Ovarian cancer misdiagnosis: when a delayed or missed diagnosis becomes negligence

Published 13 May 2026

TL;DR

Ovarian cancer misdiagnosis occurs when a GP or specialist fails to investigate symptoms that should have prompted investigation, causing the cancer to be diagnosed at a later stage
The most common failures are: dismissing persistent bloating, pelvic pain, or urinary symptoms without investigation; failing to order a CA-125 blood test; and failing to refer urgently after an abnormal ultrasound
The legal test is whether the clinician's response to the presenting symptoms fell below the standard of a responsible body of practitioners in the same field
Causation requires expert evidence on what stage the cancer would have been at with timely diagnosis, and what difference that would have made to treatment and outcome
The time limit is three years from the date of knowledge

Ovarian cancer misdiagnosis is one of the most significant categories of cancer negligence claim in the UK. Ovarian cancer is notoriously difficult to diagnose at an early stage because its symptoms (bloating, abdominal discomfort, urinary frequency, and loss of appetite) overlap with common benign conditions. This overlap makes it especially important that clinicians follow established investigation guidelines when these symptoms persist. When they do not, and the cancer progresses from an early treatable stage to an advanced one, a clinical negligence claim may arise.

What is ovarian cancer misdiagnosis in a legal context?

Ovarian cancer misdiagnosis, in the context of a negligence claim, refers to a failure by a clinician to investigate or refer a patient with symptoms consistent with ovarian pathology in accordance with the standard that a responsible body of practitioners would have applied. The Bolam test applies: the question is not whether a different clinician might have acted differently, but whether the defendant's conduct fell below the range of acceptable practice.

NICE guidance on suspected cancer (NG12) sets out clear criteria for urgent referral and investigation. A GP who sees a patient over 50 with persistent bloating and fails to request a CA-125 blood test acts outside the NICE guideline and outside the range of what a responsible body of GPs would have done. A specialist who receives an abnormal CA-125 result and an indeterminate ultrasound but fails to refer to gynaecological oncology may similarly be in breach.

For the full framework of how a cancer negligence claim is assessed, see the cancer negligence claim guide.

What are the common failures in ovarian cancer misdiagnosis?

Failure to test CA-125: the CA-125 blood test is the first-line investigation for women presenting with symptoms suggestive of ovarian cancer. Failure to order the test when NICE criteria are met is a common basis for a GP negligence claim.

Failure to refer for ultrasound: an elevated CA-125 result should prompt referral for pelvic ultrasound. Failure to act on an abnormal result, or failure to follow up an inconclusive result, is a recognised failure in the diagnostic pathway.

Misattributing symptoms to benign conditions: irritable bowel syndrome, urinary tract infections, and endometriosis share symptoms with ovarian cancer. A GP who repeatedly treats a patient for a benign condition without considering ovarian pathology, despite persistent or worsening symptoms, may be in breach if a responsible GP would have investigated further.

Failure to make an urgent two-week wait referral: where a patient's clinical picture meets the criteria for urgent referral to gynaecology, failure to make that referral within the appropriate timeframe is a breach of the referral standard.

Reporting errors on imaging: a radiologist who fails to identify an ovarian mass visible on ultrasound or CT imaging may be in breach if a responsible radiologist reviewing the same images would have identified the abnormality.

How is causation proved in an ovarian cancer misdiagnosis claim?

Causation in ovarian cancer misdiagnosis claims follows the same framework as other cancer negligence claims. The claimant must show, on the balance of probabilities, that the negligent delay caused a materially worse outcome than timely diagnosis would have produced.

Expert gynaecological oncologists assess: at what stage the cancer would have been diagnosed with timely investigation; what the treatment implications of earlier diagnosis would have been (whether the patient would have been suitable for fertility-sparing surgery, whether chemotherapy could have been avoided, whether the cancer would have been resectable); and what effect the delay had on survival.

The Gregg v Scott difficulty applies: if the claimant had a less than 50% prospect of a better outcome even with timely diagnosis, causation on the balance of probabilities is not established. In practice, this means the strength of the causation case depends heavily on the biology of the particular cancer, its growth rate, and the length of the delay.

For the full explanation of how misdiagnosis causation is assessed, see the misdiagnosis claim guide.

Compensation in an ovarian cancer misdiagnosis claim

Compensation in an ovarian cancer misdiagnosis claim is assessed by reference to the harm caused by the delay. Where the delay converted a stage 1 cancer into a stage 3, the damages reflect the difference in treatment, prognosis, and quality of life.

General damages are assessed under the Judicial College Guidelines (17th edition, April 2024). In cases where the delay has materially shortened life expectancy and the claimant is aware of a terminal prognosis, general damages for pain, suffering, and loss of amenity are substantial. Special damages include lost earnings, care costs, and the cost of private oncology treatment necessitated by the negligence.

Where the negligent delay converts an operable cancer to an inoperable one, or where the patient required significantly more aggressive treatment because of the delay, general damages reflect the additional treatment burden and its consequences for daily life.

For compensation ranges, see the compensation guide.

Time limits and starting a claim

The time limit is three years from the date of knowledge. In ovarian cancer misdiagnosis cases, the date of knowledge is often the date the patient was told their cancer was at an advanced stage and that an earlier diagnosis had been missed, or the date they obtained legal advice that the delay was attributable to a clinical failure.

A solicitor will obtain GP records, hospital records, imaging reports, pathology reports, and CA-125 results. Independent experts in gynaecological oncology and general practice will report on breach and causation. For time limits, see the time limits guide. For funding, see the funding guide.

This page provides legal information, not legal advice. If you believe an ovarian cancer diagnosis was delayed or missed due to clinical negligence, speak to a qualified solicitor who specialises in clinical negligence.