Aggressive local therapy combined with systemic chemotherapy provides long‐term control in grade II stage 2 canine mast cell tumour: 21 cases (1999–2012)

This retrospective case series evaluates the outcome of 21 dogs with grade II stage 2 mast cell tumour (MCT) treated with adequate local therapy and adjuvant systemic chemotherapy (prednisone, vinblastine and CCNU). The median survival for all dogs was 1359 days (range, 188–2340). Median disease‐free interval was 2120 days (149–2325 days). Dogs treated with surgery and chemotherapy had shorter survival (median, 1103 days; 188–2010 days) than those that underwent surgery, radiation therapy and chemotherapy as part of their treatment (median, 2056 days; 300–2340 days). Two patients had local recurrence in the radiation field and four patients had de novo MCT. Distant metastasis was not observed in any dogs. The results of this study suggest that, in the presence of loco‐regional lymph node metastasis in grade II MCT, the use of prednisone, vinblastine and CCNU after adequate local‐regional therapy can provide a median survival in excess of 40 months.     

Clinical features and outcome of dermal squamous cell carcinoma in 193 dogs (1987‐2017)

Squamous cell carcinoma (SCC) is a frequently recognized dermal tumour in dogs and has been described as a common pathology induced by solar ultraviolet radiation exposure. Little has been published about this neoplasm with regard to clinical features and outcome in dogs. This retrospective study included 193 dogs from a single institution histopathologically diagnosed with SCC of the dermis. Thirty‐eight percent of all dogs had documented histopathologic actinic change. The overall median survival time was 1004 days, with the population demonstrating actinic change associated with a significantly longer survival time (median 1359 days, range 16‐3530 days) compared to dogs without actinic change (median 680 days, range 16‐3066 days) and this achieved significance on multivariate analysis (hazard ratio 0.42, 95% confidence interval 0.193‐0.930, P = 0.032). These data demonstrate increased survival of dogs with SCC demonstrating actinic change over those with non‐actinic SCCs, and purports long‐term survival for these animals. Dogs received a variety of treatment approaches as a retrospective study, and future prospective studies will be necessary to investigate whether adjunct therapies such as radiation or chemotherapy offer improvement in survival for dermal SCC in the dog.     

Linac‐based stereotactic radiation therapy for canine non‐lymphomatous nasal tumours: 29 cases (2013‐2016)

Twenty‐nine dogs were treated with linac‐based stereotactic radiation therapy (SRT) for non‐lymphomatous nasal tumours. Only dogs with a follow‐up time >365 days were included in this retrospective analysis. No dogs had evidence of distant metastasis at diagnosis. Treatment was planned and a total of 30 Gy in 3 daily 10 Gy fractions was delivered using intensity‐modulation, cone‐beam CT‐based image guidance and a robotic treatment couch. Clinical signs improved in all cases. Nineteen dogs had CT scans 3‐4 months post‐SRT and all had partial or complete tumour response. Minimal acute toxicities were detected. Clinically significant late toxicities included oronasal or nasocutaneous fistulas (N = 3) and biopsy‐confirmed fungal rhinitis with no evidence of tumour progression (N = 2). The median progression‐free survival (PFS) was 354 days, with 49% and 39% progression‐free at 1 and 2 years post‐SRT, respectively. The median survival time (ST) was 586 days, with 69% and 22% alive 1 and 2 years post‐SRT, respectively. Neither the clinical parameters evaluated (modified Adams’ stage, histopathology, presence of intracranial extension of the tumour) nor dosimetric data were predictive for PFS or ST. This SRT protocol appears to be well tolerated, and PFI and ST are comparable or superior to those reported in other definitive‐intent radiotherapy protocols.     

Outcome following treatment of soft tissue and visceral extraskeletal osteosarcoma in 33 dogs: 2008–2013

Extraskeletal osteosarcoma (EOS) is a rare, highly malignant mesenchymal neoplasm arising from viscera or soft tissues characterised by the formation of osteoid in the absence of bone involvement. Owing to the rarity of these neoplasms very little information exists on treatment outcomes. The purpose of this study was to describe the outcome following surgical treatment of non‐mammary and non‐thyroidal soft tissue and visceral EOS in dogs. Thirty‐three dogs were identified; the most common primary tumour site was the spleen. Dogs that had wide or radical tumour excision had longer survival times compared with dogs that had only marginal tumour excision performed [median survival time of 90 days (range: 0–458 days) versus median survival time of 13 days (range: 0–20 days)]. The use of surgery should be considered in the management of dogs with non‐mammary and non‐thyroidal soft tissue and visceral EOS.     

SURVIVAL TIMES FOR CANINE INTRANASAL SARCOMAS TREATED WITH RADIATION THERAPY: 86 CASES (1996–2011)

Sarcomas comprise approximately one‐third of canine intranasal tumors, however few veterinary studies have described survival times of dogs with histologic subtypes of sarcomas separately from other intranasal tumors. One objective of this study was to describe median survival times for dogs treated with radiation therapy for intranasal sarcomas. A second objective was to compare survival times for dogs treated with three radiation therapy protocols: daily‐fractionated radiation therapy; Monday, Wednesday, and Friday fractionated radiation therapy; and palliative radiation therapy. Medical records were retrospectively reviewed for dogs that had been treated with radiation therapy for confirmed intranasal sarcoma. A total of 86 dogs met inclusion criteria. Overall median survival time for included dogs was 444 days. Median survival time for dogs with chondrosarcoma (n = 42) was 463 days, fibrosarcoma (n = 12) 379 days, osteosarcoma (n = 6) 624 days, and undifferentiated sarcoma (n = 22) 344 days. Dogs treated with daily‐fractionated radiation therapy protocols; Monday, Wednesday and Friday fractionated radiation therapy protocols; and palliative radiation therapy protocols had median survival times of 641, 347, and 305 days, respectively. A significant difference in survival time was found for dogs receiving curative intent radiation therapy vs. palliative radiation therapy (P = 0.032). A significant difference in survival time was also found for dogs receiving daily‐fractionated radiation therapy vs. Monday, Wednesday and Friday fractionated radiation therapy (P = 0.0134). Findings from this study support the use of curative intent radiation therapy for dogs with intranasal sarcoma. Future prospective, randomized trials are needed for confirmation of treatment benefits.     

Retrospective evaluation of canine heart base tumours treated with toceranib phosphate (Palladia): 2011‐2018

Heart base tumours (HBT) occur commonly in older, brachycephalic dogs. A presumptive diagnosis is made based on location and appearance of the tumour via echocardiogram. Effective treatment options are limited to surgery (when feasible) or radiation therapy. Benefit of medical management is presently unknown. The goal of this retrospective study was to assess the efficacy and tolerability of toceranib phosphate for dogs with HBT. Twenty‐eight dogs with histologically, cytologically confirmed or presumed HBT were evaluated retrospectively. Twenty‐seven dogs were treated with single agent toceranib. One dog received combination therapy with concurrent metronomic chemotherapy. This dog was not included in response or survival analysis. Factors assessed included clinical signs, hematologic/biochemical parameters and response to treatment. For the 27 dogs receiving single agent toceranib, an overall response rate of 10% was found. Overall median survival time was 823 days (range, 68‐1190 days). The overall response rate for the dogs presenting with metastasis was 28.5%, with a median survival time of 532 days (range, 77‐679 days). This was not significantly different than the median survival time of 796 days for dogs who did not present with metastasis. Of the dogs displaying clinical signs at the time of diagnosis, 90% had improvement and 81% had complete resolution of signs after starting toceranib. Toxicity was seen in 54% of dogs with gastrointestinal distress as the most common toxicity but dose reductions were infrequent required. Results demonstrate that toceranib phosphate is a well‐tolerated and effective treatment for inoperable canine heart base tumours including dogs with advanced or metastatic disease.     

Quantification of circulating tumour cells over time in dogs with appendicular osteosarcoma

Enumeration of circulating tumour cells (CTC) has shown promise for prognostication and guidance of therapeutic decisions in human cancers. The objective of this study was to enumerate CTC over time in dogs with naturally occurring osteosarcoma (OSA), and to determine correlation with patient outcome. Twenty-six dogs with OSA and no evidence of metastatic disease at the time of amputation were enrolled. Dogs were assessed for lung metastases and CTC prior to and following amputation, and at each chemotherapy visit. Twenty-one dogs completed the study. Nineteen dogs were euthanized and two were alive and free of metastases. Overall survival time ranged from 88 to 1058 days (median survival time (MST) 374 days). Increased serum alkaline phosphatase activity, advanced age, and higher body weight were significantly associated with lower MST. Dogs with OSA had a mean of 356 (0 to 4443) CTC/10⁶ leukocytes. In 12 of 15 dogs that developed radiographic evidence of metastasis, a pre-metastatic CTC spike was retrospectively detectable on average 36.5 (1–100 days) days prior to metastasis and was associated with significantly shorter MST (301 ± 64 vs. 626 ± 55 days; p = .0107). In a multivariable analysis, dogs with a CTC spike were 10× more likely to die compared with those without. These results suggest that a spike in CTC frequency precedes detection of metastasis in dogs with OSA and is associated with shorter survival. More frequent enumeration of CTC in a larger cohort of dogs with OSA may be warranted.     

Efficacy of doxorubicin‐based chemotherapy for non‐resectable canine subcutaneous haemangiosarcoma

Eighteen dogs with measurable subcutaneous haemangiosarcoma (SQHSA) were treated with doxorubicin‐based chemotherapy. Response assessment was evaluated and compared using World Health Organization (WHO), Response Evaluation Criteria in Solid Tumours (RECIST) and tumour volume criteria. The overall response rate for all dogs was 38.8% using WHO criteria, 38.8% using RECIST criteria and 44% using tumour volume criteria. One dog had a complete response. The median response duration for all dogs was 53 days (range 13–190 days). Four dogs had complete surgical excision after neoadjuvant chemotherapy. The median progression‐free interval for dogs with complete surgical excision after neoadjuvant chemotherapy was significantly longer than those not having surgical excision (207 days versus 83 days, respectively) (P = 0.003). No significant difference in metastasis‐free interval or survival time was found between the groups. Doxorubicin‐based chemotherapy appears to be effective for non‐resectable canine SQHSA, although the response duration is relatively short.     

Carcinoma of the apocrine glands of the anal sac in dogs: 113 cases (1985-1995)

OBJECTIVE: To characterize the signalment, clinical signs, biological behavior, and response to treatment of carcinoma of the apocrine glands of the anal sac in dogs. DESIGN: Retrospective study. ANIMALS: 113 dogs with histologically confirmed carcinoma of the apocrine glands of the anal sac. PROCEDURE: Data on signalment, clinical signs, and staging were reviewed and analyzed along with treatment modality for potential association with survival time. RESULTS: Sex distribution was approximately equal (54% female, 46% male). One hundred four dogs underwent treatment consisting of surgery, radiation therapy, chemotherapy, or multimodal treatment. Median survival for treated dogs was 544 days (range, 0 to 1,873 days). Dogs treated with chemotherapy alone had significantly shorter survival (median, 212 days) than those receiving other treatments (median, 584 days). Dogs not treated with surgery had significantly shorter survival (median, 402 days) than those that underwent surgery as part of their treatment (median, 548 days). Dogs with tumors > or = 10 cm2 had significantly shorter survival (median, 292 days) than dogs with tumors < 10 cm2 (median, 584 days). Hypercalcemia was identified in 27% (n = 29) of dogs, and those dogs had significantly shorter survival (median, 256 days), compared with those that were normocalcemic (median, 584 days). Dogs with pulmonary metastasis had significantly shorter survival (median, 219 days) than dogs without evidence of pulmonary metastasis (median, 548 days). CONCLUSIONS AND CLINICAL RELEVANCE: Unlike most previous reports, this study revealed an approximately equal sex distribution, and results suggest a more favorable prognosis.     

Survival analysis in dogs with urinary transitional cell carcinoma that underwent whole‐body computed tomography at diagnosis

This retrospective study aimed to evaluate factors associated with survival and to compare characteristics between tumour localizations in dogs with urinary transitional cell carcinoma (TCC) that underwent whole‐body computed tomography (CT) at diagnosis. Dogs with histologically confirmed TCC that received medical therapy between 2010 and 2017 were included; dogs that underwent surgery or radiotherapy for the primary tumour were excluded. According to the CT findings, primary tumour localization (classified into the Bladder, Urethra and Bladder and Urethra groups), prostate involvement, iliosacral lymphadenomegaly, sternal lymphadenomegaly and metastasis to the bone and lung were evaluated for survival analysis. CT at diagnosis revealed iliosacral lymphadenomegaly, sternal lymphadenomegaly, bone metastasis and lung metastasis in 47.7%, 18.5%, 24.6% and 35.4% of the 65 included dogs, respectively. The overall median survival time was 196 days. On multivariable analysis, TCC localization (hazard ratio [HR], 1.90; P = .037), bone metastasis (HR, 2.76; P = .013) and sternal lymphadenomegaly (HR, 3.56; P = .004) were significantly associated with survival. Compared to the Bladder group (n = 16), the Urethra group (n = 26) had higher metastasis rates to the bone (6.3% vs 42.3%; P = .045) and lung (6.3% vs 46.2%; P = .022). The survival time was shorter in the Urethra group than in the Bladder group (121.5 vs 420 days; P < .001), and it was similar only in female dogs (247 vs 420 days; P = .031). These findings suggest that whole‐body CT could be valuable for predicting the prognosis in urinary TCC.     

Canine spinal meningiomas and nerve sheath tumours in 34 dogs (2008‐2016): Distribution and long‐term outcome based upon histopathology and treatment modality

The purpose of this retrospective, multicentre case series was to describe the outcome following surgery and/or radiation of spinal meningiomas and nerve sheath tumours (NSTs) based upon treatment modality, with a specific aim to evaluate the survival times and time to recurrence following treatment for each histopathological diagnosis. Our hypothesis was that the addition of radiation therapy modalities to treatment will yield longer time to recurrence of clinical signs and survival time. Thirty‐four dogs met the inclusion criteria of histopathologically diagnosed extramedullary spinal meningioma or NST. Sixteen extramedullary spinal meningiomas and 18 NSTs were diagnosed. A diagnosis of meningioma was associated with a significantly longer survival time compared with NSTs, with median survival times (MST) of 508 days (95% confidence interval [CI]: 66‐881) vs 187 days (95% CI: 76‐433; P = .02). Dogs (seven) treated with stereotactic radiation therapy (SRT) for recurrence after surgery alone or SRT alone as their initial treatment gained an additional 125 to 346 days survival time.     

Biological behaviour of canine mandibular osteosarcoma. A retrospective study of 50 cases (1999–2007)

The purpose of this retrospective study was to describe the biological behaviour of canine mandibular osteosarcoma (OSA) and to examine factors for their impact on metastasis‐free interval (MFI) and survival time (ST). Records from dogs treated with mandibulectomy for OSA (1999–2007) were reviewed. Archived tumour samples were evaluated for mitotic index (MI) and tumour grade. Fifty dogs were included, 21 received chemotherapy. Twenty‐nine dogs (58%) developed metastatic disease. The median MFI was 627 days, and median ST was 525 days. In univariate analysis MI > 40 was prognostic for decreased MFI and ST. Grade also influenced MFI and ST, with 5/21 (24%) dogs with grade II/III tumours metastasis‐free at one year versus 16/22 (72%) dogs with grade I tumours (P = 0.002); and 5/21 (24%) dogs with grade II/III tumours alive versus 17/22 (77%) dogs with grade I tumours (P = 0.001). In multivariate analysis, histological grade and adjuvant chemotherapy were prognostic for MFI and ST.     

PROTON SPOT SCANNING RADIOTHERAPY OF SPONTANEOUS CANINE TUMORS

Thirty dogs with spontaneous tumors were irradiated with proton therapy using a novel spot scanning technique to evaluate the safety and efficacy of the system, and to study the acute and late radiation reactions. Nasal tumors, soft tissue sarcomas, and miscellaneous tumors of the head were treated with a median total dose of 52.5 Gy given in 3.5 Gy fractions. Acute effects, late effects, tumor response, and outcome were analyzed. No unexpected radiation reactions were seen, however two dogs did develop in-field osteosarcoma, and one dog developed in-field bone necrosis. Complete response to therapy was seen in 40% (12/30), partial response in 47% (14/30), and no response in 13% (4/30). Median survival for all dogs was 385 days (range of 14–4583 days). Dogs with nasal cavity tumors had a median survival of 385 days (range of 131–1851 days) and dogs with soft tissue sarcomas had a median survival time of 612 days (range of 65–4588 days). Treatment outcome was similar to historical controls. This new proton spot scanning technique proved to be safe and reliable.     

Palliative radiotherapy as treatment for non-resectable soft tissue sarcomas in the dog – a report of 15 cases

Fifteen dogs with various non‐resectable soft tissue sarcomas were treated with a palliative protocol of Cobalt⁶⁰ radiation. Twelve (80%) of the 15 tumours were fibrosarcomas and haemangiopericytomas. Total tumour radiation dose was 24 Gy, given in three 8 Gy fractions, on days 0, 7, 21 or weekly. Thirteen tumours (87%) responded with stable disease; median time to progression and median survival time were 263 and 332 days, respectively. Radiation toxicity was negligible. The survival and local control with this palliative protocol are almost comparable with curative intent primary radiotherapy.     

Outcome after repair of a sarcoma-related pathologic fracture in dogs: a Veterinary Society of Surgical Oncology Retrospective Study

Objective: To report outcome in dogs after internal fixation of a sarcoma‐related pathologic fracture of the appendicular skeleton. Study Design: Multi‐institutional case series. Animals: Dogs (n=16). Methods: Medical records of participating VSSO members were reviewed for dogs with pathologic fracture associated with a confirmed bone sarcoma of the appendicular skeleton repaired by external or internal fixation. Dogs were included if they had a histological diagnosis of osteosarcoma or sarcoma and excluded if they had radiation before fracture. Data collected were analyzed for signalment, fracture location, staging performed, method of fracture fixation, histopathology, adjunctive treatment and outcome. Results: Signalment and fracture location of 16 dogs that met the inclusion criteria was similar to dogs with appendicular OSA without fracture. One of 14 dogs had pulmonary metastasis and 3 of 5 dogs had bone metastasis. Bone plate or interlocking nail were used for repair in 12 dogs. Limb use immediately after surgery in 13 dogs was good (4), weight‐bearing but lame (7) and non‐weight bearing (2). Adjunctive therapy was administered in 5 dogs (chemotherapy, 3; radiation, 4; pamidronate, 3). Survival time ranged from 18 to 897 days; median survival was 166 days. Conclusions: Repair of pathologic fracture can result in palliation and prolonged survival.     

Retrospective analysis of axial skeleton osteosarcoma in 22 large-breed dogs

Medical-records of 22 large-breed dogs (>15 kg) with osteosarcoma (OSA) of the axial skeleton were reviewed to determine prevalence of metastasis and survival associated with this neoplasm. All dogs were treated with more than 1 mode of therapy including palliative radiation (n = 12), definitive radiation (n = 8), surgery (n = 7), chemotherapy (n = 12), or some combination of these therapies. Metastasis was documented in 10 of 22 dogs (46%), and the median survival for all dogs was 137 days. Primary cause of death was local tumor recurrence (54%). Breed (retriever versus purebred versus mixed-breed survival was 100, 182, and 264 days, respectively) and radiation therapy protocol (survival in dogs treated with palliative radiation therapy versus those treated with definitive radiation therapy was 79 and 265 days, respectively) were significantly related to survival (P < .05). Prevalence of metastasis and median survival for large-breed dogs with axial skeleton OSA seems to be similar to that reported for large-breed dogs with appendicular skeleton OSA. Definitive radiation therapy may have a role in the treatment of axial skeleton osteosarcoma.     

Evaluation of Risk Factors for Morbidity and Mortality after Pylorectomy and Gastroduodenostomy in Dogs

Objectives— To (1) identify and describe the type and frequency of postoperative complications after pylorectomy and gastroduodenostomy in dogs and (2) identify preoperative and intraoperative risk factors, including the presence of neoplasia, prognostic for patient mortality after surgery. Study Design— Case series. Animals— Dogs (n=24) treated by pylorectomy and gastroduodenostomy. Methods— Medical records (2000–2007) for 2 teaching hospitals of dogs treated that had pylorectomy and gastroduodenostomy were reviewed. Pre‐, intra‐, and postoperative data were obtained from the medical record. Results— Of the 24 dogs, 75% survived 14 days, but 10 (41%) died by 3 months. Overall median survival time (MST) was 578 days. On log‐rank univariate analysis, preoperative weight loss (P=.001) and malignant neoplasia (P=.01) were associated with decreased survival time. Dogs with malignant neoplasia had a MST of 33 days. Common postoperative morbidity included hypoalbuminemia (62.5%) and anemia (58.3%). Conclusions— Pylorectomy with gastroduodenostomy has a good short‐term outcome but long‐term survival time is poor in dogs with malignant neoplasia. Clinical Relevance— Overall, most dogs treated with pylorectomy and gastroduodenostomy survived the postoperative period; however, preoperative weight loss and malignant neoplasia were associated with decreased survival time. Because dogs with malignant neoplasia have markedly shortened survival times, pertinent preoperative, diagnostics steps should be exhausted to identify underlying neoplasia.     

CHOP chemotherapy for the treatment of canine multicentric T-cell lymphoma

Dogs with multicentric T-cell lymphoma are commonly treated with CHOP chemotherapy protocols that include cyclophosphamide, doxorubicin, vincristine and prednisone. The purpose of this study was to evaluate the use of CHOP chemotherapy for dogs with multicentric T-cell lymphoma. Identification of prognostic factors in this specific subset of dogs was of secondary interest. Twenty-three out of 24 dogs responded to CHOP chemotherapy and these dogs remained on the protocol for a median of 146 days. No variable was associated with progression free survival (PFS) including stage, substage, hypercalcemia or radiographic evidence of a cranial mediastinal mass. The median overall survival time (OST) for all dogs was 235 days. Dogs that were thrombocytopenic at presentation experienced a significantly longer OST (323 versus 212 days, P=0.01).