Lomustine for treatment of canine transmissible venereal tumor

ABSTRACT: Canine transmissible venereal tumor (TVTC) is a highly casuistic transmissible neoplasm in Brazil. Chemotherapy with vincristine sulfate is considered the treatment of choice, but the need for weekly applications and hematological monitoring, in addition to costs, are obstacles to owners’ adhesion to the treatment. Lomustine is an alkylating class antineoplastic agent, and because it is administered orally, it is a more practical and less costly treatment option for the owners of animals with neoplasms sensitive to the drug. This study evaluated the therapeutic efficacy of lomustine in dogs affected by TVTC. Twelve dogs with cytopathological diagnosis of natural genital TVTC were selected. The dogs were submitted to the experimental protocol with lomustine administration at doses of 70 to 85 mg/m2 orally every 21 days, totaling a maximum of two administration cycles. The animals were reevaluated every 7 days until a maximum of +49 days after the first dose of lomustine, to monitor the regression of neoplastic lesions through measurements. Among the 12 dogs submitted to the lomustine protocol, 8/12 achieved complete remission of the neoplasm and were considered cured (66.6%), 1/12 had partial response to treatment (8.33%) and 3/12 had stable disease (25%). Important adverse effects such as severe neutrophilic leukopenia were detected in 3/12 dogs (25%). The clinical study indicated that lomustine may be a treatment option for TVTC.摘要：犬传染性性病肿瘤（Canine transmissible venereal tumor, TVTC）是巴西一种高发的传染性肿瘤。硫酸长春新碱化疗被视为该病的首选治疗方案，但因其需每周给药、需进行血液学监测且治疗成本较高，导致宠物主人对该治疗方案的依从性不足。洛莫司汀属于烷基化类抗肿瘤药物，因可口服给药，对于该药物敏感的肿瘤患犬主人而言，是一种更实用且成本更低的治疗选择。本研究评估了洛莫司汀对TVTC患犬的治疗效果。研究共纳入12只经细胞病理学诊断为自然感染生殖道TVTC的患犬，采用洛莫司汀给药方案：按70~85 mg/m²的剂量口服给药，每21天一次，最多进行2个给药周期。所有受试犬自首次给药起，每7天复查一次，最长随访至给药后49天，通过病灶测量监测肿瘤病变的消退情况。在接受洛莫司汀治疗的12只患犬中，8只（66.6%）实现肿瘤完全缓解并被判定为治愈，1只（8.33%）获得部分缓解，3只（25%）病情稳定；另有3只（25%）患犬出现重度中性粒细胞减少症等严重不良反应。本临床研究表明，洛莫司汀可作为TVTC的一种治疗选择。