Impact of a national external quality assessment scheme for breast pathology in the UK

BACKGROUND

This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology.

AIMS/METHODS

The major objectives were to monitor and improve the consistency of diagnoses made by pathologists and the quality of prognostic information in pathology reports. The scheme is based on a twice yearly circulation of 12 cases to over 600 registered participants. The level of agreement was generally measured using kappa statistics.

RESULTS

Four main situations were encountered with respect to diagnostic consistency, namely: (1) where consistency is naturally very high-this included diagnosing in situ and invasive carcinomas (and certain distinctive subtypes) and uncomplicated benign lesions; (2) where the level of consistency was low but could be improved by making guidelines more detailed and explicit-this included histological grading; (3) where consistency could be improved but only by changing the system of classification-this included classification of ductal carcinoma in situ; and (4) where no improvement in consistency could be achieved-this included diagnosing atypical hyperplasia and reporting vascular invasion. Size measurements were more consistent for invasive than in situ carcinomas. Even in cases where there is a high level of agreement on tumour size, a few widely outlying measurements were encountered, for which no explanation is readily forthcoming.

CONCLUSIONS

These results broadly confirm the robustness of the systems of breast disease diagnosis and classification adopted by the NHSBSP, and also identify areas where improvement or new approaches are required.

The NHS breast screening programme (pathology) EQA: experience in recent years relating to issues involved in individual performance appraisal

BACKGROUND

The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology, and assess the consistency of pathology reporting of breast disease in the UK.

AIMS/METHODS

To examine the performance (scores) of pathologists participating in the scheme in recent years. The scheme has evolved to help identify poor performers, reliant upon setting an acceptable cutpoint. Therefore, the effects of different cutpoint strategies were evaluated and implications discussed.

RESULTS/CONCLUSIONS

Pathologists who joined the scheme improved over time, particularly those who did less well initially. There was no obvious association between performance and the number of breast cancer cases reported each year. This is not unexpected because the EQA does not measure expertise, but was established to demonstrate a common level of performance (conformity to consensus) for routine cases, rather than the ability to diagnose unusual/difficult cases. A new method of establishing cutpoints using interquartile ranges is proposed. The findings also suggest that EQA can alter a pathologist's practice: those who leave the scheme (for whatever reason) have, on average, marginally lower scores. Consequently, with the cutpoint methodology currently used (which is common to several EQA schemes) there is the potential for the cutpoint to drift upwards. In future, individuals previously deemed competent could subsequently be erroneously labelled as poor performers. Due consideration should be given to this issue with future development of schemes.

Same-day breast core biopsy result: Effect on ER/PR and HER-2 scores

e11585

Background: The peloris rapid tissue processor promises same-day biopsy results. It uses a unique ActivFlo system achieving fast processing by rapid even heating and reagent exchange. The effect on ER/PR, Her2 scores and morphology of tumour cells are assessed Methods: 80 breast core biopsies were so far included in this study. For each case, one of three core biopsies was processed by the Peloris and the other two by the Leica histology processor for next day reporting. Each core biopsy was fixed in formalin for at least 3 - 6 hours before being processed by both systems.Immunohistochemistry for ER, PR and Her2 was carried out as well as FISH for borderline Her2 cases scoring 2+. Microscopical features were compared by the same histopathologist and tumour grade and type were recorded Results: On comparing cases processed by Peloris and Leica, 47 out of 68 biopsies (69%) scored exactly the same for ER and PR. 16 biopsies (23.5%) had minor scoring differences but did not affect the overall hormone receptor status. In total, 63 out of 68 biopsies (94%) scored similar receptor status. 4 cases (6%) had differing ER/PR status. 56 cases had Her2 tested, 51 (91%) had similar scores and 5 (9%) had different scores. 14 borderline cases had FISH tests and no different results were seen between Peloris and Leica processed tissue. Morphologically there were differences in size of nuclei and nuclear chromatin appearances. We have started the second part of the study in which biopsies for the Peloris are loaded immediately on receipt giving about 30 minutes of formalin fixation. Of the 9 biopsies so far processed, there have been no noticeable differences between the fixed tissue on the Leica processor and the fresh tissue on Peloris with regards to ER, PR and Her2. Conclusions: In conclusion, immunohistochemistry for ER/PR and Her2 is similar in 93% and 91% cases respectively. Results for FISH test were similar in all 14 cases. However, morphological differences were noted and the effect on tumour grade was discussed. Further evaluation and comparison of tissue using both processors on morphological architecture need to be carried out and any differences reported.

No significant financial relationships to disclose.