Clinicopathologic characteristics, postoperative outcome, and prognostic factors in dogs with primary pulmonary carcinomas - A retrospective study of 61 dogs

Abstract

Canine primary pulmonary carcinomas (PLC) are treated surgically. The goal of this study was to increase the veterinary database concerning clinical and pathological findings, postsurgical median survival times (mST), and prognostic factors in this tumor type. Retrospective analysis of 61 dogs with 62 PLC treated surgically between 2007 and 2017. Survival analyses were performed using the Kaplan-Meier and Logrank methods. Of the 62 tumors, 35 (56 %) were located peripherally in the lung, 21 (34 %) close to the hilus and 6 (10 %) affected the entire lobe. In 49 cases, differentiated (papillary or bronchoalveolar) adenocarcinomas were diagnosed; undifferentiated carcinomas or anaplastic carcinomas (n = 10) and squamous cell carcinomas (n = 2) were rare. There was no predisposition for specific lung lobes. Thirteen (21 %) of the patients exhibited no clinical signs, and 10 (16 %) displayed unspecific signs, unrelated to the respiratory tract. In total, forty-eight (79 %) dogs showed clinical signs such as coughing, dyspnea, lethargy, weight loss, exercise intolerance, vomiting and/or fever. Histologic examination of the tracheobronchial lymph nodes (TBLN), was positive for metastasis (N1) in 9 cases, negative (N0) in 42 patients, no TBLN histology was performed in 10 cases. Long-term follow-up information was available for 50 dogs. Variables with prognostic impact were presence of TBLN metastasis (mST: N1 41 days, N0 570 days; p < 0.01), lung metastases (mST: M1 125 days, M0 630 days; p < 0.01), histologic subtype (mST: tracheobronchial or papillary carcinoma 620 days; other carcinomas 135 days; p < 0.01); tumor diameter larger than 3 cm (mST < 3 cm 1155 days, ≥ 3 cm 330 days p = 0.02), and location of the tumor (mST: hilar 330 days, peripheral 650 days; p = 0.04). In PLK, TBLN status, M1, tumor location, histological subtype and tumor size are important, prognostically relevant factors; dogs without prognostically negative factors may have a good prognosis. More than one third of the dogs present asymptomatically (21 %) or without respiratory signs (16 %).