Cancer

Descriptive Epidemiology of the Principal Asbestos-Related Diseases in Québec, 1981-2004

While awaiting the introduction of the future surveillance system for asbestos exposures and their related diseases, we created the descriptive epidemiological portrait of two of these health problems, malignant mesothelioma and asbestosis. It was constructed using the data from statutory databases available at the ministère de la Santé et des Services sociaux: the Fichier des tumeurs du Québec (tumour registry) for cancer incidence, the Fichier des décès (death registry) for mortality and the Med-Echo registry for asbestosis hospitalizations. Finally, the international comparisons of malignant mesothelioma incidence rates were made using the electronic database of the International Agency for Research on Cancer.

The study area is the Province of Québec. The incidence rates, mortality and hospitalization at the regional level (health region) were compared. The time trends of incidence rates, mortality and hospitalization were analyzed. Standardized rates using the direct met…

The Prevalence of Cancer in Quebec in 1999

Since 2000, cancer has been the main cause of death in Quebec (Institut de la statistique du Québec, 2003). However, the standardized death rate due to cancer, like most other causes of death, has been declining steadily since the early 1990s (ministère de la Santé et des Services sociaux, 2003; ministère de la Santé et des Services sociaux, 2004), while life expectancy at birth of the Quebec population has increased in recent decades. With the number of seniors growing steadily and the risk of cancer increasing with age, there is a parallel increase in the incidence of cancer. In addition, as a result of earlier diagnoses and more effective treatments, cancer patients are surviving longer, leading to a high demand for health care as follow‑up for these individuals.

A number of indicators can be used to monitor cancer and measure the burden that it represents for society. The most well‑known ones are the number of new cases reported annually (incidence), mortality, relative…

Interval cancer in women following a normal initial mammogram in the Québec Breast Cancer Screening Program in 1998-2000

Interval cancers are cancers that are diagnosed during the interval between a negative screen and the subsequent screen. The rate of interval cancers is a performance indicator in the terms of reference of the Quebec Breast Cancer Screening Program (PQDCS). The PQDCS terms of reference do not set a standard for interval cancer rates, but the Evaluation Indicators Working Group, which monitors breast cancer screening programs in Canada, has determined that the rate of interval cancers should not exceed 6 cases of invasive cancer per 10,000 person-years within 12 months of a negative screen, or 12 cases per 10,000 person-years within 24 months of a negative screen.

The primary objective of this analysis was to estimate the rate of interval cancers among women who received an initial mammography in the PQDCS in 1998-2000 and whose mammogram was interpreted as normal (including non-equivocal benign lesions). The analysis also sought to identify the characteristics of women,…

Équipe d'évaluation du PQDCS

Premature mortality caused by cancer and the public health challenge it represents have given rise to a myriad of studies on the contribution of material and social living conditions to varying risks of morbidity and mortality. Thus, European and American

Premature mortality caused by cancer and the public health challenge it represents have given rise to a myriad of studies on the contribution of material and social living conditions to varying risks of morbidity and mortality. Thus, European and American studies have shown that cancer mortality—and some cancers more than others—often hits disadvantaged socioeconomic groups and regions hardest, and that this relationship persists even when individual behavior is taken into account. Numerous studies have focused mainly on men, who are easier to characterize socioeconomically than women. Indeed, it has proven difficult to determine the socioeconomic position of women, and the indicators used are often inadequate. An examination of the social health inequalities between the sexes shows that the mortality is sensitive to the inequality measure, the causes of mortality differ for men and women, these inequalities are generally less pronounced among women, and the social condition of wome…

The Epidemiology of Asbestos-related Diseases in Quebec

Under the auspices of the Comité aviseur sur l'amiante au Québec (asbestos advisory committee), the sub-committee on the epidemiology of asbestos-related diseases reviewed the available epidemiological data on these diseases in Quebec. The sub-committee also conducted various studies to fill in certain gaps identified during the analysis of available data. 

The findings that have been summarized here show a statistically significant increase in the incidence of mesothelioma of the pleura among Quebec men between 1982 and 1996. Statistical projection suggests that this increase might level off in a few years, but this is not certain. Quebec men and women also show significantly higher rates of mesothelioma of the pleura than men and women in the rest of Canada and in several other countries. This clearly points to the necessity of monitoring the evolution of this cancer in Quebec in the coming years, especially to see whether or not the increase levels off and to describ…

Evaluation of the completeness of the Fichier des tumeurs du Québec

Cancer registries are essential tools for monitoring cancer. There are four main components to the quality of this type of registry: completeness, validity of data, timeliness of access to data, and range of data available.

Completeness refers to the ability of a cancer registry to identify and register all new cancer cases diagnosed within a population. Completeness can vary considerably from one place to another, because of variations in resources and data collection methods, or variations in diagnostic examinations. An excellent level of completeness is essential in order to produce accurate statistics and conduct valid studies on cancer in a population. Evaluating the completeness of registration of new cases is therefore a priority activity for all cancer registries.

The completeness of the cancer registry is an especially important concern for Quebec. In Canada's other provinces, several sources are used to supply data to the cancer registries, foremost of whic…

Survival Probabilities for Cancer Cases Reported between 1984 and 1998 in Quebec - Observed & Relative Survival

In May 2002, in cooperation with the Ministère de la Santé et Services sociaux, the Institut national de santé publique du Québec (INSPQ) published survival tables for the four main cancer sites—lung, breast (female), colorectal, and prostate—for cases reported to the Quebec Cancer Registry (QCR) in 1992. These cases were used to calculate the relative survival probability five years after diagnosis.

The study was designed to measure the quality of the incidence and mortality data used to calculate survival probabilities and determine vital status. It has also served to illustrate the decisive impact of data quality on results. Data was also compared with the five year relative survival probabilities in other Canadian provinces despite the fact that Quebec does not establish the date of diagnosis in the same manner and draws its incidence information from a different source.

This report is a continuation of the overall project. Here, survival probabilities have been…

Cancer Survival of Newly Diagnosed Cases, Quebec, 1992

The main purpose of this study is to describe the quality of the data used to calculate survival in Quebec. The discussion will focus on the quality of incidence and mortality data, the kind of file linkage needed to determine a person’s vital status, and the influence that this data quality has on survival results. This study is also part of a Canada-wide initiative to quantify cancer survival. Statistics Canada and the Canadian Cancer Survival Analysis Group have produced a Canadian Cancer Survival Protocol. To facilitate comparison, the protocol used in this survival study is largely based on the Canadian protocol.

The survival indicator is based primarily on the vital status of the cases reported. Vital status is not reported systematically in the Tumours File. It must be determined by matching the Tumours File against the Deaths File. Unfortunately, the Deaths File is not sufficient. A supplementary linkage with the administrative file of RAMQ subscribers shows that abo…