Essential elements of a colorectal surgeon’s breach of duty report in bowel cancer claims under Bolam and Bolitho

Breach of duty: the legal framework

A colorectal surgeon’s breach of duty opinion in a failure to diagnose bowel cancer claim must determine whether the care provided fell below the standard expected of a reasonably competent practitioner at the material time, judged by the Bolam test as qualified by Bolitho. The report must address the claimant’s symptom presentation, adherence to relevant referral guidance, and any deviations in the diagnostic pathway, while distinguishing between the evidential weight of records, imaging, and clinical examination. Where the evidential base is incomplete, the opinion must state that limitation explicitly.

Core requirements for the breach of duty opinion

The central question is whether the defendant’s management of the claimant’s symptoms met the standard of a reasonably competent colorectal surgeon or general practitioner, as applicable, at the relevant date. The Bolam test requires the expert to identify the range of responsible professional opinion available at that time, and Bolitho requires that the opinion relied upon is capable of withstanding logical analysis. The report should:

• Record the claimant’s presenting symptoms, their duration, and any features that may raise suspicion of colorectal cancer (e.g., unexplained weight loss, rectal bleeding, change in bowel habit, iron-deficiency anaemia, or a palpable mass).
• Compare the actual management against relevant referral guidance, such as NICE’s Suspected cancer: recognition and referral. The expert must state whether such guidance applied at the material time and, if so, whether the defendant’s actions were consistent with it. The assessment should reflect clinical judgement, patient factors, and the context in which decisions were made.
• Assess whether the diagnostic pathway—including blood tests, imaging, and endoscopic investigations—was followed within a timeframe that a responsible body of practitioners would have considered acceptable. Common points of dispute include delays in arranging colonoscopy, CT colonography, or flexible sigmoidoscopy.
• Address whether any deviation from the expected pathway was justified by clinical judgement, patient factors, or resource constraints. The expert must explain why, if at all, such factors would have been accepted by a responsible body of practitioners at the material time.
• State whether, on the balance of probabilities, the defendant’s management fell outside the range of acceptable practice and whether that failure was logically defensible under Bolitho.

Where the defendant is a general practitioner, the colorectal surgeon’s opinion is limited to whether the GP’s referral decision was consistent with the standard expected of a reasonably competent GP at the time. The surgeon should not opine on GP-specific matters such as consultation length or record-keeping unless the instructions explicitly frame the question to include them.

The evidential base for the opinion

The strength of the opinion depends on the completeness of the records, imaging, and witness evidence. The report must list the documents reviewed and state any limitations arising from their absence or incompleteness.

• GP records: These should include the claimant’s presenting complaints, examination findings, blood test results (e.g., full blood count and ferritin), and any correspondence with secondary care. Where records are missing or illegible, the expert must state that the opinion is qualified by that gap.
• Hospital records: These should include outpatient letters, endoscopy reports, imaging requests and reports (e.g., CT, MRI, or ultrasound), and histology results. The expert must note whether the imaging was reported by a radiologist with appropriate subspecialty expertise in gastrointestinal imaging.
• Imaging: The expert must review the actual images, not just the radiology report. Where the images are unavailable, the opinion is limited to what the report describes. The expert must state whether the imaging was of sufficient quality to detect the lesion in question and whether the radiologist’s interpretation was reasonable.
• Witness evidence: The claimant’s account of symptoms and treatment may supplement the records. The expert must state whether the account is consistent with the medical records and, if not, how that affects the opinion.

Where a key document is missing—such as an endoscopy report or radiology image—the expert must state that the opinion is expressed subject to that limitation. The report cannot assume what the missing document would have shown.

Causation: the but-for test and material contribution

The colorectal surgeon’s opinion on causation must address whether, on the balance of probabilities, the claimant’s outcome would have been different but for the defendant’s breach of duty. The ordinary test is but-for causation: would the cancer have been diagnosed at an earlier stage, and would that have altered the claimant’s prognosis?

The expert must:

• State the stage of the cancer at the time of the alleged breach and at the time of actual diagnosis, using the TNM staging system or Dukes’ classification as appropriate.
• Compare the claimant’s actual prognosis with the prognosis that would have been expected had the cancer been diagnosed at the earlier stage. This requires an assessment of survival rates and treatment outcomes for the relevant stage, adjusted for the claimant’s age and comorbidities.
• Address whether earlier diagnosis would have avoided the need for more extensive surgery, chemotherapy, or radiotherapy, and whether it would have reduced the risk of recurrence or metastasis.

Material contribution may be relevant in limited circumstances, such as where the cancer was already at an advanced stage at the time of the alleged breach, but the delay may have contributed to the need for more aggressive treatment. The expert must explain why the ordinary but-for test is not satisfied and why, in the particular circumstances, a material contribution analysis is appropriate. The report must not present material contribution as a universal or minimal threshold test.

Scope of the colorectal surgeon’s expertise

The colorectal surgeon’s expertise is limited to the diagnosis, staging, and surgical management of bowel cancer. The report must not opine on matters outside this scope, including:

• Oncology: The appropriateness of chemotherapy or radiotherapy regimens, or the claimant’s response to those treatments, falls within the expertise of a clinical or medical oncologist.
• Radiology: While the colorectal surgeon may comment on whether the imaging was of sufficient quality to detect a lesion, the interpretation of the imaging itself is a matter for a radiologist with subspecialty expertise in gastrointestinal imaging.
• General practice: The standard of care expected of a GP in recognising symptoms and making an appropriate referral is a matter for a GP expert, unless the question has been explicitly framed to include it.
• Care and quantum: The claimant’s future care needs, life expectancy, and functional limitations are matters for a care expert, occupational therapist, or actuary, depending on the question in issue.
• Psychiatry: The claimant’s psychological response to the delay in diagnosis or the impact of a stoma on mental health is a matter for a psychiatrist or psychologist.

Where the question in issue spans more than one discipline, separate opinions from each relevant expert should be obtained. The colorectal surgeon’s report must state where the question falls outside their expertise.

Jurisdictional considerations

In England and Wales, the expert’s duty is governed by CPR Part 35, which requires the report to state the substance of all material instructions, whether written or oral, on the basis of which the report was written. The expert must also state any literature or other material on which they have relied and summarise the range of opinion on the matters dealt with in the report, giving reasons for their own opinion (CPR 35.10).

In Scotland, the equivalent question arises under Chapter 43 procedure. The expert’s duty is to the court, and the report must be objective and unbiased. The authority on the admissibility of skilled evidence is Kennedy v Cordia (Services) LLP [2016] UKSC 6, which sets out the four considerations for the admissibility of expert evidence: whether the evidence will assist the court, whether the expert has the necessary knowledge and experience, whether the expert is impartial, and whether there is a reliable body of knowledge or experience to underpin the expert’s evidence.

In Northern Ireland, the Rules of the Court of Judicature apply. The expert’s duty is to the court, and the report must comply with the requirements set out in the rules, which are broadly similar to CPR Part 35 in England and Wales.

Procedural aspects of expert evidence

Under CPR 35.6 (England and Wales), a party may put written questions to an expert instructed by another party. The questions must be proportionate and relate to matters within the expert’s expertise. The colorectal surgeon must answer the questions within the time specified by the court or the instructing solicitor, and the answers form part of the expert’s report. Where a question falls outside the expert’s expertise, the expert must state that they are unable to answer it.

Where two or more experts are instructed, the court may direct them to discuss the issues in the case and prepare a joint statement under CPR 35.12. The joint statement must set out the issues on which the experts agree, the issues on which they disagree, and the reasons for any disagreement. The experts must prepare the statement without influence from the instructing solicitors and must not be asked to defend a party’s case.

Under CPR 35.7, the court may direct that a single joint expert be instructed. The instructions to the single joint expert must be agreed by the parties or, failing agreement, determined by the court (CPR 35.8). The single joint expert’s duty is to the court, and the expert must not act as an advocate for either party.

Addressing uncertainty in prognosis

Where the claimant’s prognosis is uncertain—such as where the cancer is at an early stage but the risk of recurrence is not yet clear—the colorectal surgeon’s report must state the range of possible outcomes and the factors that will determine which outcome materialises. The report must not speculate on the claimant’s life expectancy or functional limitations beyond what the evidence supports.

The expert must distinguish between a fixed prognosis and a prognosis subject to review. Where the prognosis is subject to review, the report must state the intervals at which the claimant should be monitored and the investigations that should be performed. The report must also state whether the claimant’s condition is likely to deteriorate, improve, or remain stable over time, and the factors that may influence that trajectory.

Where the claimant has pre-existing bowel disease, such as inflammatory bowel disease or diverticular disease, the expert must address whether the delay in diagnosing the cancer accelerated the progression of the pre-existing condition or exacerbated its symptoms. The report must state whether the claimant’s current symptoms are attributable to the cancer, the pre-existing condition, or both.