Incidence

There were 6,959 ovary, fallopian tube or primary peritoneal carcinoma diagnoses of per year on average in England in 2015 to 2019 (34,796 over the five-year period), including tumours with borderline malignant potential. For simplicity, the term ‘ovarian cancer’ is utilised throughout the report to refer to this group of diseases. The ICD-10 and ICD-O-2 codes used to define the cohort are detailed in Appendix 1. The overall crude incidence rate for the period was 24.7 cases per 100,000 person-years.

Age standardisation was used to enable comparison of sub-Integrated Care Boards (sub-ICBs) with different age profiles. Age standardised incidence rates in the 106 sub-ICBs ranged from 20.8 to 32.1 cases per 100,000 person-years.

Incidence data by sub-ICB, Integrated Care Board (ICB), Cancer Alliance and for all of England are available in Table 1 and Table 2 of the accompanying Excel workbook available from the data downloads section.

Figure 1. Ovary, fallopian tube and primary peritoneal carcinomas: directly age standardised incidence rates by sub-ICB, 2015 to 2019

Each point on the funnel plot represents a geographical area (in this case, sub-ICB). The population of each sub-ICB is presented on the horizontal axis and the (age standardised) incidence rate of ovarian cancer is shown on the vertical axis. Some random variation in rates between areas is expected, but the estimate of the incidence rate is likely to be more precise for a larger area than for a smaller one. This precision level is represented by the ‘funnel’ dashed lines. Points that lie outside of the dashed lines indicate that such variation may not be explained solely by randomness but may be due to real differences in incidence between areas.

Age standardised incidence rates in the 21 Cancer Alliances ranged from 20.8 to 26.8 cases per 100,000 person-years.

Figure 2. Ovary, fallopian tube and primary peritoneal carcinomas: directly age standardised incidence rates by Cancer Alliance, 2015 to 2019

These funnel plots show variation in the incidence of ovarian cancer among local geographies (identified by sub-ICBs) and regional geographies (identified by Cancer Alliances). It had previously been thought that regional variation in incidence may reflect differences in the methods and conventions used for distinguishing between ovary, fallopian tube and primary peritoneal carcinomas at diagnosis. However, the new methodology, which includes all of these diseases in the analysis, negates this as a confounding factor. Age standardisation removes the impact of differences in population age profile on incidence rates, but variation in ethnicity, and in particular clusters of ethnicities with higher genetic predisposition factors such as BRCA gene mutations, could impact on these results. Regional variation in other disease risk factors such as use of hormonal contraception may also partially explain local and regional variations in ovarian cancer incidence.

The crude incidence rate of ovarian cancer in England has fluctuated at around 25 cases per 100,000 women between 2001 and 2019. The crude rate in 2001 was 25.5 cases per 100,000 women and in 2019 it was observed to be 24.9 cases per 100,000 women. There was no significant trend in the crude incidence of ovarian cancer over the period 2001-2019.

The age-standardised rate, which accounts for the differences in age distribution of the population over time, shows a slight downward trend with 27.8 cases per 100,000 women in 2001 to 25.1 cases per 100,000 women in 2019. A trend of convergence between crude and age-standardised estimates would be consistent with the proportion of ovarian cases increasing within older populations as the wider population ages.

Figure 3. Crude and age-standardised rates of ovary, fallopian tube and primary peritoneal carcinomas in England, 2001 to 2019 (Source: CAS AV2020 and ONS2020)