Descriptive analysis and prognostic factors in cats with myeloma-related disorders: A multicenter retrospective study of 50 cases

J Vet Intern Med. 2024 May-Jun;38(3):1693-1705. doi: 10.1111/jvim.17051. Epub 2024 Mar 22.

Abstract

Background: Myeloma-related disorders (MRDs) are rare and poorly documented neoplasms of cats.

Hypothesis/objectives: To describe clinical, clinicopathologic, and imaging findings, response to treatment, and survival time and to identify factors associated with shorter outcomes in cats with MRD.

Animals: Fifty cats with a diagnosis of MRD.

Methods: Cats with paraproteinemia confirmed by serum protein electrophoresis (SPE) and either intramedullary plasmacytosis >10%, marked cytonuclear atypia with intramedullary plasmacytosis that ranged between 5% and 10%, or cytologically or histologically confirmed visceral infiltration were retrospectively included from several veterinary referral centers.

Results: Bone marrow plasmacytosis and splenic or hepatic involvement were present in 17/27 cats (63%), 36/42 cats (86%), and 27/38 cats (71%), respectively. Anemia was reported in 33/49 cats (67%) and thrombocytopenia in 16/47 cats (34%). Some of the treatments that the cats received included melphalan and prednisolone (n = 19), cyclophosphamide and prednisolone (n = 10), chlorambucil and prednisolone (n = 4), prednisolone (n = 4), or other (n = 4). The overall response rates to melphalan, cyclophosphamide, and chlorambucil in combination with prednisolone were 87%, 90%, and 100%, respectively. Adverse events to melphalan or cyclophosphamide occurred in 65% and 23% of cats, respectively. Median survival time was 122 days (range, 0-1403) and was not significantly associated with chemotherapy protocol. Anemia (hazard ratio [HR], 3.1; 95% confidence interval [CI], 1.0-9.8) and thrombocytopenia (HR, 2.7; 95% CI, 1.2-6.0) were risk factors for shorter survival.

Conclusions and clinical importance: Our study confirmed the guarded prognosis of MRD in cats and identified risk factors for shorter survival times.

Keywords: cat; oncology; plasma cell; prognosis.

Publication types

  • Multicenter Study

MeSH terms

  • Anemia / etiology
  • Anemia / veterinary
  • Animals
  • Cat Diseases* / drug therapy
  • Cat Diseases* / mortality
  • Cat Diseases* / pathology
  • Cats
  • Cyclophosphamide / therapeutic use
  • Female
  • Male
  • Melphalan / therapeutic use
  • Multiple Myeloma* / complications
  • Multiple Myeloma* / drug therapy
  • Multiple Myeloma* / mortality
  • Multiple Myeloma* / pathology
  • Multiple Myeloma* / veterinary
  • Prednisolone / therapeutic use
  • Prognosis
  • Retrospective Studies