Building on existing tools to improve chronic disease prevention and screening in public health: a cluster randomized trial.

BACKGROUND: The BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) intervention was designed to integrate the approach to chronic disease prevention and screening in primary care and demonstrated effective in a previous randomized trial. METHODS: We tested the effectiveness of the BETTER HEALTH intervention, a public health adaptation of BETTER, at improving participation in chronic disease prevention and screening actions for residents of low-income neighbourhoods in a cluster randomized trial, with ten low-income neighbourhoods in Durham Region Ontario randomized to immediate intervention vs. wait-list. The unit of analysis was the individual, and eligible participants were adults age 40-64 years residing in the neighbourhoods. Public health nurses trained as "prevention practitioners" held one prevention-focused visit with each participant. They provided participants with a tailored prevention prescription and supported them to set health-related goals. The primary outcome was a composite index: the number of evidence-based actions achieved at six months as a proportion of those for which participants were eligible at baseline. RESULTS: Of 126 participants (60 in immediate arm; 66 in wait-list arm), 125 were included in analyses (1 participant withdrew consent). In both arms, participants were eligible for a mean of 8.6 actions at baseline. At follow-up, participants in the immediate intervention arm met 64.5% of actions for which they were eligible versus 42.1% in the wait-list arm (rate ratio 1.53 [95% confidence interval 1.22-1.84]). CONCLUSION: Public health nurses using the BETTER HEALTH intervention led to a higher proportion of identified evidence-based prevention and screening actions achieved at six months for people living with socioeconomic disadvantage. TRIAL REGISTRATION: NCT03052959 , registered February 10, 2017.

Refined estimates of local recurrence risks by DCIS score adjusting for clinicopathological features: a combined analysis of ECOG-ACRIN E5194 and Ontario DCIS cohort studies.

PURPOSE: Better tools are needed to estimate local recurrence (LR) risk after breast-conserving surgery (BCS) for DCIS. The DCIS score (DS) was validated as a predictor of LR in E5194 and Ontario DCIS cohort (ODC) after BCS. We combined data from E5194 and ODC adjusting for clinicopathological factors to provide refined estimates of the 10-year risk of LR after treatment by BCS alone. METHODS: Data from E5194 and ODC were combined. Patients with positive margins or multifocality were excluded. Identical Cox regression models were fit for each study. Patient-specific meta-analysis was used to calculate precision-weighted estimates of 10-year LR risk by DS, age, tumor size and year of diagnosis. RESULTS: The combined cohort includes 773 patients. The DS and age at diagnosis, tumor size and year of diagnosis provided independent prognostic information on the 10-year LR risk (p ≤ 0.009). Hazard ratios from E5194 and ODC cohorts were similar for the DS (2.48, 1.95 per 50 units), tumor size ≤ 1 versus  > 1-2.5 cm (1.45, 1.47), age ≥ 50 versus < 50 year (0.61, 0.84) and year ≥ 2000 (0.67, 0.49). Utilization of DS combined with tumor size and age at diagnosis predicted more women with very low (≤ 8%) or higher (> 15%) 10-year LR risk after BCS alone compared to utilization of DS alone or clinicopathological factors alone. CONCLUSIONS: The combined analysis provides refined estimates of 10-year LR risk after BCS for DCIS. Adding information on tumor size and age at diagnosis to the DS adjusting for year of diagnosis provides improved LR risk estimates to guide treatment decision making.

A centrally generated primary care physician audit report does not improve colonoscopy uptake after a positive result on a fecal occult blood test in Ontario's ColonCancerCheck program.

BACKGROUND: Timely follow-up of fecal occult blood screening with colonoscopy is essential for achieving colorectal cancer mortality reduction. In the present study, we evaluated the effectiveness of centrally generated, physician-targeted audit and feedback to improve colonoscopy uptake after a positive fecal occult blood test (fobt) result within Ontario's population-wide ColonCancerCheck Program. METHODS: This prospective cohort study used data sets from Ontario's ColonCancerCheck Program (2008-2011) that were linked to provincial administrative health databases. Cox proportional hazards regression was used to estimate the effect of centralized, physician-targeted audit and feedback on colonoscopy uptake in an Ontario-wide fobt-positive cohort. RESULTS: A mailed physician audit and feedback report identifying individuals outstanding for colonoscopy for 3 or more months after a positive fobt result did not increase the likelihood of colonoscopy uptake (hazard ratio: 0.95; 95% confidence interval: 0.79 to 1.13). Duration of positive fobt status was strongly inversely associated with the hazard of follow-up colonoscopy (p for linear trend: <0.001). CONCLUSIONS: In a large population-wide setting, centralized tracking in the form of physician-targeted mailed audit and feedback reports does not improve colonoscopy uptake for screening participants with a positive fobt result outstanding for 3 or more months. Mailed physician-targeted screening audit and feedback reports alone are unlikely to improve compliance with follow-up colonoscopy in Ontario. Other interventions such as physician audits or automatic referrals, demonstrated to be effective in other jurisdictions, might be warranted.

Annual surveillance mammography after early-stage breast cancer and breast cancer mortality.

BACKGROUND: After treatment for early-stage breast cancer (bca), annual surveillance mammography (asm) is recommended based on the assumption that early detection of an invasive ipsilateral breast tumour recurrence or subsequent invasive contralateral primary bca reduces bca mortality. METHODS: We studied women with unilateral early-stage bca treated by breast-conserving surgery from 1994 to 1997 who subsequently developed an ipsilateral recurrence or contralateral primary more than 24 months after initial diagnosis, without prior regional or distant metastases. Annual surveillance mammography was defined as 2 episodes of bilateral mammography 11-18 months apart during the 2 years preceding the ipsilateral recurrence or contralateral primary. The association between asm and bca death was evaluated using a Cox proportional hazards model. RESULTS: We identified 669 women who experienced invasive ipsilateral recurrence (n = 455) or a contralateral primary (n = 214) at a median interval of 53 months [interquartile range (iqr): 37-72 months] after initial diagnosis, 64.7% of whom had received asm during the preceding 2 years. The median interval between the 2 bilateral mammograms was 12.3 months (iqr: 11.9-13.0 months), and the median interval between the 2nd mammogram and histopathologic confirmation of ipsilateral recurrence or contralateral primary was 1.5 months (iqr: 0.8-3.9 months). Median followup after ipsilateral recurrence or contralateral primary was 7.76 years (iqr: 3.68-9.81 years). The adjusted hazard ratio for bca death associated with asm was 0.86 (95% confidence limits: 0.63, 1.16). CONCLUSIONS: Annual surveillance mammography was associated with a modestly lowered hazard ratio for bca death.

Predictors of adjuvant treatment for pancreatic adenocarcinoma at the population level.

BACKGROUND: In the present study, we aimed to describe, at the population level, patterns of adjuvant treatment use after curative-intent resection for pancreatic adenocarcinoma (pcc) and to identify independent predictors of adjuvant treatment use. METHODS: In this observational cohort study, patients undergoing pcc resection in the province of Ontario (population 13 million) during 2005-2010 were identified using the provincial cancer registry and were linked to administrative databases that include all treatments received and outcomes experienced in the province. Patients were defined as having received chemotherapy (ctx), chemoradiation (crt), or observation (obs). Clinicopathologic factors associated with the use of ctx, crt, or obs were identified by chi-square test. Logistic regression analyses were used to identify independent predictors of adjuvant treatment versus obs, and ctx versus crt. RESULTS: Of the 397 patients included, 75.3% received adjuvant treatment (27.2% crt, 48.1% ctx) and 24.7% received obs. Within a single-payer health care system with universal coverage of costs for ctx and crt, substantial variation by geographic region was observed. Although the likelihood of receiving adjuvant treatment increased from 2005 to 2010 (p = 0.002), multivariate analysis revealed widespread variation between the treating hospitals (p = 0.001), and even between high-volume hepatopancreatobiliary hospitals (p = 0.0006). Younger age, positive lymph nodes, and positive surgical resection margins predicted an increased likelihood of receiving adjuvant treatment. Among patients receiving adjuvant treatment, positive margins and a low comorbidity burden were associated with crt compared with ctx. CONCLUSIONS: Interinstitutional medical practice variation contributes significantly to differential patterns in the rate of adjuvant treatment for pcc. Whether such variation is warranted or unwarranted requires further investigation.

Age at diagnosis predicts local recurrence in women treated with breast-conserving surgery and postoperative radiation therapy for ductal carcinoma in situ: a population-based outcomes analysis.

PURPOSE: The main goal of treating ductal carcinoma in situ (dcis) is to prevent the development of invasive breast cancer. Most women are treated with breast-conserving surgery (bcs) and radiotherapy. Age at diagnosis may be a risk factor for recurrence, leading to concerns that additional treatment may be necessary for younger women. We report a population-based study of women with dcis treated with bcs and radiotherapy and an evaluation of the effect of age on local recurrence (lr). METHODS: All women diagnosed with dcis in Ontario from 1994 to 2003 were identified. Treatments and outcomes were collected through administrative databases and validated by chart review. Women treated with bcs and radiotherapy were included. Survival analyses were performed to evaluate the effect of age on outcomes. RESULTS: We identified 5752 cases of dcis; 1607 women received bcs and radiotherapy. The median follow-up was 10.0 years. The 10-year cumulative lr rate was 27% for women younger than 45 years, 14% for women 45-50 years, and 11% for women more than 50 years of age (p < 0.0001). The 10-year cumulative invasive lr rate was 22% for women younger than 45 years, 10% for women 45-50 years, and 7% for women more than 50 years of age (p < 0.0001). On multivariate analyses, young age (<45 years) was significantly associated with lr and invasive lr [hazard ratio (hr) for lr: 2.6; 95% confidence interval (ci): 1.9 to 3.7; p < 0.0001; hr for invasive lr: 3.0; 95% ci: 2.0 to 4.4; p < 0.0001]. An age of 45-50 years was also significantly associated with invasive lr (hr: 1.6; 95% ci: 1.0 to 2.4; p = 0.04). CONCLUSIONS: Age at diagnosis is a strong predictor of lr in women with dcis after treatment with bcs and radiotherapy.

HER2/neu and Ki-67 expression predict non-invasive recurrence following breast-conserving therapy for ductal carcinoma in situ.

BACKGROUND: Ductal carcinoma in situ (DCIS) is a non-invasive form of breast cancer that may progress to invasive cancer. Identification of factors that predict recurrence and distinguish DCIS from invasive recurrence would facilitate treatment recommendations. We examined the prognostic value of nine molecular markers on the risks of local recurrence (DCIS and invasive) among women treated with breast-conserving therapy. METHODS: A total of 213 women who were treated with breast-conserving therapy between 1982 and 2000 were included; 141 received breast-conserving surgery alone and 72 cases received radiotherapy. We performed immunohistochemical staining on the DCIS specimen for nine markers: oestrogen receptor, progesterone receptor, Ki-67, p53, p21, cyclinD1, HER2/neu, calgranulin and psoriasin. We performed univariable and multivariable survival analyses to identify markers associated with the recurrence. RESULTS: The rate of recurrence at 10 years was 36% for patients treated with breast-conserving surgery alone and 18% for women who received breast-conserving surgery and radiotherapy. HER2/neu+/Ki-67+ expression was associated with an increased risk of DCIS recurrence, independent of grade and age (HR=3.22; 95% CI: 1.47-7.03; P=0.003). None of the nine markers were predictive of invasive recurrence. CONCLUSION: Women with a HER2/neu/neu+/Ki67+ DCIS have a higher risk of developing DCIS local recurrence after breast-conserving surgery.

Trends and Correlates of Mean Lung Dose in Patients Receiving Breast Radiotherapy in a Single Institution from 2014 to 2018.

AIMS: Higher mean lung dose (MLD) in breast cancer patients has been associated with pneumonitis, pulmonary fibrosis and secondary lung cancer primaries. This study examined MLD in a single institution from 2014 to 18 to assess trends in median MLD (Gy) over time and factors associated with higher MLD to determine best practices for limiting lung toxicity. MATERIALS AND METHODS: General linear regressions were analysed to determine significant change in median MLD over time in patients receiving conventional or hypofractionated schedules for whole breast/chest wall (WB) radiotherapy with or without sequential boost or simultaneous integrated boost, WB tangential radiotherapy only and WB locoregional radiotherapy. Univariate and multivariable linear regression analysed identified factors associated with MLD. RESULTS: In total, 3894 patients were included in the analysis. The total median MLD across all years was 6.8 Gy in patients treated with conventional fractionation and 3.4 Gy in patients treated with hypofractionation. A significant increase in MLD was observed between 2014 and 2018 in patients receiving conventional or hypofractionation, conventional WB treatment with locoregional radiotherapy, conventional WB radiotherapy with simultaneous integrated boost and hypofractionated WB radiotherapy with sequential boost. Increased MLD was significantly correlated with lower lung volume and larger treatment volume due to locoregional radiotherapy, inclusion of a boost, chest wall treatment and reverse decubitus or supine positioning (P < 0.0001). CONCLUSION: A significant increase in MLD was observed over the years in patients receiving conventional and hypofractionated radiotherapy. Techniques such as prone positioning should be considered to lower MLD, particularly for patients with predisposing pulmonary risk.

Variability in radiation oncologists' opinion on the indication of a bolus in post-mastectomy radiotherapy: an international survey.

AIMS: Post-mastectomy radiotherapy (PMRT) decreases locoregional recurrence and increases survival for women with large tumours and/or node-positive disease. The American Society of Clinical Oncology has published treatment guidelines, but has also indicated that the optimal technique for PMRT remains unknown. The objective of this study was to evaluate the variability in which a bolus is currently used in PMRT and to identify the clinical situations in which a bolus is used. MATERIALS AND METHODS: In 2004, an e-mail survey was sent to all active physician members of the American Society for Therapeutic Radiology and Oncology, the Canadian Association of Radiation Oncologists and the European Society for Therapeutic Radiology and Oncology. The survey focused on the technical details regarding the use of a bolus in PMRT. RESULTS: In total, 1035 responses were obtained: 642 from the Americas (568 from the USA), 327 from Europe and 66 from Australasia. Respondents from the Americas were significantly more likely to always use a bolus (82%) than the Europeans (31%), as were the Australasians (65%) (P < 0.0001). Europeans were significantly more likely to use a bolus for specific indications (P < 0.0001). The results also showed wide variation in the schedule of application (every day [33%] and alternate days [46%]) and thickness used (< 1 cm [35%] and > or = 1 cm [48%]). CONCLUSIONS: There is a wide variation in the use of a bolus in PMRT with significant regional differences. This probably translates into a variation in the dose delivered to the skin and may have an effect on local recurrence and/or toxicity. A randomised clinical trial is needed to evaluate the benefit and toxicity associated with the use of a bolus in PMRT.

Prevalence of screening in patients newly diagnosed with colorectal cancer in Ontario.

OBJECTIVES: The primary objective was to determine the proportion of individuals with a new diagnosis of colorectal cancer (CRC) in Ontario in whom the cancer was screen detected. The secondary objectives were to determine the cancer stage at diagnosis and the indications for the procedure in patients who received their first colonoscopy. PATIENTS AND METHODS: Individuals admitted to a hospital with a new diagnosis of CRC were randomly selected after stratifying by hospital type (teaching or community). The Canadian Institute for Health Information's Discharge Abstract Database was used to identify individuals with a first diagnosis of CRC during calendar year (CY) 2000, and Ontario Health Insurance Plan data were used to identify people 50 to 74 years of age who had their first colonoscopy during CY 2000. Up to 20 individuals were selected for each group (CRC or colonoscopy) in each of seven randomly selected community hospitals and three randomly selected teaching hospitals. Data were abstracted from the hospital charts. RESULTS: The hospital charts of 152 patients with a new diagnosis of CRC were examined. Of the 133 patients in whom screening status could be determined, eight had screen-detected cancers (6.0%). Of the 99 patients (65% of the sample) in whom stage could be determined, 43 (43.4%) had advanced disease (tumour-node-metastasis stage III or IV) at diagnosis. The hospital charts of 184 patients who underwent their first colonoscopy were examined. Of the 175 patients in whom the indication for colonoscopy could be determined, 45 underwent the procedure for screening purposes, 10 were for diagnostic workup of anemia and 120 for evaluation of symptoms. CONCLUSIONS: The low proportion (6%) of screen-detected CRC and the high proportion of patients (43.4%) with advanced disease at diagnosis reflect the lack of an organized screening program.

A tale of two time periods: ovarian cancer trends in Ontario.

We assessed population-based trends in incidence and survival rates for epithelial ovarian cancer in Ontario in two time periods. Our population-based study cohort included all women with epithelial ovarian cancer treated initially with abdominal surgery in Ontario for January 1996 through December 2001. Incident surgical cases were documented by hospital contact data and the Ontario Cancer Registry. Patient characteristics (age, for example) were obtained from electronic administrative data records. Regression analyses were used to assess the influence of time period on survival while controlling for age, comorbidity, and other factors associated with this outcome.A total of 3825 women met the inclusion criteria. We found that the age-standardized incidence of ovarian cancer remained stable during 1996-2001. A shift to a younger age at diagnosis was found between the two time periods being compared. The univariate analysis revealed a clear difference in death rate, to which age at diagnosis, Charlson comorbidity score, and treatment period contributed. Earlier time period (p < 0.0001), advancing age (p < 0.0001), higher Charlson score (p < 0.0001), and lower income quartile score (p = 0.03) were significantly associated with poorer survival in the univariate analysis. Younger age, lower Charlson score, and more recent time period of diagnosis and treatment (p < 0.0001) were associated with improved survival in the proportional hazards model.We conclude that age-standardized incidence and mortality rates for ovarian cancer in Ontario have remained stable. For women initially treated with surgery, advances in management have led to an improvement in survival.

Multistate transitional models for measuring adherence to breast cancer screening: A population-based longitudinal cohort study with over two million women.

Objective Prior work on the disparities among women in breast cancer screening adherence has been methodologically limited. This longitudinal study determines and examines the factors associated with becoming adherent. Methods In a cohort of Canadian women aged 50-74, a three-state transitional model was used to examine adherence to screening for breast cancer. The proportion of time spent being non-adherent with screening was calculated for each woman during her observation window. Using age as the time scale, a relative rate multivariable regression was implemented under the three-state transitional model, to examine the association between covariates (all time-varying) and the rate of becoming adherent. Results The cohort consisted of 2,537,960 women with a median follow-up of 8.46 years. Nearly 31% of women were continually up-to-date with breast screening. Once a woman was non-adherent, the rate of becoming adherent was higher among longer term residents (relative rate = 1.289, 95% confidence interval 1.275-1.302), those from wealthier neighbourhoods, and those who had an identifiable primary care provider who was female or had graduated in Canada. Conclusion Individual and physician-level characteristics play an important role in a woman's adherence to screening. This work improves the quality of evidence regarding disparities among women in adherence to breast cancer screening and provides a novel methodological foundation to investigate adherence for other types of screening, including cervix and colorectal cancer screening.

Prognostic factors for women with Stage 1 ovarian cancer with or without adhesions.

OBJECTIVE: To identify those prognostic factors in women with Stage 1 epithelial ovarian cancer that predict survival. METHODS: A population-based cohort study was conducted which included all newly diagnosed ovarian cancer patients treated initially with surgery from 1996-1998 in Ontario, Canada (N = 1,341). We abstracted charts from hospitals and cancer centres and used hospital and billing claims databases. Cox survival analysis was used to model the association between prognostic factors (including patient characteristics, surgical findings, pathologic findings and subsequent treatment) and survival for those with Stage 1 ovarian cancer. RESULTS: 327 women had Stage 1 or 2 ovarian cancer (where Stage 2 was based on adhesions alone). Prognostic factors that had significant, unadjusted, association with survival were patient age, presence or absence of adhesions, grade, and surface involvement. The multivariable model that best described survival included premenopausal age group (HR 0.32, 95% CI, 0.18-0.55), poor differentiation (HR 2.17, 95% CI, 1.33-3.51), and surface capsule involvement (HR 2.97, 95% CI, 1.59-5.55). A lack of influence of treatment modality stands in contrast to the literature. CONCLUSIONS: Our dataset confirmed that poor grade and surface capsule involvement are poor prognostic factors. Adjuvant therapy did not confer an improved outcome; however, it was likely used in only those patients with poor prognostic indicators and so improved their survival to that of women with good prognostic factors who received surgery alone.

The association between visiting a primary care provider and uptake of periodic mammograms as women get older.

OBJECTIVE: To determine whether visits to a primary care provider (PCP) are associated with the uptake of periodic mammograms as women get older. METHODS: The cohort consisted of 2,389,889 women resident in Ontario, Canada, aged 50 to 79 at any point from 2001 to 2010, who were cancer-free and eligible for the Ontario Health Insurance Plan prior to study entry. Non-parametric estimation was used to describe the mean cumulative number of periodic mammograms for women with and without recent exposure to a PCP, as a function of age. Using age as the time scale, a recurrent event regression model was also implemented to examine the association between exposure to a PCP and rate of periodic mammograms, adjusted for income quintile and comorbidity. RESULTS: The mean observation window was 7.0 years. Uptake of periodic mammograms was significantly higher for women with recent exposure to a PCP compared with those without. This trend remained consistent as women aged, and the magnitude of the association increased for women aged 65 or older. The relative rate of periodic mammograms was lower than 1 and consistently decreased as women from lower income quintiles were compared with women from the wealthiest quintile. CONCLUSION: Visits to a PCP play an important role in uptake of periodic mammograms, and this association increases as women age.

Socioeconomic status and cancer survival in Ontario.

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Although Canada'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.

Mortality from myocardial infarction after adjuvant radiotherapy for breast cancer in the surveillance, epidemiology, and end-results cancer registries.

PURPOSE: To compare the risk for fatal myocardial infarction (MI) after adjuvant radiotherapy (RT) for left-sided breast cancer with the risk for MI after adjuvant RT for right-sided breast cancer. METHODS: We studied women with local- and regional-stage breast cancer diagnosed from 1973 to 1992 from the Surveillance, Epidemiology, and End-Results (SEER) cancer registries. We performed life-table analysis, the log-rank test, and Cox proportional hazards regression to compare the time to fatal MI from diagnosis between left-sided and right-sided cases, censoring deaths from other causes. RESULTS: Among irradiated patients, the relative risk (RR) for fatal MI in women with left-sided breast cancer was 1.17 (95% confidence interval [CI], 1.01 to 1.36), controlling for age, compared with those with right-sided breast cancer. The RR for fatal MI among left-sided cases was increased for those under the age of 60 years (RR = 1.98; 95% CI, 1.31 to 2.97) compared with right-sided cases, but not at age 60 years or older. Among women with irradiated regional-stage cancer who were younger than 60 years of age, the risk was significantly increased (RR = 2.24; 95% CI, 1.38 to 3.64) for those with left-sided compared with right-sided breast cancer, but not among patients aged 60 years or older. Among irradiated local-stage cases, the risk for those with left-sided breast cancer was not significantly elevated in either age category. Analysis of 5-year conditional survival cohorts showed an increased risk for irradiated left-sided cases among women younger than 60 years of age in the 10- to 15-year conditional survival cohort (RR = 5.28; 95% CI, 1.82 to 15.3). CONCLUSION: Adjuvant RT for left-sided breast cancer diagnosed in women younger than 60 years of age is associated with a higher risk for fatal MI 10 to 15 years later compared with adjuvant RT for right-sided cases.

Does a centralized radiotherapy system provide adequate access to care?

PURPOSE: In the Canadian province of Ontario, all radiotherapy is provided by a centrally managed provincial network of nine cancer centers. The primary goal of this study was to determine whether this highly centralized radiotherapy system provides adequate and equitable access to care for the province's dispersed population. METHODS: The Ontario Cancer Registry (OCR) was used to identify 295,386 cases of invasive cancer, excluding nonmelanoma skin cancer, which were diagnosed in Ontario between 1984 and 1991. Electronic radiotherapy records from each of the province's radiotherapy centers were linked to the registry at the level of the individual case. RESULTS: The proportion of incident cases treated with radiotherapy was 18.8% at 4 months after diagnosis, 23.7% at 1 year, 25.8% at 2 years, 28.2% at 5 years, and 29.1% at 8 years. These rates of radiotherapy use are much lower than the accepted national and international targets, and lower than rates reported from other jurisdictions. The rate of radiotherapy use at 1 year varied significantly from county to county across Ontario (range, 18.6% to 32.4%; P < 10(-6)), and the highest rates were recorded in communities close to radiotherapy centers. There was a common geographic pattern of rate variations among several disease groups, including breast cancer, lung cancer, the genitourinary malignancies, and the gastrointestinal malignancies. CONCLUSION: The low and uneven rates of radiotherapy use across the province indicate that Ontario's centralized radiotherapy system does not, at present, provide adequate or equitable access to care.

A population-based study of the effectiveness of breast conservation for newly diagnosed breast cancer.

PURPOSE: Our objective was to evaluate the effectiveness of breast conservation for newly diagnosed breast cancer. Effectiveness was operationalized as two outcomes within 5 years of the diagnosis of breast cancer: the probability of mastectomy-free survival (either death or mastectomy count as event, whichever comes first), and the probability of mastectomy conditional on survival (mastectomy counts as event, observations censored at death). METHODS AND MATERIALS: We linked records of 46,687 new cases of breast cancer from 1982 to 1991 in the Ontario Cancer Registry to records of surgery from 1982 to 1995, radiotherapy (RT) from 1982 to 1992, and median household income from the 1986 census. We labeled breast surgery within 4 months and postoperative RT within 12 months of diagnosis as treatment for newly diagnosed breast cancer. Surgery was categorized as mastectomy, lumpectomy plus RT, lumpectomy alone, or no surgical procedure. Among cases that did not undergo mastectomy within 4 months of diagnosis, we labeled mastectomy subsequent to 4 months after diagnosis as treatment failure. We performed life-table analysis and Cox proportional hazards regression, to describe the probability of mastectomy conditional on survival and the probability of mastectomy-free survival. RESULTS: A total of 16,279 cases underwent lumpectomy as the maximum procedure on the breast within 4 months of diagnosis, and 49.7% of these received postoperative RT. Compared to the provincial mean, regions with higher rates of lumpectomy plus RT have higher probability of mastectomy-free survival and lower probability of mastectomy conditional upon survival 5 years after diagnosis of breast cancer. CONCLUSIONS: These findings are consistent with a hypothesis that breast conservation is effective in the overall breast cancer population of Ontario within the first 5 years after diagnosis.

A population-based study of rectal cancer: permanent colostomy as an outcome.

PURPOSE: The objectives of this study are to describe the utilization of surgery and of radiotherapy in the treatment of newly diagnosed rectal cancer in Ontario between 1982 and 1994, and to describe the probability of permanent colostomy at any time after the diagnosis of rectal cancer, as an outcome of the treatment of newly diagnosed rectal cancer. METHODS AND MATERIALS: Electronic records of rectal cancer (International Classification of Diseases code 154) from the Ontario Cancer Registry (n = 18,695, excluding squamous, basaloid, cloacogenic, and carcinoid histology) were linked to surgical records from all Ontario hospitals, and radiotherapy (RT) records from Ontario cancer centers. Procedures occurring within 4 months of diagnosis, or within 4 months of another procedure for rectal cancer, were considered part of initial treatment. Multivariate analyses controlled for age, sex, and year of diagnosis. RESULTS: Resection plus permanent colostomy was performed in 33.1% of cases, whereas local excision or resection without permanent colostomy was performed in 38.2%. Multivariate logistic regression demonstrated higher odds ratios (OR) for resection plus permanent colostomy in all regions of Ontario relative to Toronto. The OR for postoperative RT following local excision or resection without permanent colostomy varied among the regions relative to Toronto (e.g., OR Ottawa = 0.59, OR Hamilton = 0.76, OR London = 1.25). The relative risk (RR) of colostomy conditional upon survival within 5 years from diagnosis varied among regions relative to Toronto (e.g., RR Ottawa = 1.21, RR Hamilton = 1.20). CONCLUSIONS: There is regional variation in the utilization of resection with permanent colostomy, and in the utilization of postoperative RT among cases not undergoing permanent colostomy. Regions with higher initial rates of resection plus permanent colostomy continue to experience higher probability of permanent colostomy 5 years after diagnosis of rectal cancer. Higher initial rates of permanent colostomy may be malleable to interventions aimed at improving overall outcomes.