Whole-slide image analysis of the tumor microenvironment identifies low B-cell content as a predictor of adverse outcome in patients with advanced-stage classical Hodgkin lymphoma treated with BEACOPP

Abstract

A subset of patients with advanced-stage classical Hodgkin Lymphoma (cHL) relapse or progress following standard treatment. Given their dismal prognosis, identifying this group of patients upfront represents an important medical need. While prior research has identified characteristics of the tumor microenvironment, which are associated with cHL outcomes, biomarkers that are developed and validated in this high-risk group are still missing. Here, we applied whole-slide image analysis (WSI), a quantitative, large-scale assessment of tumor composition that utilizes conventional histopathology slides. We conducted WSI on a study cohort with pre-treatment biopsies of 340 advanced-stage cHL patients enrolled in the HD12 and HD15 trials of the German Hodgkin Study Group (GHSG), and tested our results in in a validation cohort of 147 advanced-stage cHL patients within the GHSG HD18 trial. All patients were treated with BEACOPP-based regimens. By quantifying T cells, B cells, Hodgkin-Reed-Sternberg-cells and macrophages with WSI, 80% of all cells in the tumor tissue were identified. Crucially, low B cell count was associated with significantly reduced progression-free survival (PFS) and overall survival (OS), while T cell-, macrophage- and Hodgkin-Reed-Sternberg-cell content was not associated with the risk of progression or relapse in the study cohort. We further validated low B cell content as a prognostic factor of PFS and OS in the validation cohort and demonstrate good inter-observer agreement of WSI. WSI may represent a key tool for risk stratification of advanced-stage cHL that can easily be added to the standard diagnostic histopathology work-up.

Figure 1.

Flowchart of the study cohort and validation cohort. Average values of percentage of the respective cell types are indicated. For calculation of cell counts of macrophages (CD68) and Hodgkin and Reed-Sternberg cells (CD30) see the Online Supplementary Methods.

Figure 2.

Cellular composition assessed by whole-slide imaging in the study cohort and according to histological subtypes of classical Hodgkin lymphoma. Average values of percentage of the respective cell types are indicated. For calculation of cell counts of macrophages (CD68) and Hodgkin and Reed-Sternberg cells (CD30) see the Online Supplementary Methods.

Figure 3.

Progression-free survival according to CD20 content. (A) Kaplan-Meier plots of progression-free survival (PFS) in the study cohort for the two risk groups according to B-cell content (CD20-positive cell rate: ≤21% or >21%). (B) Kaplan-Meier plots of PFS in the validation cohort for the two risk groups according to Bcell content (CD20-positive cell rate: ≤10% or >10%).

Figure 4.

Overall survival according to CD20 content. (A) Kaplan-Meier plots of overall survival in the study cohort for the two risk groups according to B-cell content (CD20- positive cell rate: ≤21% or >21%). (B) Kaplan-Meier plots of overall survival in the validation cohort for the two risk groups according to B-cell content (CD20-positive cell rate: ≤10% or >10%).