Because of increases in the detection of cancer and improving survival, the number of Canadians living with cancer is rising.
Of all persons living in Canada on January 1, 2005, 695,000 had been diagnosed with an invasive cancer at some point in the previous 10 years. Some individuals experienced more than one invasive cancer over the 10-year period, with the number of cancer cases totalling 723,000.
The most common cancers were breast, prostate and colorectal cancer, which together accounted for just over half of all cases on January 1, 2005, that had been diagnosed in the previous decade.
The 695,000 people who had been diagnosed with cancer during the 10-year period represented 2.2% of the Canadian population, or about 1 in 46 people. Overall, 1 in 111 women had been diagnosed with breast cancer, and 1 in 118 men had been diagnosed with prostate cancer.
About one-fifth (20.5%) of all cases in the population were breast cancer, and 18.7% were prostate cancer. These two cancers were the most common owing not only to the relatively high numbers of cases diagnosed, but also to favourable survival rates.
Colorectal cancer was the third most common, at 12.9%. It was followed by lung cancer (5.1%), bladder cancer (5.0%), non-Hodgkin lymphoma (4.1%) and skin melanoma (4.1%).
Among men still living on January 1, 2005, prostate cancer accounted for the largest share of cases diagnosed within the 10-year period (38.2%). The next most common were colorectal cancer (14.0%), bladder cancer (7.5%) and lung cancer (5.4%). Among women still alive, the corresponding most common cancers were breast, accounting for 40.0% of cases, colorectal (11.9%), uterine (7.2%) and lung (4.9%).
The most prevalent cancer in people aged 20 to 39 was thyroid. The most common cancer in the age groups 40 to 49 and 50 to 59 was breast. And the most common cancer in the older age groups 60 to 69, 70 to 79, and 80 or older was prostate.
The percentage of Canadians living with a diagnosis of cancer rose sharply with age, peaking at 80 to 84. However, the patterns of increase differed between the sexes.
The percentage was higher in women than in men before age 60. Thereafter, the percentage in men surpassed that for women, mostly because of a sharp rise in prostate cancer, and increased much more rapidly in men than in women.
Differences between the sexes in the percentage of people with cancer were attributable to differences in the number of cancers diagnosed and survival.
The prevalence of most cancers increased with age. Exceptions were testicular cancer among men, cervical and thyroid cancer among women, and Hodgkin lymphoma and brain cancer among both sexes.
This article in Health Reports presents the most precise and specific estimates of the number of Canadians living with cancer reported to date. It also provides estimates for a much more extensive list of cancers than has previously been available.
Data tabulated by type of cancer, age, sex and time since diagnosis provide important information about the demand for cancer-related health care and social services.
The article is based on data from the Canadian Cancer Registry, linked with mortality data from the Canadian Vital Statistics Death Database.
Cancer prevalence can be defined as the number of previously diagnosed cases of cancer among people still alive.
Some cancers were more common among young people. For testicular cancer and Hodgkin lymphoma, the percentages of people who had been diagnosed from 2000 through 2004, and were still alive on January 1, 2005, were highest in young adults aged 20 to 39. The decrease with age was statistically significant.
Cervical cancer and cancer of the thyroid were most common in women in the 40-to-49 age group. Both of these cancers declined at older ages.
As noted by cancer researchers in other countries, estimates of the prevalence of cancers diagnosed within 2, 5 and 10 years are useful for resource allocation and cancer care planning.
Just over 217,000 cancers had been diagnosed in the two-year period 2003 and 2004 among people who were still alive on January 1, 2005. People in the first or second year post-diagnosis are generally at a stage of the disease when they are undergoing primary treatment or recovering from its effects.
In the period from two to five years since diagnosis, a time requiring close clinical follow-up for recurrence, just over 237,000 cancers had been diagnosed in people still alive on January 1, 2005.
The article, "Cancer prevalence in the Canadian population," which is part of today's Health Reports (82-003-XWE, free) online release, is now available from the Publications module of our website. For more information about this article, contact Larry F. Ellison (613-951-5244; firstname.lastname@example.org), Health Statistics Division, or Kathryn Wilkins (613-951-1769; email@example.com), Health Information and Research Division.
Today's online release of Health Reports also includes "Medication use among senior Canadians." This article examines patterns in the use of prescription medications, over-the-counter products and alternative medicines by seniors living in private households and in institutions, based on information from the 1996/1997 and 1998/1999 National Population Health Survey. For more information, contact Pamela L. Ramage-Morin (613-951-1760; firstname.lastname@example.org), Health Information and Research Division.
The complete version of the latest issue of Health Reports, Vol. 20, no. 1 (82-003-XWE, free) is now available from the Publications module of our website. A printed version (82-003-XPE, $24/$68) is also available. See How to order products.
For more information about Health Reports, contact Christine Wright (613-951-1765; email@example.com), Health Information and Research Division.