Stereotactic radiation therapy for canine multilobular osteochondrosarcoma: Eight cases

Abstract

Radiotherapy is often considered in the management of canine multilobular osteochondrosarcoma (MLO), but its efficacy against bulky MLO tumours is poorly described. This retrospective case series describes the clinical outcomes of pet dogs with MLO treated with a stereotactic radiation therapy (SRT) prescription of 30 Gy in three consecutive daily 10 Gy fractions. Dogs with an imaging (via computed tomography [CT] scan) and/or pathologic diagnosis of MLO were included. Patient demographics, tumour characteristics, radiation plan dosimetry, toxicity and outcome data were obtained retrospectively from the records. The median progression‐free survival time (MPFST) and median overall survival time (MST) were calculated using a LOGLOG test. Eight dogs were included. None had evidence of metastasis at the time of SRT. Clinical signs associated with the MLO included a mass noted by owner, stertor, vestibular signs, exophthalmos and abnormal mentation. Of the five dogs that had CT scans performed 3 to 9 months after SRT, tumour volume decreased by 26% to 87% in four dogs and increased by 32% in one dog. Late radiation toxicity was documented in three dogs (VRTOG Grade 1 skin and/or ocular, n = 2; Grade 3 central nervous system, n = 1). Confirmed local disease progression (n = 3; two were treated with a second course of SRT) and suspected pulmonary metastasis (n = 2) occurred 90 to 315 days after SRT. The MPFST was 223 days (interquartile range [IQR]: 144.5‐276.5 days). The MST was 329 days (IQR: 241.5‐408 days). This protocol was well‐tolerated, but the duration of response was short‐lived.

Tumor ósseo multilobular em cão da raça yorkshire terrier: relato de caso

“…A remoção cirúrgica costuma ser difícil devido à localização da neoplasia e a recorrência local ocorre em cerca de 50% dos casos (COOK et al, 2017;MAXIE et al, 2007), fato descrito, anteriormente, pelo tutor do animal. A excisão cirúrgica agressiva com margens amplas é considerada o tratamento de escolha e pode resultar na remissão da neoplasia em longo prazo (GALLEGOS; SCHWARZ; MCANULTY, 2008; HOLMES; KEYERLEBER; FAISSLER, 2019), uma vez que a quimioterapia e radioterapia apresentem uma resposta clínica variável e de curta duração (STRAW et al, 1989;SWEET et al, 2020). Histologicamente, foi observada uma proliferação mesenquimal com trechos formando esboços lobulares delineados por feixes de células fusiformes.…”

Megaoesophagus and dysphagia presumed secondary to medulla oblongata compression by multilobular tumour of bone in a dog

“…23 In a group of eight dogs undergoing stereotactic radiation alone, the MST was 329 days (range: 241.5-408). 11 With combined resection and reconstruction with titanium mesh implant and high-dose definitive…”

“…8 This is an uncommon tumour typically arising from the flat bones of the skull in middle-aged to older animals, occurring most frequently in medium or large breeds. [9][10][11] Invasion into the calvarium is a characteristic finding of MTB that can be identified by computed tomography (CT) and magnetic resonance imaging (MRI). 9,12 Surgery is the treatment method of choice in dogs; however, local recurrence has been reported to be 47%, with a median disease-free interval of 797 days.…”

Cranioplasty for Multilobular Osteochondrosarcoma Using 3-Dimensional Printing Technology in Dogs: A Report of Two Cases with a Long-Term Follow-Up

“…Although chemotherapy and radiotherapy may have benefits of local control of tumors or palliation of residual tumors (13,30,31), surgery remains the treatment of choice. Clean surgical margins are strongly associated with favorable prognosis (5,7,8,16).…”