Carreras-Delgado, José L.

Delgado-Bolton, Roberto C.

Fernández-Pérez, Cristina

Gambhir, Sanjiv S.

Jiménez-Requena, Felisa

Pérez-Vázquez, José M.

Schwimmer, Judy

English

PubMed

eScholarship - University of California

Reply to: The diagnostic accuracy of 18F-FDG PET in cutaneous malignant melanoma

Roberto C. Delgado-Bolton

Felisa Jiménez-Requena

Cristina Fernández-Pérez

Sanjiv S. Gambhir

Judy Schwimmer

José M. Pérez-Vázquez

José L. Carreras-Delgado

Springer - Publisher Connector

LETTER TO THE EDITOR
Reply to: The diagnostic accuracy of 18F-FDG PET
in cutaneous malignant melanoma
Roberto C. Delgado-Bolton & Felisa Jiménez-Requena & Cristina Fernández-Pérez &
Sanjiv S. Gambhir & Judy Schwimmer & José M. Pérez-Vázquez &
José L. Carreras-Delgado
Received: 6 April 2010 /Accepted: 11 April 2010 /Published online: 26 May 2010
# The Author(s) 2010. This article is published with open access at Springerlink.com
Dear Sir,
Following the publication of our study entitled “Meta-
analysis of the performance of 18F-FDG PET in cutaneous
melanoma” in the February 2010 issue [1], we reply to the
comments presented in the above letter to the editor.
First, as described in the “Materials and methods”
section, we performed a systematic search of the literature
to identify relevant studies published between January 2000
and January 2006. Then, the meta-analysis was performed
and the manuscript was prepared for publication. Finally, it
was accepted for publication in 2009. Because of this 3-
year delay between the literature search and publication,
studies published after January 2006 were not included. The
delay between the presentation of results as abstracts and full
publication of results has been previously studied in the meta-
analysis published by Scherer et al. [2]. In this meta-analysis,
most studies were published in full within 2 years of their
appearance as abstracts, although some studies presented a
delay of up to 3 years. However, the results of our meta-
analysis may be updated to include the most recent studies.
Second, the methodological quality criteria applied in our
meta-analysis had been developed and applied in previous
meta-analyses by Huebner et al. [3], Gould et al. [4],
Delgado-Bolton et al. [5] and Schwimmer et al. [6]. These
methodological quality criteria were developed to systemat-
ically analyse studies focusing on the performance of 18F-
FDG PET. They apply 7 guidelines which include 38 items,
in order to extensively evaluate the methodological quality of
the studies and, also, establish guidelines for carrying out
methodologically rigorous studies. These criteria are based
on evidence-based medicine criteria and, to the best of our
knowledge, are not biased. Regarding the quality assessment
of studies of diagnostic accuracy included in systematic
reviews (QUADAS) criteria [7, 8], which is a 14-item
instrument, it can be useful for the assessment of diagnostic
accuracy studies and, if used extensively, it will facilitate
comparison among meta-analyses. However, the QUADAS
tool has not been designed specifically for 18F-FDG PET. As
evidenced in the meta-analysis by Kwee et al. [9], the
QUADAS criteria present certain limitations when analysing
18F-FDG PET diagnostic accuracy studies. These authors
eliminated 3 of the 14 criteria and added another different
one. This indicates that the QUADAS criteria may not be the
optimal tool for evaluating the methodological quality in 18F-
This reply refers to the letter to the editor at http://dx.doi.org/10.1007/
s00259-010-1475-4
R. C. Delgado-Bolton (*) : J. L. Carreras-Delgado
Nuclear Medicine Department, Hospital Clínico San Carlos,
C/ Prof. Martín Lagos S/N,
28040 Madrid, Spain
e-mail: rbolton@telefonica.net
F. Jiménez-Requena : J. M. Pérez-Vázquez
Nuclear Medicine Department,
Hospital General Universitario Gregorio Marañón,
C/ Doctor Esquerdo, 46,
28007 Madrid, Spain
C. Fernández-Pérez
Research Unit, Hospital Clínico San Carlos,
Madrid, Spain
S. S. Gambhir
Department of Radiology, James H. Clark Center,
Stanford University School of Medicine,
Stanford, CA, USA
J. Schwimmer
Department of Molecular & Medical Pharmacology,
David Geffen School of Medicine at UCLA,
Los Angeles, CA, USA
Eur J Nucl Med Mol Imaging (2010) 37:1436–1437
DOI 10.1007/s00259-010-1476-3
FDG PET studies. Furthermore, the methodological quality
criteria applied in our meta-analysis include certain
guidelines and items not analysed or incomplete in the
QUADAS criteria, such as: description of study design
and patient selection criteria, characteristics of patient
population finally studied, sensitivity and specificity
data, and change in management information. These
additional aspects not included in the QUADAS criteria
can be of relevance when assessing the methodological
quality and establishing guidelines for performing meth-
odologically rigorous studies on 18F-FDG PET.
Third, regarding the end-points chosen for our meta-
analysis, it would have been very interesting to analyse the
diagnostic performance of 18F-FDG PET depending on the
American Joint Committee on Cancer (AJCC) stage.
Unfortunately, most of the original papers did not supply
enough information on the AJCC stage of the patients
included. Many studies included heterogeneous populations
regarding the AJCC stage and the results of the 18F-FDG
PET were not presented independently for each AJCC
stage. Therefore, it was not possible to study this end-point.
If future studies include enough details of population
characteristics and present the results of sensitivity and
specificity for each subgroup of patients, it will be possible
to analyse this end-point in a meta-analysis.
Fourth, in our meta-analysis the quantitative analysis
evaluated subgroups of studies that presented the same
method of counting findings (patients, lesions, basins, etc.).
We separately analysed like data (patients, lesions, basins,
lymph nodes, areas or scans), because we considered the
results of studies that referred to different data (patients,
lesions, basins, etc.) not comparable. Because of this, the
pooled data were reduced. However, we considered it
methodologically more rigorous than pooling together
different data.
Finally, we agree with the comment regarding the need
for standardization in the reporting of studies to improve
the information provided by each individual study, which
will allow future meta-analyses and cost-effectiveness
analyses to establish the role of 18F-FDG PET.
Open Access This article is distributed under the terms of the
Creative Commons Attribution Noncommercial License which per-
mits any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and source are credited.
References
1. Jiménez-Requena F, Delgado-Bolton RC, Fernández-Pérez C,
Gambhir SS, Schwimmer J, Pérez-Vázquez JM, et al. Meta-
analysis of the performance of (18)F-FDG PET in cutaneous
melanoma. Eur J Nucl Med Mol Imaging 2010;37:284–300.
2. Scherer RW, Dickersin K, Langenberg P. Full publication of results
initially presented in abstracts. A meta-analysis. JAMA
1994;272:158–62.
3. Huebner RH, Park KC, Shepherd JE, Schwimmer J, Czernin J,
Phelps ME, et al. A meta-analysis of the literature for whole-body
FDG PET detection of recurrent colorectal cancer. J Nucl Med
2000;41:1177–89.
4. Gould MK, Maclean CC, Kuschner WG, Rydzak CE, Owens DK.
Accuracy of positron emission tomography for diagnosis of
pulmonary nodules and mass lesions: a meta-analysis. JAMA
2001;285:914–24.
5. Delgado-Bolton RC, Fernández-Pérez C, González-Maté A, Carreras
JL. Meta-analysis of the performance of 18F-FDG PET in primary
tumor detection in unknown primary tumors. J Nucl Med 2003;
44:1301–14.
6. Schwimmer J, Essner R, Patel A, Jahan SA, Shepherd JE, Park K,
et al. A review of the literature for whole-body FDG PET in the
management of patients with melanoma. Q J Nucl Med
2000;44:153–67.
7. Whiting P, Rutjes AW, Reitsma JB, Bossuyt PM, Kleijnen J. The
development of QUADAS: a tool for the quality assessment of
studies of diagnostic accuracy included in systematic reviews.
BMC Med Res Methodol 2003;3:25.
8. Whiting PF, Weswood ME, Rutjes AW, Reitsma JB, Bossuyt PN,
Kleijnen J. Evaluation of QUADAS, a tool for the quality
assessment of diagnostic accuracy studies. BMC Med Res
Methodol 2006;6:9.
9. Kwee TC, Kwee RM. Combined FDG-PET/CT for the detection of
unknown primary tumors: systematic review and meta-analysis.
Eur Radiol 2009;19:731–44.
Eur J Nucl Med Mol Imaging (2010) 37:1436–1437 1437


A meta-analysis of the literature for whole-body FDG PET detection of recurrent colorectal cancer.

A review of the literature for whole-body FDG PET in the management of patients with melanoma.

Accuracy of positron emission tomography for diagnosis of pulmonary nodules and mass lesions: a meta-analysis.

Combined FDG-PET/CT for the detection of unknown primary tumors: systematic review and meta-analysis.

Evaluation of QUADAS, a tool for the quality assessment of diagnostic accuracy studies.

Full publication of results initially presented in abstracts. A meta-analysis.

Meta-analysis of the performance of 18F-FDG PET in primary tumor detection in unknown primary tumors.

The development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2886141

Reply to: The diagnostic accuracy of 18F-FDG PET in cutaneous malignant melanoma

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