Do Pre-Treatment Biopsy Characteristics Predict Early Tumour Progression in Feline Diffuse Large B Cell Nasal Lymphoma Treated With Radiotherapy?

in Veterinary and comparative oncology by Valerie J Poirier, Valeria Meier, Michelle Turek, Neil Christensen, Jacqueline Bowal, Matthew D Ponzini, Stefan M Keller

TLDR

  • The study evaluated the predictive value of pre-RT biopsy characteristics on early tumour progression in feline nasal lymphoma (FeNL) following radiation therapy (RT) treatment, but found no significant association with progression-free survival (PFS).
  • The study suggests that further research is needed to identify potential biomarkers or improved treatment strategies for FeNL.

Abstract

The standard of care treatment for localised feline nasal lymphoma (FeNL) is radiation therapy (RT). Early local or systemic failure occurs in 17%-45% of cats treated with RT with or without chemotherapy. The aim of this study was to determine if pre-treatment biopsy characteristics could predict early tumour progression in FeNL. Inclusion criteria consisted of histologically confirmed FeNL, available paraffin blocks of diagnostic quality, localised to the sinonasal cavity on staging pre-RT, treated with IMRT/IGRT (10 × 4.2 Gy) without chemotherapy and at least 1 year follow-up. All pre-RT biopsies were reviewed and evaluated with CD3, CD20, CD79a, pan-CK and Ki-67 immunohistochemistry and the mitotic activity index was determined. The primary endpoint was progression-free survival (PFS) at 1 year and hazard-ratios (HR) with confidence interval (CI) were calculated. Twenty-eight cats fit the inclusion criteria, and all had diffuse large B-cell lymphoma. Seventeen cats (61%) were progression free at 1 year. Of the 11 cats that progressed in the first year, two had local progression, two had both local and systemic progression and seven had systemic progression. The mitotic index (HR: 1.03, CI 0.9-1.19, p = 0.645), Ki-67 (HR: 1.00, CI 0.98-1.02, p = 0.845) and > 30% of tumour-infiltrating T cells (HR: 0.38, CI 0.09-1.56, p = 0.175) were not significantly associated with PFS. In this uniformly RT treated population of FeNL, none of the evaluated pre-RT histologic parameters could predict early treatment failure.

Overview

  • The study aimed to determine if pre-treatment biopsy characteristics could predict early tumour progression in feline nasal lymphoma (FeNL) following radiation therapy (RT) treatment.
  • The study included 28 cats with histologically confirmed FeNL, treated with IMRT/IGRT (10 × 4.2 Gy) without chemotherapy, and had at least 1 year follow-up.
  • The primary endpoint was progression-free survival (PFS) at 1 year, and the study aimed to evaluate the potential predictive value of pre-RT biopsy characteristics on PFS.

Comparative Analysis & Findings

  • The study found that none of the evaluated pre-RT histologic parameters (mitotic index, Ki-67, and > 30% of tumour-infiltrating T cells) were significantly associated with progression-free survival (PFS) following RT treatment.
  • Of the 11 cats that progressed in the first year, two had local progression, two had both local and systemic progression, and seven had systemic progression.
  • Seventeen cats (61%) were progression-free at 1 year.

Implications and Future Directions

  • The study suggests that current RT treatment strategies may not be sufficient to control tumour progression in all cases of FeNL, and further research is needed to identify potential biomarkers or improved treatment strategies.
  • Future studies may consider evaluating additional histologic or molecular parameters to predict early treatment failure or to identify potential responders to alternative treatments.
  • The findings of this study may also have implications for the development of personalized treatment plans for cats with FeNL, taking into account individual tumour characteristics and patient outcomes.
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