Overview of Gynaecological Cancers in Australia
Gynaecological cancers refer to cancers affecting the female reproductive organs, including the ovaries, uterus, cervix, vagina, and vulva. In Australia, these cancers collectively represent a significant health concern. In 2020, there were 6,380 new cases of gynaecological cancers diagnosed, with an estimated increase to 6,963 cases in 2024 [11]. By age 85, it is estimated that approximately 1 in 23 females (4.3%) will be diagnosed with a gynaecological cancer [11]. Despite advances in treatment, these cancers resulted in 2,171 deaths in Australia in 2022[11].
Types of Gynaecological Cancers
Ovarian cancer includes cancers of the ovaries and fallopian tubes. In 2019, there were 1,625 new cases diagnosed in Australia, with an estimated increase to 1,786 cases in 2023[2]. The age-standardised incidence rate is approximately 13 cases per 100,000 females[2]. A female has about a 1 in 87 (1.2%) risk of being diagnosed with ovarian cancer by age 85[2].
Uterine cancer, primarily endometrial cancer affecting the lining of the uterus, is the most commonly diagnosed gynaecological cancer in Australia. More than 3,300 Australians are diagnosed with uterine cancer each year, reflecting a doubling of case numbers over the last 20 years[20]. It is notably the only gynaecological cancer showing increasing mortality rates between 2001 and 2018[20].
In 2020, there were 982 new cases of cervical cancer diagnosed in Australia[19]. The estimated risk for a female being diagnosed with cervical cancer by age 85 is 1 in 175 (0.57%)[19]. The incidence rate has significantly decreased from 15.5 cases per 100,000 females in 1982 to 7.6 cases per 100,000 females in 2020, largely due to screening programs[19].
These rarer cancers account for a smaller percentage of gynaecological malignancies. About 390 women are diagnosed with vulvar cancer each year in Australia[6]. Vaginal cancer is even less common, making up less than 2% of all gynaecological malignancies[8].
Population Risk Factors
Age
The risk of most gynaecological cancers increases with age, with incidence rates generally highest in the 65-79 age group[11]. However, cervical cancer shows a different pattern, peaking in those aged 35-39[19].
Obesity
Obesity is a significant risk factor particularly for endometrial cancer and is considered a contributing factor to the rising incidence of this cancer type in Australia[20].
HPV Infection
Human Papillomavirus (HPV) infection is the primary risk factor for cervical cancer and also contributes to some vaginal and vulvar cancers[19].
Socioeconomic Factors
Studies have shown that uterine cancer diagnoses increase with socioeconomic disadvantage, with higher associated mortality in patients from lower socioeconomic backgrounds[20]. Indigenous women in Australia are disproportionately affected by endometrial and cervical cancer compared to non-Indigenous women[20].
Prior Medical History
Previous cancers, particularly breast cancer, can increase the risk of ovarian cancer. Additionally, untreated precancerous conditions can progress to invasive cancers[8].
Hereditary Cancer Risk
For some women, genetic factors significantly increase their risk of developing gynaecological cancers:
BRCA1/2 Mutations
Women with mutations in the BRCA1 or BRCA2 genes have substantially elevated risks of developing ovarian and breast cancers[3]. These mutations can be inherited and account for approximately 15% of ovarian cancers[16].
Lynch Syndrome
Women with Lynch syndrome (hereditary non-polyposis colorectal cancer) can have a 40-60% lifetime risk of endometrial cancer and a 10-12% lifetime risk of ovarian cancer[4]. This is significantly higher than the general population risk.
Risk-Reducing Surgical Options
For women at high risk of gynaecological cancers, several surgical interventions may be considered:
Risk-Reducing Bilateral Salpingo-Oophorectomy (RRBSO)
This procedure involves removing both fallopian tubes and ovaries to reduce ovarian and fallopian tube cancer risk. For BRCA1 carriers, RRSO is typically recommended between ages 35-40, after childbearing is complete[13]. For BRCA2 carriers, it may be delayed until ages 40-45 due to a later onset risk profile[3][13].
Prophylactic Hysterectomy
Removal of the uterus may be considered for women with Lynch syndrome to prevent endometrial cancer[4]. It may also be considered at the time of RRBSO, as there is evidence of an increased risk of endometrial cancer with BRCA mutation carriers. Prophylactic hysterectomy also affords omission of progesterone for women using hormone replacement therapy. Progesterone is associated with an increased risk of breast cancer.
Risk-Reducing Salpingectomy with Delayed Oophorectomy
Given the most common form of ovarian cancer originates in the fallopian tubes in most cases, removal of fallopian tubes alone will reduce risk. Opportunistic removal of fallopian tubes during surgery for other indications is being trialled in several countries for women at average risk. However, this approach is not yet fully established as standard care for individuals at increased risk and is generally only recommended within clinical trials[13] in this population.
Benefits of Risk-Reducing Surgery
Risk-reducing surgeries have demonstrated significant benefits for women at high genetic risk:
Cancer Risk Reduction
Studies have shown that RRBSO can reduce ovarian cancer risk by 90-95% in BRCA mutation carriers[10]. Similarly, prophylactic hysterectomy with bilateral salpingo-oophorectomy has been shown to be 100% effective in preventing endometrial and ovarian cancer in women with Lynch syndrome in studied populations[4].
Mortality Reduction
Beyond cancer prevention, risk-reducing surgeries are associated with lower all-cause mortality. Compared to women who did not undergo RRBSO, those who did had a 60% reduction in all-cause mortality, a 56% reduction in breast cancer-specific mortality, and a 79% reduction in ovarian cancer-specific mortality[13].
Breast Cancer Risk Reduction
For BRCA mutation carriers, RRBSO has been associated with reduced breast cancer risk, particularly when performed before age 50[5]. The risk reduction is most significant within the first 5 years after surgery, with a 72% reduction in the risk of breast cancer for BRCA1 carriers and 81% reduction in the risk of breast cancer for BRCA2 carriers[5].
Considerations and Side Effects
While risk-reducing surgeries offer significant benefits, they also have important implications that should be considered:
Premature Menopause
RRBSO performed before natural menopause results in surgical menopause, which can cause vasomotor symptoms (hot flashes), sexual dysfunction, cognitive changes, and increased risks of cardiovascular disease and osteoporosis[3][10].
Fertility Impact
These surgeries result in permanent infertility. Women who have not completed childbearing need to carefully consider timing and may benefit from fertility preservation discussions before surgery[10].
Hormone Replacement Therapy
For premenopausal women undergoing RRBSO, hormone replacement therapy may be recommended to mitigate menopausal symptoms and long-term health effects, particularly in relation to breast cancer[3][10].
Residual Risk
Even after RRBSO, there remains a small risk of primary peritoneal cancer, which resembles ovarian cancer but develops in the abdominal lining[13].
Quality of Life Impact
Research is ongoing into the impact on quality of life of risk reducing surgery. All surgical interventions carry potential complications that should be discussed with healthcare providers.
Gynaecological cancers represent a significant health concern for Australian women, with approximately 1 in 23 females developing these cancers by age 85[11]. While population screening exists for cervical cancer, there are no similar programs for other gynaecological cancers. For women at high genetic risk, particularly those with BRCA1/2 mutations or Lynch syndrome, risk-reducing surgeries provide substantial benefits in cancer prevention and mortality reduction.
The decision to undergo risk-reducing surgery is complex and highly personal. It should take into account individual risk factors, age, family history, desire for future pregnancies, and quality of life considerations.
References
- Pregnancy‐associated gynecological cancer in New South Wales, Australia 1994–2013: A population‐based historical cohort study
- Ovarian cancer statistics in Australia
- Risk-Reducing Breast and Gynecological Surgery for BRCA Mutation Carriers: A Narrative Review
- Prophylactic surgery to reduce the risk of gynecologic cancers in the …
- Association of Risk-Reducing Salpingo-Oophorectomy With Breast ..
- Vulvar cancer – Cancer Council Queensland
- Gynaecological cancers in Australia: an overview, Summary
- Vaginal cancer
- The Lymphedema Evaluation in Gynecological cancer Study (LEGS): Design of a prospective, longitudinal, cohort study
- Hereditary Women’s Cancer: Management and Risk-Reducing Surgery
- Gynaecological cancer in Australia statistics
- The Prevalence, Incidence, and Quality-of-Life Impact of Lymphedema After Treatment for Vulvar or Vaginal Cancer
- 3814-BRCA1 or BRCA2 – risk management (female) – eviQ
- Insights into ovarian cancer care: report from the ANZGOG Ovarian Cancer Webinar Series 2020
- ABO blood groups as a prognostic factor for recurrence in ovarian and vulvar cancer
- Incidence of germline BRCA1/2 mutations in women with tubo-ovarian high-grade serous carcinomas with and without serous tubal intra-epithelial carcinomas
- The incidence risk of gynecological cancer by antipsychotic use: a meta-analysis of 50,402 patients
- Cancer Incidence in Migrants in Australia: Patterns of Three Infection-Related Cancers
- Cervical cancer in Australia statistics
- The Rise of Endometrial Cancer – ANZGOG