Observer Variability and Reliability in Lung Cancer Diagnosis

Our plain-English summary of Observer Variability and Reliability in Lung Cancer Diagnosis, by R. Yesner (1973).

The study

• Author: R. Yesner
• Published: Cancer Chemotherapy Reports, Part 3 Volume 4 No2. March 1973
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1973 article does not concern asbestos. It is about how reliably pathologists classify types of lung cancer. A panel of three pathologists for the Veterans' Administration Lung Cancer Chemotherapy Study Group read the same slides independently, using a modified version of a World Health Organization classification. The article recounted the panel's previously published experience with 2897 surgical specimens. Squamous cell carcinomas made up 49.1% of cancers. All three pathologists agreed in 95.7% of highly differentiated and 91.4% of moderately differentiated squamous tumors, but in only 46.6% of poorly differentiated ones. Agreement was 84.0% for oat cell, 34.4% for polygonal small cell, 42.5% for poorly differentiated adenocarcinoma and only 10% for large cell undifferentiated carcinoma. In 617 patients who also had autopsies, poorly differentiated squamous diagnoses fell from 24.5% of surgical diagnoses to 11.0% at autopsy, while adenocarcinomas rose from 16.0% to 25.6%. The author concluded that the diagnosis of poorly differentiated squamous cell carcinoma is uncertain and that many such tumors are revealed at autopsy to be adenocarcinomas.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Observer-agreement study of lung cancer histologic classification by a three-pathologist panel, with a comparison of surgical and autopsy diagnoses in the same patients
• Who was studied: Lung carcinoma specimens submitted to the Veterans' Administration Lung Cancer Chemotherapy Study Group pathology panel (group organized 1957): a previously published series of 2897 surgically removed specimens, and 617 patients for whom autopsies were available
• Exposure: Not applicable: the article studies diagnostic agreement in lung cancer typing and does not mention asbestos or any other exposure
• Main results:
  • In the 2897-specimen series, squamous cell carcinomas made up 49.1% of all carcinomas
  • Highly differentiated squamous tumors (1a): unanimous diagnosis in 95.7% of cases
  • Moderately differentiated squamous tumors (1b): unanimous diagnosis in 91.4% of cases
  • Poorly differentiated squamous tumors (1c): unanimous diagnosis in only 46.6% of cases
  • The oat cell group (2a) was diagnosed unanimously in 84.0% of cases. The polygonal small cell group (2b) had 34.4% reliability.
  • Poorly differentiated adenocarcinomas (3c): unanimous diagnosis in 42.5% of cases
  • Large cell undifferentiated carcinomas made up 15.5% of the total, with unanimity in only 10% of that group
  • In the 617 surgical-autopsy cases, epidermoid (1a and 1b) percentages stayed about the same: 23.3% surgical versus 23.5% autopsy
  • In the 617 cases, poorly differentiated squamous tumors (1c) declined from 24.5% of surgical diagnoses to 11.0% at autopsy
  • In the 617 cases, adenocarcinomas (group 30) rose from 16.0% of surgical diagnoses to 25.6% at autopsy
  • Of surgical cases diagnosed as 1c, the autopsy findings included 28% undifferentiated large cell, 21% adenocarcinoma and 13% undifferentiated small cell. The rest were squamous cell or combined; the squamous figure is garbled in the text.
  • At autopsy, half of the epidermoid cancers (1a and 1b) remained within the thorax without distant metastases
  • At autopsy, over 90% of the small cell undifferentiated carcinomas showed widely disseminated metastases
• The authors' conclusion: The author concluded that the diagnosis of poorly differentiated squamous cell carcinoma (1c) is uncertain, and that many such tumors are revealed by autopsy to be adenocarcinomas

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Chemotherapy, Squamous Cell Carcinoma, Adenocarcinoma, Carcinoma, Autopsy.

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