Korean J Intern Med.  2021 Mar;36(Suppl 1):S245-S252. 10.3904/kjim.2019.376.

Different roles of surveillance positron emission tomography according to the histologic subtype of non-Hodgkin’s lymphoma

• Kim YR
• Kim SJ
• Cheong JW
• Kim Y
• Jang JE
• Cho H
• Chung H
• Min YH
• Yang WI
• Cho A
• Kim JS

• KMID: 2513832
• DOI: http://doi.org/10.3904/kjim.2019.376

Abstract

Background/Aims
Although the use of surveillance ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is discouraged in patients with diffuse large B-cell lymphoma, its usefulness in different subtypes has not been thoroughly investigated.
Methods
We retrospectively evaluated 157 patients who showed positive results on surveillance FDG-PET/CT every 6 months following complete response for up to 5 years. All of the patients also underwent biopsies.
Results
Seventy-eight (49.6%) of 157 patients had true positive results; the remaining 79 (50.3%), including eight (5.1%) with secondary malignancies, were confirmed to yield false positive results. Among the 78 patients with true positive results, the disease in seven (8.9%) had transformed to a different subtype. The positive predictive value (PPV) of FDG-PET/CT for aggressive B-cell non-Hodgkin’s lymphoma (NHL) was lower than that for indolent B-cell or aggressive T-cell NHL (p = 0.003 and p = 0.018, respectively), especially in patients with a low/low-intermediate international prognostic index (IPI) upon a positive PET/CT finding. On the other hand, indolent B-cell and aggressive T-cell NHL patients showed PPVs of > 60%, including those with low/low-intermediate secondary IPIs.
Conclusions
The role of FDG-PET/CT surveillance is limited, and differs according to the lymphoma subtype. FDG-PET/CT may be useful in detecting early relapse in patients with aggressive T-cell NHL, including those with low/low-intermediate risk secondary IPI; as already known, FDG-PET/CT has no role in aggressive B-cell NHL. Repeat biopsy should be performed to discriminate relapse or transformation from false positive findings in patients with positive surveillance FDG-PET/CT results.

Keyword

Positron emission tomography computed tomography; Sensitivity and specificity