Page 132 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation
P. 132
Chapter 6a
baseline MTV to the multivariable Cox model improved prediction. Statistical analyses were performed using SPSS Statistics (version 22; IBM) and R (version 3.6.3). A P-value of less than 0.05 was considered statistically significant.
Results
Study population
In total, 574 eligible DLBCL patients were included in the HOVON-84 study; 534 (93%) underwent I-PET4. Twenty-one I-PET4 scans were not evaluable (Fig. 1). The distribution of baseline characteristics and 2-y PFS were similar for patients with and without baseline MTV, I-PET4, and ∆SUVmax evaluations (Table 1).
Prognostic value of baseline aaIPI and MTV
After a median follow-up of 91 mo (interquartile range, 84-101 mo) the estimated 2-y PFS was 79% (95% CI, 76%-83%). Most patients belonged to the low- intermediate or high-intermediate aaIPI groups (35% and 50%, respectively, Table 1). In the Kaplan-Meier analysis both low and low-intermediate aaIPI survival curves and high-intermediate and high aaIPI survival curves crossed each other without statistically significant differences (Supplemental Fig. 1a; supplemental materials are available at http://jnm.snmjournals.org). Dichotomization into low or low-intermediate and high-intermediate or high yielded a 2-y PFS of 91% (95%CI,87%-95%) and 71% (95%CI,66%-76%),respectively,with a corresponding univariate HR of 3.6 (95%CI, 2.2-5.9; Supplemental Fig. 1b; Table 2).
Of 384 patients who underwent baseline PET, baseline MTV was measurable in 296 (52%; Fig. 1). The continuous log-transformed MTV had a univariate HR of 1.4 (95%CI, 1.2-1.8; Supplemental Table 1). Patients in the low-MTV group (MTV≤345 cm3, n=137; 46%) had a 2-y PFS of 86% (95%CI, 80%-92%) versus 75% (95%CI, 68%-81%) in the high-MTV group (MTV>345 cm3, n=159; 54%), with a corresponding univariate HR of 2.0 (95%CI, 1.1-3.4; Table 2). I-PET and end-of-treatment PET scans were both available in 474 patients (Supplemental Table 2), with an overall agreement of 87% (95%CI, 84%-90%).
130
