Reproducibility of Major Diagnoses in a Binational Study of Lung Cancer in Uranium Miners and Atomic Bomb Survivors

Abstract

A binational panel of four Japanese and four American pathologists examined 208 pulmonary neoplasms, according to the World Health Organization (WHO) recommendations, second edition, for the histologic typing of lung tumors. The study design included independent evaluations by pathologists working alone, followed by group reviews. The individual evaluations, and their implications for reproducibility of the WHO recommendations, are reported. Consensus (agreement by six or more pathologists) with respect to major (ie, first digit) diagnosis was obtained for 76.4% of the cases. Consensus was obtained for 72.5% of the cases with any major diagnosis of small cell cancer; the comparable figures for adenocarcinoma and squamous cell carcinoma were 56% and 48%, respectively. American pathologists were twice as likely as Japanese pathologists to diagnose large-cell cancer, the only significant national difference. Consensus was far less frequent with the minor (ie, second digit) diagnosis categories. This study shows that lung cancers continue to be difficult to classify reproducibly.

The value of central histopathological review of testicular tumours before treatment

“…In both studies the discrepancies found were important, as they altered the treatment given. A diagnostic concordance rate of 94% is higher than that for tumours of the breast (92% for the presence of invasive carcinoma, with poor agreement on histological type [ 3]) and lung (72% for small cell carcinoma [ 4]). In seven biopsies the initial report used confusing terminology; it is essential that standard terminology is used in the pathology report.…”

The challenge of classifying poorly differentiated tumours in the lung

“…This issue is one that is poorly understood by many outside of pathology who fail to appreciate the limitations of tumour classification on small biopsy specimens or the necessity for using such terms as ‘non‐small cell’ carcinoma. It is clear that even when very experienced pulmonary pathologists spend time examining small biopsy specimens against agreed criteria for squamous or glandular differentiation, there will be insufficient features present to classify these accurately in around 50% of cases 2–5 . It must also be appreciated that even when specific features of glandular or squamous differentiation are identified in small biopsy specimens, the frequency of variable differentiation in lung carcinomas means that a subsequent resection, if performed, may be classified differently 2,5 .…”

“…It is clear that even when very experienced pulmonary pathologists spend time examining small biopsy specimens against agreed criteria for squamous or glandular differentiation, there will be insufficient features present to classify these accurately in around 50% of cases. [2][3][4][5] It must also be appreciated that even when specific features of glandular or squamous differentiation are identified in small biopsy specimens, the frequency of variable differentiation in lung carcinomas means that a subsequent resection, if performed, may be classified differently. 2,5 Equally, pathologists need to be aware of the increasing requirements of oncologists in relation to future potential treatment options for tumour subtypes and be prepared to adapt their practice accordingly.…”

“…In this situation it has to be accepted that the pathologist may be able to achieve little more than confirm the presence of a malignant tumour and suggest a cell type. Although in most instances identification of small cell carcinoma appears to be reasonably robust, 2,3 accurate subtyping of non‐small cell carcinomas in small biopsy specimens is often problematic 2–4 . This has led to the use of the rather generic term ‘non‐small cell carcinoma, not otherwise specified (NOS)’ which is widely used when reporting these cases 2,5 …”

“…Although in most instances identification of small cell carcinoma appears to be reasonably robust, 2,3 accurate subtyping of non-small cell carcinomas in small biopsy specimens is often problematic. [2][3][4] This has led to the use of the rather generic term 'non-small cell carcinoma, not otherwise specified (NOS)' which is widely used when reporting these cases. 2,5 The histological approach to any tumour, whether present in a small biopsy specimen or a resection, is to assess and describe the appearances of the cells forming the tumour.…”