Evaluation of lung lobectomy and adjuvant treatment for primary pulmonary carcinoma in dogs: 89 cases (2005-2022).

Objective: Primary lung cancer is relatively common in dogs. Despite the existing literature on long-term follow-up and outcome, further clinical studies focusing on a single histotype are needed, specifically about epithelial tumours since they are the ones most frequently detected.

Methods: The medical records of four European institutions were reviewed to identify dogs undergoing lung lobectomy for a primary lung carcinoma between 2005 and 2022.

Results: A total of 89 dogs were included. Median age was 11 years (range 5 to 17 years) and median body weight was 23 kg (range 2.5 to 47 kg). Overall median survival time was 252 days (range 6 to 1558 days) and overall progression-free interval was 140 days (range 7 to 684 days). The 1-, 2- and 3-year survival rates were 61%, 47% and 30%, respectively. Presence of clinical signs at presentation, pleural effusion, completeness of surgical margins, histopathological features and use of adjuvant chemotherapy did not influence survival. Patients with maximum tumour diameter ≥ 5 cm had a reduced survival compared to patients with smaller tumours (median survival time 284 days vs. 717 days, 95% CI 8 to 719), and dogs with histologically confirmed lymph node metastasis had a reduced survival compared to patients with no evidence of local metastasis (median survival time 162 days vs. 614 days, 95% CI 39 to 760). None of the other assessed variables influenced progression-free interval.

Conclusions: Dogs with primary pulmonary carcinoma with no lymph node involvement and with a maximum tumour diameter of < 5 cm may have a better prognosis and prolonged survival. Further studies are needed to elucidate the role of adjuvant chemotherapy in case of clinically aggressive lung cancer.