Current status of FDG-PET/CT in staging of adult lymphoma

Abstract

Staging defines disease location and extent, suggests prognostic information and provides a baseline against which response or disease progression can be compared. Studies in Hodgkin (HL) and non-Hodgkin lymphoma (NHL) generally conclude that PET/CT is more accurate for diagnosing both nodal and extranodal disease than computed tomography (CT), thus having a strong potential impact on the staging of these lymphomas. Due to the high sensitivity and specificity of PET/CT in detecting bone marrow disease in newly diagnosed HL, bone marrow biopsy (BMB) is no longer indicated in HL; in aggressive NHL the detection of bone marrow involvement is still a topic of debate. In patients with a negative PET/CT, BMB is currently suggested to identify discordant histology, but its clinical role need to be further investigated. In indolent lymphoma FDG-PET enables staging the disease and characterization of intensity of glycolytic metabolism and this information provides additional prognostic information. In indolent lymphoma the pattern of marrow involvement is diffuse and PET/CT can be false negative in many cases. The main criteria to interpret staging PET/CT were reviewed. In 2014 were published the updated guidance on the evaluation, staging and response assessment of patients affected by HL and NHL and on the use of PET/ CT for staging and response assessment. The guidelines suggest that a reasonable approach would be omit the standard full dose contrast-enhanced CT (ceCT) if not already performed, and perform a low-dose non-enhanced PET/CT as a single imaging modality, with ceCT performed selectively determined by PET/CT findings.

PET/CT Imaging of Lymphoma Outside the Western World

“…FL is an FDG-avid disease in more than 95% of the cases. PET/CT is recommended for baseline staging by international guidelines, as it is able to detect nodal and most of all extranodal disease, including bone marrow, with a superior sensitivity (93%) and specificity compared to a CeCT, thus being able to upstage a significant proportion of the CeCT-staged patients and to ensure a more appropriate treatment for them (34,45,46). PET/CT was also useful to suspect a histological transformation to high-grade lymphoma, based on an elevated value of the maximum Standardized Uptake Value (SUVmax).…”

Value of PET-CT Staging in Lymphoma Patients at Baseline over Clinical Staging

“…Remaining one-third of NHL present with symptoms associated with involvement of extra nodal sites like skin, stomach or brain. Treatment strategy of lymphoma depends upon the staging of disease which defines disease location, extension, suggests prognostic information and provides a baseline against which treatment response or disease progression can be compared (3). Accurate staging can minimize the therapeutic toxic effect and reduces the morbidity and mortality associated with therapy.…”

The Strategies to Homogenize PET/CT Metrics: The Case of Onco-Haematological Clinical Trials

“…PET/CT has already been a fundamental tool for staging and restaging in lymphoma [ 3 , 4 ] and its use is now standardized in the so-called Lugano criteria [ 5 ]. Recently, several clinical trials demonstrated that treatment could be guided by PET/CT also during the treatment itself, changing the ongoing therapy based on its results [ 6 , 7 ].…”