Ovarian cancer refers to any cancer that begins in the ovaries, which are the reproductive glands in women responsible for producing eggs and hormones. This disease presents a considerable health challenge globally, largely due to its often-silent progression and the difficulties associated with detecting it in its early stages. Understanding the characteristics of ovarian cancer, including its mortality rates, is important for appreciating its impact on public health.
Current Landscape of Ovarian Cancer Mortality
Ovarian cancer has the highest mortality rate among all gynecological cancers. Globally, there were approximately 207,252 new deaths due to ovarian cancer in 2020, with an age-standardized mortality rate of 4.2 per 100,000 people. In the United States, between 1999 and 2020, about 337,619 deaths were attributed to ovarian cancer in females aged 25 and older. The age-adjusted mortality rate (AAMR) in the U.S. decreased from 14.62 per 100,000 in 1999 to 10.15 per 100,000 in 2020.
The rate of ovarian cancer deaths in the U.S. has decreased by 43% since 1976. In the UK, age-standardized mortality rates for females decreased by 23% between 1971-1973 and 2017-2019. Despite these improvements, ovarian cancer remains the sixth most common cause of cancer death in females in the UK. Mortality rates are highest in older women, with nearly half of all ovarian cancer deaths in the UK occurring in females aged 75 and over.
Challenges in Early Detection
The difficulty in detecting ovarian cancer early contributes to its high death rate. The disease often presents with vague and non-specific symptoms. Many early-stage ovarian cancers are asymptomatic. These symptoms can include:
- Bloating
- Increased abdominal size
- Abdominal or pelvic pain
- Difficulty eating
- Feeling full quickly
- Changes in bowel or urinary habits
There is currently no universally endorsed screening program for ovarian cancer in the general population. Tests like CA-125 have limitations; it is elevated in only about 50% of stage I epithelial ovarian cancers and can also be raised in many non-cancerous conditions, leading to poor sensitivity for early-stage disease and high false-positive rates. Transvaginal ultrasound (TVUS) also faces challenges, as it can detect ovarian lesions but suffers from poor specificity, often identifying benign lesions, leading to unnecessary surgeries. The low prevalence of ovarian cancer in the general population means that any effective screening tool would require extremely high sensitivity and specificity to avoid a large number of false positives.
Advancements in Treatment and Management
Medical advancements aim to improve outcomes and reduce the ovarian cancer death rate. Standard treatments typically involve optimal cytoreductive surgery, followed by platinum-based chemotherapy. While over 80% of patients may initially respond to first-line chemotherapy, around 70% of those with advanced disease experience recurrence within five years and can develop drug resistance.
Newer therapeutic approaches, including targeted therapies and immunotherapies, are showing promise by focusing on specific characteristics of cancer cells. Poly (ADP-ribose) polymerase inhibitors (PARPis), such as olaparib, niraparib, and rucaparib, are important for patients with BRCA1/2 mutations or homologous recombination repair deficiencies (HRD), as they exploit the cancer cells’ inability to repair DNA damage. Anti-angiogenic agents like bevacizumab, which block the formation of new blood vessels that feed tumors, have also demonstrated the ability to extend progression-free survival when combined with chemotherapy. Immunotherapy involves agents like immune checkpoint inhibitors (e.g., PD-1, PD-L1, CTLA-4 antibodies). While their effectiveness can vary and is still under investigation, these agents have shown durable responses in some patients, contributing to improved survival and quality of life.
Risk Factors and Prevention
Several factors increase ovarian cancer risk. Age is a factor, with most diagnoses occurring in women over 50. A family history of ovarian, breast, or colorectal cancer, due to genetic mutations like BRCA1 and BRCA2, also increases risk. Women with a BRCA1 mutation have an estimated lifetime ovarian cancer risk between 35% and 70%, while for BRCA2 mutations, the risk is estimated between 10% and 30% by age 70. Lynch syndrome genes also increase the risk of ovarian and uterine cancer.
Other risk factors include endometriosis, a condition where uterine lining tissue grows outside the uterus, and certain reproductive factors such as never having given birth, starting periods at a young age, or experiencing late menopause. Lifestyle considerations, like being overweight or smoking, can also increase risk. Strategies for risk reduction include genetic counseling for individuals with a strong family history. Prophylactic surgeries, such as the removal of fallopian tubes or ovaries, can significantly reduce risk for high-risk individuals. Using oral contraceptives for five or more years reduces ovarian cancer risk by approximately 50%, even in women with BRCA mutations.