Objective:

To evaluate the value of PET parameters including maximum standard uptake value (SUVmax)

wholebody metabolic tumor volume (WBMTV)

whole-body total lesion glycolysis (WBTLG) in predicting the progression-free survival (PFS) and overall survival (OS) of extranodal NK/T-cell lymphoma

nasal type (ENKTL).

Methods:

Retrospective analysis was performed on 35 initial ENKTL who underwent

18

F-FDG PET/CT examination before treatment. The volume of interests (VOI) of all lesions were measured automatically based on 41% SUVmax thresholds

and then SUVmax

metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of each VOI were recorded. WBMTV and WBTLG were calculated manually for all VOI. X-tilesoftware was used to find the cutoff values of PET parameters. Survival curves were produced by Kaplan-Meier method and compared by Log-Rank test. Univariate and multivariate Cox regression were used to identify the factors related to OS and PFS.

Results:

The median follow-up period of the patients was 36 months and 13 patients showed disease progression and 13 patients died from the disease during the follow-up period. X-tile software showed cut-off values for SUVmax

WBMTV

WBTLG of 13.34

11.28 cm

3

303.79

respectively. Compared to low SUVmax and WBTLG

high SUVmax and WBTLG were significantly associated with poor 3-year OS rate (41.2% vs 83.3% for SUVmax

P

=0.008

and 25.0% vs 74.1% for WBTLG

P

=0.006). Univariate analysis indicated that SUVmax and WBTLG were significant predictors of OS (HR: 4.9

95% CI: 1.3-17.9

P

=0.016 for SUVmax

and HR: 0.308

95% CI: 0.100-0.952

P

=0.041 for WBTLG). Multiple analysis showed that WBTLG was the best predictor of OS (HR: 0.308

95% CI: 0.100-0.952

P

=0.041).

Conclusion:

High SUVmax and high WBTLG were poor prognostic factors on OS of the initial ENKTL

and WBTLG was

the best independent predictor of OS.