Letters Preventing overdiagnosis

Potential sources of overdiagnosis in histopathology

BMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e5722 (Published 24 August 2012) Cite this as: BMJ 2012;345:e5722
  1. Murali Varma, consultant histopathologist1,
  2. Varsha Shah, consultant histopathologist2
  1. 1University Hospital of Wales, Cardiff CF14 4XN, UK
  2. 2Royal Gwent Hospital, Newport NP20 2UB, UK
  1. varma_murali{at}hotmail.com

We highlight two potential sources of overdiagnosis related to histopathological examination of surgical specimens and terminology.1

Firstly, submitting multiple sections from background macroscopically normal tissue for microscopy is standard practice for histopathologists. These samples may contain coincidental in situ or invasive cancer. For example, background breast tissue from excision of a fibroadenoma may show ductal carcinoma in situ and that from a multinodular goitre may show papillary thyroid microcarcinoma. Examining such background tissues could be regarded as a form of screening to which the patient has not specifically consented.

Secondly, most non-invasive papillary urothelial tumours of the urinary bladder are designated as transitional cell carcinoma without the qualifying suffix in situ. This results in patients with papillary dysplastic urothelial proliferations being diagnosed as having bladder cancer. Moynihan and colleagues describe excessive widening of disease definitions as a cause of overdiagnosis.1 The most extreme example relates to the term cancer.

The public perception of cancer as a lethal disease stems from the fact that in most cases it was originally diagnosed only after spread and hence was associated with a dismal outcome. However, currently most cancers are clinically localised diseases interpreted as having metastatic potential on the basis of their microscopic appearances. Thus the term cancer is currently commonly used for tumours with very low risk of causing clinically significant harm to the patient. More recent thought is that some clinically indolent tumours should be considered as cancer on the basis of genetic abnormalities.2 Such an approach could lead to further widening of the definition of cancer and risks medicalisation of clinically harmless disease.

Notes

Cite this as: BMJ 2012;345:e5722

Footnotes

  • Competing interests: None declared.

References

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