18F-FDG PET/CT in gastric MALT lymphoma: a bicentric experience
The role of 18F-FDG-PET/CT in evaluating gastric MALT lymphoma is still controversial. In the literature the detection rate of 18F-FDG-PET/CT in patients with gastric MALT lymphoma is variable, and the reason for this heterogeneity is not still clear. Our aim was to investigate the particular metabolic behavior of these lymphoma.
Materials and methods
Sixty-nine patients (26 female, 43 male) with histologically confirmed gastric MALT lymphoma who underwent a 18F-FDG-PET/CT for initial staging from two centers were included. The PET images were analyzed visually and semi-quantitatively by measuring the maximum standardized uptake value (SUVmax), lesion-to-liver SUVmax ratio, and lesion-to-blood pool SUVmax ratio and compared with Ann Arbor stage, epidemiological (age, sex), histological (presence of gastritis, ulcer, H. pylori infection, plasmacytic differentiation, Ki-67 index), and morphological (tumor size, superficial lesions or mass-forming) characteristics.
Thirty-six patients (52 %) had positive PET/CT (average SUVmax was 9±6.7; lesion-to-liver SUVmax ratio 3.7±2.6, lesion-to-blood pool SUVmax ratio 4.8±3.3) at the corresponding gastric lesion; the remaining 33 were not 18F-FDG-avid. In the univariate analysis, 18F-FDG avidity was significantly associated with morphological features (mass forming p<0.001 and high maximum diameter p<0.001), Ann Arbor stage (p=0.010), and Ki67 index (p<0.001) and not correlated with age, sex, presence of gastritis, ulcer, Helicobacter pylori infection, and plasmacytic differentiation. In the multivariate analysis, the correlations with gross morphological appearance, Ann Arbor stage, and Ki-67 score were confirmed. SUVmax, lesion-to-liver SUVmax ratio, and lesion-to-blood pool SUVmax ratio correlated significantly only with Ki67 index (p=0.047; p=0.012; p=0.042).
18F-FDG avidity was noted in 52 % of gastric MALT lymphoma and this avidity is correlated with gross morphological characteristics, tumor stage, and Ki-67 index. SUVmax, lesion-to-liver SUVmax ratio, and lesion-to-blood pool SUVmax ratio are correlated only with Ki-67 index, and only lesion-to-liver SUVmax ratio was independently associated with Ki-67 score.
KeywordsGastric MALT lymphoma Gastric lymphoma MALT lymphoma FDG avidity 18F-FDG PET/CT
- 2.Jaffe ES, Harris NL, Stein H, Vardinam JW. Tumours of haematopoietic and lymphoid tissues: world health organization classification of tumours, pathology, and genetics. Lyon: IARC Press; 2001.Google Scholar
- 3.A clinical evaluation of the International Lymphoma Study Group classification of non-Hodgkin’s lymphoma. The non-Hodgkin’s lymphoma classification project. Blood. 1997;89:3909–18.Google Scholar
- 5.Taal BG, Burgers JM, van Heerde P, Hart AA, Somers R. The clinical spectrum and treatment of primary non-Hodgkin’s lymphoma of the stomach. Ann Oncol. 1993;4:839–46.Google Scholar
- 13.Zucca E, Copie-Bergman C, Ricardi U, Thieblemont C, Raderer M, Ladetto M. Gastric marginal zone lymphoma of MALT type: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2013;24(Suppl 6):vi144–8.Google Scholar
- 14.National Comprehensive Cancer Network guidelines on non-Hodgkin’s lymphomas, version 2. 2014. Available at http://www.nccn.org/professionals/physician_gls/pdf/nhl.pdf.