Use of positron emission tomography for response assessment of lymphoma: consensus of the Imaging Subcommittee of International Harmonization Project in Lymphoma.
OBJECTIVE
To develop guidelines for performing and interpreting positron emission tomography (PET) imaging for treatment assessment in patients with lymphoma both in clinical practice and in clinical trials.


METHODS
An International Harmonization Project (IHP) was convened to discuss standardization of clinical trial parameters in lymphoma. An imaging subcommittee developed consensus recommendations based on published PET literature and the collective expertise of its members in the use of PET in lymphoma. Only recommendations subsequently endorsed by all IHP subcommittees were adopted.


CONCLUSIONS
PET after completion of therapy should be performed at least 3 weeks, and preferably at 6 to 8 weeks, after chemotherapy or chemoimmunotherapy, and 8 to 12 weeks after radiation or chemoradiotherapy. Visual assessment alone is adequate for interpreting PET findings as positive or negative when assessing response after completion of therapy. Mediastinal blood pool activity is recommended as the reference background activity to define PET positivity for a residual mass > or = 2 cm in greatest transverse diameter, regardless of its location. A smaller residual mass or a normal sized lymph node (ie, < or = 1 x 1 cm in diameter) should be considered positive if its activity is above that of the surrounding background. Specific criteria for defining PET positivity in the liver, spleen, lung, and bone marrow are also proposed. Use of attenuation-corrected PET is strongly encouraged. Use of PET for treatment monitoring during a course of therapy should only be done in a clinical trial or as part of a prospective registry.
Juweid
Malik E
ME
Department of Radiology, University of Iowa, Iowa City, IA 52242, USA. malik-juweid@uiowa.edu
Stroobants
Sigrid
S
Hoekstra
Otto S
OS
Mottaghy
Felix M
FM
Dietlein
Markus
M
Guermazi
Ali
A
Wiseman
Gregory A
GA
Kostakoglu
Lale
L
Scheidhauer
Klemens
K
Buck
Andreas
A
Naumann
Ralph
R
Spaepen
Karoline
K
Hicks
Rodney J
RJ
Weber
Wolfgang A
WA
Reske
Sven N
SN
Schwaiger
Markus
M
Schwartz
Lawrence H
LH
Zijlstra
Josee M
JM
Siegel
Barry A
BA
Cheson
Bruce D
BD
D002986:Clinical Trials as Topic / Q000592:standards; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007391:International Cooperation; D008223:Lymphoma / Q000000981:diagnostic imaging* / Q000628:therapy*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D019275:Radiopharmaceuticals