Ovarian Cancer
Ovarian cancer is a malignancy arising in or around the ovaries, and it behaves differently from most other gynaecological cancers in one crucial respect: it produces vague symptoms that are easily attributed to something else, and there is no effective screening test. The result is that most women are diagnosed once the disease has already spread within the abdomen. Understanding has shifted considerably in recent years—many of the most common tumours are now thought to originate in the fallopian tube rather than the ovary itself, and genetic testing has become central to both treatment and family risk assessment. Treatment has also changed substantially, with targeted maintenance therapy meaningfully extending the time many women remain free of disease.
What is it?
The ovaries are paired organs sitting on either side of the uterus, producing eggs and the hormones oestrogen and progesterone. They lie free within the abdominal cavity rather than being enclosed in a confined space, and this anatomical fact shapes much of how ovarian cancer behaves: cells shed from a tumour can circulate in the fluid within the abdomen and implant across peritoneal surfaces, spreading widely before causing symptoms that would prompt investigation.
Ovarian cancer is not a single disease but a group of tumours with different origins, behaviour, and treatment.
Epithelial tumours account for the large majority. Within these, high-grade serous carcinoma is by far the most common and the most consequential. Other types include low-grade serous, endometrioid, clear cell, and mucinous carcinomas, each with distinct behaviour—endometrioid and clear cell tumours are associated with endometriosis, and mucinous tumours are often diagnosed at an earlier stage.
A significant shift in understanding concerns where high-grade serous cancer actually starts. Evidence accumulated over the past two decades indicates that many of these tumours originate not in the ovary but in the fimbrial end of the fallopian tube, from a precursor lesion that then spreads to the ovary and peritoneum. This has practical consequences: it explains why removing the tubes alone may reduce risk, why the disease is often widespread when the ovaries themselves look relatively unremarkable, and why the terms ovarian, fallopian tube, and primary peritoneal cancer are increasingly treated as one entity for treatment purposes.
Germ cell tumours arise from egg-producing cells, occur predominantly in adolescents and young women, and—importantly—are usually curable even when advanced, with fertility-preserving surgery often possible.
Sex cord-stromal tumours, including granulosa cell tumours, arise from hormone-producing tissue. They often produce oestrogen, which can cause abnormal bleeding or, in young girls, early puberty, and this hormonal effect sometimes brings them to attention earlier.
Borderline tumours, also called tumours of low malignant potential, are an intermediate category: they have abnormal cells but do not invade in the usual way, occur in younger women, and have a very good outlook with surgery alone, often preserving fertility.
The risk factors reflect two broad mechanisms—the number of times a woman ovulates over her lifetime, and inherited genetic susceptibility.
Anything that reduces lifetime ovulation appears protective. Pregnancy, breastfeeding, and combined hormonal contraception all reduce risk, with the pill conferring substantial protection that increases with duration of use and persists for decades afterwards. Conversely, never having been pregnant, early first period, and late menopause increase risk.
Endometriosis increases risk, particularly of clear cell and endometrioid types, though the absolute increase remains modest.
Inherited factors are the most important individual determinant. Around 15 to 20 percent of ovarian cancers are associated with an inherited gene alteration. BRCA1 and BRCA2 are the most common, carrying substantially elevated lifetime risks—considerably higher for BRCA1 than BRCA2—alongside increased breast cancer risk. Lynch syndrome, and alterations in other genes including RAD51C, RAD51D, and BRIP1, also contribute. This proportion is high enough that genetic testing is now recommended for every woman diagnosed with ovarian cancer regardless of family history, because a meaningful number of carriers have no suggestive family history at all.
A family history of ovarian, breast, bowel, or endometrial cancer—particularly at younger ages or in multiple relatives—warrants genetic assessment even in the absence of a personal diagnosis.
The symptoms of ovarian cancer are the crux of the problem, and they deserve careful explanation rather than a simple list.
The commonly cited symptoms are persistent bloating or increased abdominal size, feeling full quickly or loss of appetite, pelvic or abdominal pain, and urinary urgency or frequency. The difficulty is that these are extremely common symptoms with overwhelmingly benign causes, and most women experiencing them do not have ovarian cancer.
What distinguishes concerning symptoms is their pattern rather than their nature. Symptoms that are persistent rather than intermittent, frequent—typically occurring more than twelve times in a month—and new, having begun within the past year rather than being a lifelong pattern, are the ones that warrant investigation. A woman who has had bloating on and off for twenty years is describing something different from a woman whose abdomen has become persistently distended over three months.
The phrase often used is that the symptoms are vague but not silent. Studies have consistently shown that most women with ovarian cancer did have symptoms before diagnosis, frequently for months, and that these were attributed to irritable bowel syndrome, menopause, ageing, stress, or dietary causes—by the women themselves and sometimes by clinicians.
Other features include change in bowel habit, unexplained fatigue, back pain, pain during intercourse, unintentional weight loss, and abnormal vaginal bleeding, which is less common than in endometrial cancer but does occur.
Advanced disease produces a rapidly enlarging abdomen from ascites, breathlessness from fluid restricting the diaphragm or accumulating around the lungs, a palpable mass, bowel obstruction, and significant weight loss with preserved or increasing abdominal girth—a combination that is particularly characteristic.
New irritable bowel syndrome presenting for the first time in a woman over 50 is specifically worth noting, as this is an unusual age for genuinely new IBS and is a recognised pattern in delayed ovarian cancer diagnosis.
Diagnosis begins with recognising that investigation is warranted.
Transvaginal ultrasound is the first-line test. It assesses ovarian size and the characteristics of any mass, with concerning features including solid components, thick or irregular internal divisions, irregular walls, papillary projections, increased blood flow within solid areas, and accompanying fluid in the abdomen. Structured reporting systems have improved consistency in describing and categorising ovarian masses.
CA-125 is a blood marker measured alongside ultrasound, and its limitations deserve clear statement. It is normal in a substantial proportion of early-stage cancers, so a normal result does not exclude the diagnosis. It is raised in many benign conditions—endometriosis, fibroids, pelvic infection, liver disease, heart failure, recent surgery, pregnancy, and even normal menstruation—so an elevated result does not establish it. It is most useful in postmenopausal women and for monitoring response once a diagnosis is confirmed. In younger women with a suspicious mass, additional markers are measured to assess for germ cell tumours.
Risk scoring systems combine ultrasound appearance, CA-125 level, and menopausal status to estimate the likelihood of malignancy and to direct referral to specialist gynaecological oncology services, which matters because outcomes are better when surgery is performed by specialist teams.
CT of the chest, abdomen, and pelvis assesses the extent of disease and helps determine whether complete surgical removal is realistic.
MRI characterises masses that remain indeterminate on ultrasound and is particularly useful for distinguishing benign from malignant features.
Tissue diagnosis is confirmed at surgery in many cases, or by image-guided biopsy where chemotherapy is planned first.
Screening deserves specific comment because it is a common question. There is no effective screening test for ovarian cancer in the general population. Large randomised trials, including a major long-term UK study, tested annual screening with CA-125 and ultrasound and found that although it detected some cancers earlier, it did not reduce deaths from the disease. It also produced false positives leading to unnecessary surgery. Screening is therefore not recommended for women at average risk, which places the emphasis firmly on prompt investigation of symptoms and on risk-reducing strategies for women with inherited susceptibility.
Important to Know
Ovarian cancer is frequently diagnosed at an advanced stage, but advanced disease is not the same as untreatable disease. Many women respond very well to treatment, and maintenance therapy has substantially extended the time women remain free of progression. Care should be coordinated by a specialist gynaecological oncology team, and this is one of the clearest examples in cancer medicine where where a woman is treated affects her outcome.
Surgery is central, and the single most important surgical factor is completeness. Outcomes are meaningfully better when all visible disease is removed, and achieving this often requires extensive surgery involving the omentum, peritoneal surfaces, and sometimes bowel. This is why referral to a specialist centre with surgeons experienced in complex cytoreductive surgery matters, and why it is reasonable to ask whether the operating team performs this surgery regularly.
The sequence of treatment varies. Surgery first, followed by chemotherapy, is preferred where complete removal appears achievable. Where disease is very extensive or a woman is not fit for major surgery initially, chemotherapy is given first, with surgery performed partway through once the disease has responded. Both approaches are legitimate and the choice is individualised.
Chemotherapy is platinum-based, usually carboplatin combined with paclitaxel. Most high-grade serous cancers respond well initially, and response to platinum is an important predictor of how the disease will behave subsequently.
Maintenance therapy represents the most significant advance in this field in decades. PARP inhibitors, given after chemotherapy, substantially extend the time before disease returns, with the greatest benefit in women with BRCA alterations or with homologous recombination deficiency, and benefit also demonstrated in broader groups. Antiangiogenic treatment with bevacizumab is used in selected women. Which options apply depends directly on genetic and molecular testing of both the woman and her tumour, which is why that testing is performed early rather than deferred.
Genetic testing is recommended for every woman diagnosed with ovarian cancer. It determines eligibility for maintenance treatment, and it identifies inherited risk that has major implications for relatives. Sisters, daughters, and other family members of a woman found to carry a BRCA alteration can be tested and, if they carry it, offered risk-reducing measures that are highly effective.
For women known to carry a high-risk gene alteration, risk-reducing surgery—removal of the tubes and ovaries, usually after childbearing is complete and at an age guided by the specific gene—substantially reduces the risk of ovarian cancer and is the most effective intervention available. It causes surgical menopause, and hormone replacement is generally appropriate for younger women without a contraindication. Removing the tubes first with delayed ovary removal is being studied as an alternative that defers menopause, and is available in some settings and trials.
Opportunistic salpingectomy—removing the fallopian tubes at the time of other pelvic surgery such as hysterectomy or instead of tubal ligation for sterilisation—is increasingly recommended as a population-level risk reduction measure, on the basis that many high-grade serous cancers begin in the tube. It adds little to the operation and does not affect ovarian hormone production.
Fertility preservation is relevant for younger women, particularly those with germ cell tumours, borderline tumours, or early-stage disease confined to one ovary, where surgery preserving the uterus and the other ovary may be appropriate. This should be discussed before treatment begins.
Recurrence is common in advanced disease, and the approach to it depends heavily on how long it has been since platinum chemotherapy. Longer intervals predict better response to further platinum treatment. Many women go through multiple lines of treatment over years, and the disease is increasingly managed as a long-term condition with periods of treatment and periods off it.
Managing ascites, bowel obstruction, and nutrition is an important part of care in advanced disease. Drainage of abdominal fluid provides substantial relief, and an indwelling drain allows this at home for recurrent accumulation. Palliative care involvement improves quality of life and is appropriately introduced alongside active treatment rather than only at the end.
Because symptoms are the only early warning available, awareness matters more in this cancer than in most. Persistent bloating, early satiety, abdominal or pelvic pain, and urinary urgency that are new, frequent, and ongoing warrant assessment—not reassurance that they are probably nothing. It is reasonable for a woman to ask specifically for an ultrasound and CA-125 if these symptoms persist, and to return if symptoms continue despite initial reassurance.
Care is coordinated by gynaecological oncology, with genetics, medical oncology, radiology, pathology, palliative care, and specialist nursing. Imaging, markers, pathology, and genetic findings are interpreted together alongside a woman’s age, fitness, and priorities.
Patient education plays an important role. Understanding that symptoms are vague but usually present, that persistence and frequency are what matter, that no screening test exists, that CA-125 is unreliable in isolation, that genetic testing benefits both the woman and her family, and that maintenance therapy has changed the outlook considerably all contribute to appropriate care.
Red flag symptoms include persistent bloating or a lasting increase in abdominal size; feeling full quickly or a persistent loss of appetite; pelvic or abdominal pain occurring most days; needing to pass urine more often or more urgently; any of these occurring more than twelve times a month or persisting beyond three weeks; new bowel symptoms or a diagnosis of irritable bowel syndrome made for the first time over the age of 50; unexplained weight loss, particularly alongside increasing abdominal size; breathlessness or abdominal swelling that is worsening; abnormal vaginal bleeding; severe sudden pelvic pain, which may indicate torsion or rupture of an ovarian mass and requires urgent assessment; and a family history of ovarian or breast cancer alongside any of these. These warrant prompt medical evaluation, typically with ultrasound and a CA-125 blood test.