47-Year-Old Dolphin at Brookfield Zoo Receiving Cryotherapy to Treat Cancer
Brookfield, Ill. — In September, the Chicago Zoological Society announced Lucky, a 47-year-old bottlenose dolphin was flown home to Brookfield Zoo to receive further testing and treatment after being diagnosed with squamous cell carcinoma, a common type of skin and oral cancer. (Lucky had been at another accredited facility in Florida since 2008.)
Upon his return to Brookfield Zoo, Lucky underwent a thorough health assessment that included diagnostic imaging—ultrasound examinations and a CT scan—at the zoo’s Animal Hospital to assess whether the cancer had spread to other parts of his body.
“Having advanced medical diagnostic imaging equipment on the zoo’s premises presents a tremendous advantage and opportunity to evaluate and monitor the health of the animals in our care. In Lucky’s case, we were able to conduct a full-body CT scan to assess his condition that thankfully did not show any evidence of cancer in his lymph nodes or other parts of his body at this time,” said Dr. Jennifer Langan, senior staff veterinarian for CZS.
Squamous cell carcinoma, which can develop in humans and other animals, originates from cells found on the surface of the skin, the lining of hollow organs, and the respiratory and digestive tracts. Abnormal cells develop into a locally invasive cancer with spiderweb-like projections that often require large surgical margins for successful resection to cure the disease. In cases where the cancer is already locally invasive or can’t be fully removed, treatment focuses on minimizing local disease and trying to prevent systemic spread.
After consultation with other facilities that have experience treating similar cancer lesions in dolphins and discussing therapeutic options with veterinary oncologists, cryotherapy, which uses a topical cold application to freeze and destroy abnormal tissue, was chosen as Lucky’s initial treatment modality.
Due to the close relationship between Lucky and the marine mammal staff, this 500-pound bottlenose dolphin is voluntarily participating in his treatments that he receives three to four times a week. During each procedure, which takes approximately two minutes per lesion, Lucky holds his mouth open while staff applies a specialized cryotherapy applicator to the cancerous tissue. To effectively target the larger areas of cancerous cells, CZS’s board-certified veterinarians have incorporated a more aggressive cryotherapy technique using liquid nitrogen into Lucky’s treatment regime. It is applied with custom-made specialized brass medical instruments, which were engineered by one of the zoo’s own welders. Throughout his treatments, Lucky receives constant praise from staff and afterwards he is rewarded with an extra special fish such as a large herring or salmon.
“We are so happy to have Lucky back at Brookfield Zoo, although we wish it were under different circumstances,” said Rita Stacey, curator of marine mammals for CZS. “Due to Lucky’s calm nature, he is making this important medical treatment easy to accomplish by being 100 percent cooperative.”
Lucky will continue to receive cryotherapy treatments, the frequency of which will depend on response to therapy. To monitor his condition, Lucky will have regular follow-up examinations and diagnostic imaging to screen for metastasis (spread) of his cancer, including ultrasound and CT scans as part of his ongoing medical care.
At 47 years old, Lucky is the sixth oldest male bottlenose dolphin in human care at a facility accredited by the Alliance of Marine Mammal Parks. While Lucky is active and playful, he does show some signs of being a geriatric animal with age-related health issues similar to humans, including arthritis and diminishing vision. For his eyes, Lucky, voluntarily receives drops and CZS staff is hopeful they will help his vision improve over time. Also, like human senior citizens, Lucky is experiencing early degenerative changes to his spine and joints that occur as part of the normal aging process.
To monitor and assess Lucky’s health and wellbeing, marine mammal and veterinary staff is regularly collecting data, including on his body condition, system functions, diet consumption, locomotion ability, cognitive awareness, and how Lucky socializes with the other dolphins, among other factors.
“Brookfield Zoo is now Lucky’s permanent home,” said Stacey. “He is such a special animal and we want to provide him with the necessary medical care to ensure he has the best quality of life during his golden years.”
At the zoo, Lucky can be seen at the zoo’s Seven Seas, along with the other resident dolphins that include Tapeko, 39; Allie, 34; Spree, 19; Noelan,18; Allison,16; and Merlin, 8.
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About the Chicago Zoological Society
The mission of the Chicago Zoological Society is to inspire conservation leadership by engaging people and communities with wildlife and nature. The Chicago Zoological Society is a private nonprofit organization that operates Brookfield Zoo on land owned by the Forest Preserves of Cook County. The Society is known throughout the world for its international role in animal population management and wildlife conservation. Its Center for the Science of Animal Care and Welfare is at the forefront of animal care that strives to discover and implement innovative approaches to zoo animal management. Brookfield Zoo is the first zoo in the world to be awarded the Humane Certified™ certification mark for the care and welfare of its animals, meeting American Humane Association’s rigorous certification standards. The zoo is also accredited by the Association of Zoos and Aquariums, Alliance of Marine Mammal Parks and Aquariums, and the International Marine Animal Trainers’ Association. The zoo is located at 8400 31st Street in Brookfield, Illinois, between the Stevenson (I-55) and Eisenhower (I-290) expressways and also is accessible via the Tri-State Tollway (I-294), Metra commuter line, and CTA and PACE bus service. For further information, visit CZS.org.