Factors influencing ovarian cancer survival worldwide.

Ovarian cancer survival varies widely worldwide. This variation may be explained by several factors, including international variation in the histological subtypes of ovarian cancer, stage at diagnosis and race/ethnicity. Data used for this thesis were extracted from the CONCORD-2 study. The CONCORD-2 study collected data for 793,098 adult women (aged 15-99 years) in 61 countries who were diagnosed during the 15-year period 1995-2009 with a cancer of the ovary. Ovarian cancer was defined broadly to include tumours of the fallopian tube, uterine ligaments and adnexa, other specified and unspecified female genital organs, peritoneum or retroperitoneum. Age-standardised net survival was the main outcome for each analysis. The worldwide distribution of and international variation in histological groups of ovarian cancer was examined, as an approach to understanding international differences in overall ovarian cancer survival. International comparisons of ovarian cancer survival have traditionally analysed ovarian cancer as a single homogenous group. However, ovarian cancer comprises several histologically distinct subtypes, which have very different survival outcomes. Survival from the most common histology, type II epithelial, was much lower than that for other histological groups in most countries. International differences in stage-specific net survival were also explored, where adequate data were available, in order to understand the impact of stage at diagnosis on survival. Survival from localised tumours was much higher overall, and for each histological group, than for advanced-stage disease in all countries. Net survival by race was estimated for Israel, New Zealand and the United States. Survival was consistently higher for the majority racial group than for the minority group.

The results presented in this thesis provide a valuable contribution to the understanding of variations in ovarian cancer survival, which may thus be used to inform health care policies and plans to reduce disparities in survival.