Although a relatively uncommon cancer, ovarian cancer is often diagnosed at a stage where the cancer has spread beyond the ovary. Such cases often have a poor prognosis.
Ovarian cancer in Australia: an overview, 2010 provides a comprehensive picture of national statistics on ovarian cancer using a range of data sources, with the latest available data and trends over time presented. Throughout this report, the term 'ovarian cancer' refers to invasive ovarian cancers; borderline tumours are not included.
The number of ovarian cancer cases is increasing
In 2006, ovarian cancer was the ninth most commonly diagnosed cancer among Australian women (excluding non-reportable skin cancers) and the second most commonly diagnosed gynaecological cancer, with a total of 1,226 ovarian cancer cases diagnosed. Ovarian cancer is mainly a disease of postmenopausal women, with six in ten (60%) cases diagnosed in women aged 60 years and over.
The number of ovarian cancer cases increased by 47% between 1982 and 2006 (from 833 cases to 1,226 cases) due to an ageing and growing population. It is anticipated that the number of new cases will continue to increase, with an estimated 1,434 women expected to be diagnosed with ovarian cancer in 2015.
Nonetheless, the age-standardised incidence rate of ovarian cancer decreased significantly by 14% between 1982 and 2006 (from 12.4 to 10.7 new cases per 100,000 females).
The rate of death from ovarian cancer has fallen
A total of 795 women died from ovarian cancer in 2006, making it the sixth most common cause of cancer-related death for Australian women, and the most common cause of gynaecological cancer death, representing over half (55%) of such deaths.
The age-standardised mortality rates for ovarian cancer decreased significantly by 26% between 1968 and 2006 (from 9.1 to 6.7 deaths per 100,000 females). In addition, the 2006 mortality rate was the lowest rate observed for any year to date. Possible reasons for the decrease in the mortality rate over time include the observed decline in the incidence rate, improvements in access to and quality of treatments, and change over time in the types of ovarian cancers occurring among women. However, the data also indicate that the decline in the mortality rate was not observed for all age groups, with the ovarian cancer mortality rate for older women (those aged 70 years and over at death) increasing rather than decreasing over the period considered.
The prognosis of women with ovarian cancer has improved
The prognosis for women with ovarian cancer is relatively poor. Women who were diagnosed with ovarian cancer between 2000 and 2006 were 40% as likely to live five years after diagnosis as their counterparts in the general population. Significantly poorer survival was seen for older women, with 5-year relative survival estimates ranging from a high of 86% for those aged less than 30 years when diagnosed with ovarian cancer to a low of 15% for those aged 80 years or older at diagnosis. Possible reasons for poorer survival of older women include a greater likelihood that these women were diagnosed with advanced stage cancer and/or with more-aggressive types of cancers, as well as a greater likelihood of co-morbidities. Differences by age in the treatment provided to those with ovarian cancer are also believed to be a factor.
Improvement in the prognosis of those diagnosed with ovarian cancer has occurred over time, with the 5-year relative survival rate increasing significantly from 33% in 1982-1987 to 40% in 2000-2006. Nonetheless, the improvements in survival were focused on women in the middle age groups, with no significant change in the survival estimates over time for those aged less than 40 years and those aged 80 years and over.