Continuing Medical Education
Critical Appraisal
Assessing Incidence Rates and Secular Trends in Nonmelanocytic Skin Cancer: Which Method Is Best?

Richard P. Gallagher*†‡  and Tim Lee*

Critical Appraisal Review covers various topics in epidemiology and related fields that are useful to the practicing physician in understanding and using published studies on skin disease topics. Readers may suggest future topics for this series by writing to the Editorial Office.

We hear a lot about how commonly nonmelanoma skin cancer occurs, but just how is this measured, and how reliable are the resulting figures? What should we look for when evaluating these reports? In the article that follows, Gallagher and Lee provide us with some basic tools to evaluate reported incidence rates and trends.

Martin A. Weinstock


Background: Evaluating the incidence of nonmelanocytic skin cancers in white populations and assessing the direction and strength of secular trends in these cancers have become important issues to dermatologists, oncologists, health policy analysts, and health care funders.

Objective: The objective of this paper is to evaluate the three principal methods used to assess incidence rates and secular trends.

Conclusion: Each of the three methods has strengths and weaknesses. An understanding of these will enable proper assessment of the value and significance of findings presented in the literature.


Antécédents: L’incidence de cancers de la peau non mélanocytaires dans les populations de race blanche et l’évaluation de leur orientation et de leur évolution temporelle sont devenues des questions d’importance pour les dermatologistes, les oncologistes, les analystes des politiques de santé et les organismes qui financent les soins de santé.

Objectif: Évaluer les trois Méthodes principalement utilisées pour déterminer les taux d’incidence et l’évolution temporelle de la maladie.

Conclusion: Chacune des trois Méthodes comporte des forces et des faiblesses, dont la compréhension va permettre l’évaluation correcte de l’importance des conclusions présentées dans la littérature.

Received 12/30/97. Accepted for publication 2/9/98.

*Cancer Control Research Program, BC Cancer Agency, Vancouver; †Department of Health Care and Epidemiology and  ‡Division of Dermatology Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada

Reprint requests: Richard P. Gallagher, Head, Cancer Control Research Program, BC Cancer Agency, 600 West 10th Avenue, Vancouver, BC, Canada V5Z 4E6

Full text available in the print edition / Pour le texte intégral veuillez consulter la version imprimée.

JCMS 3(1) Contents