891MO - Role of baseline PET SUVmax in predicting early progression in follicular lymphoma (FL): A single-center retrospective analysis

Background

FL is biologically and clinically heterogeneous with wide variations in outcomes. Progression of disease within 24 months after treatment (POD24) predicts overall survival (OS) in patients (pts) treated with rituximab-based therapy. Pts with POD24 have a < 50% long-term survival. Identifying predictors of POD24 at outset is an area of unmet need. Total metabolic tumor volume (TMTV) is an independent predictor of outcomes in FL. However, TMTV calculations are not routinely available, unlike SUVmax. Thus, we aimed at determining the correlation of baseline SUVmax with POD24 in FL.

Methods

We performed a retrospective chart review of pts with newly diagnosed FL from January 2011-January 2019. Comparison of PFS was done with log-rank test and multivariate analysis was conducted with Cox regression.

Results

100 pts with median age 60 years (29-86 years) were included. Baseline characteristics are mentioned in the attached figure. 21% of pts relapsed within 24 months (POD24) however median OS was unable to be calculated due to insufficient OS events. Baseline PET-CT analysis showed median SUV max value of 8.55 (0-38.9). No difference in correlation was noted between baseline SUVmax and initial laboratory data collected (ANC, ALC, Hgb, Plt, LDH, albumin, and globulin). Median SUV max for POD24 pts was higher at 9.19 vs 7.40 for non-POD24 however, comparison of SUVmax by POD24 status showed no statistically significant difference between the two groups (p=0.95). T-test also failed to note a difference between baseline laboratory variables and PET-CT determinates (number of nodal and extranodal sites) between POD24 and non-POD24 pts.

Conclusions

In our analysis, baseline SUVmax did not predict POD24 nor were there significant differences in the comparison of clinical variables between the two POD24 groups. Gene-expression profiling (GEP) scores have been developed to predict PFS in FL and high-risk signatures have been found to react differently to different chemotherapy backbones. Future research efforts should focus on increasing the feasibility and adoption of GEP in clinical practice, defining molecular subtypes of FL prior to treatment, and assigning therapy on the basis of those results.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.