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Endocrine Care: Anastasia Tsigkou, Daniele Marrelli, Fernando M. Reis, Stefano Luisi, Agnaldo L. Silva-Filho, Franco Roviello, Sérgio A. Triginelli, and Felice Petraglia Total Inhibin Is a Potential Serum Marker for Epithelial Ovarian Cancer J Clin Endocrinol Metab 2007; 92: 2526-2531 [Abstract] [Full text] [PDF]

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Likelihood Ratios Associated with Diagnostic Tests for Ovarian Cancer

W. Paul McKinney, THIS FIELD BLANK   (13 July 2007)

Likelihood Ratios Associated with Diagnostic Tests for Ovarian Cancer 13 July 2007
W. Paul McKinney, Professor University of Louisville School of Public Health and Information Sciences, THIS FIELD BLANK Send letter to journal: Re: Likelihood Ratios Associated with Diagnostic Tests for Ovarian Cancer mckinney{at}louisville.edu W. Paul McKinney, et al.	Tsigkou et al. (1) in their paper describing the use of total inhibin and CA-125 as markers for epithelial ovarian cancer appear to overestimate the likelihood ratios applicable to positive tests for each marker used individually and for a composite index reflecting positivity for either one. The likelihood ratio for a positive test is defined as the sensitivity of the test divided by the quantity one minus the specificity of the test, or LR+ = Sensitivity/(1-Specificity) (2). Using this definition, the authors' statement that the diagnostic cutoff was set for a specificity of 95% in all cases, and the data in Table 2 for the "percentage of ovarian cancers detected," i.e., the sensitivity of each parameter ranging from 84 to 99, the LR+ results in Table 3 appear to be miscalculated. Instead of values for the LR+ of 26.7, 27.4, and 18.8 for the total inhibin, CA-125, and total inhibin plus CA-125, these results should be 84/5=16.8, 87/5=17.4, and 99/5=19.8, respectively. For a specificity set at 95% for the LR+ linked to high inhibin and CA-125 values individually to exceed 20 as reported, the corresponding sensitivities would need to exceed 100%, an impossible range,. Nonetheless, even with these adjusted values, the LR+ results are of relatively high magnitude and merit further exploration for clinical usefulness in diagnosis of ovarian cancer. References 1. Tsigkou A, Marrelli D, Reis FM, Luisi S, Silva-Filho AL, Roviello F, Triginelli SA, Petraglia F. 2007. Total inhibin is a potential serum marker for epithelial ovarian cancer. J Clin Endocrinol Metab 92:2526-2531 2. Jaeschke R, Guyatt G, Lijmer J. 2002. Diagnostic Tests. In: Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. Guyatt G, Rennie D, eds. AMA Press, Chicago, p 132