed cancer mortality differentials by SES in Canada. The cancer mortality differential by SES observed in th...
Evidence suggests that current levels of tritium emissions from CANDU reactors in Canada are not ... more Evidence suggests that current levels of tritium emissions from CANDU reactors in Canada are not related to adverse health effects. However, these studies lack tritium-specific dose data and have small numbers of cases. The purpose of our study was to determine whether tritium emitted from a nuclear-generating station during routine operation is associated with risk of cancer in Pickering, Ontario. A retrospective cohort was formed through linkage of Pickering and north Oshawa residents (1985) to incident cancer cases (1985-2005). We examined all sites combined, leukemia, lung, thyroid and childhood cancers (6-19 years) for males and females as well as female breast cancer. Tritium estimates were based on an atmospheric dispersion model, incorporating characteristics of annual tritium emissions and meteorology. Tritium concentration estimates were assigned to each cohort member based on exact location of residence. Person-years analysis was used to determine whether observed cancer ...
Canadian Journal of Surgery Journal Canadien De Chirurgie, Aug 1, 2006
BackgroundThere is a lack of information from Canadian hospitals on the role of hospital characte... more BackgroundThere is a lack of information from Canadian hospitals on the role of hospital characteristics such as procedure volume and teaching status on the survival of patients who undergo major cancer resection. Therefore, we chose to study these relationships using data from patients treated in Ontario hospitals.MethodsWe used the Ontario Cancer Registry from calendar years 1990–2000 to obtain data on patients who underwent surgery for breast, colon, lung or esophageal cancer or who underwent major liver surgery related to a cancer diagnosis between 1990 and 1995 in order to assess the influence of volume of procedures and teaching status of hospitals on in-hospital death rate and long-term survival. For each disease site and before observing patient outcomes data, volume cut-off points were selected to create volume groups with similar numbers of patients. Teaching hospitals were those directly affiliated with a medical school. Logistic regression and proportional hazards models were used to consider the clustering of data at the hospital level and to assess operative death and long-term survival. We also used 4 measures to gauge the degree of procedure regionalization across the province including (1) the number of hospitals performing a procedure; (2) the percentage of patients treated in teaching hospitals; (3) the percentage of rural patients treated in higher volume procedure hospitals; and (4) median distances travelled by patients to receive care.ResultsThe number of patients in our cohorts who underwent resection of the breast, colon, lung, esophagus or liver was 14 346, 8398, 2698, 629 and 362, respectively. Surgery in a high-volume versus a low-volume hospital did not have a statistically significant influence on the odds of operative death for patients who underwent colon, liver, lung or esophageal cancer resection. The risk of long-term death was increased in low-volume versus high-volume hospitals for patients who underwent resection of the breast (hazard ratio [HR] 1.2, 95% confidence interval [95% CI] 1.0–1.4, p < 0.05), lung (HR 1.3, 95% CI 1.1–1.6, p < 0.01) and liver (HR 1.7, 95% CI 1.0–2.7, p = 0.04). There were no significant differences in the odds of operative (in-hospital) death or risk of long-term death among patients treated in teaching compared with nonteaching hospitals. There was more regionalization of liver, lung and esophageal operations versus breast and colon operations.ConclusionsIncreased hospital procedure volume correlated with improved long-term survival for patients in Ontario who underwent some, but not all, cancer resections, whereas hospital teaching status had no significant impact on patient outcomes. Across the province, further regionalization of care may help improve the quality of some cancer procedures.
A population-based cohort study of soft tissue sarcoma of the extremities (STSE) in Ontario, Cana... more A population-based cohort study of soft tissue sarcoma of the extremities (STSE) in Ontario, Canada was conducted using linked administrative databases. Electronic administrative databases were linked from the Ontario Cancer Registry, the Canadian Institute for Health Information, and Radiation Oncology Research Unit database of radiation therapy (RT) records. The definitive surgery was amputation for 6.0%, resection for 60.9%, biopsy for 7.5%; the remainder had no surgical record. Adjuvant RT was administered to 40.2% of cases. Among cases initially treated by surgical resection, 2.0% later underwent amputation and 9.5% underwent further resection during follow-up. The adjusted odds ratio (OR) for amputation as definitive surgery was 2.3 (1.19, 4.45) in eastern Ontario relative to Toronto. The likelihood of adjuvant RT among those not registered at a cancer centre within 3 months of diagnosis was decreased (OR = 0.20 (95% CI (0.13, 0.30)) relative to those registered. The adjusted relative risk of amputation at any time following diagnosis was 3.48 (95% CI (1.63, 7.46)) among cases not attending a cancer centre. The adjusted relative risk of death was 1.4; 95% CI (1.1, 1.7) among those not attending a cancer centre. Cases not seen at a multidisciplinary cancer centre within 3 months following diagnosis of STSE have an increased relative risk for amputation at any time, and for death due to any cause. Many hypotheses for further study are suggested by the results of this analysis.
Canadian journal of public health. Revue canadienne de santé publique
A case-control study of the etiology of lung cancer in women was conducted in the Niagara Region ... more A case-control study of the etiology of lung cancer in women was conducted in the Niagara Region of Ontario, because of local concerns about a high incidence of lung cancer. 51 female patients with lung cancer and 45 matched controls were interviewed. Information was collected about active and passive smoking, occupation and residential history. There was a strong association between active cigarette smoking and lung cancer (ever/never odds ratio 10.0; p less than .001) and 85% of the cases of lung cancer were attributed to active cigarette smoking. No other factors were significantly associated with lung cancer; there was weak evidence of an association between urban environment during childhood and lung cancer (p = 0.07). Associations between lung cancer and air pollution, and residential history, were not demonstrated, contrary to public perception. Thus, a previously reported excess of lung cancer in Niagara females is most likely attributable to cigarette smoking.
It is known that the socioeconomic status (SES) of the patient is associated with cancer survival... more It is known that the socioeconomic status (SES) of the patient is associated with cancer survival in the United States. The purpose of this study was to determine whether the association between SES and survival is also present in Canada, a society with a comprehensive, universal, health insurance program. A population-based cancer registry was used to identify the 357,530 cases of invasive cancer diagnosed in the Canadian province of Ontario between 1982 and 1991. Information from the 1986 Canadian census was linked to the registry and used to describe the SES of the area in which each patient resided. Cox regression was used to describe the association between median household income and survival while controlling for age, sex, and the region in which the patient resided. The Cox model was fitted in a competing risk framework to assess the association between income and the probability of specific causes of death. Lung cancer and cancers of the head and neck region were relatively more common in poor-income communities, and cancers of the breast, CNS, and testis were relatively more common in richer communities. A strong and statistically significant association between community income and survival was observed in cancers of the head and neck region, cervix, uterus, breast, prostate, bladder, and esophagus. Smaller, but significant associations were seen in cancers of the lung and rectum. No significant association between community income and survival was observed in cancers of the stomach, colon, pancreas, or ovary. Analysis of the cause of death showed that community income is associated both with the probability of death from cancer and with the probability of death from other causes. Although Canada&#39;s health care system was designed to provide equitable access to equivalent standards of care, it does not prevent a difference in cancer survival between rich and poor communities.
To analyse the extent of variation by county and hospital in the use of breast-conserving surgery... more To analyse the extent of variation by county and hospital in the use of breast-conserving surgery in the initial management of breast cancer and to assess some factors that might explain the observed variation. Population-based retrospective cohort study. Ontario. All women with breast cancer newly diagnosed from Jan. 1, 1989, to Dec. 31, 1991. Proportion of women undergoing unilateral breast cancer surgery who had breast-conserving surgery in each hospital and county. Of the 14,570 women with newly diagnosed breast cancer 12,815 (88.0%) underwent unilateral breast cancer surgery. The mean proportion of breast-conserving procedures by county was 52% and ranged from 11% to 84%. The proportion of breast-conserving procedures in individual hospitals with one or more cases of breast cancer per month ranged from 6% to 84%. The variations in the rates between hospitals was greater than that expected by chance alone (p < 0.0001). There was marked variation at the hospital and county lev...
Objectives. We examined health insurance mediation of Mexican American (MA) non-Hispanic white (N... more Objectives. We examined health insurance mediation of Mexican American (MA) non-Hispanic white (NHW) disparities on breast cancer care and survival. Based on social capital and barrio advantage theories, we hypothesized a 3-way ethnicity by poverty by health insurance interaction, that is, that 2-way poverty by health insurance interaction effects would differ between ethnic groups. Methods. We analyzed registry data for 303 MA and 3,611 NHW women diagnosed between 1996 and 2000 and followed until 2011. Socioeconomic data were obtained from the 2000 census to categorize neighborhood poverty: high (> 30% poor), middle and low (< 5% poor). Barrios were neighborhoods where 50% or more of the residents were MA. Primary health insurers were Medicaid, Medicare, private or none. Results. MA-NHW diagnostic, treatment and survival disparities were completely mediated by the main and interacting effects of health insurance. Advantages of health insurance were largest in low poverty neig...
Cancer prevention & control: CPC = Prévention & contrôle en cancérologie: PCC
To observe the association between socioeconomic status (SES) and cancer incidence in a cohort of... more To observe the association between socioeconomic status (SES) and cancer incidence in a cohort of Canadians. Cases of primary malignant cancer (83,666) that arose in metropolitan Toronto, Ont., from 1986 to 1993 were ascertained by the Ontario Cancer Registry and linked by residence at the time of diagnosis to a census-based measure of SES. Socioeconomic quintile areas were then compared by cancer incidence. Significant associations between SES and cancer incidence in the hypothesized direction--greater incidence in low-income areas--were observed for 15 of 23 cancer sites. These findings, together with the recently observed consistent pattern of significant associations between SES and cancer survival in the United States and the equally consistent pattern of nonsignificant associations in Canada, support the notion that differences in cancer incidence alone explain the observed cancer mortality differentials by SES in Canada. The cancer mortality differential by SES observed in th...
Evidence suggests that current levels of tritium emissions from CANDU reactors in Canada are not ... more Evidence suggests that current levels of tritium emissions from CANDU reactors in Canada are not related to adverse health effects. However, these studies lack tritium-specific dose data and have small numbers of cases. The purpose of our study was to determine whether tritium emitted from a nuclear-generating station during routine operation is associated with risk of cancer in Pickering, Ontario. A retrospective cohort was formed through linkage of Pickering and north Oshawa residents (1985) to incident cancer cases (1985-2005). We examined all sites combined, leukemia, lung, thyroid and childhood cancers (6-19 years) for males and females as well as female breast cancer. Tritium estimates were based on an atmospheric dispersion model, incorporating characteristics of annual tritium emissions and meteorology. Tritium concentration estimates were assigned to each cohort member based on exact location of residence. Person-years analysis was used to determine whether observed cancer ...
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