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Pterygia are indicators of an increased risk of developing cutaneous melanomas
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  • Published on:
    Reply to 'Big data, selection bias and clinical significance
    • Julie Crewe, Research fellow Lions Eye Institute, Centre for Ophthalmology and Vision Science, University of Western Australia, Australia.
    • Other Contributors:
      • Tim Threlfall, Research Fellow
      • Antony Clark, Consultant Ophatlmologist
      • Paul Sanfilippo, Research Fellow
      • David Mackey, Consultant Ophthalmologist/Director

    We thank the authors for their comments and insights on our paper ‘Pterygia are indicators of an increased risk of developing cutaneous melanomas’.
    We agree that there was selection bias within the pterygium cases. All cases were identified as hospital in-patients and therefore represent that small select portion of the population who were receiving treatment for (or removal of) their pterygium. We made no assumptions about whether these cases were more or less severe than untreated pterygia or whether the removals were performed for cosmetic or other reasons. The strengths of this study are that it included all in-hospital cases treated in Western Australia over a 30 year time period, without prejudice.
    While melanoma is an uncommon problem in China, it is a major health issue in Australia and New Zealand. The clinical relevance of this study should be viewed against the background of the world’s highest incidence rates of cutaneous melanoma that currently exist, with up to 60 cases per 100,000 population1-3 in Australia and New Zealand. Contrast this with the incidence rates of East Asian countries of approximately 0.7 cases per 100,000 population.4 Both non-melanoma and melanoma skin cancers are a major health priority for cancer prevention research. We are not suggesting that pterygium be used as the sole indicator for a population wide screening program. There are well established major screening and surveillance programs in place in Australia. Our study a...

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    Conflict of Interest:
    None declared.
  • Published on:
    Big data, selection bias and clinical significance
    • Jingjing Shen, ophthalmologist 1. Zhongshan Hospital Affiliated to Fudan University 2. Center for Evidence-based Medicine, Fudan University
    • Other Contributors:
      • Minqian Shen, ophthalmologist
      • Yuanzhi Yuan, ophthalmologist

    Title Page

    Letter to the Editor

    The article in question:
    Crewe JM, Threlfall T, Clark A, Sanfilippo PG, Mackey DA. Pterygia are indicators of an increased risk of developing cutaneous melanomas. Br J Ophthalmol 2017.

    Jingjing Shen
    Minqian Shen
    Yuanzhi Yuan

    Corresponding author:
    Yuanzhi Yuan

    Address:#180 Fenglin Rd., Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai 200032, P.R. China
    Phone: +86-186 1688 1220 or +86-21-64041990 ext. 2684

    Dear Editor,

    We read with great interest the paper by Crewe et al.1 The authors showed that patients with pterygium had higher risk of cutaneous melanomas (CM) in a large retrospective matched-cohort study in Western Australia (WA), and suggested pterygium as an indicator for CM. The finding was interesting. However, we doubt the conclusion and its clinical relevance and public health significance.

    Compared to control group, patients with pterygium had a 20% or 24% increased risk of developing CM in terms of odds ratio(OR) or incidence rate ratio (IRR), respectively. The incidence rate difference(IRD), however, was only 27.7/100 000 person-years (PY) (Table 5., by subtracting the IR of the control group from that of the pterygium group, i.e. (186.5-158.8)/100 000 PY). The rate difference corres...

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    Conflict of Interest:
    None declared.