Veterinary Medicine - March 2008 - (Page 166)

Primary lung tumors PEER-REVIEWED approach allows access to the primary bronchi for lobectomy of the side involved but prevents adequate examination of the opposite hemithorax. During thoracotomy, examine and palpate all accessible lung lobes and tracheobronchial lymph nodes for metastasis or multifocal primary masses. If the tracheobronchial lymph nodes appear enlarged, they should at least be biopsied and preferentially be extirpated. Adjuvant chemotherapy After the primary tumor and associated draining lymph nodes are removed, adjunctive chemotherapy may be warranted based on host factors (clinical stage) and tumor characteristics (histologic ndings). Despite the availability of new chemotherapeutic drugs, few well-designed prospective studies have investigated the ef cacy of one or multiple agents for treating primary pulmonary neoplasms in dogs and cats. Vinorelbine, a semisynthetic derivative of vinca alkaloids, has recently been described for treating various neoplasms, including primary lung tumors, in dogs.50 Vinorelbine is widely distributed in all tissues except for the brain, with concentrations in the lungs reaching 13.8-fold higher than other vinca alkaloids.51 In one study, two of seven dogs with macroscopic bronchoalveolar carcinoma achieved a partial remission after vinorelbine treatment. Furthermore, in dogs with microscopic bronchoalveolar carcinoma (incompletely excised primary or lymph node metastases), vinorelbine’s anticancer activity was suggested by the relatively durable survival times of 113, 196, and 730+ days in three dogs treated with surgery and systemic vinorelbine.50 Further investigations are warranted to determine the effectiveness of adjunctive vinorelbine for treating bronchoalveolar carcinomas as well as other pulmonary neoplasms in dogs. In a study of 15 dogs with primary lung tumors treated by lobectomy, ve dogs with advanced recurrent pulmonary carcinoma received one of three chemotherapy protocols: 1) cyclophosphamide, vincristine, and methotrexate, 2) vindesine alone, or 3) vindesine and cisplatin.8 Two dogs treated with vindesine and cisplatin showed partial responses, with greater than 50% reduction in radiographic lesions. Anorexia was the only side effect of the cyclophosphamide, vincristine, and methotrexate protocol, while reversible neurotoxicity was the only side effect of vindesine alone. In the dogs treated with vindesine and cisplatin, mild leukopenia and gastrointestinal upset TABLE 2 Comparison of Canine Survival Times in Three Prognostic Studies* Study 1 OVERALL SURVIVAL TIMES — CLINICAL SIGNS Study 2 120 days — Study 3 361 days 240 days 545 days — — — — 26 days 452 days 44 days 495 days 5 days 790 days 81 days 196 days 790 days Present Absent Large Normal Large Normal Positive Negative CELL TYPE 10 months (300 days) 30 months (900 days)** — — — — — 8.5 months (255 days) 10 months (300 days) 8 months (240 days) 14 months (420 days) — — — 10 months (300 days) 10 months (300 days) 60 days 285 days 60 days 345 days 60 days 120 days 60 days 251 days 150 days 251 days 45 days 120 days 224 days LYMPH NODES ASSESSED BEFORE SURGERY LYMPH NODES ASSESSED DURING SURGERY HISTOLOGY OF LYMPH NODES Other Differentiated adenocarcinoma DIFFERENTIATION Poor Well TUMOR INVOLVEMENT Tumor invading neighboring tissues Multiple tumors Solitary tumor Study 1: Mehlhaff CJ, Leifer CE, Patnaik AK, et al. Surgical treatment of pulmonary neoplasia in 15 dogs. J Am Anim Hosp Assoc 1984;20:799-803. Study 2: Ogilvie GK, Weigel RM, Haschek WM, et al. Prognostic factors for tumor remission and survival in dogs after surgery for primary lung tumors: 76 cases (1975-1985). J Am Vet Med Assoc 1989;195(1):109-112. Study 3: McNiel EA, Ogilvie GK, Powers BE, et al. Evaluation of prognostic factors for dogs with primary lung tumors: 67 cases (1985-1992). J Am Vet Med Assoc 1997;211(11):1422-1427. * All are median values. * * Only one dog. 166 March 2008 VETERINARY MEDICINE

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Veterinary Medicine - March 2008 Contents Toxicology Brief Idea Exchange A Challenging Case An Update on Diagnosing and Treating Primary Lung Tumors CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - March 2008

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