• Open Access

Evaluation of Cytoreductive Efficacy of Vincristine, Cyclophosphamide, and Doxorubicin in Dogs with Lymphoma by Measuring the Number of Neoplastic Lymphoid Cells with Real-Time Polymerase Chain Reaction

Authors

  • M. Sato,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • J. Yamazaki,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
    2. MD Anderson Cancer Center, The University of Texas, Houston, TX.
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  • Y. Goto-Koshino,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • M. Takahashi,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • Y. Fujino,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • K. Ohno,

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • H. Tsujimoto

    1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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  • The study was performed at Veterinary Medical Center of the University of Tokyo. The study was presented at European College of Veterinary Internal Medicine-Companion Animals Congress 2009.

Corresponding author: Hajime Tsujimoto, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; e-mail: atsuji@mail.ecc.u-tokyo.ac.jp.

Abstract

Background: The cytoreductive efficacy of the individual components of multidrug chemotherapy for canine lymphoma is difficult to evaluate after complete remission.

Objectives: To compare the cytoreductive efficacy of vincristine (VCR), cyclophosphamide (CPA), and doxorubicin (DXR) in dogs that received a 6-month modified version of the University of Wisconsin-Madison chemotherapy protocol (UW-25).

Animals: Twenty-nine dogs with high-grade B-cell multicentric lymphoma.

Methods: Rearranged immunoglobulin heavy chain gene fragments from lymphoma cells were amplified by polymerase chain reaction (PCR) and sequenced to prepare clone-specific primers and probes for real-time PCR. The number of lymphoma cells in peripheral blood was measured from diagnosis to week 11 of UW-25.

Results: The number of lymphoma cells after the 1st administration of VCR, CPA, and DXR in weeks 1–4 was decreased in 29/29 (100%), 15/29 (51.7%), and 26/27 (96.3%) dogs, respectively. The cytoreductive efficacy of CPA was less than that of VCR and DXR. VCR, CPA, and DXR administered in weeks 6–9 were effective in 5/26 (19.2%), 5/20 (25.0%), and 14/19 (73.7%) dogs, respectively, indicating the sustained cytoreductive efficacy of DXR. CPA nonresponders were heavier and exhibited a shorter 1st remission than CPA responders.

Conclusion and Clinical Importance: When using UW-25 for treatment of canine lymphoma, CPA was found to have less cytoreductive efficacy than VCR and DXR. Real-time PCR-based quantification of tumor cells is an objective marker of the efficacy of chemotherapeutic agents.

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