Letters
Dermatology General medicine
Volume 188 - Issue 2

Diagnosing skin cancer in primary care: how do main-stream general practitioners compare with primary care skin cancer clinic doctors?

Authors:  Philippa H Youl, Peter D Baade, Monika Janda, Christopher B Del Mar, David C Whiteman and Joanne F Aitken

Med J Aust 2008; 188 (2): 125-126. || doi: 10.5694/j.1326-5377.2008.tb01546.x
Published online: 21 January 2008
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In reply: We thank Heal and Raasch, and Keir for their comments and suggestions. First, as acknowledged in our article, it is possible that general practitioners with an interest in skin cancer may have been over-represented in our sample. It is also the case that the comparison between GPs and skin cancer clinic doctors may have been affected by characteristics of patients attending each type of practice. Patients attending skin cancer clinics are self-selected (often worried about a specific skin lesion), while for those attending GPs in mainstream practice, skin lesions are more likely mentioned during a consultation for something else.1 Case selection, which helps increase diagnostic ability by Bayesian principles (improving pretest probability of malignant lesions), may thus be more likely for skin cancer clinic doctors than GPs.2

Our study represented a broad cross-section of skin cancer clinics, and the number of melanomas excised per doctor per week ranged from 0 to 1.7. The ratio of basal cell carcinomas to squamous cell carcinomas excised ranged from 0.1 to 6.0 for mainstream GPs and 0.8 to 8.0 for skin cancer clinic doctors. Whether clinical and histological features of skin lesions or the type of skin examination undertaken influence diagnostic accuracy was beyond the scope of our initial study. This question will be the subject of future analyses.

It has been suggested that a limitation of our study was that it did not assess or compare the number of skin cancers each group missed. However, as specifically stated in our article, the aim of our study was to examine diagnostic accuracy of excised or biopsied lesions. To examine the sensitivity and specificity of all lesions (excised and non-excised) and of screening examinations would require a different study design.

We disagree that meaningful comparisons between the two groups cannot be made from the data collected in our study. Our prospective study included over 11 000 skin excisions or biopsies from a large group of mainstream GPs and from doctors working in a variety of skin cancer clinics. One of the most important outcome measures of our study was the degree of accuracy of skin cancer diagnoses within the primary care setting.

We have demonstrated that primary care practitioners, whether mainstream GPs or skin cancer clinic doctors, diagnose skin cancer with similar, high levels of accuracy. This is a reassuring result, particularly in a country with the world’s highest incidence of skin cancer.

Authors

  • Philippa H Youl1
  • Peter D Baade1
  • Monika Janda2
  • Christopher B Del Mar3
  • David C Whiteman4
  • Joanne F Aitken1
  • 1. Viertel Centre for Research in Cancer Control, The Cancer Council Queensland, Brisbane, QLD.
  • 2. Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, QLD.
  • 3. Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD.
  • 4. Cancer and Population Study Group, Queensland Institute of Medical Research, Brisbane, QLD.

Correspondence: PipYoul@cancerqld.org.au

References

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