Evaluation of outcome and prognostic factors for dogs living greater than one year after diagnosis of osteosarcoma: 90 cases (1997–2008)

Abstract

Objective To evaluate clinical characteristics, outcome, and prognostic variables in a cohort of dogs surviving > 1 year after an initial diagnosis of osteosarcoma. Design Retrospective case series. Animals 90 client-owned dogs. Procedures Medical records for an 11-year period from 1997 through 2008 were reviewed, and patients with appendicular osteosarcoma that lived > 1 year after initial histopathologic diagnosis were studied. Variables including signalment, weight, serum alkaline phosphatase activity, tumor location, surgery, and adjuvant therapies were recorded. Median survival times were calculated by means of a Kaplan-Meier survival function. Univariate analysis was conducted to compare the survival function for categorical variables, and the Cox proportional hazard model was used to evaluate the likelihood of death > 1 year after diagnosis on the basis of the selected risk factors. Results 90 dogs met the inclusion criteria; clinical laboratory information was not available in all cases. Median age was 8.2 years (range, 2.7 to 13.3 years), and median weight was 38 kg (83.6 lb; range, 21 to 80 kg [46.2 to 176 lb]). Serum alkaline phosphatase activity was high in 29 of 60 (48%) dogs. The most common tumor location was the distal portion of the radius (54/90 [60%]). Eighty-nine of 90 (99%) dogs underwent surgery, and 78 (87%) received chemotherapy. Overall, 49 of 90 (54%) dogs developed metastatic disease. The median survival time beyond 1 year was 243 days (range, 1 to 1,899 days). Dogs that developed a surgical-site infection after limb-sparing surgery had a significantly improved prognosis > 1 year after osteosarcoma diagnosis, compared with dogs that did not develop infections. Conclusions and Clinical Relevance Results of the present study indicated that dogs with an initial diagnosis of osteosarcoma that lived > 1 year had a median survival time beyond the initial year of approximately 8 months. As reported previously, the development of a surgical-site infection in dogs undergoing a limb-sparing surgery significantly affected prognosis and warrants further study.

The animal-dependent risk factors in canine osteosarcomas

“…Some studies have also implied that the age distribution of dogs with OSA has two peaks: the first between 18-24 months, and the second between 7-10 years, however, the majority of skeletal OSAs in dogs occur in the latter period (Dernall et al 2007, Culp et al 2014, Fanger et al 2014, Nagamine et al 2015. The mean age was similar in our study, however, we did not observe bimodal distribution of the disease.…”

“…It is probably a result of differences in genetic diversity of dogs in various countries, however the influence of environmental factors and the attitude of the dogs' owners to performing cytological or histopathological tests should also be included. Compared to other studies we enrolled fewer mongrels -11% vs. 20-30% (Culp et al 2014, Nagamine et al 2015, Romano et al 2016. Even though, genetic diversity in dogs' population in various geographic regions could play its role, the owners of mongrels might be less committed in diagnostic process and economic aspect might affect the study population.…”

“…The mean age was similar in our study, however, we did not observe bimodal distribution of the disease. Some studies have suggested that dogs with appendicular OSA are younger than animals with non-appendicular tumors, whereas other have not (Eberle et al 2010, Coyle et al 2013, Culp et al 2014). Analogically to the results of the study conducted on the population of large breed dogs with primary bone tumors (Anfinsen et al 2011), we did not find differences in mean age between any subclasses of dogs enrolled in our study population.…”

“…Al. 2012, Dobson 2013, Culp et al 2014, Fanger et al 2014, Romano et al 2016). An important discrepancy is lack of predilection of German shepherds and Labradors in the present study.…”

“…This highly malignant tumor is a suitable model for OSA in humans due to similarities in biological behaviour, common molecular features, sharing the same environment, and last but not least, relatively high incidence in dogs (Morello et al 2011, Fenger et al Correspondence to: R. Sapierzyński, e-mail: rafal -sapierzynski@sggw.pl, tel. : +48 22 593 61 53 Shepherds, Borzoi, Leonberger, and Greyhounds are consistently mentioned (Thompson and Pool 2002, Morello et al 2011, Dobson 2013, Culp et al 2014, Fanger et al 2014, Romano et al 2016. The most common location for canine OSA is the appendicular skeleton, whereas axial bones are less often affected.…”