Outcome comparison between radiation therapy and surgery as primary treatment for dogs with periarticular histiocytic sarcoma: An Italian Society of Veterinary Oncology study

Abstract

Localized histiocytic sarcoma may occur as a primary lesion in periarticular tissues of large appendicular joints. Treatment options for the primary lesion include radical surgical excision, radiation therapy (RT), or both, in combination with chemotherapy for potential systemic metastases. In an effort to better characterize the time to progression (TTP) following surgical vs non-surgical approaches for periarticular histiocytic sarcoma (PAHS), a contemporary European population of affected dogs was retrospectively surveyed. Medical records were queried for newly-diagnosed PAHS cases undergoing surgery (predominantly limb amputation) or RT followed by systemic chemotherapy. Of 49 dogs, 34 underwent RT and 15 underwent surgery. All dogs received adjuvant chemotherapy. There was no statistically significant difference in TTP or overall survival between groups. The median TTP was 336 days for the operated dogs and 217 days for the irradiated dogs (P = .117). The median overall survival time was 398 days for the operated dogs and 240 days for the irradiated dogs (P = .142). On multi-variable analysis, the variables significantly associated with an increased risk of both tumour progression and tumour-related death were regional lymph node and distant metastasis at admission. Survival and local control rates following RT may be comparable to radical resection. These data may better inform shared decision-making processes between multidisciplinary care providers and owners.

Periarticular histiocytic sarcoma with heart metastasis in a cat

“…While dogs with localized HS receiving multimodal treatments of surgery and chemotherapy could live longer than 1 year, [28][29][30] adjuvant lomustine did not provide any survival benefit in this cat.…”

An invasive primary nasal histiocytic sarcoma in a cat

“…12 RT is an appropriate local treatment, and in a study of canine periarticular HS treated with RT or surgery, the overall radiation response rate was 91.2%, and the median time to progression survival was 217 days in the RT group, though with adjuvant chemotherapy. 13 Thus, RT seems to be effective against HS and can be used for local tumour control and to ameliorate clinical signs. Adjuvant chemotherapy such as lomustine should also be considered.…”

Bite-size introduction to canine hematologic malignancies

“… 97 A recent report describing the treatment of 49 dogs with periarticular HS reported no significant differences in outcome between the use of external-beam radiotherapy and surgical excision for local control when adjuvant chemotherapy was prescribed in all cases. 98 Activity of CCNU in canine HS has also been documented outside the adjuvant setting, where an ORR of 46% was observed in 56 dogs with bulky disease. 99 Various other cytotoxic agents have been prescribed for dogs with HS, but CCNU is considered the treatment of choice based on the reported responses rates.…”

“…Dogs with localized HS can exhibit prolonged survival times following adequate local control with surgery and/or radiation and adjuvant CCNU, the median overall survival for 16 dogs treated like this was found to be 568 days 97 . A recent paper describing the treatment of 49 dogs with periarticular HS reported no significant differences in outcome between the use of external beam radiation therapy or surgical excision for local control when adjuvant chemotherapy was prescribed to all cases 98 . Activity of CCNU in canine HS has also been documented outside of the adjuvant setting where an ORR of 46% was observed in 56 dogs with bulky disease 99 .…”