For home prepared diets, a list of ingredients and the source of the recipe was requested. Participants also identified where they obtained information on choosing the diet. For the supplement section, participants answered questions on which products were added or stopped in response to the cancer diagnosis, in addition to which supplements participants maintained both before and after the diagnosis. Participants were then asked where they obtained information on supplements and where they purchased these products for their dogs. The treat section asked for the names of commonly given treats, how often the treat was given, and if the treat was used as a food topper or given with medications. The diet and supplement sections collected both past and present information, whereas the treat section only collected present information. To accommodate requests from initial survey testers and increase the overall survey experience, some questions did not force a response . This was to allow dog owners to complete the survey, even if they did not remember specifics for a particular question, and to reduce the total number of survey pages. Owners who altered their dog’s diets because of a cancer diagnosis were given questions on the previous diet, but responses were not forced for brand , form of diet , ingredients , or recipe source . For the supplement section, responses were only forced for general supplement categories . Questions involving specific supplement types , informational resources used, and where supplements were bought did not force a response. The questions in the treat section did not force responses.Data were collected from the medical record including date of birth, date of first visit to the oncology services, body weight at first visit , sex, spay/neuter status, diagnosis, time from diagnosis to survey completion, breed, body condition score , appetite level at first visit ,cannabis growing system whether or not any signs of gastrointestinal disease were present at latest visit, and address. Address information was used to determine 2021 estimated census tract median family income.
Survey data were exported into RStudio version 2022.12.0 for statistical analysis using R version 4.2.2 . Descriptive statistics were used to describe dog demographics. For diets and supplement use, reasons for changes and informational resources were reported as n values and percentages. Data were checked for normality using a Shapiro-Wilk’s test. A logistic regression model was fitted to predict diet swapping based on information in the medical record or survey. We used the Akaike information criterion to select from the possible variables of using veterinarians as a diet information resource, weight , diagnosis group, estimated family income , BCS, sex, and appetite at first visit . A P value of <.05 was considered statistically significant.The survey was distributed to 438 owners . Ten owners completed the survey but did not meet inclusion criteria, and these responses were omitted from analysis. One hundred twenty-eight responses included data for at least 1 nutrition related question and were retained for analysis. One hundred twenty of the responses were complete; any survey that reached the end was considered complete, regardless of optional questions answered. The median time from diagnosis to survey response was 61 days, with a range of 2 to 472 days . Most questions forced responses and the reported sample sizes will align with the number of respondents reaching a particular part of the survey . However, the sections that did not force a response had fluctuating sample sizes resulting from respondents proceeding through the survey without answering a particular question.Out of the 128 dogs for which we had available survey data, 55.5% were male and 44.5% were female . Omitting 2 dogs without date of birth in their medical records, the ages of 126 dogs were normally distributed with a mean of 9.9 years and a SD of 3.1 years. Omitting 1 dog without weight recorded at time of visit, 127 dogs had a median weight of 26.0 kg, with a range of 3.2 to 64.0 kg. All dogs had their breed recorded in the medical record, with 25.0% listed as mixed breed.
Among purebred dogs , the most common breeds were golden retrievers , Labrador retrievers , and German shepherds . Only 102 of the 128 dogs had a BCS recorded in their medical record; the median BCS was a 5, with a minimum of 3 and a maximum of 9. Diagnoses for all 128 dogs were divided into 5 categories: epithelial origin tumors , mesenchymal origin tumors , round cell tumors , benign tumors with clinical effect diagnosed as pituitary tumors or thymomas, and undefined masses . For the 108 dogs with appetite described in the medical record at the time of visit, 13 had decreased appetite , 91 had normal appetite , and 4 had increased appetite . 22.7% of all respondents reported any GI clinical signs in the time between initial presentation and survey completion. Out of 128 respondents who answered diet information questions, 47.7% altered their dog’s diet in response to a cancer diagnosis. Out of 124 respondents providing supplement information, 28.2% altered supplements in response to a cancer diagnosis, 20.9% altered both diets and supplements, and 54.8% altered diets and/or supplements.The informational resource most widely used for both diets and supplements was veterinarians . Among owners who changed their dog’s diet , the most common reason was loss of appetite , followed by veterinarian recommendation , and felt old diet was unhealthy . Only 8% of respondents who changed their dog’s diet did so for both reasons of loss of appetite and a veterinarian recommendation. Many owners selected the “other” option . In this textbox, owners listed out reasons including previous dogs with cancer doing well on another diet, adding more meat, or reducing carbohydrates. Owners could select multiple options, with 28% of owners reporting multiple reasons. Before diagnosis , 72.7% of dogs were fed commercial diets exclusively, 3.1% of dogs were fed home prepared diets exclusively, and 24.2% were fed a combination of commercial and home-prepared diets.
After diagnosis, 59.4% of dogs were fed commercial diets exclusively, 7.0% of dogs were fed home-prepared diets exclusively, and 33.6% were fed a combination of commercial and home-prepared diets. There was a significant increase in proportion of dogs fed at least some home-prepared foods as part of their diet after the cancer diagnosis . However, there was no significant difference in the proportion of dogs fed any portion of their intake from a commercial diet after the cancer diagnosis . However, many dogs fed commercial diets both before and after diagnosis changed commercial formulas; out of 49 respondents that provided this information for both time points, 23 switched diets . The most common recipe source for those making home-prepared diets, both before and after a cancer diagnosis, was self formulation . Of the 31 owners using home-prepared diets before diagnosis, 45% reported using self-formulation as the only recipe source. Of the 51 owners using home-prepared diets after diagnosis, 39% only used self-formulation. Veterinarians were the second most used resource both before and after a cancer diagnosis . The most common special diet category fed before diagnosis was grain-free diets, and the most common after diagnosis was diets for a medical condition . The term “natural” was included in the brand or product name of 6.9% of commercial diets before diagnosis and 6.0% of diets after, which was not significantly different .An overview of supplements given,flood table including proportions given both before and after diagnosis, is presented in Table 4. Out of 124 respondents providing full or partial supplement information, 85 owners reported supplement use at any time, including 70 owners who reported supplement usage before diagnosis and 76 who reported supplement usage after diagnosis. There was no significant difference in number of dogs receiving supplements before or after a diagnosis . The most common supplements were joint support products . The most commonly added supplements after diagnosis were herbal products . Out of the 14 owners who added herbal supplements, 12 owners provided specific types; among these owners, 7 reported adding mushroom supplements, and 4 reported adding cannabidiol or tetrahydrocannabinol . Among 83 respondents who specified where supplements were purchased, they were most likely to buy some or all of them online , followed by veterinary offices and pet stores . Other responses included warehouse stores , pharmacies , dispensaries , or other locations .This study examined owner decisions regarding diet and supplement alterations after a cancer diagnosis. The average age of dogs in this sample, around 10 years old, is similar to what has been reported in other studies for the age of development of cancer.Given that older dogs have a higher incidence of degenerative joint disease, this might be related to the finding that joint support products were the most commonly used supplements, both before and after a cancer diagnosis; this is consistent with supplement use in dogs with cancer.For total number of dogs receiving supplements, our data showed no significant change after a cancer diagnosis. Dogs with cancer are more likely to receive supplements than healthy dogs in the general population,which was not evaluated in this study.
Our findings might also reflect the owner’s focus on supporting their dog during chemotherapy and other treatments during the period of time close to diagnosis. Some owners added supplement products after diagnosis. Mushroom-based and CBD/THC supplements were added at the highest rates after a cancer diagnosis; this is consistent with these supplements being more commonly given to dogs with cancer when compared to healthy dogs.This helps to confirm that some of these differences are attributable to a cancer diagnosis, rather than solely because of other factors such as age. Although mushrooms have anticancer potential in mice, this has not been shown in dogs.Similarly, although CBD use is common and has some efficacy in inducing apoptosis and perturbing mitochondrial function in canine glioma cell lines,there are currently no studies on its anti-cancer effect in vivo. Furthermore, the addition of CBD to treats, foods, and supplements intended for animals is not allowed by the United States Food and Drug Administration and remains an illegal practice, which might have led to under reporting in this survey.Another potential instance of under reporting was loss of appetite; more owners reported loss of appetite in the survey than during their initial visit to the oncology service. However, this could also be the result of appetite normalizing before the visit, or appetite loss occurring between the visit and survey completion. We predicted this increase before conducting the survey, and this increase was in-line with the results of a previous study.An increase in feeding of home-prepared foods is similarly reported when comparing the general dog population to those with cancer.The increased use of these foods could potentially lead to inadequate nutrient intake, given that home prepared diets are commonly unbalanced.This concern is compounded by self-formulation of recipes, which was the most common source for home-prepared diets in the present study. However, this could be skewed by owners who added just a couple self-selected ingredients to supplement a commercial diet, rather than fully developed recipes, since many owners gave home-prepared meals in conjunction with commercial diets. One strategy to address this potential problem would be referral to a board-certified veterinary nutritionist to ensure any home-prepared diet is complete and balanced. An alternative strategy could be to discuss with the owner their concerns with commercial pet foods. Collecting a comprehensive nutritional history is not only important for ensuring dietary needs are met, but the conversation could lead to discussion regarding perceived problems of commercial pet foods. The current study did not find the accompanying decrease in commercial diets that has been shown elsewhere with the vast majority of owners using a commercial diet for part or all of their dog’s foods. As our sample comprised dogs with a recent diagnosis of cancer, this might suggest that inclusion of home-prepared elements precedes the complete exclusion of commercial diets, and our survey was conducted too close to the time of diagnosis to find exclusion of commercial diets. However, for owners feeding a commercial diet both before and after diagnosis, nearly half stopped feeding the pre-cancer diagnosis diet. It is possible that our sample would ultimately have stayed on their second commercial diet, rather than eliminating commercial elements entirely.