Neoadjuvant chemotherapy and radiation therapy in veterinary cancer treatment: a review

Multi-modality treatment strategies are more becoming commonplace in veterinary oncology practice yet the evidence base is far inferior to what has been generated in people. Surgery is unquestionably the cornerstone of most solid tumour treatment plans but certain scenarios dictate combining surgery with systemic chemotherapy and radiation therapy as an adjunct. By using these in the neoadjuvant setting, one can leverage certain effects of the treatment to improve local disease control, improve overall survival, gain insight into drug efficacy, reduce surgical morbidity and reduce long-term complications. An unintended consequence of combining therapies is an increased flow of information between members of the care team upfront that in almost all cases leads to improved patient outcomes albeit a difficult metric to quantify. This review sets out to explore some of the principles of neoadjuvant therapies and discuss potential opportunities to expand the evidence base in veterinary medicine.

Development, analytical validation, and initial clinical evaluation of a radioimmunoassay for the measurement of soluble CD25 concentrations in canine serum

During immune activation, CD25 is expressed by T cells, and its soluble form (sCD25) is released into the extracellular matrix and the bloodstream. In humans, serum sCD25 concentrations are used as a surrogate marker for autoimmune diseases, malignancies, and transplant rejection. However, a canine-specific assay for the measurement of sCD25 in dog serum has not previously been described. Therefore, the aims of this study were to develop and analytically validate a radioimmunoassay to measure sCD25 in canine serum, to establish a reference interval for canine sCD25, and to test the clinical utility of this assay with serum samples for dogs with various diseases. A competitive radioimmunoassay (RIA) was developed and analytically validated. Analytical validation consisted of lower limit of detection (LLOD), dilutional parallelism, spiking recovery, and intra- and inter-assay variability using pooled surplus canine serum samples. A reference interval was established in healthy dogs and serum samples from dogs with various types of neoplasia, IBD, liver disease, suspected pancreatitis, or suspected small intestinal disease and serum samples with an increased C-reactive protein concentration (CRP) were analyzed to test the clinical utility of the assay. LLOD was calculated to be 0.5 ng/mL. The mean (±SD) observed-to-expected ratio (O/E) for serial dilutions was 101.7 ± 14.0%, and the mean (± SD) O/E for spiking recovery was 93.2 ± 4.2%. Coefficients of variation (CVs) for intra-assay variability were ≤12.5% (mean ± SD: 7.5 ± 4.2%), and inter-assay CVs were ≤15.7% (mean ± SD: 11 ± 4.4%). A reference interval (RI) for canine sCD25 of 1.2-4.2 ng/mL was established from a population of 112 clinically healthy dogs. Dogs with neoplasia and dogs with suspected small intestinal disease had decreased concentrations of serum sCD25 when compared to healthy dogs (p < 0.0001, respectively). However, the majority of clinical samples used in this study were within the reference interval. Median concentrations of serum sCD25 were 1.9 ng/mL for healthy dogs. Dogs with cancer, IBD, liver disease, suspected pancreatitis, or suspected small intestinal disease, as well as sera with an increased serum CRP concentration, had median serum sCD25 concentrations of 1.6 ng/mL, 2.1 ng/mL, 2.2 ng/mL, 1.7 ng/mL, 1.5 ng/mL, and 1.8 ng/mL, respectively. Thus, the RIA described here is linear, accurate, precise, and reproducible for measuring sCD25 in canine serum. However, this assay shows little clinical utility of sCD25 as a biomarker for dogs with inflammatory, autoimmune, and/or neoplastic conditions.

Geographical differences in survival of dogs with non-Hodgkin lymphoma treated with a CHOP based chemotherapy protocol

BACKGROUND

In humans geographical differences in the incidence and presentation of various cancers have been reported. However, much of this information has not been collected in veterinary oncology.

AIM

The purpose of this study was to determine if a geographic difference in progression free survival exists for dogs with lymphoma treated within the US.

MATERIALS AND METHODS

Medical records of 775 cases of canine lymphoma from 3 US regions (west, south and north), treated with CHOP chemotherapy, were retrospectively evaluated. Cases were collected from referral institutions and were required to have received at least one doxorubicin treatment and have follow up information regarding time to progression.

RESULTS

Significant differences in sex (p = 0.05), weight (p = 0.049), stage (p < 0.001), immunophenotype (p = <0.001), and number of doxorubicin doses (p = 0.001) were seen between regions. Upon univariate analysis, progression free survival (PFS) differed by region (p = 0.006), stage (p = 0.009), sub-stage (p = 0.0005), and immunophenotype (p = 0.001). A multivariable Cox regression model showed that dogs in the western region had a significantly shorter PFS when compared to the south and east.

CONCLUSION

PFS was significantly affected by stage, sub-stage and phenotype.