• High Grade T and B cell lymphoblastic lymphomas (n= 36) with possible prednisolone only treatment. States that there is no evidence that prednisolone alone is better than no treatment (HR 0.50; 95% CI, 0.064-3.90; p=0.51). Centroblastic B cell lymphomas (n= 186). Risk of death of dogs treated with prednisolone alone similar to that with no treatment (HR 1.65;95%CI, 0.56-4.87; p=0.36).
• Immunoblastic B cell lymphomas (n= 57). Prednisolone only therapy associated with poorer survival than chemotherapy (HR 47.22 CI95% 2.67-834.74 p=0.009) but 0 dogs in this group were were in the no treatment group.
• This paper also compared treatment to histological grade of lymphoma. The numbers of dogs in this part of the analysis was not stated. Survival following the different treatments (chemotherapy including hydroxydaunorubicin, chemotherapy without hydroxydaunorubicin or prednisone alone) was compared to that of dogs that received no treatment.
• Low grade lymphomas (n=81) were treated with chemotherapy including hydroxydaunorubicin, chemotherapy without hydroxydaunorubicin , prednisone alone and no treatment however the numbers in each group were not stated. However those treated with prednisone only had increased risk of death (HR 40.57 6.8-242.09 P <0.001) compared to dogs receiving no treatment.
• Intermediate grade lymphomas (n=242): dogs treated with prednisolone only (HR 1.920.68-5.39 p = 0.22) showed no significant difference from those not treated. Dogs treated with chemotherapy including hydroxydaunorubicin or  chemotherapy without hydroxydaunorubicin , showed a reduced risk of death
• High grade lymphomas (n=103) treated with prednisolone only (HR 1.63 95% CI 0.53-5.03 p=0.39) showed no significant difference compared to chemotherapy including hydroxydaunorubicin, chemotherapy without hydroxydaunorubicin and no treatment) was not stated.

Based on this study prednisone only showed no advantage over no treatment for dogs with diffuse large centroblastic B cell lymphoma.

Across all grades of lymphoma (including some T cell lymphoma dogs) treatment with prednisolone alone increased the risk of death but this increase was only significant when compared to chemotherapy treatment with or without hydroxydaunorubicin and not when compared to the no treatment group. 

• The paper is a retrospective study assessing a wide variety of aspects of dogs with histologically confirmed lymphoma. These include classification of cell type (T vs B, mitotic rate and histological types.) It aims to show how survival varies in different treatment regimens and relate this to disease variables.
• Cases were recruited through a Veterinary Cancer Society newsletter which could result in loss of patients from veterinary practices without a special interest in cancer treatment which would mean there might be fewer patients in the prednisolone alone or no treatment groups. There was an ongoing study into one treatment regime so this may have been over-represented.
• The authors state that the majority of cases came from the USA with a few from Europe and Canada. It is possible that there were variations in treatment choices or histological diagnosis in the cases from Europe however there is no detail provided about the patient numbers involved.
• Patients were only included where there was histological confirmation and immunohistochemistry had been performed. Again this might reduce recruitment of patients whose owners were unwilling or unable to perform these tests or where a diagnosis was reached by cytology alone.
• Survival time was recorded for all patients and those who remained alive at the time of the study were censored.
• As this was a retrospective study, patients were allocated to a particular treatment option based on clinician and owners preference. It is not clear from the paper if cases from particular practices or regions had differing treatment regimes.
• There is no reporting of the dose of prednisolone used for the prednisolone alone group or any reporting of the chemotherapy doses used.
• Similarly there is no reporting of the numbers of dogs in each treatment group within each category. This reflects the focus on survival for the group as a whole rather than in respect of differing treatment regimes.

Cytomorphological analysis was similar to previous reports with high malignant lymphoma in 25 dogs, intermediate grade lymphoma in 13 dogs and low malignant lymphoma in 1 dog.

There is no information on outcome in 26 dogs and it is not clear if they received any treatment.

13 dogs were treated these comprised 6 dogs with high grade, 6 dogs with intermediate and 1 dog with low grade. Details on which treatment each dog received are provided but the numbers in each subgroup are two small to draw any further information on the survival times associated with each lymphoma type.

However within all grades of tumour  treated  median survivals were:

COP-treated dogs (n=6)  160 days,

COPA treated dogs (n=4) 225 days

Doxorubicin treated dogs (n=2) were alive at 90 days

Methylprednisolone alone (n=1) 240 days

Median first remission was longer in females (n= 6; 215 days) than males (n=7; 159 days)

• Only one patient out of 39 received prednisolone alone.
• Authors do not state how cases were selected or give any inclusion or exclusion criteria for this study

The following dosage regimes were used:

Cyclophosphamide 0.3mg/kg/day for 14 days followed by 14 days with no treatment

Prednisolone 0.5mg/kg/day for 14 days followed by 7 days without treatment and the schedule then repeated.

Chlorambucil 0.2mg/kg/day for 14 days followed by 14 days without treatment and the schedule then repeated.

Prednisolone 0.5mg/kg/day for 14 days followed by chlorambucil 0.2mg/kg/day for 14 days and the schedule then repeated.

• 6 dogs were given no treatment and mean survival time was 2.5 weeks and disease was extensive in 4 of the dogs. However grade was not mentioned.
• Prednisolone regime was administered to 6 dogs however one of these also received radiotherapy on one occasion. Survival time ranged from 1-7.5 months with a mean of 2.5 months.
• Of the 6 dogs and 2 cats that received prednisolone alone only 7 had a temporary reduction in node size.

• The paper is a retrospective study but does not state how patients were identified or if any cases were excluded.
• Diagnosis was based on a combination of clinical signs (anorexia, depression, weight loss, anaemia and generalized lymphadenopathy) haematology results and a biopsy of tonsil or popliteal lymph node or bone marrow which would be acceptable assuming all patients had all three criteria assessed. This is not stated in the paper. Furthermore the paper does not state whether dogs had all or some of these symptoms and whether there was a difference in the presentation of dogs and cats.  
• The paper does not specify the stage/sub stage of the cases reported except to state that the patients that had no treatment had widespread disease.
• Mean survival was reported rather than median which given the low numbers of cases is far from ideal.
• Paper does not state the survival time of 1 dog that also received radiation therapy and does not state which of the 6 dogs and 2 cats did not get a reduction in node size. There is no indication if location or grade of disease affected this finding.
• Regime is not continuous prednisolone as usually recommended in current veterinary practice across the world.

1. Prednisone 2 mg/kg/day orally for 7 days followed by 1 mg/kg/day thereafter (n=49)
2. Prednisone as above plus cyclophosphamide 5 mg/kg/day orally for 7 days followed by 2.5 mg/kg thereafter (n=34)
3. Vincristine 0.03mg/kg intravenously on day 1 and 8. Prednisone 1 mg/kg/day orally on days 1 and 8 and days 9-21. Cyclophosphamide 5 mg/kg/day on days 2-7. Regime repeated every 14 days (n=19)
4. Vincristine 0.03mg/kg intravenously on day 1 and 8. Prednisone 2 mg/kg/day orally on days 1 and 8 followed by 1 mg/kg/day on days 9-21. Cyclophosphamide 5 mg/kg/day on days 15-21. 6-mercaptopurine 5 mg/kg/day on days 15-21. Regime repeated every 30 days (n=25)

Dogs that failed to respond to one regime were moved to treatment schedules 2 or 3 and then reported in that group

• This study excluded 18 dogs that died or were euthanased due to advanced disease or an unsatisfactory response to therapy within 14 days of admission from the survival and remission duration data.
• Of the 49 dogs on prednisolone only 20 (41%) achieved complete remission with a mean objective remission time of 53 days (range 14-210 days). Remission induction rapid and usually reached its maximum at 7 days but was often partial within 72h. Partial remissions were not reported.
• In 34 dogs on schedule 2, 13 achieved complete remission with a mean objective remission time of 62 days (range 17-130 days). 25 dogs had previously received prednisolone alone. 7 that that had failed to achieve remission with prednisolone alone showed some sensitivity but the objective remission time is not stated. 2 dogs failed to respond to schedule 2 despite achieving complete remission with prednisolone alone
• In 19 dogs on schedule 3, 15 achieved complete remission with a mean objective remission time of 184 days (range 30-282 days). 14 of these dogs had previously received prednisolone alone or schedule 2.
• In 25 dogs on schedule 4, 19 achieved complete remission with a mean objective remission time of 136 days (range 18-300 days). None had received prior treatment
• No severe side effects reported except in 1 dog which developed a gastric ulcer after several months of treatment.
• In several patients polyuria and polydipsia necessitated a reduction in dosage to 0.25-0.5 mg/kg/day.
• Increased appetite and mild signs of Cushing’s syndrome were noted in several animals (number not stated)
• 9 dogs that failed to achieve remission on prednisolone alone were then treated with schedule 2. 7 of these dogs responded and 2 of these dogs failed to respond to schedule 2.
• 14 dogs that failed to respond to prednisolone alone or to schedule 2 were treated with schedule 3. Of these 12 achieved complete remission.
• Dogs on prednisolone alone were subsequently given chemotherapy if response was unsatisfactory or when refractoriness developed.

• Stage of lymphoma was defined as one of 4 stages  (Stage 1 = one lymph node or one anatomic location
• Stage 2 = involvement of multiple lymph nodes but limited to one side of the diaphragm
• Stage 3 generalized involvement but limited to lymphoid tissue
• Stage 4 involvement of any non-lymphoid tissue including viscera or blood or bone marrow nervous system etc. Viscera would normally be classed as stage 4 on the WHO system and the other areas would be as stage 5 on the WHO system Definition of Stage 3 in this study was generalised involvement but limited to lymphoid tissues i.e. lymph nodes, spleen, tonsils, thymus. In the current staging system this would be a group containing Stage 3 and Stage 4 patients.
• Only included animals surviving to 14 days. 18 died or were euthanised due to advanced disease or an unsatisfactory response to therapy.
• Doesn’t state which of the prednisolone alone group went on to get chemotherapy and if this was taken into account in the survival times. However as there are no survival times given for this group we assume that most went onto get other treatments.
• Mean remission duration is provided rather than median. Given the extremely wide range of 14-210 days this is far from ideal.
• No data on patients who did not get treatment as patients were recruited to be part of this study and given a treatment regime.