Evaluation of radiotherapy alone or in combination with doxorubicin chemotherapy for the treatment of cats with incompletely excised soft tissue sarcomas: 71 Cases (1989-1999)

Abstract

Objective - To determine whether the addition of doxorubicin chemotherapy affected the outcome of cats with incompletely excised, nonvisceral soft tissue sarcomas undergoing postoperative radiotherapy. Design - Retrospective case series. Animals - 71 cats. Procedures - Medical records were reviewed for clinically relevant data on cats that underwent postoperative radiotherapy for treatment of incompletely excised soft tissue sarcomas with or without concurrent doxorubicin chemotherapy. Radiotherapy was performed on an alternate-day schedule, with a total dose of 58.8 to 63 Gy delivered in 21 fractions. Doxorubicin was administered every 21 days for 3 to 5 cycles. Follow-up information was obtained by means of physical examination or through telephone conversations with referring veterinarians or owners. Results - Median disease-free interval with concurrent radiotherapy and doxorubicin chemotherapy (15.4 months; range, 2.4 to 44.9 months) was significantly longer than median disease-free interval with radiotherapy alone (5.7 months; range, 1.0 to 50.8 months). However, survival time was not significantly different between groups. Conclusion and Clinical Relevance - Results suggested that doxorubicin chemotherapy may play a role in extending the disease-free interval in cats undergoing radiotherapy for treatment of incompletely excised soft tissue sarcomas.