Risk stratify of the patients of Diffuse Large B Cell Lymphoma (DLBCL) based on germinal centre subtype, Ki 67 and Bcl-2 expression, and IPI scoring and study the prognostic significant of each of these variables. Previous studies are available with conflicting results and there is a paucity of such study from India.
It is a retrospective study of 112 patients. Ki 67 cutoff of 70% or more was used to classify into high and low. Ki 67 analysis was available for 76 patients and BCL-2 analysis for 96 patients. All patients received treatment with CHOP based chemotherapy. Survival curves were estimated by the Kaplan-Meier analysis, using log-rank test.
Of the total patients, 64 were GCB type and 48 were non-GCB type. The median survival was 34 months in former and 22 months in latter (P = 0.043). Median survival was greater in Bcl-2 negative patients (n = 52) as compared to the positive ones (n = 44) (36 vs 24.5 months, P = 0.003), and was greater in patients with low Ki 67 (n = 32) as compared to high Ki 67 (n = 44) (32 m vs 21.5 m, P = 0.033). Further, subgroup analysis in Ki 67 arm was done based on subtype (GCB or non-GCB) and IPI risk (high or low). In the GCB subtype, low Ki 67 had a better survival as compared to high Ki 67 (35 m vs 28 m, P = 0.044). Whereas, in the non-GCB subtype, the results were same but insignificant (26.5 m vs 18 m, P = 0.7). In the high IPI arm, low Ki 67 had a better survival (26.5 m vs 17 m, P = 0.02), whereas, in low IPI arm, the results were similar but statistically insignificant (39 m vs 38 m, P = 0.837). Similarly, subgroup analysis was done in the Bcl-2 arm based on subtype and IPI risk. In the non-GCB type, patients with Bcl-2 negativity had a survival advantage over the Bcl-2 positive ones (36.5 m vs 17 m, P = 0.02), similarly in the GCB subtype (36 m vs 33 m, P = 0.032). In the high IPI arm, Bcl-2 negativity had a survival advantage (30 m vs 18.5 m, P = 0.002). In the low IPI arm, similar results were obtained (44 vs 39 months, P = 0.037).
GCB subtype, Bcl-2 negativity, and low Ki 67 independently had a survival benefit. Also, the number of patients with low Ki 67 and Bcl-2 negativity were higher in the GCB type, and vice versa. Low Ki 67 had a survival advantage in GCB subtype and high IPI. Bcl-2 negativity had a survival advantage irrespective of GCB and IPI status.
Clinical trial identification
All authors have declared no conflicts of interest.