Efficacy and Toxicosis of VELCAP-C Treatment of Lymphoma in Cats

Feline high-grade and large granular lymphocyte alimentary lymphomas treated with COP- or CHOP-based chemotherapy: A multi-centric retrospective study of 57 cases

Specific data regarding outcome of cats with high-grade and large granular lymphocyte alimentary lymphoma (HGAL and LGL, respectively) treated with multi-agent chemotherapy are scarce. The aims of this multi-centric, retrospective study were to describe the outcome of cats with HGAL and LGL treated with COP- or CHOP-based chemotherapy and to identify potential prognostic factors. Cats with a cytological or histological diagnosis of HGAL or LGL lymphoma treated with COP- or CHOP-based protocol as first-line chemotherapy were included. Data regarding diagnosis, staging, treatment and follow-up were collected. Fifty-seven cats treated with CHOP (n = 37) or COP (n = 20) protocols were included. Complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 20%, 22%, 36% and 22% of cats, respectively, for an overall response rate of 42%. Median progression-free interval (PFI) was 148 days and overall median survival time (OST) was 131 days. Cats achieving CR, PR or SD showed significantly longer PFI (p < .01) and OST (p < .015) compared with cats with PD. Other positive prognostic factors in multi-variate analysis were rescue treatment (p < .001) and absence of lymph node involvement (p < .03). Negative prognostic factors were diffuse infiltration of the gastrointestinal tract (p = .035) and infiltration of a non-haematopoietic organ (p < .01).

Treatment of feline intermediate to high-grade alimentary lymphoma: A retrospective evaluation of 55 cats treated with the VAPC combination chemotherapy protocol (2017-2021)

The most commonly utilized protocols to treat lymphoma in cats employ vincristine, cyclophosphamide and prednisone; with additional drugs sometimes used including L-asparaginase and doxorubicin. Medical records were reviewed for 55 cats with alimentary lymphoma treated with a novel multiagent protocol using prednisolone, L-asparaginase, doxorubicin, vinblastine instead of vincristine, a higher dosage of cyclophosphamide and oral procarbazine (VAPC protocol). Outcomes evaluated were response to therapy, toxicity and progression-free survival (PFS). Grade 3 or 4 neutropenia was the most common treatment-related reason for chemotherapy dosage adjustment, occurring in 8 of 52 cats receiving vinblastine, 7 of 55 cats receiving cyclophosphamide and 1 of 40 cats receiving doxorubicin, but febrile neutropenia was identified in only two cats. Of 38 cats receiving chemotherapy for measurable disease, 26 (68.4%) achieved complete response (CR). Three cats achieved a partial response and 9 cats failed to achieve a remission. There were no identified factors influencing whether a cat was likely to achieve CR. For all 55 cats (including those receiving chemotherapy and surgery), median PFS was 184 days with 1, 2 and 3-year survival rates of 35.4%, 26.5% and 26.5%, respectively. On multivariate analysis, 40 cats that achieved CR had a median survival time of 341 days (78 days for PR, 45 days for NR); PFS times were also significantly affected by lymphocyte:monocyte L:M ratio (>3.4 = 700 days vs. ≤3.4 = 126 days) and B-cell versus T-cell phenotype (220 days vs. 42 days, respectively).

Case Report: Use of PET/CT to Guide Treatment in a Cat With Presentation Consistent With Hodgkin's-Like Lymphoma

An 8-year-old male neutered Domestic Long Hair cat was presented for a cervical swelling that was suspected to be an enlarged left retropharyngeal lymph node. In the absence of other lymphadenopathy, this was initially suspected to be Hodgkin's-like lymphoma. A positron emission tomography–computed tomography (PET/CT) scan was performed using 2-deoxy-2-[¹⁸F]-fluorodeoxyglucose (¹⁸F-FDG) to assess for evidence of disease in other locations to guide treatment. Multifocal increased radiopharmaceutical uptake was identified, indicating disease in multiple organs. High-grade lymphoma was confirmed on tissue biopsy. As such, systemic cytotoxic chemotherapy was recommended instead of lymph node extirpation surgery. The cat received a modified CHOP chemotherapy protocol and attained a temporary partial remission. After 2 months of treatment, the cat stopped responding to chemotherapy and was eventually euthanized due to a relapse of disease and decreased quality of life. This case describes the utility of PET/CT to guide treatment in a cat with a presentation consistent with Hodgkin's-like lymphoma.

Cyclophosphamide rescue therapy for relapsed low-grade alimentary lymphoma after chlorambucil treatment in cats

OBJECTIVES

The aims of this study were to evaluate the response, outcome and prognostic factors in cats with clinically presumed relapsed low-grade alimentary lymphoma (LGAL) receiving cyclophosphamide as a first-line rescue therapy after failing chlorambucil treatment.

METHODS

The medical records of 20 cats (from three institutions, between 2002 and 2017) treated with cyclophosphamide for relapsed LGAL after initial treatment with chlorambucil were retrospectively reviewed. Progression-free survival (PFS), overall survival time (OST) and the association of select variables with measures of outcome were assessed. Adverse events (AEs) were also described.

RESULTS

Eighteen cats (90%) achieved a complete clinical response (CR) for a median duration of 239 days. The median PFS was 215 days. The median OST was 1065 days. The only clinical factor associated with a longer PFS was achievement of a CR with cyclophosphamide treatment. Cyclophosphamide was associated with few and reversible constitutional, gastrointestinal and hematologic AEs.

CONCLUSIONS AND RELEVANCE

Cyclophosphamide appears to be a safe and effective first-rescue therapeutic option for cats with relapsed LGAL.

Incidence and treatment of feline renal lymphoma: 27 cases

OBJECTIVES

Lymphoma is the most common feline hematopoietic malignancy. Incidence of renal lymphoma has not been reported as a subset of a large population of feline lymphoma cases. Previous studies have reported renal lymphoma as both a singular entity as well as a component of multicentric disease. The clinical presentation, diagnostic evaluation, therapy and outcomes related to renal lymphoma have not been reported since Mooney et al in 1987. This retrospective study aimed to describe the incidence of renal lymphoma, clinical signs, treatment and survival.

METHODS

Using a database of cats diagnosed with lymphoma between January 2008 and October 2017, cats with renal lymphoma were selected for further analysis. Cases were retrospectively staged according to Mooney et al (1987) and Gabor et al (1998). Data collected included age, clinical signs, clinicopathologic data, diagnostic imaging findings, lymphoma diagnostic method(s), treatment protocol(s) and survival time. Analyses comparing median survival based on therapy administered, renal lymphoma vs multicentric lymphoma, central nervous system involvement, presence of azotemia, anemia and International Renal Interest Society (IRIS) stage at diagnosis were performed.

RESULTS

From a population of 740 cats with lymphoma, 27 cats had renal lymphoma (incidence, 3.6%), and 14 of those cats had multicentric lymphoma. Fewer stage IV and V cases were identified in this data set compared with Mooney et al; however, not all cats were completely staged. Median survival (range) for cats receiving corticosteroids alone compared with those receiving an L-CHOP (L-asparaginase, vincristine, cyclophosphamide, doxorubicin, prednisolone)-based protocol was 50 days (20-1027 days) in the corticosteroid group and 203 days (44-2364 days) for the L-CHOP group (P = 0.753) for cats that died secondary to lymphoma.

CONCLUSIONS AND RELEVANCE

Neither clinical stage nor other factors were predictive of survival. Prospective studies are required to determine the optimal chemotherapy protocol.

LOPH: a novel chemotherapeutic protocol for feline high-grade multicentric or mediastinal lymphoma, developed in an area endemic for feline leukemia virus

OBJECTIVES

The aim of this study was to establish the safety and efficacy of a novel multidrug lomustine-based chemotherapeutic protocol for cats with high-grade multicentric or mediastinal lymphoma, in an area endemic for feline leukemia virus (FeLV).

METHODS

This prospective study included owned cats, diagnosed (cytologically) with multicentric or mediastinal lymphoma and treated with the LOPH (lomustine, vincristine [Oncovin; Antibióticos do Brasil], prednisolone and hydroxydaunorubicin [doxorubicin]) protocol. A complete blood count was performed before every chemotherapy session and any significant abnormalities recorded as possible related toxicities. Median survival time (MST) and disease-free interval were estimated by Kaplan-Meier curves.

RESULTS

Twenty-one cats were included in this study. Nineteen (90.5%) tested positive for FeLV and were therefore considered to have persistent viremia. Complete response was reported in 81% (n = 17/21), while three had partial remission and one had no response. Seven cats finished the induction protocol within 20-31 weeks (23.1 ± 4.5; median 20) and all seven received a maintenance protocol. The MST (lymphoma-related survival) for the 21 cats was 214 days. The MST was 214 days for cats with mediastinal lymphoma (n = 13), but it was not reached for multicentric lymphoma (n = 8; P = 0.9). The MST of cats with persistent FeLV antigenemia was 171 days. Grade I anorexia and vomiting occurred in 19% of the cats (n = 4/21). Hematologic toxicity was found in 100% of the cats at some point during their treatment, but it was mostly grade I or II. Neutropenia, thrombocytopenia and anemia occurred in 16/21, 21/21 and 15/21 cats, respectively.

CONCLUSIONS AND RELEVANCE

The LOPH protocol was well tolerated by cats with lymphoma and persistent FeLV viremia, and resulted in a better MST than similar studies with other protocols. Novel studies and controlled trials are necessary in order to evaluate the efficacy of different protocols according to the lymphoma subtype, anatomic form and FeLV status.

Phase I dose escalating study of oral cyclophosphamide in tumour-bearing cats

Cyclophosphamide is an alkylating agent used to treat cats with lymphoma, carcinomas and sarcomas. However, no clear consensus exists regarding the maximum tolerated dose (MTD) of oral cyclophosphamide in cats. Toxicities are rarely reported at published oral dosages of cyclophosphamide (200-300 mg/m²). The primary aim of this prospective study was to determine the MTD of oral cyclophosphamide in tumour-bearing cats via a modified phase I trial. A secondary aim was to define any toxicity. Forty-six client-owned tumour-bearing cats were enrolled. The cyclophosphamide dosage was escalated by approximately 10% (300, 330, 360, 400, 440, 460 and 480 mg/m²) in cohorts of at least six cats. The MTD of oral cyclophosphamide in this study was 460 mg/m² with an inter-treatment interval of two to three weeks. Haematology is recommended 7 and 14 days after first cyclophosphamide treatment, and immediately before each subsequent dosage of cyclophosphamide or any potentially myelosuppressive chemotherapy agent. The dose-limiting toxicity was neutropenia with nadir at 7-21 days. This higher dosage was considered safe in combination with prednisolone and L-asparaginase. However, the higher dose of oral cyclophosphamide has not been evaluated in combination with other chemotherapy agents and thus should not be administered with these agents.

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

BACKGROUND

Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions.

RESULTS

A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract.

CONCLUSIONS

The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine.

Does categorisation of lymphoma subtypes according to the World Health Organization classification predict clinical outcome in cats?

Objectives

The purpose of this study was to specify lymphoma subtypes according to the World Health Organization (WHO) classification in a group of cats and to investigate their potential prognostic value.

Methods

Records of cats from the University of Veterinary Medicine Vienna suffering from lymphoma were reviewed in this retrospective study. To diagnose various subtypes specified in the WHO classification, histopathological and immunohistochemical examinations, as well as clonality assays in some cases, were performed.

Results

Of the 30 cats included in this study and classified according to the WHO guidelines, peripheral T-cell lymphoma was the most prevalent lymphoma subtype (37% of cases; n = 11), followed by diffuse large B-cell (23%; n = 7), intestinal T-cell (10%; n = 3), T-cell-rich B-cell (10%; n = 3), large granular lymphocytic (7%; n = 2), anaplastic large T-cell (7%; n = 2), B-cell small lymphocytic (3%; n = 1) and T-cell angiotropic lymphoma (3%; n = 1). The median survival time (MST) was 5.4 months (range 6 days to 2.2 years), with two cats still alive after 1.7 and 2.0 years, respectively. Treating cats prior to chemotherapy with glucocorticoids did not worsen their prognosis. Adding to chemotherapy, radiotherapy or surgery did not improve the clinical outcome. We observed that patients with intestinal T-cell lymphoma lived significantly longer (MST 1.7 years) than those with a diffuse large B-cell (MST 4.5 months) or peripheral T-cell lymphoma (MST 6.1 months). Cats with T-cell-rich B-cell lymphoma survived significantly longer (MST 1.2 years) than those with a diffuse large B-cell lymphoma.

Conclusions and relevance

A detailed diagnosis of feline lymphoma can be obtained by allocating different subtypes according to the WHO classification. From the eight detected lymphoma subtypes, two, intestinal T-cell lymphoma and T-cell-rich B-cell lymphoma, showed promising survival times in cats.

A retrospective evaluation of lomustine (CeeNU) in 32 treatment naïve cats with intermediate to large cell gastrointestinal lymphoma (2006-2013)

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.

Is Serum Total LDH Evaluation Able to Differentiate between Alimentary Lymphoma and Inflammatory Bowel Disease in a Real World Clinical Setting?

Context

An increase in enzyme lactate dehydrogenase (LDH) in serum is a negative prognostic factor for survival in cats affected by lymphoma. Measuring LDH at the time of diagnosis has been studied for differentiating neoplastic disease from non-neoplastic disease in dogs. Inflammatory bowel disease (IBD) and alimentary lymphoma are common diseases in cats.

Objective

The aim of this study was to determine whether elevation of total LDH occurred in cats with alimentary lymphoma and non-neoplastic gastrointestinal disease, such as IBD, and to evaluate whether this enzyme is useful in supporting the differential diagnosis of these specific diseases.

Materials and Methods

A prospective non-randomized controlled study was carried-out in a real world setting of three Italian private veterinary clinics. Seventy-one client-owned cats with a history of chronic gastrointestinal symptoms were enrolled; 33 cats were histologically diagnosed as having alimentary lymphoma and 38 cats as having IBD. Serum samples of total LDH analysis were measured.

Results

Gender (P = 0.016) and age (P = 0.046) were found to be significant factors influencing the differentiation of serum total LDH between cats with alimentary lymphoma and those with IBD. Despite low diagnostic accuracy in the overall population (63%), a cut-off value of serum total LDH ranging from 0.85- to 1.04-times the upper reference limit showed good capability (accuracy >80%) of differentiating these two conditions in neutered males and cats younger than 8 years of age (AUC: 0.805, 0.833; sensitivities: 76.9%, 83.3%; specificities: 80.0%, 76.5%; PPV: 76.9%, 55.6%; NPV: 80.0%, 92.9%; respectively).

Conclusions

Although our study showed that gender and age are significant factors in differentiating serum total LDH between cats with alimentary lymphoma and those with IBD, this test had poor diagnostic accuracy in differentiating between these two conditions in the overall population.

Treatment of feline intermediate- to high-grade lymphoma with a modified university of Wisconsin-Madison protocol: 119 cases (2004-2012)

CHOP-based (cyclophosphamide, doxorubicin, vinca alkaloid, prednisolone) chemotherapy protocols are often recommended for treatment of feline lymphoma. While maintenance-free CHOP-based protocols have been published and readily used in dogs, there is limited literature regarding similar maintenance-free protocols in cats. The purpose of this study was to describe the outcome of cats with intermediate- to high-grade lymphoma that were prescribed a modified 25-week University of Wisconsin-Madison (UW-25) chemotherapy protocol. A secondary objective was examination of potential prognostic factors. One hundred and nineteen cats from five institutions treated with a UW-25-based protocol were included. The Kaplan-Meier median progression-free interval (PFI) and survival time (MST) were 56 and 97 (range 2-2019) days, respectively. Cats assessed as having a complete response (CR) to therapy had significantly longer PFI and MST than those with partial or no response (PFI 205 versus 54 versus 21 days, respectively, P < 0.0001 and MST 318 versus 85 versus 27 days, respectively, P < 0.0001).

Extranodal lymphoma in the cat: prognostic factors and treatment options

PRACTICAL RELEVANCE

The majority of feline lymphoma is extranodal. While the gastrointestinal (GI) tract is the most commonly affected site, non-GI extranodal lymphomas, which are the focus of this review, account for a large proportion of lymphomas in cats. This article discusses prognostic factors for the most common of these extranodal lymphomas, both in general terms and specifically for individual sites.

CLINICAL CHALLENGES

Prognostic factors remain poorly defined for feline lymphoma. Many cats with extranodal lymphoma have stage I disease at an accessible site. A major question for patients with apparently localised extranodal lymphoma is whether the tumour can be treated with localised therapy alone or requires systemic treatment as well. Again there is often no specific information available for a particular site, such as a localised intramuscular lymphoma. Instead, reliance must be placed on careful patient staging, particularly if local therapy alone is planned.

EVIDENCE BASE

Until such time as further studies looking at stage, anatomic site, histological grade and immunophenotype are available to assist treatment decision making for an individual cat with extranodal lymphoma, it seems reasonable to draw inferences from other common extranodal sites for which more specific information exists, such as nasal lymphoma.

Comparison of the antitumor effects of an MDM2 inhibitor, nutlin-3, in feline lymphoma cell lines with or without p53 mutation

The P53 tumor suppressor protein is a multifunctional transcription factor that prevents the malignant transformation of normal cells. In human malignancies, p53 is the most frequently altered gene and is mutated in approximately 50% of all malignancies. In contrast, p53 gene mutation has been rarely detected in feline malignancies, and most feline malignancies conceivably retain the wild-type p53 (wt-p53) gene. MDM2 negatively regulates the P53 protein by inhibiting its transcriptional activity and nuclear transport and by inducing its degradation. Inhibition of P53-MDM2 interaction stabilizes P53 protein and activates P53 pathway. Nutlin-3, a small molecule that inhibits P53-MDM2 interaction, was shown to have an antitumor effect in several human cancer cells retaining the wt-p53 gene. In the present study, we evaluated and compared the antitumor effect of nutlin-3 in 5 different feline lymphoma cell lines, of which 3 harbored wt-p53, and 2, mutated p53 (mt-p53). Treatment with nutlin-3 resulted in increased amounts of P53 protein in conjunction with augmented expression of P53-target genes in 3 feline lymphoma cell lines with the wt-p53 gene, but not in 2 feline lymphoma cell lines with the mt-p53 gene. Nutlin-3 treatment also induced G1-S and/or G2-M cell cycle arrest and apoptosis in lymphoma cell lines with wt-p53. Nutlin-3 treatment induced cell cycle arrest but not apoptosis in the cell lines with mt-p53. From these results, we concluded that nutlin-3 has an antitumor effect on feline lymphoma cell lines harboring the wt-p53 gene through accumulation and activation of P53 leading to cell cycle arrest and apoptosis. The present study suggests that inhibition of P53-MDM2 interaction using nutlin-3 may be a new therapeutic strategy for treating feline lymphoma retaining the wt-p53 gene.

Feline alimentary lymphoma

Practical relevance Accurate diagnosis of the distinct subtypes of alimentary lymphoma (AL) that occur in cats is important as there are major differences between them in clinical presentation, treatment and prognosis. Unlike intermediate- and high-grade alimentary lymphoma (I/HGAL) and large granular lymphocyte lymphoma (LGLL), which can often be diagnosed by aspiration cytology, full-thickness intestinal biopsies are usually required for the diagnosis of low-grade alimentary lymphoma (LGAL).

Clinical challenges LGAL is an increasingly recognised clinical problem and it can be challenging to differentiate from inflammatory disease. Where there is ambiguity on histology, further diagnostics (immunophenotyping and clonality analysis) may be required. The diagnosis of LGLL requires an index of suspicion as it may be missed with routine diagnostics. While cats with LGAL typically achieve durable remissions with oral prednisolone and chlorambucil, I/HGAL runs a more aggressive clinical course and requires multi-agent chemotherapeutic protocols. Information on the treatment of LGLL is limited and this form of AL has the poorest prognosis. Preliminary studies suggest that abdominal irradiation may potentially be of benefit in cats with AL and further investigations are warranted.

Evidence base The evidence supporting this review is derived from grade II, III and IV prospective studies, retrospective case series, reviews, extrapolation from other species, pathophysiological justification and the combined clinical experience of those working in the field.

Prognostic Significance of Weight Changes during Treatment of Feline Lymphoma

The study purpose was to determine the prognostic significance of weight changes during feline lymphoma treatment. A secondary purpose was to compare weight changes according to baseline body weight, cell type and location. Records of 209 cats treated for lymphoma with chemotherapy from 1995 to 2007 were evaluated. Signalment, cell type, lymphoma location, baseline body weight, weight during treatment, and outcome information were collected. Lymphoma specific survival (LSS) was compared according to baseline weight and weight changes during treatment. Weight change over time was compared according to cell type (small versus large), location (gastrointestinal versus non-gastrointestinal) and baseline weight. Cats with large cell lymphoma that lost ≥5% body weight at 1 month had significantly shorter LSS than those that gained or had stable weight ( P = 0.004). Percentage weight change over time differed significantly according to baseline weight group. These findings demonstrate the prognostic importance of weight loss in feline large cell lymphoma.

Computed tomography of a cat with primary intratracheal lymphosarcoma before and after systemic chemotherapy

A 12 yr old male neutered domestic shorthair cat presented with worsening tachypnea of 1 mo duration and open mouth breathing. Radiographs revealed tracheal narrowing at the thoracic inlet. Computed tomography (CT) revealed a contrast enhancing 8-cm long fusiform mass within the dorsal tracheal membrane. Tracheobronchoscopy confirmed the presence of the tracheal mass at the thoracic inlet, and lymphoma was diagnosed based on uniformly atypical lymphoid cells on aspirated bronchoalveolar lavage fluid. The cat was treated with combination chemotherapy consisting of cyclophosphamide, vincristine, doxorubicin, and prednisolone. Thoracic radiographs and CT performed 1 mo after completion of the 6 mo chemotherapy protocol revealed resolution of the tracheal mass. The cat remained clinically normal at 21 mo after treatment.

Abdominal irradiation as a rescue therapy for feline gastrointestinal lymphoma: A retrospective study of 11 cats (2001–2008)

In this retrospective study medical records of 11 cats with gastrointestinal lymphoma were evaluated to determine the efficacy of radiation therapy when used in a rescue therapy setting. All cats had relapsed or resistant lymphoma. Two fractions of radiation were delivered over 2 days for a total of 800 cGy. Acute effects of radiation were not noted, except one cat that had a self-limiting loss of appetite. Response was noted in 10/11 cats. Median survival post-radiation therapy was 214 days and the overall median survival in this study was 355 days. This study suggests that abdominal irradiation for feline gastrointestinal lymphoma was well tolerated and may contribute to a positive clinical response.

Feline extranodal lymphoma: response to chemotherapy and survival in 110 cats

OBJECTIVE

To determine response to treatment, survival and prognostic factors for feline extranodal lymphoma in the UK.

METHODS

Records of cats diagnosed with lymphoma of extranodal sites at seven referral centres were reviewed and information on signalment, tumour location, prior treatment and chemotherapy protocol recorded. Factors influencing response to treatment and survival were assessed.

RESULTS

One hundred and forty-nine cases met inclusion criteria. Sixty-nine cats had nasal lymphoma, 35 renal, 15 central nervous system, 11 laryngeal and 19 miscellaneous locations. Sixty-six cats received cyclophosphamide, vincristine, prednisolone, 25 Wisconsin-Madison doxorubicin-containing multi-agent protocol, 10 prednisolone alone and nine other combinations. The response rate for the 110 treated cats was 85.5 per cent. Of cyclophosphamide, vincristine, prednisolone treated cats 72.7 per cent achieved complete remission, median survival 239 days. Sixty-four per cent of Wisconsin-Madison treated cats achieved complete remission, median survival 563 days. Cats with nasal lymphoma achieving complete remission had the longest survival (749 days) and cats with central nervous system lymphoma the shortest (70 days). If complete remission was achieved, prior treatment with corticosteroids significantly reduced survival time.

CLINICAL SIGNIFICANCE

Cats with extranodal lymphoma respond to chemotherapy and achieve survival times comparable to other locations. Corticosteroid pretreatment reduced survival time in cats achieving complete remission.