Cancer of the Uterine Cervix

Abstract

HEALTH ISSUE: Cervical cancer is one of the most common malignant diseases of women; it is diagnosed in almost half a million women every year and half as many die from it annually. In Canada and other industrialized countries, its incidence has decreased due to cytology screening. However, invasive cases still occur, particularly among immigrant groups and native Canadian women. Although incidence of squamous cell carcinomas has decreased, the proportion of adenocarcinomas has increased because Pap cytology is ineffective to detect these lesions. KEY FINDINGS: In Canada, cervical cancer will cause an estimated 11,000 person-years of life lost. In most Canadian provinces, early detection is dependent on opportunistic screening. Primary prevention can be achieved through health education (sexual behavior modification) and vaccination to prevent infection from Human Papillomavirus (HPV). The initial results from vaccination trials are encouraging but wide scale use is more than a decade away. DATA GAPS AND RECOMMENDATIONS: Most cases of cervical cancer occur because the Pap smear was either false negative, was not done or not done often enough. Appropriate recommendations and guidelines exist on implementation of cytology-based programs. However, most Canadian women do not have access to organized screening. Further research is needed to 1) evaluate automated cytology systems; 2) define appropriate management of precursor lesions and 3) deliver definitive evidence of HPV testing efficacy in long-term follow-up studies with invasive cancer as an outcome and 4) provide Canadian data to justify augmenting or modifying current programs to use HPV testing in secondary triage of equivocal Pap smears.

Figure 1

Average (Period 1994–1998), Annual Age-Standardized Incidence and Mortality Rates of Invasive Cervical Cancer for Individual Canadian Provinces, for Canada, and for the United States All rates refer to numbers of new cases or deaths per 100,000 and are standardized according to the Canadian population of 1991. Incidence data for the U.S. refer to the nine main state or metropolitan area registries belonging to the Surveillance, Epidemiology, and End Results (SEER) Program from the Cancer Surveillance Research Program of the U.S. National Cancer Institute (NCI), and mortality data refer to the entire U.S.population. Source: Statistics Canada and SEER database.[4]

Figure 2

Trends in Incidence and Mortality Rates for Invasive Cervical Cancer for Canada (Since 1969) and for the United States (Since 1973). Rates are per 100,000 and are standardized according to the Canadian population of 1991. Incidence data for the United States refer to the nine main SEER registries and mortality data refer to the entire U.S. population. Source: Statistics Canada and SEER database.[4]

Figure 3

Trends in Incidence Rates for Invasive Cervical Cancer for CanadianProvinces Rates are standardized according to the Canadian population of 1991 and are presented as annual averages (per 100,000) for successive five-year periods. Source: Statistics Canada.

Figure 4

Trends in Age-Specific Incidence Rates for Invasive Cervical Cancer inCanada Since 1969 Rates are presented as annual averages (per 100,000) for successive five-year periods. Source: Statistics Canada.

Figure 5

Annual Age-Standardized Incidence Rates of Invasive Cervical Cancer (Projection for 2000) for Canada and Selected European, Latin American, Caribbean and African Countries. Rates are per 100,000 and are standardized according to the world population of 1960. Source: Globocan, International Agency for Research on Cancer.[2]

Figure 6

Five-Year Relative Survival Rates Following a Diagnosis of Invasive Cervical Cancer in Canada (Quebec Used as Example), in the United States (SEER Registries) and in Selected European and Developing Countries. Source: Ministère de la santé et des services sociaux du Québec; SEER program; National Cancer Institute of Canada; International Agency for Research on Cancer.