Guidance

Cervical screening: review and classification of previous screening results

Updated 26 September 2024

Applies to England

The guidance below sets out the 3 possible classifications (‘satisfactory’, ‘satisfactory with learning points’ or ‘unsatisfactory’) for the review of screening histories involving:

• cervical cytology slide reviews
• histology slide reviews
• colposcopy management reviews

For cases where the review classification is ‘unsatisfactory’, apply duty of candour. See section 7 in the guidance on disclosure of cervical screening history review results and applying duty of candour.

Cervical cytology slide reviews

A flowchart (with text description) is available which describes the cervical cytology slide review process.

Any cytology slide review undertaken in line with requirements set out in NHS Cervical Screening Programme (NHS CSP) guidance is for education and audit purposes. It is not undertaken as a medico-legal review, which is a different approach and would be done to a different set of standards.

All slide results reviewed for the invasive cervical cancer audit must be categorised into one of the 3 classifications below. Audit classifications of ‘unsatisfactory’ must be agreed as such by at least 2 senior consultant members of staff qualified in that area of clinical practice, are actively working in the NHS CSP, and meet the standards set out for the programme.

Cervical cytology slide review classifications

Satisfactory

A satisfactory classification is one which, on review, agrees with the previous cytology report(s).

Satisfactory with learning points

This classification means abnormalities are present, but only seen on review and with hindsight and full knowledge that this is a cancer case. This will include cases known to be difficult to perceive or identify, or cases that are not clearly abnormal. Whilst many of these cases are identified at screening, some are not. These cases may provide learning for the programme as they are likely to be an unavoidable error.

The ‘satisfactory with learning points’ classification are cases that evidence indicates are at the limit of detection by cytology screening staff. They include:

• low abnormal cell numbers (less than 50 cells in a liquid-based cytology (LBC) sample)
• hyperchromatic crowded groups (HCGs)
• small cell dyskaryosis
• pale cell dyskaryosis
• bland cell dyskaryosis
• small cell severe dyskaryosis
• small keratinised cells
• glandular abnormalities of low number and/or subtle architectural/cytological changes
• poorly preserved abnormal cells
• borderline changes on review in the absence of any definite dyskaryotic changes

In some cases there may be a combination of these features.

Cases where, in hindsight, the slide is considered likely to have been of poor technical quality at the time of initial reporting (taking into account technical deterioration judged to have occurred due to storage over time since the slide was prepared) should also be considered as ‘satisfactory with learning points’.

Unsatisfactory

This classification includes:

• cases where on review the appearances are obvious and the cytology should have been reported as requiring further action; these are cases that competent screeners and reporting staff would have identified and as such are an avoidable error of the cervical screening programme*
• cases not managed according to national guidance and that do not have adequate explanation, for example if a negative cytology result following treatment required a human papillomavirus (HPV) test to be carried out and this was not done
• cases not managed according to national guidance and for which no apparent reason is recorded

*The performance of all staff is closely monitored within the NHS CSP and any identified issue does not necessarily reflect an individual’s skills or abilities.

‘Unsatisfactory’ classifications fall under duty of candour.

Cervical histology slide reviews

A flowchart (with text description) is available which describes the cervical histology slide review process.

Any histology slide review undertaken in line with requirements set out in NHS CSP guidance is for education and audit purposes. It is not undertaken as a medico-legal review, which is a different approach and would be done to a different set of standards.

All slides reviewed for the invasive cervical cancer audit must be categorised into one of the 3 classifications below. Audit classifications of ‘unsatisfactory’ must be agreed as such by at least 2 senior consultants who are actively reporting histology for the NHS CSP and meet the standards set out for the programme.

Cervical histology slide review classifications

Satisfactory

A ‘satisfactory’ classification is one which, on review, agrees with original pathology report and no material differences are found that would have affected management at the time of the original report.

Satisfactory with learning points

This classification, on review, shows minor differences or learning points that would not have materially affected the report and management at the time of the original report, but which are of educational value.

This includes issues such as:

• under or over use of stains, levels, or other ancillary techniques
• inappropriate use of stains, levels, or other ancillary techniques
• clarity of pathological information could have been better
• inappropriate stage based on pathology report information (which would have been clarified and resolved at colposcopy multi-disciplinary team (MDT) meeting discussion)
• a difficult case where there is acceptable and appropriate professional disagreement
• the specimen is not considered to be satisfactory for diagnostic purposes, for example does not contain appropriate tissue
• a low grade or negative lesion called high grade (for both cervical intraepithelial neoplasia (CIN) and cervical glandular intraepithelial neoplasia (CGIN)

Unsatisfactory

This classification, on review, has significant differences identified that would have affected patient management at the time of the original report.

‘Unsatisfactory’ classifications fall under duty of candour.

Reasons for an unsatisfactory classification may include:

• a high grade lesion called low grade or negative (for both cervical intraepthelial neoplasia (CIN) and cervical glandular intraepithelial n neoplasia (CGIN))
• missed invasive cancer (of any size, type or stage)
• undercall of an invasive lesion as not invasive
• overcall of a non-invasive lesion as invasive
• incorrect tumour classification that would have resulted in different management, for example, sarcoma, lymphoma, missed small cell carcinoma, non-identification of metastatic disease

Colposcopy management reviews

Any colposcopy review undertaken in line with requirements set out in NHS CSP guidance is for education and audit purposes. It is not undertaken as a medico-legal review, which is a different approach and would be done to a different set of standards.

All colposcopy attendances reviewed for the invasive cervical cancer audit must be categorised into one of the 3 classifications below. Audit classifications of ‘unsatisfactory’ must be agreed by at least 2 senior colposcopists actively working in the NHS CSP, who meet the standards set out for the programme.

Colposcopy review classifications

Satisfactory

‘Satisfactory’ management is that which, on review, shows the colposcopy management and related documentation is fully in line with national guidance in place at the time, and no material differences are found that would have affected management.

Satisfactory with learning points

This classification includes cases which show:

• incomplete documentation
• management was in line with national guidance but with the benefit of hindsight could have been improved, for example:
  • not undertaking treatment in a poor attender with a high grade referral
  • repeat excisional treatment was not considered at the first follow up after treatment with previous incomplete excision of high grade and squamo-columnar junction not seen
  • a surveillance option chosen over immediate treatment
  • inadequate depth of treatment without clear excision margins and without adequate explanation
  • the case met criteria for discussion at a colposcopy MDT meeting but was not discussed
  • multiple pieces of tissue excised during treatment without explanation

Unsatisfactory

This classification is for cases which, on review, identify significant differences that would have affected patient management at the time of colposcopy attendance.

‘Unsatisfactory’ colposcopy management cases fall under duty of candour.

Reasons for an ‘unsatisfactory’ classification include:

• high grade cytology referral with no biopsy taken without appropriate reason recorded
• treatment indicated based on cytology referral or colposcopic findings but not carried out and no reason or colposcopy MDT discussion recorded
• ablative treatment for CIN/CGIN undertaken without a biopsy being taken in advance
• failure to follow up and issue appointment at the appropriate interval, for example, pregnant patients or those requiring future colposcopic follow up
• clinical management plan not carried out and no reason recorded
• confirmed CGIN with incomplete excision margins not offered re-excision
• inappropriate discharge to routine recall
• failure to follow national guidance with no explanation and no discussion at colposcopy MDT
• cancer diagnosed within 12 months of colposcopy assessment and cancer stage such that it is judged to have probably been present at colposcopy

Duty of candour application

All assessments are considered in the context of an individual being diagnosed with cervical cancer.

An individual’s screening history can involve any or all of a combination of cervical cytology, cervical histology and colposcopy attendances. Each must be given a classification of satisfactory, satisfactory with learning points or unsatisfactory.

Classifications of satisfactory or satisfactory with learning points do not fulfil the definition of harm that requires the duty of candour process to be followed.

However, they are disclosed if the individual has requested feedback as part of the routine disclosure of audit process.

Cases identified as unsatisfactory fulfil the definition of moderate or severe harm and are therefore classified as a notifiable safety incident. The duty of candour process is followed in these circumstances.

The classification of each element of the screening history must be disclosed when discussing with individuals, whether or not duty of candour applies.