Projected estimates of cancer in Canada in 2024.

BACKGROUND: Cancer surveillance data are essential to help understand where gaps exist and progress is being made in cancer control. We sought to summarize the expected impact of cancer in Canada in 2024, with projections of new cancer cases and deaths from cancer by sex and province or territory for all ages combined. METHODS: We obtained data on new cancer cases (i.e., incidence, 1984-2019) and deaths from cancer (i.e., mortality, 1984-2020) from the Canadian Cancer Registry and Canadian Vital Statistics Death Database, respectively. We projected cancer incidence and mortality counts and rates to 2024 for 23 types of cancer, overall, by sex, and by province or territory. We calculated age-standardized rates using data from the 2011 Canadian standard population. RESULTS: In 2024, the number of new cancer cases and deaths from cancer are expected to reach 247 100 and 88 100, respectively. The age-standardized incidence rate (ASIR) and mortality rate (ASMR) are projected to decrease slightly from previous years for both males and females, with higher rates among males (ASIR 562.2 per 100 000 and ASMR 209.6 per 100 000 among males; ASIR 495.9 per 100 000 and ASMR 152.8 per 100 000 among females). The ASIRs and ASMRs of several common cancers are projected to continue to decrease (i.e., lung, colorectal, and prostate cancer), while those of several others are projected to increase (i.e., liver and intrahepatic bile duct cancer, kidney cancer, melanoma, and non-Hodgkin lymphoma). INTERPRETATION: Although the overall incidence of cancer and associated mortality are declining, new cases and deaths in Canada are expected to increase in 2024, largely because of the growing and aging population. Efforts in prevention, screening, and treatment have reduced the impact of some cancers, but these short-term projections highlight the potential effect of cancer on people and health care systems in Canada.

Incidence of Breast Cancer in Younger Women: A Canadian Trend Analysis.

Purpose: Breast cancer (BC) incidence is increasing globally. Age-specific BC incidence trend analyses are lacking for women under age 50 in Canada. In this study, we evaluate the incidence trends in breast cancer in women under age 50 in Canada and compare them with corresponding trends among women 50 to 54. Methods: BC case counts were obtained from the National Cancer Incidence Reporting System (1984-1991) and the Canadian Cancer Registry (1992-2019) both housed at Statistics Canada. Population data were also obtained from Statistics Canada. Annual female BC age-specific incidence rates from 1984 to 2019 were derived for the following age groups: 20 to 29, 30 to 39, 40 to 49, 40 to 44, 45 to 49, and 50 to 54. Changes in trends in age-specific BC incidence rates, if any, and annual percent changes (APCs) for each identified trend, were determined using JoinPoint. Results: Statistically significant increasing trends in BC incidence rates were noted for almost all age groups: since 2001 for 20 to 29 (APC = 3.06%, P < .001); since 2009 for 30 to 39 (APC = 1.25%, P = .007); since 1984 for both 40 to 49 (APC = 0.26%, P < .001) and 40 to 44 (APC = 0.19%, P = .011), increased since 2015 for 40 to 49 (APC = 0.77%, P = .047); and since 2005 for 50 to 54 (APC = 0.38%, P = .022). Among women 45 to 49 there was a non-significant increase since 2005 (APC = 0.24, P = .058). Statistically significant average annualized increases in BC incidence rates were observed for each age group studied. Conclusions: Examining age-specific incidence rates formed a more complete picture of BC time trends with significant increasing trends in the incidence of BC among women in their 20s, 30s, 40s, and early 50s. A greater awareness regarding the increasing number of cases of BC in women younger than 50 is critical to allow for earlier diagnosis with its resultant reduced mortality and morbidity.

Progress in site-specific cancer mortality in Canada over the last 70 years.

In Canada, the absolute number of cancer deaths has been steadily increasing, however, age-standardized cancer mortality rates peaked decades ago for most cancers. The objective of this study was to estimate the reduction in deaths for each cancer type under the scenario where peak mortality rates had remained stable in Canada. Data for this study were obtained the Global Cancer Observatory and Statistics Canada. We estimated age-standardized mortality rates (ASMR, per 100,000) from 1950 to 2022, standardized to the 2011 Canadian standard population. We identified peak mortality rates and applied the age-specific mortality rates from the peak year to the age-specific Canadian population estimates for subsequent years (up to 2022) to estimate the number of expected deaths. Avoided cancer deaths were the difference between the observed and expected number of cancer deaths. There have been major reductions in deaths among cancers related to tobacco consumption and other modifiable lifestyle habits (417,561 stomach; 218,244 colorectal; 186,553 lung; 66,281 cervix; 32,732 head and neck; 27,713 bladder; 22,464 leukemia; 20,428 pancreas; 8863 kidney; 3876 esophagus; 290 liver). There have been 201,979 deaths avoided for female-specific cancers (breast, cervix, ovary, uterus). Overall, there has been a 34% reduction in mortality for lung cancer among males and a 9% reduction among females. There has been a significant reduction in cancer mortality in Canada since site-specific cancer mortality rates peaked decades ago for many cancers. This shows the exceptional progress made in cancer control in Canada due to substantial improvements in prevention, screening, and treatment. This study highlights priority areas where more attention and investment are needed to achieve progress.

Progress in cancer control leads to a substantial number of cancer deaths avoided in Canada.

It is currently not known how many more cancer deaths would have occurred among Canadians if cancer mortality rates were unchanged following various modern human interventions. The objective of this study was to estimate the number of cancer deaths that have been avoided in Canada since the age-standardized overall cancer mortality rate peaked in 1988. We applied the age-specific overall cancer mortality rates from 1988 to the Canadian population for all subsequent years to estimate the number of expected deaths. Avoided cancer deaths were estimated as the difference between the observed and expected number of cancer deaths for each year. Since 1988, there have been 372 584 (standardized mortality ratio = 0.77) and 120 045 (standardized mortality ratio = 0.90) avoided cancer deaths in males and females, respectively (492 629 total). Nearly half a million cancer deaths have been avoided in Canada since the overall cancer mortality rate peaked, which demonstrates the exceptional progress made in modern cancer control in Canada.

Impact of Breast Cancer Screening on 10-Year Net Survival in Canadian Women Age 40-49 Years.

PURPOSE: In Canada, some provincial/territorial mammography screening programs include women age 40-49 years, whereas others do not. This study examines the impact of this dichotomy on the 10-year breast cancer (BC) net survival (NS) among women age 40-49 years and 50-59 years at diagnosis. METHODS: Using the Canadian Cancer Registry data record linked to death information, we evaluated the cohort of Canadian women age 40-49 years and 50-59 years diagnosed with BC from 2002 to 2007. We compared 10-year NS estimates in the jurisdictions with organized screening programs that included women age 40-49 years, designated as screeners (Northwest Territories, British Columbia, Alberta, Nova Scotia, and Prince Edward Island), with comparator programs that did not (Yukon, Manitoba, Saskatchewan, Ontario, Quebec, New Brunswick, and Newfoundland and Labrador). RESULTS: BC was the primary cause of 10-year mortality in women age 40-49 years diagnosed with BC (90.7% of deaths). Among these women, the 10-year NS for screeners (84.8%; 95% CI, 83.8 to 85.8) was 1.9 percentage points (pp) higher than that for comparators (82.9%; 95% CI, 82.3 to 83.5; P = .001). The difference in favor of screeners was significant among women age 45-49 years (2.6 pp; P = .001) but not among women age 40-44 years (0.9 pp; P = .328). Similarly, the incidence-based BC mortality rate was significantly lower in screener jurisdictions among women age 40-49 years and 45-49 years, but not for 40-44 years. Provincial/territorial NS increased significantly with higher mammography screening participation (P = .003). The BC incidence rate was virtually identical in screener and comparator jurisdictions among women age 40-49 years (P = .976) but was significantly higher for comparators among women age 50-59 years (P < .001). CONCLUSION: Screening programs that included women in their 40s were associated with a significantly higher BC 10-year NS in women age 40-49 years, but not an increased rate of BC diagnosis. These results may inform screening guidelines for women age 40-49 years.

Five-year cancer survival by stage at diagnosis in Canada.

Background: Cancer survival estimates provide insights into the effectiveness of early detection and treatment. The stage of cancer at diagnosis is an important determinant of survival, reflecting the extent and spread at the time of disease detection. This work provides stage-specific, five-year survival results not previously available for Canada. Data and methods: Data reflect the population-based Canadian Cancer Registry death-linked analytic file covering the period from 2010 to 2017. The stage at diagnosis was determined by the Collaborative Stage Data Collection System. Five-year net survival (NS) estimates for Canada excluding Quebec were derived using the Pohar Perme estimator for the five most commonly diagnosed cancers. Results: Except for prostate cancer, NS decreased monotonically with increased stage at diagnosis. For example, female breast cancer NS estimates were 100% (stage I), 92% (stage II), 74% (stage III) and 23% (stage IV). Apart from lung cancer, stage I NS exceeded 90% for all cancers studied. The largest sex-specific difference in NS was for lung cancer stage I (female 66%; male 56%). Stage-specific NS generally decreased with age, particularly for early-stage lung cancer. Between the 2010-to-2012 and 2015-to-2017 periods, NS improved among stage IV prostate, female breast and lung cancer cases, as well as for stage I and III lung cancer cases; however, it did not improve at any stage for colon or rectal cancer cases. Interpretation: The work highlights the importance of detecting cancer early, when treatment is most effective. It demonstrates some progress in stage-specific survival among top cancers in Canada and offers data to inform health policy, including screening, and clinical decisions regarding cancer treatment.

Are "immortals" an issue for survival estimates derived from Canadian Cancer Registry data?

Background: The validity of survival estimates from cancer registry data depends, in part, on the identification of the deaths of deceased cancer patients. People whose deaths are missed seemingly live on forever and are informally referred to as "immortals." Their presence in registry data can result in inflated survival estimates. This study assesses the issue of immortals in the Canadian Cancer Registry (CCR) using a recently proposed method that compares the survival of long-term survivors of cancers for which "statistical" cure has been reported with that of similar people from the general population. Data and methods: Data are from the population-based CCR record linked to the Canadian Vital Statistics - Death Database and tax data. Yearly interval-specific relative survival (IRS) estimates were derived up to 15 years after diagnosis for colon cancer cases, and for colon, rectal and melanoma cancer cases combined, diagnosed from 1992 to 2002. Results: With increasing follow-up time since diagnosis, national colon cancer IRS estimates levelled off at 1.00, or slightly less, for each age group studied, indicating that survival did not exceed that of the general population. Similar results were obtained among males and females, and for colon, rectal and melanoma cancer cases combined. Provincial IRS point estimates for the three cancers combined also levelled off around 1.00, though with more variation in the estimates than at the national level. Interpretation: Based on the results of this study, immortals do not appear to be an issue at either the national or the provincial level for survival estimates derived from CCR data.

The Impact of Organised Screening Programs on Breast Cancer Stage at Diagnosis for Canadian Women Aged 40-49 and 50-59.

The relationship between Canadian mammography screening practices for women 40−49 and breast cancer (BC) stage at diagnosis in women 40−49 and 50−59 years was assessed using data from the Canadian Cancer Registry, provincial/territorial screening practices, and screening information from the Canadian Community Health Survey. For the 2010 to 2017 period, women aged 40−49 were diagnosed with lesser relative proportions of stage I BC (35.7 vs. 45.3%; p < 0.001), but greater proportions of stage II (42.6 vs. 36.7%, p < 0.001) and III (17.3 vs. 13.1%, p < 0.001) compared to women 50−59. Stage IV was lower among women 40−49 than 50−59 (4.4% vs. 4.8%, p = 0.005). Jurisdictions with organised screening programs for women 40−49 with annual recall (screeners) were compared with those without (comparators). Women aged 40−49 in comparator jurisdictions had higher proportions of stages II (43.7% vs. 40.7%, p < 0.001), III (18.3% vs. 15.6%, p < 0.001) and IV (4.6% vs. 3.9%, p = 0.001) compared to their peers in screener jurisdictions. Based on screening practices for women aged 40−49, women aged 50−59 had higher proportions of stages II (37.2% vs. 36.0%, p = 0.003) and III (13.6% vs. 12.3%, p < 0.001) in the comparator versus screener groups. The results of this study can be used to reassess the optimum lower age for BC screening in Canada.

Measuring progress in cancer survival across Canadian provinces: Extending the cancer survival index to further evaluate cancer control efforts.

Background: A comprehensive evaluation of progress in cancer survival for all cancer types combined in Canada has recently been accomplished. An analogous evaluation across Canadian provinces has yet to be conducted. Data and methods: Data from 1992 to 2017 are from the population-based Canadian Cancer Registry death-linked analytic file. Provincial cancer survival index (CSI) estimates were calculated as the weighted sum of the sex- and cancer-specific age-standardized provincial net survival estimates. Provincial sex-specific CSI estimates were calculated separately using sex-specific cancer type weights. Data availability (Quebec) and sufficiency (Prince Edward Island and the territories) issues precluded CSI calculations for all jurisdictions. Results: For the most recent period, 2013 to 2017, the five-year CSI was highest in Ontario (64.1%) and Alberta (63.3%), and lowest in Nova Scotia (60.8%). Significant progress in the five-year CSI since the period from 1992 to 1996 was observed in each province; the largest increases occurred in Alberta (8.7 percentage points) and Ontario (8.6 percentage points). Alberta's increase improved its relative provincial ranking from eighth to second. The influence of prostate cancer on provincial changes in the CSI since the period from 2003 to 2007 varied considerably from strongly counterproductive in New Brunswick, Saskatchewan and Nova Scotia because of decreasing prostate cancer survival, to strongly productive in Manitoba. Interpretation: Significant progress has been made in five-year cancer survival for all cancers combined since the early 1990s in each Canadian province studied. However, the magnitude of the progress has not been uniform across the provinces, and the cancer and sex combinations that have most influenced it have varied by province and period.

Projected estimates of cancer in Canada in 2022.

BACKGROUND: Regular cancer surveillance is crucial for understanding where progress is being made and where more must be done. We sought to provide an overview of the expected burden of cancer in Canada in 2022. METHODS: We obtained data on new cancer incidence from the National Cancer Incidence Reporting System (1984-1991) and Canadian Cancer Registry (1992-2018). Mortality data (1984-2019) were obtained from the Canadian Vital Statistics - Death Database. We projected cancer incidence and mortality counts and rates to 2022 for 22 cancer types by sex and province or territory. Rates were age standardized to the 2011 Canadian standard population. RESULTS: An estimated 233 900 new cancer cases and 85 100 cancer deaths are expected in Canada in 2022. We expect the most commonly diagnosed cancers to be lung overall (30 000), breast in females (28 600) and prostate in males (24 600). We also expect lung cancer to be the leading cause of cancer death, accounting for 24.3% of all cancer deaths, followed by colorectal (11.0%), pancreatic (6.7%) and breast cancers (6.5%). Incidence and mortality rates are generally expected to be higher in the eastern provinces of Canada than the western provinces. INTERPRETATION: Although overall cancer rates are declining, the number of cases and deaths continues to climb, owing to population growth and the aging population. The projected high burden of lung cancer indicates a need for increased tobacco control and improvements in early detection and treatment. Success in breast and colorectal cancer screening and treatment likely account for the continued decline in their burden. The limited progress in early detection and new treatments for pancreatic cancer explains why it is expected to be the third leading cause of cancer death in Canada.

The cancer survival index: Measuring progress in cancer survival to help evaluate cancer control efforts in Canada.

BACKGROUND: A comprehensive evaluation of progress in cancer survival for all cancer types combined has not previously been conducted for Canada. The cancer survival index (CSI) is superior to age standardization in measuring such progress. DATA AND METHODS: Data are from the population-based Canadian Cancer Registry, record-linked to the Canadian Vital Statistics Death database. CSI estimates for both sexes combined were calculated as the weighted sum of the sex- and cancer-specific age-standardized net survival estimates. Sex-specific CSI estimates were calculated separately using sex-specific cancer type weights. RESULTS: From the 1992-to-1994 period to the 2015-to-2017 period, the five-year CSI increased 8.6 percentage points to 63.7%. It increased by 8.9 percentage points to 61.8% among males, and by 8.2 percentage points to 65.8% among females. The contribution of a cancer and sex combination to change in the CSI over time is a function of its assigned weight and changes in its age-standardized net survival. Female breast was the most influential cancer and sex combination, contributing 10.1% to the overall increase, followed by prostate (8.2%) and female lung (7.3%). The increase in the index since the 2005-to-2007 period was most impacted by lung cancer among both females (11.1%) and males (9.4%). While prostate cancer survival increased over the entire study period, it has recently decreased, resulting in a counterproductive 8.1% contribution since the 2005-to-2007 period. INTERPRETATION: Steady progress has been made in overall cancer survival in Canada since the early 1990s. Female breast cancer has contributed the most to this progress overall, but more recently female lung cancer has been the most influential.

Trends in paediatric cancer survival in Canada, 1992 to 2017.

BACKGROUND: While impressive gains in childhood cancer survival have been reported both in Canada and internationally, it has been almost 15 years since the last comprehensive evaluation of Canadian data. DATA AND METHODS: Data are from the population-based Canadian Cancer Registry, record-linked to the Canadian Vital Statistics Death database. Children aged 0 to 14 diagnosed with new primary malignant cancers from 1992 to 2017 in Canada except Quebec were included. Overall survival was measured using observed survival proportions (OSPs). Estimates for the 2013-to-2017 period were predicted using the period method; otherwise, the cohort method was used. RESULTS: For the 2013-to-2017 period, five-year OSPs were at least 90% for 10 of 24 individual cancer groups or subgroups reported. Survival was highest for thyroid carcinomas (100%) and Hodgkin lymphomas (99%) and lowest for other gliomas (42%). A significant increase in the five-year OSP from the 1992-to-1996 period (77%) to the 2013-to-2017 period (84%) was observed for all childhood cancers combined, but not since the 2003-to-2007 period. The greatest increase was for chronic myeloproliferative diseases (35.4 percentage points); for lymphoid leukemias, survival increased from 85% to 93%. Survival was relatively poor at baseline for hepatic tumours, malignant bone tumours, and soft tissue and other extraosseous sarcomas, and it remained virtually unchanged. Once children survived five years, the probability of surviving another five years exceeded 95% across most diagnoses. DISCUSSION: Significant improvements in both short- and long-term paediatric cancer survival have been made in Canada since the early to mid-1990s. These findings are clinically meaningful and are likely to be reassuring to families.

Projected estimates of cancer in Canada in 2020.

BACKGROUND: Cancer projections to the current year help in policy development, planning of programs and allocation of resources. We sought to provide an overview of the expected incidence and mortality of cancer in Canada in 2020 in follow-up to the Canadian Cancer Statistics 2019 report. METHODS: We obtained incidence data from the National Cancer Incidence Reporting System (1984-1991) and Canadian Cancer Registry (1992-2015). Mortality data (1984-2015) were obtained from the Canadian Vital Statistics - Death Database. All databases are maintained by Statistics Canada. Cancer incidence and mortality counts and age-standardized rates were projected to 2020 for 23 cancer types by sex and geographic region (provinces and territories) for all ages combined. RESULTS: An estimated 225 800 new cancer cases and 83 300 cancer deaths are expected in Canada in 2020. The most commonly diagnosed cancers are expected to be lung overall (29 800), breast in females (27 400) and prostate in males (23 300). Lung cancer is also expected to be the leading cause of cancer death, accounting for 25.5% of all cancer deaths, followed by colorectal (11.6%), pancreatic (6.4%) and breast (6.1%) cancers. Incidence and mortality rates will be generally higher in the eastern provinces than in the western provinces. INTERPRETATION: The number of cancer cases and deaths remains high in Canada and, owing to the growing and aging population, is expected to continue to increase. Although progress has been made in reducing deaths for most major cancers (breast, prostate and lung), there has been limited progress for pancreatic cancer, which is expected to be the third leading cause of cancer death in Canada in 2020. Additional efforts to improve uptake of existing programs, as well as to advance research, prevention, screening and treatment, are needed to address the cancer burden in Canada.

Changing trends in thyroid cancer incidence in Canada: A histologic examination, 1992 to 2016.

BACKGROUND: Age-standardized incidence rates (ASIRs) of thyroid cancer (TC) have increased in many parts of the world, primarily because of increased papillary TC detection. While rapid increases in TC incidence have also been reported in Canada, an analysis of incidence and survival by histologic subtype has been lacking. Moreover, recent data points in Canada suggest that the era of rapid annual increases may have ended. DATA AND METHODS: Data are from the Canadian Cancer Registry, the Canadian Vital Statistics-Death Database and an analytic file linking the two. Annual percent changes (APCs) in incidence and mortality rates are estimated using Joinpoint regression. Net survival (NS) is derived using the Pohar Perme estimator. RESULTS: Among females, TC ASIRs decreased by 3.0% annually from 2012 to 2016, following years of rapid growth. Among males, a long period of rapid increase ended in 2012 with no subsequent decline. For both sexes the overall incidence trend was driven by changes over time in papillary TC and incidence trends in non-papillary TC varied significantly. From 1992 to 2016, TC mortality rates were stable among females and increased slightly among males (APC = 1.2). Five-year NS was higher among papillary cases (99%) than among non-papillary cases (80%) and among females (99%) than among males (94%). Overall, five-year NS increased by 2.1 percentage points from the period from 1992 to 1996 to the period from 2010 to 2014. DISCUSSION: The results of this study confirm the central role of papillary TC cases in TC incidence and survival trends in Canada. Given recent changes in trend and TC management guidelines, projected increases in TC rates after 2016 could be re-examined.

Progress in net cancer survival in Canada over 20 years.

BACKGROUND: Monitoring the progress of cancer survival in a population over time is an important part of cancer surveillance. DATA AND METHODS: Data are from the Canadian Cancer Registry with mortality follow-up through record linkage to the Canadian Vital Statistics Death Database and tax files. Net survival (NS) was derived using the Pohar Perme method. Predicted estimates of NS for the period from 2012 to 2014 were calculated using the period method. Age-standardized and age-specific changes in five-year NS between the periods from 1992 to 1994 and 2012 to 2014 were determined for 30 individual cancers. RESULTS: Predicted five-year NS for 2012 to 2014 ranged from 98% for thyroid cancer to 7% for mesothelioma. Between 1992 to 1994 and 2012 to 2014, improvements in five-year age standardized NS were greatest for chronic myeloid leukemia (23.9 percentage points), though a large majority of the increase occurred in the first decade. Increases exceeding 15.0 percentage points were also observed for non-Hodgkin lymphoma (19.5), cancer of the small intestine (17.4) and multiple myeloma (16.9). In contrast, little to no improvement was observed for cancers of the anus, larynx, soft tissue or uterus, or for mesothelioma. Increases in five-year NS were greatest for chronic myeloid leukemia in each age group with the exception of those aged 75 to 84 years (thyroid). DISCUSSION: This study reveals important areas of progress in cancer outcomes in Canada since the early 1990s. It also sheds light on cancers for which there has seemingly been no improvement in five-year net survival over a 20-year period.

Increasing survival from leukemia among adolescents and adults in Canada: A closer look.

BACKGROUND: Survival from adult onset leukemia has increased substantially in Canada since at least the early 1990s. However, an analysis of the extent of this improvement by type of leukemia is lacking. DATA AND METHODS: Data are from the Canadian Cancer Registry, with mortality follow-up through record linkage to the Canadian Vital Statistics Death Database. Increases in five-year relative survival ratios (RSRs) between 1992-to-1994 and 2006-to-2008 were calculated by age and sex for all leukemias combined and for each of the main types. RESULTS: Increases in five-year RSRs were significant for all leukemia types studied, ranging from 9.2 percentage units for acute myeloid leukemia (AML) to 24.9 percentage units for chronic myeloid leukemia (CML). For all leukemias combined, additional adjustment for case-mix reduced the increase in survival from 14.6 to 11.8 units; increases were significant among both sexes and each age group. Improvement in survival for chronic lymphocytic leukemia (CLL) was greater at older ages. For AML, improvements were greater among people younger than age 55; no significant change was detected among those diagnosed at ages 75 to 99. A significant survival advantage for women relative to men was apparent in the 2006-to-2008 period for all leukemias combined and for CLL and CML. INTERPRETATION: Despite recent significant gains in survival for each main type of leukemia, room remains for improvement.

Differences in cancer survival in Canada by sex.

BACKGROUND: Research in the United States and Europe has found that women have an advantage over men in surviving a diagnosis of cancer, but the issue has not been systematically studied in Canada. DATA AND METHODS: Data are from the Canadian Cancer Registry, with mortality follow-up through record linkage to the Canadian Vital Statistics Death Database. The percentage unit difference in five-year relative survival ratios (RSRs) between women and men and the relative excess risk (RER) of death for women compared with men were used as measures of differences in cancer survival. RESULTS: A significant advantage for women compared with men was observed in 13 of the 18 cancers studied. Point estimates of RER were almost uniformly lower among those diagnosed at younger ages (15 to 54). For all cancers combined, women had a 13% lower excess risk of death-23% lower among women younger than 55. The overall advantage was greatest for thyroid cancer (RER = 0.31), skin melanoma (0.52) and Hodgkin lymphoma (0.65). The advantage for thyroid cancer was somewhat attenuated, though still significant, in earlier time periods. Bladder cancer was the only cancer for which women had a significant disadvantage (RER = 1.23); this excess risk seemed to be restricted to the first 12 to 18 months after diagnosis. INTERPRETATION: The reasons behind sex-specific differences in cancer survival are not well understood. Many explanations are possible, and differences are best explored on a cancer-by-cancer basis. The pronounced advantage for women at younger ages lends indirect support to a hypothesized hormonal influence.

Adjusting relative survival estimates for cancer mortality in the general population.

BACKGROUND: In theory, expected survival probabilities used in the derivation of relative survival ratios (RSR) are determined from a control group free of the cancer under study. In practice, expected survival is typically estimated from general population life tables--which include people previously diagnosed with cancer--potentially leading to an overestimation of relative survival. DATA AND METHODS: Data are from the Canadian Cancer Registry with mortality follow-up through record linkage to the Canadian Vital Statistics Death Database. Period method RSRs for 2006-to-2008 were derived using general population life tables adjusted for cancer mortality and then compared with estimates derived using corresponding unadjusted life tables. RESULTS: For all cancers combined, the use of general population life tables to derive expected survival probabilities overestimated RSRs by 0.6 (1-year), 2.4 (5-year) and 4.6 (10-year) percentage units. Biases in 5-year survival were highest among males (3.0) and among people aged 75 to 99 at diagnosis (4.1). The bias was negligible for most individual cancers; biases were highest for prostate cancer, followed by colorectal and female breast cancer. INTERPRETATION: Canadian estimates of relative survival for all cancers combined calculated using general life tables warrant adjustment for cancer mortality. Consideration of adjustment for cancer mortality is recommended for estimates of colorectal, female breast and especially prostate cancer.

Trends in incidence, mortality, and survival for kidney cancer in Canada, 1986-2007.

PURPOSE: Kidney cancer is one of the fastest rising cancers worldwide. We aimed to examine the trends in incidence, mortality, and survival for this cancer in Canada. METHODS: Incidence data for kidney cancer for 1986-2010 were from the Canadian Cancer Registry and the National Cancer Incidence Reporting System. These data were only available up to 2007 for the province of Quebec and consequently for the same year nationally, for Canada. Mortality data for 1986-2009 were from the Canadian Vital Statistics Death Database. Changes in age-standardized rates were analyzed by Joinpoint regression. Incidence rates were projected to 2025 using a Nordpred age-period-cohort model. Five-year relative survival ratios (RSR) were analyzed for 2004-2008 and earlier periods. RESULTS: Between 1986 and 2007, the age-standardized incidence rate (ASIR) per 100,000 rose from 13.4 to 17.9 in males and 7.7 to 10.3 in females. Annual increases in ASIR were greatest for age groups <65 years (males) and ≥65 years (females). The ASIRs increased significantly over time in both sexes for renal cell carcinoma (RCC) but not for other kidney cancer types. RCC rates are projected to increase until at least 2025. Mortality rates decreased only slightly in each sex since 1986 (0.4%/year in males; 0.8%/year in females). The 5-year RSR for kidney cancer was 68% but differed largely by morphology and age, and has increased slightly over time. CONCLUSIONS: The incidence rate of kidney cancer in Canada has risen since at least 1986, led largely by RCC. Increasing detection of incidental tumors, and growing obesity and hypertension rates are possible factors associated with this increase. Greater prevention of modifiable risk factors for kidney cancer is needed.

Estimating relative survival for cancer: An analysis of bias introduced by outdated life tables.

BACKGROUND: Relative survival analyses of cancer data often incorporate outdated information about expected survival when current information is not readily available. The assumption is that any bias introduced into the estimation of expected survival, and hence, into the estimate of relative survival, will be negligible. However, empirical studies of potential bias have yet to be published. DATA AND METHODS: Data are from the Canadian Cancer Registry with mortality follow-up through record linkage to the Canadian Vital Statistics Death Database. Period method relative survival ratios (RSRs) for 2005-2007 were derived using life tables centred on the 2006 Census of Population to estimate expected survival. The analysis was repeated using life tables from 5 and 10 years earlier. RESULTS: Deriving expected survival from life tables 5 years out of date resulted in increases in RSRs for all cancers. These increases became greater with lengthening survival duration. For example, increases in 1-, 5- and 10-year RSRs were 0.2, 0.8 and 1.7 percentage units, respectively, for all cancers combined. Increases in 5-year survival were highest for prostate (2.0) and bladder cancer (1.6); among males (1.2); and among people aged 75 to 99 at diagnosis (1.9). Differences were approximately double when life tables 10 years out of date were used. INTERPRETATION: The use of historical rather than current expected survival data in calculating RSRs for cancer may lead to consequential overestimation of survival.