Reduced cervical cancer incidence and mortality in Canada: national data from 1932 to 2006

Abstract

BackgroundHigh levels of participation in cervical screening are reported in Canada from the 1970’s as a result of early uptake of the Pap smear and universal Medicare. Despite recommendations to the contrary, the programs have featured early age of initiation of screening and frequent screening intervals. Other countries have achieved successful outcomes without such features. We analyzed national data to better understand mortality and incidence trends, and their relationships to screening.MethodsThe Canadian Cancer Registry, National Cancer Incidence Reporting System, and the Canadian Vital Statistics Database were used to measure mortality and incidence rates. Cases and deaths from invasive cervical cancer were classified by 5 year age groups at diagnosis and death (15 to 19 years through to 80 to 84 years), year of diagnosis (1972 to 2006), and year of death (1932 to 2006). Probabilities of developing and dying from cervical cancer were calculated for age-specific mortality and incidence. The proportion of women reporting a timely Pap test was estimated for 1978 to 2006.ResultsCervical cancer mortality has declined steadily from a peak of 13.5 to 2.2 per 100,000 (83%,) between 1952 and 2006, and 71% between 1972 and 2006. Incidence of invasive cervical cancer has declined by 58% since 1972. These declines have occurred more among older age groups than younger. Invasive cervical cancer incidence and mortality is less in each successive birth cohort of women. Participation rates in screening are high especially in women under age 50.ConclusionsDespite increasing risk factors for cervical cancer, both incidence and mortality have declined over time, across age groups, and across birth cohorts. Earlier increasing mortality (1932 – 1950) was likely related to improved classification of cancers and the early subsequent reduction (1950 – 1970) to improved treatment. Recent improvements in incidence and mortality are likely due to high rates of screening. For women under age 30 years there are low rates of disease but lesser improvement related to screening.

A Systematic Review of Economic Aspects of Cervical Cancer Screening Strategies Worldwide: Discrepancy between Economic Analysis and Policymaking

“…The incidence and mortality of cervical cancer has decreased due to cytology screening in many countries (Arbyn et al, 2011;Dickinson et al, 2012). To prevent only one death from cervical cancer many screening program recommend cytology screening every year for 10 years, this is the area that many researchers want to show the importance of finding optimal intervals for screening (Kobayashi et al, 2012).…”

Colonial legacy and the experience of First Nations women in cervical cancer screening: a Canadian multi-community study

“…National media coverage emphasized Canada's role as a mid-twentieth century pioneer in cervical cancer screening and an exemplar of early detection through regular Papanicolaou (Pap) screening. Citing an 83% drop in cervical cancer deaths in Canada between 1952 and 2006 (from 13.5/100,000 to 2.2/100,000) as reported in Dickinson et al (2012), the Canadian Broadcasting Corporation noted that 'what was a rare cancer has become rarer still ' (2012). Media coverage and health education materials introducing the general public and health care providers (HCPs) to the new screening guidelines did not report the elevated risk of cervical cancer morbidity and mortality among vulnerable populations in Canada (Canadian Medical Association Journal, 2013;Cancer Care Ontario, 2012a, 2012b, leaving the impression that the picture had improved for all groups of Canadian women.…”

Pathoepidemiology of Cervical Cancer in National Institute of Cancer Research and Hospital of Bangladesh

“…The understanding that nearly all cervical cancer is caused by oncogenic strains of the human papillomavirus (HPV) has assisted in better interpretation of the associations between behavior and cervical cancer. 8 Epidemiological studies conducted during the past 30 years have consistently indicated that cervical cancer risk is strongly influenced by measures of sexual activity, number of sexual partners, age at first sexual intercourse and sexual behavior of the women's male partners. 9 Many studies have also suggested that women with multiple sexual partners are at high risk for HPV acquisition and cervical cancer.…”