The Beginning of ESCRA - yes, birds get cancer.
While I was a resident at UC-Davis in the Companion Avian and Pet Exotics group, I was fortunate enough to be part of an amazing team of exotics clinicians and oncologists who were willing to think outside the box and come up with new protocols and techniques to treat a wide variety of animals with cancer. Some of my favorite patients were parrots that were on chemotherapy because they had such dedicated and amazing owners. However, we quickly noted that chemotherapy and radiation were just not terribly effective in treating avian tumors and these cases always ended badly for the patient. I wanted to know why. Why do some species get squamous cell carcinomas and other get renal tumors? Why are beak tumors so aggressive? How does chronic feather-picking and skin disease contribute to tumor progression?
One problem - I was NOT an oncologist and was NOT planning to do another residency. I need to learn more about basic cancer mechanisms and how they are the same and different between species. This is when I learned that Stanford had a program specifically for vets who want to do a PhD (its a T32, an NIH program supporting veterinarians, learn more here). I was fortunate to be granted an interview and was very excited to have a chance to work with some of the preeminent cancer researchers in the country. However, during my interview, I had a realization. It came when the professor asked me, somewhat quizzically, why someone with my background (exotics clinician) was pursuing a cancer biology PhD. I explained that I saw so many different patients with different kinds of tumors and I wanted to know the mechanisms behind those differences. He looked at me and, with furrowed brows, asked "Birds get cancer??".
Trying to not appear shocked, I explained that yes, practically all species get cancer. It was then that I realized the researchers advancing the field of cancer treatments do not realize that animals get these same diseases. This is a problem because they are missing a novel way to understand basic cancer mechanisms!
I was accepted into the cancer biology program and worked for 6 years for projects related to highly conserved cancer mechanisms in many tumor types, even working with some canine tumors (thanks Michael Kent!). What I learned is that the most important cancer genes function largely the same very far down the evolutionary tree. Towards the end of my PhD, I was looking for a way to link my training in cancer with my veterinary knowledge. Realizing that there was a huge knowledge gap in even the most basic statistics about cancers in exotic species (including survival times), I worked with Stanford Clinical Informatics group to develop the first version of the database we are using today with a tool called REDCap.
We started with studying squamous cell carcinomas in birds as its a pretty common tumor and often occurs on the skin, so its often diagnosed fairly early and is easier to monitor. I was very fortunate to connect with Ash Sundara and Laura Swift - two students who put in long hours to work with clinics, enter cases and run our statistics, all in addition to their normal work and without pay because they believed in the mission.
We learned a lot with that original study of 87 birds, including providing the first survival estimates for birds treated with different protocols (see figure below at the end of this article, reprinted from JAVMA February 1, 2018, Vol. 252, No. 3, Pages 309-315). We changed and adapted that original survey tool to all species and tumor types, have recruited a small army of vet students (and other students). Tara Harrison, current project leader of ESCRA, has also been working on exotic cancer projects for years, particularly in big cats and tenrecs and connected with me to expand this work into now dozens of zoos and an amazing partnership with the Arizona Cancer and Evolution Center, which allows us to start to do what I imagined doing way back during my residency, look at the biological mechanisms that drive the clinical differences we see in our patients and use that knowledge to design new cancer therapies for all species!
To do all of this, we need your help! If you believe that there is much more we can learn about cancer by studying more than 1 or 2 species, support our work by clicking the link at the bottom of this page and THANK YOU!
Figure legend: Kaplan-Meier curves of survival time from initial evaluation for birds with SCC treated by complete excision (solid line; n = 12), conservative treatment (dotted line; 27; no treatment other than surgical debulking [ie, partial excision] of the tumor; NSAIDs; supportive care including nutritional support, antimicrobials, antifungals, or other medical treatments not related to cancer treatments, or euthanasia), or any other treatment approach (dashed line; 18; excluding complete excision and including any other treatment approach used except NSAIDs alone). Birds with < 6 months of documented follow-up information available or with unknown survival status were excluded from this analysis, as were birds that received a diagnosis after death or that died or were euthanized within 5 days after initial evaluation. Compared with birds with SCC that received conservative treatment, birds that underwent complete excision of the tumor had a 62% lower risk of death (hazard ratio, 0.38; 95% CI, 0.19 to 0.77; P = 0.01). Median survival time from initial evaluation for birds receiving complete excision was 628 days (95% CI, 210 to 1,008 days), compared with 171 days (95% CI, 89 to 286 days) for birds receiving only surgical debulking or conservative treat- ment. Birds receiving any other additional treatment had a median survival time of 357 days (95% CI, 143 to 562 days).
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