Ovarian cancer: symptoms, treatment and survival

Ovarian cancer is a malignant tumour arising from the ovaries, fallopian tubes or peritoneum. It is the UK's fourth most common cancer in women, with approximately 7,500 new diagnoses each year, and the most deadly gynaecological cancer — causing around 4,200 deaths annually. The vast majority (90–95%) are epithelial ovarian cancers; the most common subtype is high-grade serous carcinoma.

The NHS highlights four key symptoms that, when persistent (occurring more than 12 times per month), should prompt a GP visit: persistent bloating (not coming and going); pelvic or abdominal pain; difficulty eating or feeling full quickly; and increased urinary urgency or frequency. Other symptoms include unexplained weight loss, changes in bowel habits and extreme fatigue. These symptoms are common and non-specific — the persistence and frequency matter more than the symptoms themselves.

The exact cause is unknown but is related to a combination of genetic and hormonal factors. High-grade serous ovarian carcinoma (the most common type) is strongly associated with BRCA1 and BRCA2 mutations and appears to originate in the fallopian tube rather than the ovary itself. Factors that increase the number of ovulation cycles (nulliparity, late menopause, no breastfeeding) increase risk, while factors that suppress ovulation (combined pill, pregnancy) are protective. Lynch syndrome (mismatch repair gene mutations) also significantly increases risk.

CA-125 (cancer antigen 125) is a protein produced by ovarian cancer cells that is measurable in the blood. It is elevated in approximately 80% of advanced epithelial ovarian cancers and is used in diagnosis and monitoring of treatment response and recurrence. However, CA-125 is not a reliable early detection test — it is normal in some ovarian cancers and elevated in benign conditions including endometriosis, fibroids, menstruation and pelvic inflammatory disease. It is used in conjunction with ultrasound scan, not as a standalone test.

Approximately 15–20% of epithelial ovarian cancers are hereditary, most commonly caused by mutations in BRCA1 or BRCA2. A BRCA1 mutation confers a 44–46% lifetime risk of ovarian cancer; BRCA2 confers 12–20% risk. Lynch syndrome (mutations in MLH1, MSH2, MSH6 or PMS2) also significantly increases risk. Germline BRCA testing is offered to all women diagnosed with high-grade epithelial ovarian cancer, and cascade testing to their relatives through NHS Clinical Genetics. Risk-reducing salpingo-oophorectomy is recommended for BRCA carriers after childbearing is complete.

Diagnosis begins with a CA-125 blood test and transvaginal/pelvic ultrasound, combined to calculate a Risk of Malignancy Index (RMI). If RMI or clinical suspicion is high, urgent referral to a specialist gynaecological oncology centre is made. A CT scan stages the disease. Definitive diagnosis requires histopathological examination of tumour tissue — at surgery or via image-guided biopsy. Molecular testing (BRCA germline and tumour BRCA/HRD status) is performed on all high-grade epithelial ovarian cancers.

Ovarian cancer is staged I–IV using the FIGO staging system. Stage I: confined to the ovary/fallopian tube. Stage II: spread to pelvic organs (uterus, fallopian tube, peritoneum). Stage III: spread to the abdominal peritoneum beyond the pelvis or retroperitoneal lymph nodes. Stage IV: distant metastasis (pleural effusion, liver parenchyma, distant organs). Approximately 85% of UK ovarian cancers are diagnosed at Stage III or IV.

Standard first-line treatment is cytoreductive surgery followed by six cycles of carboplatin and paclitaxel chemotherapy. Surgery aims to remove all visible tumour — complete cytoreduction is the strongest predictor of survival. For advanced disease, chemotherapy may be given before surgery (neoadjuvant) to reduce tumour bulk. Maintenance therapy with PARP inhibitors (olaparib — NICE approved for BRCA-mutated disease) or bevacizumab follows first-line chemotherapy in eligible patients.

PARP inhibitors are targeted drugs that exploit a weakness in tumour cells with BRCA1, BRCA2 or other homologous recombination repair gene mutations — blocking a DNA repair pathway on which these cells depend. Olaparib (Lynparza) is NICE-approved as maintenance therapy for BRCA-mutated advanced ovarian cancer after response to first-line platinum chemotherapy, significantly prolonging progression-free survival. Niraparib is approved for all platinum-sensitive recurrent ovarian cancers regardless of BRCA status. PARP inhibitors are tablets taken daily.

Five-year survival rates in England: Stage I — over 90%; Stage II — approximately 65–70%; Stage III — approximately 35–40%; Stage IV — approximately 20%. Overall five-year survival for all stages combined is approximately 47%, reflecting the high proportion diagnosed at advanced stage. Survival has improved over the past decade with the introduction of PARP inhibitor maintenance therapy, particularly for BRCA-mutated disease.

Risk reduction options for high-risk women (BRCA carriers) include risk-reducing bilateral salpingo-oophorectomy — surgical removal of the fallopian tubes and ovaries — which reduces ovarian cancer risk by over 95%. For women of average risk, long-term use of the combined oral contraceptive pill reduces lifetime ovarian cancer risk by approximately 40–50%. There is currently no national ovarian cancer screening programme in the UK — large trials (UKCTOCS) found that CA-125-based screening did not reduce ovarian cancer mortality.

Most advanced ovarian cancers recur within two to three years of completing first-line treatment, despite an initial good response to chemotherapy. Recurrence is classified as platinum-sensitive (relapse more than six months after completion of platinum chemotherapy — re-treatment with platinum is effective) or platinum-resistant (relapse within six months — different chemotherapy agents and targeted therapies are used). Managing recurrent ovarian cancer is complex and is best done at a specialist gynaecological oncology multidisciplinary team.

Debulking surgery (cytoreductive surgery) is the primary surgical treatment for ovarian cancer. The aim is to remove all visible tumour — achieving 'complete cytoreduction' (no residual disease). The standard procedure is total hysterectomy, bilateral salpingo-oophorectomy, omentectomy and removal of all peritoneal disease, which may include bowel resection, splenectomy or peritoneal stripping. Surgeries are performed by specialist gynaecological oncology surgeons at designated cancer centres. Complete cytoreduction is the single most important factor predicting long-term survival.

Ovarian cysts are fluid-filled sacs within or on the ovary and are extremely common — most are benign and resolve without treatment. Ovarian cancer is a malignant tumour with the capacity to invade surrounding tissue and metastasise. Most ovarian cysts are functional (follicular or corpus luteum cysts), dermoid cysts, endometriomas or serous/mucinous cystadenomas — all benign. Risk of malignancy is assessed using CA-125, ultrasound features and RMI. Most simple ovarian cysts in premenopausal women can be managed conservatively with repeat ultrasound.

Long-term use of combined HRT (oestrogen and progesterone) modestly increases ovarian cancer risk by approximately 20–40%. Oestrogen-only HRT (used in women without a uterus) carries a slightly higher risk than combined HRT. The absolute risk increase is small — the Million Women Study estimated approximately one extra ovarian cancer per 1,000 women using HRT for five years. The decision about HRT should weigh menopausal symptom impact against individual risk factors. Short-term HRT use for symptom control is generally considered acceptable for average-risk women.

Endometriosis is associated with an increased risk of certain ovarian cancer subtypes — particularly clear cell and endometrioid carcinoma. However, the absolute risk of ovarian cancer in women with endometriosis remains low. The presence of endometriosis does not mean that ovarian cancer will develop, and the vast majority of women with endometriosis never develop ovarian cancer. Women with endometriosis are encouraged to report new or changing symptoms and attend regular gynaecological follow-up.

A BRCA test is a blood or saliva test that analyses the BRCA1 and BRCA2 genes for mutations that significantly increase the risk of breast and ovarian cancer. In the NHS, BRCA testing is offered to all women diagnosed with high-grade epithelial ovarian cancer (as the result affects treatment choices, particularly PARP inhibitor eligibility) and to their first-degree relatives through NHS Clinical Genetics. Women found to carry a BRCA mutation can access enhanced surveillance and risk-reduction options.

Yes — ovarian cancer symptoms can closely mimic bowel conditions, particularly IBS and constipation. Bloating, abdominal discomfort and altered bowel habit are common to both. The key distinguishing feature of ovarian cancer symptoms is their persistence and frequency — occurring more than 12 times per month, rather than being intermittent. Women over 50 who develop persistent bloating, pelvic pain, or urinary symptoms for the first time should be assessed for ovarian cancer, not automatically attributed to IBS.

Germ cell tumours of the ovary arise from the egg-producing cells and account for approximately 2–3% of all ovarian cancers. They are more common in younger women and girls. The most common type is a dysgerminoma. Unlike epithelial ovarian cancer, germ cell tumours are usually highly responsive to chemotherapy (BEP regimen — bleomycin, etoposide, cisplatin) and can often be treated with fertility-sparing surgery (removing only the affected ovary). Five-year survival for germ cell tumours is generally excellent — over 90% even for advanced disease.

In low-income countries, the combination of late-stage diagnosis, absence of cytoreductive surgical expertise at district level, and unaffordability of platinum chemotherapy and PARP inhibitors means ovarian cancer outcomes are far worse than in the UK. Many patients present with advanced disease and receive no systemic treatment. World Aid Network funds cancer treatment for poor patients through locally-licensed oncologists, supporting access to chemotherapy and surgical care that would otherwise be inaccessible.