Distribution of histopathologic types of primary pulmonary neoplasia in dogs and outcome of affected dogs: 340 cases (2010–2019)

Abstract

OBJECTIVE To provide updated information on the distribution of histopathologic types of primary pulmonary neoplasia in dogs and evaluate the effect of postoperative adjuvant chemotherapy in dogs with pulmonary carcinoma. ANIMALS 340 dogs. PROCEDURES Medical records of dogs that underwent lung lobectomy for removal of a primary pulmonary mass were reviewed, and histopathologic type of lesions was determined. The canine lung carcinoma stage classification system was used to determine clinical stage for dogs with pulmonary carcinoma. RESULTS Pulmonary carcinoma was the most frequently encountered tumor type (296/340 [87.1%]), followed by sarcoma (26 [7.6%]), adenoma (11 [3.2%]), and pulmonary neuroendocrine tumor (5 [1.5%]); there was also 1 plasmacytoma and 1 carcinosarcoma. Twenty (5.9%) sarcomas were classified as primary pulmonary histiocytic sarcoma. There was a significant difference in median survival time between dogs with pulmonary carcinomas (399 days), dogs with histiocytic sarcomas (300 days), and dogs with neuroendocrine tumors (498 days). When dogs with pulmonary carcinomas were grouped on the basis of clinical stage, there were no significant differences in median survival time between dogs that did and did not receive adjuvant chemotherapy. CLINICAL RELEVANCE Results indicated that pulmonary carcinoma is the most common cause of primary pulmonary neoplasia in dogs; however, nonepithelial tumors can occur. Survival times were significantly different between dogs with pulmonary carcinoma, histiocytic sarcoma, and neuroendocrine tumor, emphasizing the importance of recognizing the relative incidence of these various histologic diagnoses. The therapeutic effect of adjuvant chemotherapy in dogs with pulmonary carcinoma remains unclear and warrants further investigation.

Prognosis of primary pulmonary adenocarcinoma after surgical resection in small‐breed dogs: 52 cases (2005‐2021)

“…Surgical margins were associated with PFI in both univariable and multivariable analyses in our study. Previous studies have reported that surgical margins of PPCs or primary pulmonary neoplasia (PPN) are associated with OST 6,17,18 and tumor‐specific survival 17,18 in univariable analysis but not in multivariable analysis 6,18 . These reports suggested that increased tumor size and invasiveness and location within the lung lobes (hilar and peripheral) may have been associated with surgical margins and influenced the results of multivariable analysis 6,18 .…”

“…Each CLCSC component, tumor size, lymph node metastasis, and distant metastasis was associated with survival time in PPC of dogs, suggesting that the CLCSC is an important prognostic factor for dogs with PPC. Subsequently, a relationship between CLCSC and survival also was observed in a larger population of dogs 6 …”

“…These data were reported as median and interquartile range (IQR). Lymph node metastasis was evaluated by histopathologic examination, and as in previous reports, for dogs in which lymph node resection or biopsy was not performed, lymph node status was recorded as N0 6,18,20 . Dogs that died perioperatively were excluded from the analysis of PFI and OST of adjuvant chemotherapy.…”

“…Primary lung cancer is a common malignancy in people 1 but is relatively rare in dogs 2 . Among lung tumors in dogs, primary pulmonary carcinomas (PPCs) are most common, and among PPC cases, pulmonary adenocarcinomas (PACs) are reported to account for 60%‐80% 3‐6 …”

“…However, unlike humans, dog breeds have large differences in body size. In the 2 reports that evaluated CLCSC, the median weight of the dogs was >20 kg 6,18 . To our knowledge, the prognosis of surgically resected PACs in small‐breed dogs has not been clarified, and whether the tumor size classification of CLCS could be applied to PAC of small‐breed dogs has not been examined.…”