Background Appendicular osteosarcoma (OSA), the most common bone tumor in dogs, is typically treated by amputation and adjuvant chemotherapy. Despite numerous efforts, the median survival time (MST) for dogs receiving a platinum compound, doxorubicin, or a combination of these remains at 8–12 months. Evidence from studies in mice suggests that gemcitabine has activity against OSA in vivo. Our preliminary work demonstrated that the addition of low-dosage (10mM) gemcitabine to carboplatin resulted in synergistic inhibition of OSA cell viability in vitro. Objective The purpose of the following study was to determine whether the addition of low-dosage (2 mg/kg) gemcitabine to carboplatin chemotherapy in dogs with OSA after amputation would improve MST over carboplatin monotherapy. Animals Fifty dogs with histologically confirmed appendicular OSA. Methods Dogs were treated prospectively with amputation and up to 4 dosages of carboplatin and gemcitabine in combination every 3 weeks. Results The chemotherapeutic regimen was well tolerated with only 5 episodes of grade 3 or 4 hematologic toxicity. The median disease-free interval (DFI) was 203 days and the MST was 279 for all dogs in this study. The 1- and 2-year survival rates were 29.5 and 11.3%, respectively. Dogs with proximal humeral OSA had a shorter median DFI (P = .04) compared with dogs with OSA in other locations. Conclusions and Clinical Importance These results are comparable to those reported for carboplatin monotherapy indicating that the addition of gemcitabine to carboplatin in dogs with appendicular OSA does not appear to improve outcome.

Gemcitabine exhibited biological activity against canine OSA cell lines in vitro, and a combination of gemcitabine and carboplatin exhibited synergistic activity at biologically relevant concentrations. Findings support future clinical trials of gemcitabine alone or in combination with carboplatin for the treatment of dogs with OSA.

Heated intraperitoneal chemotherapy (HIPEC) has several potential benefits. Higher doses of chemotherapy can be used with HIPEC because the plasma-peritoneal barrier results in little absorption into the blood stream. HIPEC offers higher peritoneal penetration in comparison to an intravenous (IV) regimen and does not have the traditional normothermic intraperitoneal (IP) regimen limitation of post-operative adhesions. Hyperthermia itself has cytotoxic effects and can potentiate antineoplastic effects of chemotherapy in part by increasing the depth of tumor penetration by up to 3 mm. For the treatment of ovarian cancer, HIPEC has been evaluated in the recurrent setting with secondary cytoreduction. Recent studies, including a prospective trial, have evaluated its role in primary management of ovarian cancer. This review summarizes previous and ongoing studies regarding the use of HIPEC in the management of ovarian cancer.