Screening for oral malignancy: Evaluating diagnostic failure in the primary care setting

In the clinical environment of primary dental care, the early identification of suspicious oral soft tissue lesions is a key component of the clinician’s professional obligations. The diagnostic pathway involves clinical examination, comprehensive record-keeping, and appropriate referral for specialist assessment. Medico-legal complications often arise when these steps are perceived as omitted or delayed, leading to a later stage of presentation and potential challenges in determining whether the outcome was adversely affected.

Assessing breach of duty in these cases requires an analysis of the records against the standard of care as defined in Bolam v Friern Hospital Management Committee [1957] and Bolitho v City and Hackney Health Authority [1998]. The court must determine whether the clinician’s failure to act constituted a departure from a responsible body of professional opinion, and whether that action, or inaction, has a logical basis. In the context of clinical evaluation in primary and acute care, the assessment focuses on whether the clinician identified the presence of an abnormality, assessed its features, and acted within a timeframe consistent with reasonable clinical practice.

Clinical Context and Diagnostic Standards

Diagnosis of oral malignancy is inherently challenging because many soft tissue lesions may initially present in a manner similar to inflammatory conditions, such as traumatic ulceration. Clinicians are generally expected to perform a systematic soft tissue examination during routine care and to document their findings. This documentation is central to any subsequent medico-legal review. The absence of details such as the size, precise location, or appearance of a lesion in the clinical notes often complicates the ability to defend or support a claim.

When a lesion is identified, the clinician must exercise professional judgement regarding whether to place the patient on a structured review or to make an urgent referral. This decision typically considers the duration of the lesion, symptoms, and clinical features such as induration or a lack of resolution. Failure to order appropriate investigations, such as clinical photography or timely biopsy, or over-reliance on clinical appearance, may form part of an expert’s assessment of whether a diagnostic failure occurred.

The Burden of Causation

Causation remains a central and often contested element in delayed referral claims. Establishing that a delay resulted in a worse clinical outcome—such as a change in the required therapeutic modality—requires evidence that differentiates the patient’s prognosis at the time of the alleged breach from the prognosis at the time of the actual diagnosis. This analysis must be evidence-based, considering the known biological behaviour of the suspected malignancy.

Legal teams should note that a delay in diagnosis does not necessarily equate to a compensable loss of chance. Following Gregg v Scott [2005], practitioners must ensure that the expert’s report clearly links the delay to a tangible worsening of the patient’s condition. A comprehensive review of the patient’s records is necessary to provide an objective assessment of what was known, or what ought to have been known, at every stage of the clinical interaction.

Expert Instruction and Procedure

Identifying an appropriate expert witness is a vital step in building a claim. Cases involving oral malignancy often require the input of a consultant in oral and maxillofacial surgery, who may be uniquely positioned to comment on the transition of care between primary dental settings and hospital-based oncology units. Solicitors should frame instructions to ensure the expert addresses:

• Whether the clinical records indicate that the patient’s symptoms were assessed and acted upon appropriately.
• Whether a reasonable clinician would have suspected malignancy or acted with greater urgency.
• The extent to which any identified delay contributed to the patient’s staging and treatment requirements.
• Whether the patient was informed of the risks and the necessity of follow-up for non-diagnostic findings, consistent with the principles in Montgomery v Lanarkshire Health Board [2015].

When instructing experts, it is essential to provide a complete chronological set of records, including all relevant imaging and medical history. Where a single joint expert is appointed under CPR 35.7, the letter of instruction should be precise and governed by CPR 35.8. If the court directs, or if it is otherwise appropriate, experts may be asked to discuss the case under CPR 35.12 to narrow the issues in a joint statement. This process must remain independent, focusing on the objective interpretation of the clinical timeline and scientific evidence surrounding tumour progression, ensuring the court receives a clear and impartial view of the evidence.