Do Pre-Treatment Biopsy Characteristics Predict Early Tumour Progression in Feline Diffuse Large B Cell Nasal...

Area of Science:

• Veterinary Oncology
• Comparative Pathology
• Radiation Oncology

Background:

• Feline nasal lymphoma (FeNL) is commonly treated with radiation therapy (RT), but early treatment failure occurs in 17%-45% of cases.
• Predicting treatment failure is crucial for optimizing therapeutic strategies in veterinary oncology.
• The role of pre-treatment biopsy characteristics in predicting early FeNL progression remains unclear.

Purpose of the Study:

• To investigate whether pre-treatment biopsy features can predict early tumor progression in cats with localized feline nasal lymphoma (FeNL).
• To evaluate the association between specific immunohistochemical markers and mitotic activity with progression-free survival (PFS) in FeNL patients treated with RT.

Main Methods:

• Retrospective analysis of 28 cats with histologically confirmed FeNL, treated with intensity-modulated/image-guided radiation therapy (IMRT/IGRT) without chemotherapy.
• Evaluation of pre-treatment biopsies using CD3, CD20, CD79a, pan-CK, Ki-67 immunohistochemistry, and determination of mitotic activity index.
• Primary endpoint was 1-year progression-free survival (PFS); hazard ratios (HR) and confidence intervals (CI) were calculated.

Main Results:

• All 28 cats had diffuse large B-cell lymphoma; 61% (17/28) were progression-free at 1 year.
• No significant association was found between mitotic index (HR: 1.03), Ki-67 (HR: 1.00), or >30% tumor-infiltrating T cells (HR: 0.38) and PFS.
• None of the evaluated pre-treatment histologic parameters could predict early treatment failure in this uniformly RT-treated FeNL population.

Conclusions:

• Pre-treatment biopsy characteristics, including mitotic index and Ki-67, do not reliably predict early treatment failure in cats with localized feline nasal lymphoma treated with RT.
• Further research is needed to identify reliable predictive biomarkers for treatment response in FeNL.
• Current histologic parameters are insufficient for guiding therapeutic decisions regarding early treatment failure in FeNL.