High amounts of intra-tumoral reactive macrophages have been reported to be associated with a poor prognosis in patients with follicular lymphoma (FL) (
Analysis of the relative risk of event according to the intra-follicular MC (IF-MC) led us to determine a single cut-off point to categorize the covariate, the best cut-off point being estimated to be 10 macrophages/hpf. The IF-MC was equal or less than 10 intra-follicular KP1+ macrophages/hpf in 53 patients, and more than 10 in 141 patients. With this cut-off of 10, a low MC was significantly associated with a better EFS for all patients (p=0.011). However, this effect was predominantly observed in patients that received CHVP-I (p=0,012, OR) but not in those receiving R-CHVP-I (p=0.15).Multivariate analysis adjusting for 10 IF-MC cut-off (p<0.01), arm (p=0.07) and FLIPI (0.05) confirmed the significant predictive value of the MC for EFS in this population. In contrast, using a cut-off of 15 IF-MC, we found no significant association between MC and patients EFS (p=0.07), in the whole population or in each treatment arm. We extended our observation to the extra-follicular MC (EF-MC), the best cut-off point was estimated at 22 macrophages/hpf, which allowed to separate two equal groups of 97 patients. This cut-off was significantly correlated with EFS in a multivariate analysis adjusting for EF-MC cut-off (p=0.01), arm (p=0.04) and FLIPI (p<0.01). However, the prognostic value for EFS was significant in the group of patients treated with CHVP-I (p=0.02) but not for patients treated with R-CHVP-I. R-CHVP-I was significantly (p=0.01) associated with a better EFS than CHVP-I in high EF-MC patients. These results show that, if appropriate cut-offs are selected, both intra-follicular or extra-follicular MC can predict outcome of FL patients. Moreover, they indicate that rituximab is able to circumvent the poor prognosis associated with high MC in FL patients.
Disclosure: No relevant conflicts of interest to declare.