Outcome of appendicular or scapular osteosarcoma treated by limb amputation in cats: 67 cases (1997–2018)

Abstract

OBJECTIVE To evaluate the metastasis rate, survival time, and prognostic factors associated with appendicular or scapular osteosarcoma treated by limb amputation in cats. ANIMALS 67 cats with histologically confirmed appendicular or scapular osteosarcoma treated by limb amputation. PROCEDURES This retrospective cohort study included cats with histologically confirmed appendicular or scapular osteosarcoma between January 1997 and December 2018. A questionnaire survey was conducted at veterinary clinics where limb amputation was performed. Distant metastasis, local recurrence, and lymph node metastasis rates and survival time were determined. Factors associated with distant metastasis and survival were investigated. RESULTS The distant metastasis rate after limb amputation was 41.9% (26/62). The overall distant metastasis rate was 46.3% (31/67), including 5 cats with distant metastasis at the time of amputation. Osteosarcoma of the humerus resulted in distant metastasis in 6 of 7 cases. Osteosarcoma of the humerus was significantly associated with distant metastasis in univariate and multivariate analyses (adjusted OR, 9.56). The rate of lymph node metastasis after limb amputation was 3.0% (2/66), and the local recurrence rate was 9.0% (6/67). The median survival time was 527 days. Age and tumor location were not significantly associated with survival time. CLINICAL RELEVANCE Distant metastasis occurs in approximately 40% of cats with appendicular or scapular osteosarcoma after limb amputation. In addition, osteosarcoma of the humerus has a particularly high incidence of distant metastasis. Detailed follow-up is therefore necessary, even after limb amputation, especially in cases of osteosarcoma of the humerus.

Limb sparing in a cat with a humeral osteosarcoma using a customised three-dimensional printed endoprosthesis

“…Although osteosarcoma in cats has previously been reported to have a better prognosis than in dogs, recent evidence suggests that there is a high rate of distant metastasis (40%). 3 The recommended treatment for feline osteosarcoma tends to be limb amputation alone, and there is open debate on whether adjuvant therapy will prolong survival times. 5 In one study of cats after limb amputation, most cats returned to a normal quality of life; however, there were reduced levels of activity and speed in approximately 50% of cats with amputated limbs.…”

“…2 Feline osteosarcoma is usually less aggressive and carries a more favourable prognosis than canine osteosarcoma. 3 Limb amputation is considered the gold standard of care for the treatment of bone and joint neoplasia in small animals. 4 Although cats tolerate limb amputation well, recent methods of limb salvage have allowed for preservation of the affected limb without complete amputation.…”

Feline Oncogenomics: What Do We Know about the Genetics of Cancer in Domestic Cats?

“…Prognosis is dependent upon the location of the tumour, with axial OSA generally being poor (with an average survival time of 6 months) in contrast to appendicular OSA, which is associated with a more favourable outcome, particularly when treated with complete surgical excision or amputation (with an average survival time of 26–49 months) [ 137 ]. Although historically considered to have a better prognosis compared to dogs, a more recent report suggests a shorter median survival time and metastatic rate than previously reported, with a median survival time of 527 days after limb amputation and distant metastases in 46.3% of all cases [ 138 ].…”

A retrospective Italian Society of Veterinary Oncology (SIONCOV) study of 56 cats with appendicular osteosarcoma

“…1,2 In contrast, appendicular osteosarcoma in cats is less common, resulting in limited published research on this matter. 1,[3][4][5] From the existing data, it appears that hindlimbs are more commonly affected than forelimbs. 1,6 Also, feline osteosarcoma is generally considered to exhibit less aggressive behaviour compared to its canine counterpart, with a low metastatic rate ranging from 5% to 10% and a median survival time of 12-64 months after surgical treatment alone.…”