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Multiagent chemotherapy is considered the most effective treatment for canine high‐grade lymphoma; however, due to cost and time requirements, single‐agent protocols have also been described. The aim of our study was to evaluate the outcome and prognostic factors of dogs affected by multicentric lymphoma treated with lomustine and prednisolone as first‐line treatment. Cases of medium‐large‐cell multicentric lymphoma treated with lomustine and prednisolone were included in the study. Response to therapy, time to progression (TTP), median disease‐free interval (MDFI) and median survival time (MST) were retrospectively described. Thirty cases were included. Eleven (36.67%) were T cell, 11 (36.67%) were B cell and 8 (26.66%) had unknown immunophenotype. The overall response rate (RR) was 87%, with 15 patients achieving CR (50%) and 11 patients PR (37%). The median TTP, MDFI and MST were 42, 63 and 90 days, respectively. The only factor significantly associated with MDFI and MST was the stage. Dogs with multicentric lymphoma treated with lomustine and prednisolone have lower RR, TTP, MDFI and MST compared with dogs receiving multiagent protocols. Based on the short‐lasting response, this study confirms that this protocol might have minimal utility beyond palliation. [ABSTRACT FROM AUTHOR]

Despite an initial strong response in most dogs with multicentric lymphoma treated with chemotherapy, relapse remains common. There is no clearly superior first rescue protocol described either for resistant or relapsed canine multicentric lymphoma. The objectives of this study were to assess clinical response and outcomes for canine multicentric lymphoma treated with first rescue protocols. The secondary objective was to assess prognostic variables for dogs undergoing these protocols. This was a bi‐institutional retrospective cohort study. Two hundred and sixty‐five dogs were treated with first rescue chemotherapy, including anthracycline‐based combination chemotherapy (CHOP‐like, n = 50), nitrosourea alkylating agent‐rich chemotherapy (n = 45), anthracycline‐based or related compound chemotherapy (n = 34), or nitrosourea single‐agent chemotherapy (n = 136). The overall median progression free survival time of first rescue protocol was 56.0 days (0–455 days). Important prognostic factors identified for first rescue protocol included the attainment of a complete response to the first rescue chemotherapy (p <.001), the use of a CHOP‐like first rescue protocol (p =.009), duration of first remission (HR 0.997, p =.028), and if prednisolone was included in the first rescue protocol (HR 0.41, p =.003). Adverse events (AE) were common, with 81.1% of dogs experiencing at least one AE during first rescue chemotherapy. This study highlights the need for improved first rescue therapies to provide durable remission in canine resistant or relapsed lymphoma. [ABSTRACT FROM AUTHOR]

Canine cutaneous lymphoma is an uncommon lymphoma in dogs. Most canine cutaneous lymphoma cases have a T‐cell origin. Canine cutaneous T‐cell lymphoma (CTCL) is classified into epitheliotropic and nonepitheliotropic cutaneous lymphomas, and each type of lymphoma is subclassified into several histological subtypes. Limited information is available regarding the prognostic significance of clinical variables and histopathological subtypes in dogs with CTCL. This retrospective study aimed to investigate the influence of clinical variables and histopathological subtypes on the prognosis of dogs with CTCL. Forty‐six dogs diagnosed with CTCL by histopathological examination were included. Histopathological specimens were reexamined and classified into CTCL subtypes. The influence of the type of skin lesion, histopathological subtype, haematological examination results and treatment response on the overall survival time (OS) was examined. Thirty‐one dogs were diagnosed with epitheliotropic CTCL (mycosis fungoides in 28 dogs; pagetoid reticulosis in 3 dogs) and 15 dogs were diagnosed with nonepitheliotropic CTCL (anaplastic large T‐cell lymphoma in 6 dogs; peripheral T‐cell lymphoma, not otherwise specified, in 9 dogs). The OS of dogs diagnosed with epitheliotropic CTCL (141 days) was significantly shorter than that of dogs diagnosed with nonepitheliotropic CTCL (374 days). As clinical variables, the presence of neoplastic lymphocytes in peripheral blood, thrombocytopenia and initial chemotherapeutic response was related to prognosis. Our results demonstrated that histopathological subtype and several clinical variables were found to influence the prognosis of dogs with CTCL. [ABSTRACT FROM AUTHOR]

The standard of care treatment for canine lymphoma is multi‐agent chemotherapy containing prednisolone, cyclophosphamide, vincristine and an anthracycline such as doxorubicin (CHOP) or epirubicin (CEOP). Lomustine, vincristine, procarbazine, and prednisone (LOPP) has been evaluated as a rescue, with encouraging results; however, resistance to vincristine is likely in patients relapsing on CHOP/CEOP, and this agent may enhance LOPP toxicity without improving efficacy. The aim of this study was to evaluate responses to a modified‐LOPP protocol that does not include vincristine (LPP) and is administered on a 21‐day cycle. Medical records of dogs with high‐grade multicentric lymphoma from 2012 to 2017 were reviewed. Dogs with relapsed lymphoma that received LPP as a rescue protocol were enrolled. Response, time from initiation to discontinuation (TTD) and toxicity of LPP were assessed. Forty‐one dogs were included. Twenty‐five dogs (61%) responded to LPP including 12 complete responses (CR) and 13 partial responses (PR). Responders had a significantly longer TTD (P < .001) compared to non‐responders with 84 days for CR and 58 days for PR. Neutropenia was documented in 20 dogs (57%): 12 grade I to II, 8 grade III to IV. Thrombocytopenia was infrequent (20%): 5 grade I to II, 2 grade III to IV. Twelve dogs developed gastrointestinal toxicity (30%): 10 grade I to II and 2 grade III. Nineteen dogs had elevated ALT (59%): 9 grade I to II, 10 grade III to IV. Treatment was discontinued due to toxicity in 8 dogs (19%). The LPP protocol shows acceptable efficacy and toxicity‐profile and minimizes in‐hospital procedures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Multi-drug chemotherapy protocols for feline lymphoma have demonstrated variable efficacy and tolerability. In phase I trials, lomustine has demonstrated efficacy for cats with lymphoma though its use for treatment naïve feline intermediate/large cell gastrointestinal (GI) lymphoma remains unknown. This study evaluated the efficacy and tolerability of lomustine for the treatment of feline GI lymphoma. Thirty-two cats with histologically or cytologically confirmed intermediate/large cell GI lymphoma were evaluated retrospectively. Factors assessed included clinical signs, hematologic/biochemical parameters and use of l-asparaginase at induction. A response rate of 50% (16/32), with median duration of response of 302 days (range 64-1450 days), was found. Median progression-free interval was 132 days (range 31-1450 days), with overall median survival time of 108 days (range 4-1488 days). History of hyporexia, presence of anaemia and dose of lomustine were significantly associated with progression-free survival. Overall, lomustine is a well-tolerated and effective treatment for feline GI lymphoma. [ABSTRACT FROM AUTHOR]

Brain neoplasia is diagnosed in an increasing number of dogs. Consequently, there is a higher need for an effective treatment. Chemotherapy is considered in cases where surgery or radiation is not optional. The objective of this retrospective study was to evaluate the difference in median survival time (MST) of dogs with intracranial masses, treated symptomatically with corticosteroids and anti-epileptic drugs, compared with the same symptomatic treatment supplemented with lomustine. The records of 71 dogs with intracranial masses were retrospectively evaluated. Fifteen dogs were treated symptomatically with corticosteroids and anti-epileptics, and 56 dogs received additional therapy with lomustine. There was no statistically significant difference in MST between both groups, being 60 and 93 days, respectively. Age, duration of symptoms, intracranial localization of the mass and intra- or extra-axial localization had no influence on survival time. However, female dogs survived significantly longer than male dogs. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate prevalence of serum alanine transaminase (ALT) elevation in dogs receiving lomustine (CCNU) and to analyse the pattern of occurrence and potential risk factors. Serum ALT activity in 109 dogs during single-agent CCNU chemotherapy was retrospectively analysed. The median initial dose, dose-intensity and cumulative dose of CCNU were 64 mg m−2, 21 mg m−2 week−1 and 171 mg m−2, respectively. The overall prevalence of major ALT elevation [> 5-fold upper reference limit (URL)] was 29% (32/109) and developed most commonly after one to three doses of CCNU. These ALT elevations occurred without preceding mild ALT elevation in 53% (17/32) of the cases. Three dogs (2.8%) developed clinical hepatopathy. For severe ALT elevation (>10-fold URL), age ≤5-year-old was associated with higher risk. The findings of this study showed that elevation of ALT is common during CCNU chemotherapy in dogs and severe elevation can develop on a sudden onset. [ABSTRACT FROM AUTHOR]

In mice and people, administering corticosteroids before chemotherapy can reduce the severity of myelosuppression without reducing antitumour effects. This study investigated whether pretreatment with dexamethasone would reduce the incidence of grade 4 neutropenia in dogs receiving CCNU. Twenty-five dogs received dexamethasone [0.1 mg kg−1 per os (PO) every 12 h] for 5 days and on the sixth day received CCNU (90 mg m−2 PO). Historical dogs ( n = 67) received CCNU alone (90 mg m−2 PO). Forty-five percent of historical dogs had grade 4 neutropenia, while 64% of dogs pretreated with dexamethasone had grade 4 neutropenia ( P = 0.16). Dexamethasone plasma levels were quantified by enzyme-linked immunosorbent assay in three healthy dogs. Peak plasma concentrations after a single oral 0.1-mg kg−1 dose were <80 ng mL−1, the minimum level associated with chemoprotective effects of dexamethasone in people. Pretreatment with dexamethasone did not reduce the incidence of grade 4 neutropenia in dogs receiving CCNU. [ABSTRACT FROM AUTHOR]

Small to intermediate cell alimentary lymphoma was diagnosed in a cat after abdominal exploratory surgery with no prior history of pulmonary disease. Initial response to several chemotherapy regimens was poor, but a long-term remission was achieved with CCNU (lomustine) and corticosteroid therapy. After receiving a total cumulative CCNU dose of 552 mg m−2 over 12 months, an acute episode of respiratory distress occurred and the cat died. Necropsy identified severe diffuse pulmonary fibrosis and no signs of lymphoma. This is the first report of pulmonary fibrosis following high cumulative dose nitrosourea chemotherapy in a cat. [ABSTRACT FROM AUTHOR]

Thirty-seven cases of histiocytic-like sarcomas (HLSs) in flat-coated retriever dogs were evaluated retrospectively. This tumour accounted for 36% of the malignant tumours seen in this breed during the study period. The median age at presentation was 8.2 years. Thirty-four dogs presented with a swelling or mass in a muscle group or surrounding a joint. The remaining three presented for rib (1), cutaneous (1) or primary splenic origin (1). A high rate of metastasis to local lymph nodes (45%), thorax (20%) and abdominal organs (20% confirmed) was seen. Overall metastastic rate by the time of death was 70%. The median survival for all dogs was 123 days. The most significant prognostic indicator was presence of distant metastasis at the time of diagnosis with median survival of 68 or 200 days, with or without metastasis, respectively. Chemotherapy and radiation therapy significantly improved survival. Dogs given chemotherapy survived a median of 185 versus 34 days for dogs that were not ( P = 0.0008). Dogs treated with radiation survived a median of 182 versus 60 days for those that were not ( P = 0.0282). Dogs receiving only palliative therapy survived a median of 17 versus 167 days in dogs receiving any kind of radiation, chemotherapy, surgery or combinations. A set protocol of radiation and CCNU (RTCCNU) induced minimal toxicity and provided a median survival of 208 versus 68 days for all other dogs. While this tumour carries a poor long-term prognosis in flat-coated retrievers, it is reasonable to treat these dogs for palliation of signs and extension of life. [ABSTRACT FROM AUTHOR]