Hypofractionated radiotherapy in nine dogs with unresectable solitary lung adenocarcinoma

Retrospective study evaluating the efficacy of stereotactic body radiation therapy for the treatment of confirmed or suspected primary pulmonary carcinomas in dogs

Canine primary pulmonary carcinomas (PCCs) are commonly treated with surgery with overall median survival times (MST) around a year; however, due to extent of disease, prognosis, or client preference, alternative treatments have been considered. Stereotactic body radiation therapy (SBRT) has been utilized in human cancer patients for local control of lung tumours as a surgical alternative. Twenty-one PCCs in 19 dogs that received SBRT for local control were retrospectively evaluated. Dogs were staged according to the canine lung carcinoma stage classification (CLCSC) system with three as Stage 1, five as Stage 2, three as Stage 3, and eight as Stage 4. Overall MST was 343 days with 38% of patients alive at 1 year. Stage did not significantly impact survival time (p = .72). Five (26%) dogs had lymphadenopathy and MST was not significantly different from dogs without lymphadenopathy (343 vs. 353 days; p = .54). Five out of 18 evaluable dogs (28%) experienced acute lung VRTOG effects and 2 of 12 dogs (17%) experienced late lung VRTOG effects. Median lung dose, V5, V20, and D30 to the lung did not correlate significantly with the development of adverse radiation events. Twelve dogs had follow-up imaging and the best response included a complete response (17%), partial response (42%), and stable disease (42%). Progressive disease was noted in seven dogs a median of 229 days after SBRT. SBRT was documented to be a safe and effective alternative to surgery and may have survival advantages for Stage 3 or 4 dogs according to the CLCSC.

Vinorelbine as First-Line Treatment in Stage IV Canine Primary Pulmonary Carcinoma

Vinorelbine (VRL), a semi-synthetic vinca alkaloid commonly used in humans with advanced lung cancer, reaches high concentrations in the lung tissue, has proven antineoplastic activity and a low toxicity profile in dogs. Treatment-naïve, client-owned dogs with a cyto/histological diagnosis of advanced pulmonary carcinoma, selected from a laboratory database and previously subjected to imaging, were enrolled in the study. Vinorelbine (15 mg/m2) was administered weekly for 4 weeks and then fortnightly until progressive disease was documented. Staging work-up was repeated by means of diagnostic imaging after the fourth VRL (i.e., 28 days) and monthly thereafter; response to treatment was evaluated according to the RECIST. Toxicity was graded following the VCOGC group. Ten dogs met the inclusion criteria. Partial response was documented in eight dogs. Median time to progression was 88 days (range: 7-112) and median survival time for all dogs was 100 days (range 7-635). The most common side effect was neutropenia. The main limitations of the study were the absence of histological diagnosis in eight cases and the limited number of treated dogs. VRL is well tolerated with an adequate toxicity profile and may be useful in the management of advanced lung tumours if used as a first-line treatment strategy.

Percutaneous microwave ablation of solitary presumptive pulmonary metastases in two dogs with appendicular osteosarcoma

OBJECTIVE

To describe percutaneous microwave ablation (MWA) of presumptive pulmonary metastases and the outcome of two dogs.

ANIMALS

Two dogs with pulmonary lesions after treatment of spontaneously occurring appendicular osteosarcoma.

STUDY DESIGN

Preliminary prospective clinical study.

METHODS

Two large-breed dogs were referred from tertiary veterinary hospitals 146 and 217 days after limb amputation to pursue MWA as an alternative therapy to metastasectomy. Both dogs had been receiving chemotherapy protocols at their respective referral centers.

RESULTS

A novel percutaneous approach for MWA with ultrasonographic or computed tomographic (CT) guidance was successfully performed. The only complications consisted of pneumothoraxes, requiring treatment in one dog. In the weeks after their procedures, both dogs were reported to do well at home. Dog 1 died and dog 2 was euthanized 82 and 19 days, respectively, after their MWA of confirmed (dog 1) or presumed (dog 2) metastatic disease.

CONCLUSION

Percutaneous MWA of pulmonary nodules was technically feasible in two dogs without major complications.

CLINICAL SIGNIFICANCE

Percutaneous MWA may provide a minimally invasive option for treatment of osteosarcoma pulmonary metastases. Additional studies are required to evaluate the benefits of MWA on survival and confirm histologic cell death within pulmonary neoplastic lesions.