A Tale of Two Time Periods: Ovarian Cancer Trends in Ontario

Laurie M Elit, Susan J Bondy, Zhongliang Chen, Lawrence Paszat


Objectives: To assess the population-based trends in incidence and survival rates for epithelial ovarian cancer trends in Ontario in two time periods.
Methods: A population-based study cohort of all cases of epithelial ovarian cancer treated initially with abdominal surgery in Ontario from January 1996 through December 2001. Incident surgical cases were documented by hospital contact data and the Ontario Cancer Registry. Patient characteristics (ie., age) were obtained from electronic administrative data records. Regression analyses were used to assess the influence of time period on survival while controlling for age, comorbidity and other factors associated with these outcomes.
Results: 3825 women met the inclusion criteria. The age-standardized incidence of ovarian cancer has remained stable from 1996 to 2001. There has been a shift to younger age of diagnosis between the two time periods. There is clearly a difference in death rate contributed to by age, Charlson comorbidity and treatment period in the univariate analysis. The earlier time period (p<0.0001), advancing age (p<0.0001), higher Charlson score (p<0.0001) and lower income quartile scores (p=0.03) were significantly associated with a poorer survival in the univariate analysis. Younger age, lower Charlson score and later time period of diagnosis and treatment (p<0.0001) led to an improved survival in the proportional hazards model.
Conclusion: Age-standardized incidence and mortality rates for ovarian cancer in Ontario have remained stable. For those treated with initial surgery, advances in management have led to an improvement in survival.

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DOI: http://dx.doi.org/10.3747/co.v14i2.125

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ISSN: 1198-0052 (Print) ISSN: 1718-7729 (Online)