Prognostic significance of histologic grade and Ki‐67 proliferation index in follicular lymphoma

Abstract

The prognostic value of histologic grading and the Ki-67 proliferation index in follicular lymphoma (FL) is controversial. This study investigated the clinical usefulness of these two factors in Asian FL patients. Four hundred and thirty-three patients diagnosed with FL were retrospectively reviewed with a median follow-up time of 47.0 months (range, 24.0-168.0). The 10-year overall survival (OS) rate and progression-free survival (PFS) rate were 91.0% and 47.1%, respectively. Grade 3B and grade 3B with diffuse large B cell lymphoma (DLBCL) showed a better PFS than grade 1-3A (P < 0.001), and similar findings were noted in patients who received rituximab-containing regimens (P = 0.002). In contrast, no significant differences in terms of OS or PFS were observed between grades 1-2 and 3A. In addition, patients with Ki-67 ≥ 30% had a significantly better PFS than patients with Ki-67 < 30% (P = 0.014), although the difference was eliminated in the multivariate analysis. Both grade and Ki-67 index had no impact on prognosis in patients who did not receive rituximab treatment. In conclusion, grade 3A is closely related to grade 1-2, as reflected by a similar indolent clinical course and a lower PFS rate than grade 3B/3B + DLBCL. In addition, a higher Ki-67 index seems to have a positive effect on PFS in FL patients.

Histological Impact on Follicular Lymphoma Grade 3 Treated With Frontline&nbsp;RCHOP Regimen

“…Biologically, FL grade 3B, compared with grade 3A, is often IRF4/MUM1 positive but CD10 negative and less likely to harbor Bcl2 rearrangement [10]. Moreover, patients with FL grade 3B or 3B with DLBCL were associated with a higher level of Ki-67 than those of FL grade 3A [11]. This support the concept the underlying genetic events were different between these two subtypes.…”

“…Whereas we do observe a plateau in the PFS curve in aggressive FL. This could be explained by the fact that aggressive FL is a curable disease which was con rmed in a recent study showed a better PFS in aggressive FL compared with FL grade 3A [11].…”

Immune infiltrate diversity confers a good prognosis in follicular lymphoma

“…Analysis shown for OS, where patients have been split into two groups based on the optimal cut points. Cut points were selected using the Contal & O’Quigley test [ 38 ] method. P Log Rank : significance for the log rank test and P C.O.…”

“…FLIPI was selected for multivariable analyses as a state-ofthe-art, widely validated prognostic index. We did not test histologic grade in multivariable analyses as its prognostic value for FL is limited and patients with grade 1-2 and 3a have similar survival rates [37][38][39]. Kaplan-Meier analysis for the diversity features was carried out by dichotomising the variables at the optimal cut point.…”

“…The TMA technology employed is equivalent to whole section assessments in lymphomas [51], enabling rapid processing of large number of samples. Furthermore, the diversity metrics demonstrated low intra-patient heterogeneity [38], adjusted for the fact that the optimal cut point has been selected to maximise separation of patient groups. Shaded areas represent 95% confidence intervals [42].…”