Mechlorethamine,vincristine, melphalan and prednisone (MOMP) for the treatment of relapsed lymphoma in dogs

Eighty‐eight dogs with relapsed lymphoma were treated with the MOMP (mechlorethamine, vincristine, melphalan and prednisone) protocol on a 28‐day treatment cycle. The overall response rate (ORR) to the MOMP protocol was 51.1% for a median of 56 days (range 7–858 days). Twelve percent of dogs experienced a complete response for a median of 81 days (range 42–274 days) and 38.6% experienced a partial response for a median of 49 days (range 7–858 days). Dogs with T‐cell lymphoma had an ORR of 55% for a median of 60 days (range 49–858 days) while those with B‐cell lymphoma had an ORR of 57% for a median of 81 days (range 7–274 days) (P = 0.783). The overall survival time for all dogs was 183 days (range 17–974 days). Fifty‐four percent of dogs experienced toxicity with the majority classified as grade I. The MOMP protocol seems well‐tolerated and is an option for dogs with relapsed lymphoma.     

Retrospective comparison of first‐line adjuvant anthracycline vs metronomic‐based chemotherapy protocols in the treatment of stage I and II canine splenic haemangiosarcoma

Splenectomy followed by adjuvant chemotherapy is commonly used to treat canine splenic haemangiosarcoma (HSA), although it is unclear if different treatment protocols may have a similar efficacy. The objective of this retrospective study was to assess outcome in dogs with stage I and II splenic HSA treated with either first‐line adjuvant anthracycline (AC) or metronomic (MC)‐based chemotherapy protocols, by comparing median time to progression (TTP) and median survival time (MST). Medical records of nine institutions were searched for dogs diagnosed with stage I and II splenic HSA that underwent adjuvant treatment with AC‐ or MC‐based protocols following splenectomy. Patients treated with MC following AC were included in an additional group (AMC). Ninety‐three dogs were included: 50 in the AC group, 23 in the AMC group and 20 in the MC group. The overall MST was 200 days (range 47‐3352) and the overall median TTP was 185 days (range 37‐1236). The median TTP of stage I dogs was significantly longer compared to stage II dogs (338 vs 151 days, respectively, P = .028). When adjusting for treatment type, the MST was 154 days for the AC group (range 47‐3352 days), 338 days for the AMC group (range 79‐1623 days) and 225 days for the MC group (range 57‐911 days). The difference in MST and median TTP was not found to be statistically significant between treatment groups. This study suggests that adjuvant MC in canine splenic HSA may result in a similar outcome when compared to other treatment protocols. Further studies are warranted to confirm these findings.     

Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs†

Sixty‐four dogs were treated with single‐agent doxorubicin (DOX) for presumptive cardiac hemangiosarcoma (cHSA). The objective response rate (CR + PR) was 41%, and the biologic response rate (CR + PR + SD), or clinical benefit, was 68%. The median progression‐free survival (PFS) for treated dogs was 66 days. The median survival time (MST) for this group was 116 days and was significantly improved compared to a MST of 12 days for untreated control dogs (P = 0.0001). Biologic response was significantly associated with improved PFS (P < 0.0001) and OS (P < 0.0001). Univariate analysis identified larger tumour size as a variable negatively associated with PFS. The high rate of clinical benefit and improved MST suggest that DOX has activity in canine cHSA.     

Alternating rabacfosadine and doxorubicin for treatment of naïve canine lymphoma

The current standard of care treatment for canine lymphoma is a multi-agent, CHOP-based chemotherapy protocol. Single agent doxorubicin (DOX) is less burdensome; however, multi-agent chemotherapy protocols are often superior. The recently approved drug rabacfosadine (RAB, Tanovea) provides an attractive option for combination therapy with DOX, as both drugs demonstrate efficacy against lymphoma and possess different mechanisms of action. A previous study evaluating alternating RAB/DOX reported an overall response rate (ORR) of 84%, with a median progression-free survival time (PFS) of 194 days. The aim of this prospective trial was to evaluate the same protocol in an additional population of dogs. Fifty-nine dogs with treatment naïve lymphoma were enrolled. RAB (1.0 mg/kg IV) was alternated with DOX (30 mg/m² IV) every 21 days for up to six total treatments (3 cycles). Response assessment and adverse event (AE) evaluation were performed every 21 days using VCOG criteria. The ORR was 93% (79% CR, 14% PR). The median time to maximal response was 21.5 days; median PFS was 199 days. T cell immunophenotype and lack of treatment response were predictive of inferior outcomes. AEs were mostly gastrointestinal. Six dogs developed presumed or confirmed pulmonary fibrosis; four were grade 5. One dog experienced grade 3 extravasation injury with RAB that resolved with supportive treatment. These data mirror those of the previously reported RAB/DOX study, and support the finding that alternating RAB/DOX is a reasonable treatment option for canine lymphoma.     

Epirubicin in the treatment of canine histiocytic sarcoma: sequential,alternating and rescue chemotherapy

The aims of this study were to report treatment outcomes for dogs with histiocytic sarcoma (HS) treated with both lomustine and epirubicin, and to report response rates to epirubicin as a rescue therapy in dogs previously treated with lomustine. Medical records of dogs with a diagnosis of HS that were treated with both lomustine and epirubicin were retrospectively evaluated. Of 29 dogs receiving epirubicin alternating with, or subsequent to lomustine treatment, including in a rescue setting, response to epirubicin could be assessed in 20 with an overall response rate (ORR) of 29% and biological response rate (BRR) of 71%. Median time to progression (TTP) in 12 of these 20 dogs in which it was assessable was 69 days (range: 40‐125 days). For dogs treated in the rescue setting epirubicin specific ORR was 19% and BRR 63%. Median TTP in the 9 of these 16 dogs in which it was assessable was 62 days (range: 40‐125 days). Median survival time for all dogs treated with both epirubicin and lomustine was 185 days (range: 27‐500 days). Some dogs with HS respond to epirubicin and dogs treated with combinations of epirubicin and lomustine have modestly improved survival times compared with single agent studies, and similar to dogs with HS treated with alternating lomustine and doxorubicin. Single agent epirubicin is also a valid short term rescue therapy for canine HS.     

Oral melphalan for the treatment of relapsed canine lymphoma

Oral melphalan has been included in multi‐agent rescue protocols for canine lymphoma but its activity as a single‐agent for this purpose has not been established. Inexpensive cost, ease of administration and tolerability make oral melphalan an attractive candidate for single‐agent rescue therapy of canine lymphoma. Retrospective evaluation of 19 cases of relapsed canine lymphoma treated with oral melphalan was performed. Melphalan was primarily administered (n = 16) via a high dose protocol (HDM ) with a median dosage of 19.4 mg m^?2. Fifteen dogs (78.9%) were treated concurrently with corticosteroids. Response evaluation was possible for all dogs with a calculated overall clinical benefit (partial response [PR ] + stable disease [SD ]) of 31.6% (PR 3/19; SD 3/19). Times to progression following melphalan (TTP ‐M) were 14, 24 and 34 days for responders and 20, 28 and 103 days for dogs experiencing SD . Twelve of 17 dogs evaluable for toxicity experienced an adverse event (AE ) with only 3 dogs experiencing a grade III or higher AE . Haematologic toxicity was common (11/17) while gastrointestinal toxicity was rare (1/17). Although treatment resulted in limited clinical benefit and non‐durable responses, oral melphalan was well‐tolerated and may be a reasonable rescue option in cases where minimal effective agents remain.     

Response rate and duration associated with a 4Gy 5 fraction palliative radiation protocol

The purpose of this retrospective study was to determine if 4Gy fractions over 5 consecutive days is an effective and safe palliative radiation protocol for dogs and cats. Eighty patients (22 cats, 58 dogs) with complete follow-up information were evaluated. Overall response rate (ORR) for all patients was 67%. Median progression free survival (MPFS) was 3.3 months and median survival (MST) was 4.2 months. Primary bone tumors were the most common tumors treated. The ORR for primary bone tumors was 66.6%, the MPFS was 3.5 months, and MST was 3 months. The most common tumor treated in cats was oral squamous cell carcinoma and ORR was 54.5 %, the MPFS was 1.8 months, and MST was 3 months. Soft tissue sarcomas were the second most common tumor treated in dogs (10). ORR was 80% and the two other patients had stable disease. MPFS was 5.7 months and MST was 7.9 months. Overall rate of toxicity was 18.4% in 65 sites that were evaluated for toxicity. Acute toxicities were all grade I or II and occurred in 16.9 % of patients evaluated. All late toxicity was grade I alopecia and leukotrichia. There appears to be a comparable response rate for this palliative protocol as compared to others historically. This response was seen over a wide range of tumors. We also documented a low toxicity profile in a shorter overall treatment time, making this protocol more attractive for some clients.     

Efficacy and toxicity of BOPP and LOPP chemotherapy for the treatment of relapsed canine lymphoma*

Mechlorethamine (Mustargen^®, Oncovin^® (vincristine), procarbazine and prednisone (MOPP) chemotherapy is useful for relapsed canine lymphoma. This study evaluates the efficacy of MOPP after substitution of CCNU (lomustine, LOPP protocol) or BCNU (carmustine, BOPP protocol) for mechlorethamine in 60 dogs with relapsed lymphoma. Seven of 14 (50%) dogs treated with BOPP responded, for a median of 129.5 days for complete responders (range 9–354 days) and a median of 140 days for partial responders (range 4–276 days). Twenty‐three of 44 (52%) dogs treated with LOPP responded for a median of 112 days for complete responders (range 48–250 days) and a median of 84.5 days for partial responders (range 69–290 days). Two dogs receiving a combination of LOPP and BOPP partially responded for 28 and 163 days, respectively. With BOPP chemotherapy, nine dogs (20.5%) and seven dogs (50%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seven dogs (50%) had one or more episodes of Grade II or higher gastrointestinal toxicity. While receiving LOPP chemotherapy, 28 dogs (63.6%) and 17 dogs (38.6%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seventeen dogs (38.6%) had one or more episodes of Grade II or higher gastrointestinal toxicity. Overall, there were 17 non‐fatal treatment‐related episodes of sepsis requiring hospitalization. Eight dogs (13%) died or were euthanized because of treatment‐related sepsis and/or chemotherapy‐related complications. Severe haematologic toxicity, coupled with the improved response duration observed in dogs receiving reduced doses during B/L‐OPP rescue, underscores the need for protocol optimization.     

Clinical characteristics and outcome in dogs with small cell T‐cell intestinal lymphoma

Small cell intestinal lymphoma has not been well characterized in dogs. The objective of this study was to describe clinical characteristics and outcome in dogs with small cell intestinal lymphoma. We hypothesized that affected dogs would have prolonged survival compared with high‐grade gastrointestinal (GI) lymphoma. Pathology records were searched for dogs with histologically confirmed small cell GI lymphoma. Seventeen dogs with confirmed small cell intestinal lymphoma were identified, and clinical and outcome data were retrospectively collected. Histopathology was reviewed by a board‐certified pathologist, and tissue sections were subjected to immunophenotyping and molecular clonality assessment. All dogs had small cell, T‐cell, lymphoma confirmed within various regions of small intestine, with 1 dog also having disease in abdominal lymph nodes. All dogs had clinical signs attributable to GI disease; diarrhoea (n = 13) was most common. Ultrasonographic abnormalities were present in 8 of 13 dogs with abnormal wall layering (n = 7) and hyperechoic mucosal striations (n = 7) representing the most common findings. In total, 14 dogs received some form of treatment. The median survival time (MST) for all dogs was 279 days and the MST for the 14 dogs that received any treatment was 628 days. Dogs with anaemia and weight loss at presentation had significantly shorter survival times and dogs that received a combination of steroids and an alkylating agent had significantly longer survival times. Small cell, T‐cell, intestinal lymphoma is a distinct disease process in dogs, and those undergoing treatment may experience prolonged survival.     

A feasibility study of low-dose total body irradiation for relapsed canine lymphoma

Seven client owned dogs with confirmed relapsed lymphoma were enrolled in a prospective feasibility study investigating the effects of low‐dose total body irradiation (LDTBI) delivered in a single 1 Gy fraction. LDTBI for relapsed lymphoma was safe and well tolerated. The only major side‐effect of LDTBI was asymptomatic thrombocytopenia in all dogs. The median platelet nadir was 17 000/μL (range 4000–89 000), which occurred a median of 10 days (range 8–30) post irradiation. Three dogs had short‐term partial responses, two stable disease and two progressive disease (PD). Six dogs were euthanatized for PD, and one dog died while in partial remission. No dogs had clinical complications. Survival analysis was not performed, because the study design did not allow for evaluation of survival time. Larger studies incorporating LDTBI in the induction/consolidation phase of treatment need to be performed to determine the therapeutic efficacy of LDTBI.     

Minimal residual disease in lymph nodes after achievement of complete remission predicts time to relapse in dogs with large B‐cell lymphoma

Most dogs with large B‐cell lymphoma (LBCL) that undergo chemotherapy and achieve clinical complete remission (CR) eventually relapse. However, time to relapse (TTR) is unpredictable. The aims of this prospective study were to assess the influence of post‐chemotherapy lymph node (LN) infiltration by large CD21+ cells using flow cytometry (FC) on TTR, and to establish a cut‐off value of prognostic significance. Dogs with newly‐diagnosed, completely staged LBCL in CR after treatment were enrolled. Minimal residual disease (MRD) analysis by FC was performed on LN aspirates. TTR was calculated between MRD and relapse. Thirty‐one dogs were enrolled: 4% had stage V disease, and diffuse large B‐cell lymphoma was the most common histotype (74%). Based on LN infiltration at MRD evaluation, three groups were created: (a) acellular samples, (b) ≤0.5% infiltration and (c) >0.5% infiltration. Overall median TTR was 154 days (range, 31‐1974): 22 (71%) dogs relapsed during the study period, whereas 9 (29%) dogs did not. The difference among the three groups was significant (P = 0.042 log‐rank test): median TTR was not reached for dogs with LN infiltration ≤0.5% (range, 195‐429 days), 164 days (range 63‐1974) for dogs with acellular LN samples, and 118 days (range, 31‐232) for dogs with LN infiltration >0.5%. These results demonstrate that MRD assessment by FC on LN aspirates in dogs with LBCL in clinical CR predicts TTR. LN infiltration by >0.5% large CD21+ cells after treatment is an unfavourable prognostic factor.     

Dacarbazine as Single-Agent Therapy for Relapsed Lymphoma in Dogs

Background: Multidrug resistance is the most common cause of treatment failure in dogs with multicentric lymphoma. 5-(3,3-Dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) is an atypical alkylator used as standard treatment in human Hodgkin's lymphoma, and has been effective in combination treatment to treat resistant lymphoma in dogs. However, no data are available on the use of DTIC as a single agent in the treatment of relapsed canine lymphoma.
Hypothesis: Single-agent DTIC is effective and safe in treating dogs with lymphoma that relapsed or failed to respond to previous chemotherapy.
Animals: Forty client-owned dogs with relapsed lymphoma.
Methods: Dogs were eligible for the retrospective study if they had a histologically or cytologically confirmed diagnosis of lymphoma and had relapsed. Dogs received DTIC (800–1,000 mg/m² every 2–3 weeks as a 4–5-hour IV infusion) and were evaluated for response rate and duration. Hematologic and gastrointestinal toxicity was assessed.
Results: The overall response rate for dogs being treated with DTIC was 35% (14 dogs) with a median progression-free interval of 43 days. Thirteen dogs had a partial response and 1 dog had a complete response. Stable disease was achieved in 3 dogs. Mild gastrointestinal toxicity was reported in 3 dogs posttreatment. Thrombocytopenia was the principal toxicity observed 7–14 days after the treatment. Treatments were delayed because of thrombocytopenia.
Conclusions: DTIC, when used alone, is effective in the treatment of dogs with relapsed lymphoma.     

Outcome and toxicity associated with a dose‐intensified,maintenance‐free CHOP‐based chemotherapy protocol in canine lymphoma: 130 cases

A dose‐intensified/dose‐dense chemotherapy protocol for canine lymphoma was designed and implemented at the Veterinary Hospital of the University of Pennsylvania. In this study, we describe the clinical characteristics, prognostic factors, efficacy and toxicity in 130 dogs treated with this protocol. The majority of the dogs had advanced stage disease (63.1% stage V) and sub‐stage b (58.5%). The median time to progression (TTP) and lymphoma‐specific survival were 219 and 323 days, respectively. These results are similar to previous less dose‐intense protocols. Sub‐stage was a significant negative prognostic factor for survival. The incidence of toxicity was high; 53.9 and 45% of the dogs needed dose reductions and treatment delays, respectively. Dogs that required dose reductions and treatment delays had significantly longer TTP and lymphoma‐specific survival times. These results suggest that dose density is important, but likely relative, and needs to be adjusted according to the individual patient's toxicity for optimal outcome.     

Adjuvant anthracycline‐based vs metronomic chemotherapy vs no medical treatment for dogs with metastatic splenic hemangiosarcoma: A multi‐institutional retrospective study of the Italian Society of Veterinary Oncology

Treatment options for dogs with metastatic (stage III) splenic hemangiosarcoma are limited. A doxorubicin‐based chemotherapy regimen is commonly administered; however, there are no published data to support this practice. The aim of this study was to investigate the impact of maximum‐tolerated‐dose chemotherapy (MTD), metronomic chemotherapy (MC) and no adjuvant treatment on outcome in dogs with stage III splenic hemangiosarcoma undergoing splenectomy. Medical records of dogs with stage III splenic hemangiosarcoma that underwent splenectomy followed by MTD chemotherapy, MC or no adjuvant treatment were retrieved. Time to progression (TTP), survival time (ST) and toxicity were evaluated. One hundred three dogs were identified: 23 received adjuvant MTD, 38 MC and 42 were not medically treated. Overall median TTP and ST were 50 (95% confidence interval [CI], 39‐61) and 55 days (95% CI, 43‐66), respectively. Dogs treated with adjuvant MTD had a significantly longer TTP and ST compared with dogs receiving MC (median TTP, 134 vs 52 days, P = .025; median ST, 140 vs 58 days, P = .023, respectively). Dogs treated by splenectomy only had the shortest median TTP (28 days) and ST (40 days). However, treatment‐related adverse events (AEs) were significantly more frequent in the MTD group (P = .017). The outcome for dogs with metastatic splenic hemangiosarcoma is poor. While MTD showed greater efficacy compared to MC, toxicity was higher in this group. Treatment‐related AEs need to be carefully balanced against this modest survival prolongation when offering adjuvant MTD to dogs with advanced stage hemangiosarcoma.     

Treatment of Relapsed Canine Lymphoma With Doxorubicin and Dacarbazine

Fifteen dogs with relapsed lymphoma were treated with doxorubicin and dacarbazine (ADIC) to reinduce remission. All the dogs' lymphomas had become resistant to prior therapy with doxorubicin alone. Five of the 15 dogs had a complete response to the first treatment with ADIC, and three had partial responses. Of the eight dogs receiving a second cycle, two had complete responses, and one had a partial response. One dog that received a third ADIC treatment no longer responded. The median survival time from the first ADIC treatment for all dogs was 45 days (range, 18-241 days). The five dogs having complete responses to the first ADIC treatment had a median survival time of 105 days (range, 45-241 days) after this treatment. Toxicity due to ADIC treatment was acceptable and did not exceed that seen when doxorubicin was given as a single agent. The treatment resulted in severe neutropenia in three dogs. One dog died due to neutropenic sepsis. Vomiting, diarrhea, and anorexia occurred, but were tolerable, resulting in hospitalization in only one instance. ADIC is apparently a useful chemotherapeutic combination to reinduce remission in some dogs with relapsed lymphoma.     

Clinical presentation,treatment and outcome in 31 dogs with presumed primary colorectal lymphoma (2001–2013)

The objective of this multicentre retrospective study was to describe clinical presentation, treatment and outcome and to determine prognostic factors for dogs with presumed primary colorectal lymphoma (PCRL). A total of 31 dogs were included. The predominant features of PCRL were high grade (n = 18) and immunophenotype B (n = 24). Most dogs were substage b (n = 25) with higher prevalence of haematochezia (n = 20). One dog had surgery only. Thirty dogs received chemotherapy; amongst them 13 had surgery or radiotherapy. Progression free survival (PFS) was 1318 days and disease‐related median survival time (MST) was 1845 days. Fourteen dogs were alive at the end of the study with a median follow‐up time of 684 days (3–4678 days). Younger dogs had longer PFS (P = 0.031) and disease‐related MST (P = 0.01). Presence of haematochezia corresponded with longer PFS (P = 0.02). Addition of local treatment to chemotherapy did not significantly improve the outcome (P = 0.584). Canine PCRL has considerably longer PFS and MST than other forms of non‐Hodgkin's lymphoma.     

Clinical characteristics, treatment, and outcome of dogs with presumed primary hepatic lymphoma: 18 cases (1992-2008)

OBJECTIVE-To determine outcome of dogs with presumed primary hepatic lymphoma treated with various multiagent, doxorubicin-based chemotherapeutic protocols and identify factors associated with prognosis. DESIGN-Retrospective case series. ANIMALS-18 dogs with presumed primary hepatic lymphoma. PROCEDURES-Medical records were reviewed for information on signalment, treatment, and outcome. RESULTS-8 dogs had a complete remission (CR), with a median remission duration of 120 days. Dogs with leukocytosis, neutrophilia, hypoalbuminemia, hyperbilirubinemia, or a combination of hypoalbuminemia and hyperbilirubinemia were less likely to achieve a CR. Overall median survival time (MST) was 63 days (range, 2 to 402 days). In a multivariate analysis, response to treatment and serum albumin concentration were associated with MST. Dogs that did not achieve a CR had a significantly shorter MST than did dogs that did achieve a CR (13 vs 283 days, respectively). Dogs with serum albumin concentration < 2.5 g/dL at the time treatment was initiated had a significantly shorter MST than did dogs with serum albumin concentration within reference limits (10 vs 128 days, respectively). There was also a positive correlation between serum albumin concentration and survival time (r = 0.74). CONCLUSIONS AND CLINICAL RELEVANCE-Results suggested that dogs with primary hepatic lymphoma that underwent chemotherapy had a poor prognosis, with a low response rate. Dogs that responded to treatment had a better prognosis, and dogs with hypoalbuminemia had a poorer prognosis.     

Dexamethasone, melphalan, actinomycin D, cytosine arabinoside (DMAC) protocol for dogs with relapsed lymphoma

BACKGROUND: In general, treatment of relapsed lymphoma is associated with a lower probability of response and shorter duration of remission. The purpose of this study was to evaluate the efficacy of the combination chemotherapy protocol DMAC (dexamethasone, melphalan, actinomycin D, and cytosine arabinoside) for reinduction of remission in dogs with relapsed lymphoma. HYPOTHESIS: That DMAC would be an effective reinduction protocol for dogs with relapsed lymphoma. ANIMALS: Fifty-four dogs. RESULTS: Seventy-two percent of the dogs achieved remission (44% complete remission [CR] and 28% partial remission [PR]), 11% had stable disease (SD), and 17% had progressive disease (PD). The median remission duration was 61 days (range, 2-467+ days). The median remission durations for dogs with CR, PR, and SD were 112, 44, and 27 days, respectively. Factors that affected the response rate were previous treatment with doxorubicin and an inability to achieve remission with the previous protocol. Thrombocytopenia occurred in 56% of the dogs (grade 1 in 3 dogs, grade 2 in 6 dogs, grade 3 in 7 dogs, and grade 4 in 7 dogs) and neutropenia in 17% of the dogs (grade 2 in 1 dog, grade 3 in 2 dogs, and grade 4 in 4 dogs). Gastrointestinal toxicosis occurred in 22% of the dogs (grades 1 in 5 dogs, grade 2 in 3 dogs, and grade 3 in 1 dog). CONCLUSIONS AND CLINICAL IMPORTANCE: The DMAC protocol is an effective rescue protocol for dogs with relapsed multicentric lymphoma. Although thrombocytopenia is a common manifestation of toxicity, in general, the protocol is well tolerated.     

Toxicity and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of canine appendicular osteosarcoma following limb amputation

Objective To evaluate the safety and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of dogs with appendicular osteosarcoma following limb amputation. Design Retrospective study. Procedure Dogs diagnosed with appendicular osteosarcoma, with no evidence of metastatic disease, treated with amputation and adjuvant chemotherapy consisting of two doses of doxorubicin given 14 days apart, followed by four doses of carboplatin at 3‐weekly intervals between September 2003 and December 2009 were identified from the medical records of Perth Veterinary Oncology. Haematological and gastrointestinal toxicities were assessed based on information in the medical records and recorded complete blood count results. The efficacy of the protocol was assessed by determining the median disease‐free interval (DFI) and overall survival time (OST) using the Kaplan‐Meier product‐limit method. Results In total, 33 dogs met the inclusion criteria. The median DFI was 231.5 days and the median OST was 247 days. With regard to haematological toxicity, 56% of dogs had a grade 1–2 neutropenia recorded as their highest marrow toxicity and 9% of dogs experienced a grade 3–4 neutropenia, all subsequent to doxorubicin administration. The highest gastrointestinal toxicity was grade 1–2 in 15 dogs (47%) and 5 dogs (16%) experienced grade 3–4 gastrointestinal toxicity. Conclusion This chemotherapy protocol did not result in a longer time to disease recurrence or OST in this population of dogs. Dual‐agent protocols have failed to improve survival times and therefore we conclude that a single‐agent protocol using carboplatin may be equally effective with less toxicity.