Dingus, a 17-year-old cat, was already being treated at Ryan Hospital for small cell gastrointestinal (GI) lymphoma.
Diagnosed in November 2016, he had responded well to medication, but through the following summer Dingus was slowly losing weight. He came back to Ryan for an examination where an abdominal ultrasound showed his intestinal tract was normal, but revealed something else.
Dingus had a mass in one of his lung lobes.
Longtime Patient
Dingus is a remarkable cat with an extensive medical history and two very loving owners, Christopher Lengner and Heather Steinman.
“The eye was the first to go, then the ear,” said Lengner.
In 2011, Ryan clinicians removed Dingus’ left eye due to uveitus and glaucoma caused by a Bartonella bacterial infection. Then in 2014, he developed a benign tumor in his right ear, which necessitated the removal of the ear canal. In addition to lymphoma, Dingus also has heart disease and chronic lower airway disease.
Dr. Beth Callan, Professor of Internal Medicine, has been present through most of Dingus’ maladies over the past five years.
“Dr. Callan is outstanding,” said Lengner. “She’s Dingus’ primary vet.”
When Dingus returned to Ryan for the weight loss, Callan suspected it was caused by progression of his GI lymphoma.
“My main thoughts were, did his small cell lymphoma undergo a transformation into a large cell lymphoma,” said Callan. “We repeated an ultrasound to see if the intestinal changes were more dramatic.” That was when Radiology resident Dr. Emily Elser discovered the lung tumor, a purely incidental finding. Chest x-rays confirmed the solitary mass.
“It was pretty surprising finding out about the tumor,” said Lengner. “I’m glad they found it and didn’t find any metastases. Lung cancer is usually found too late, due partly to lack of good early detection methods.”
Lengner and Steinman discussed surgery for Dingus and agreed to proceed, as his quality of life was still very good. The decision was made easier by the fact that surgeons wouldn’t have to compromise his ribcage or sternum to remove the tumor.
Comprehensive Cancer Care
Callan spoke with Dr. James Perry, Assistant Professor of Surgical Oncology, the newest member of the Comprehensive Cancer Care team, and he agreed to take Dingus’ case.
Comprehensive Cancer Care is a cross-disciplinary approach to the diagnosis and treatment of cancer in pets. Ryan clinicians provide a comprehensive assessment of each patient’s cancer care needs within one appointment. They work with clients through the diagnosis and subsequent treatment plan for their pets, be it chemotherapy, surgery, radiation therapy, or supportive care.
“One thing that is nice and unique about Penn Vet, and this certainly applies to surgical oncology cases, is that we’re considered part of the Oncology team,” remarked Surgery resident Dr. Hilary Ludwig. “It’s great to work with Oncology, share patients, and round with them. Comprehensive Cancer Care is not something other schools have.”
“Just catching the tumor early was a big component in Dingus’ case,” said Perry. “Most of the time when we see cats with this disease, it’s too far advanced to do surgery.”
Two Sides
Not only is Lengner Dingus’ owner, he is an Associate Professor of Biomedical Sciences at Penn Vet, and a cancer researcher. “On one hand,” said Lengner, “I’m the owner of a cat with cancer; on the other, I’m a cancer researcher.”
Dingus’ other owner, Steinman, is a former cancer researcher, and is now a Vice President at the Wistar Institute where she continues to focus on bringing new cancer therapies, including tumor vaccines and immunotherapies, to patients.
Lengner is a stem cell biologist with a particular interest in cancer. In his lab, Lengner studies colorectal cancer within a framework that cancer is really a disease of stem cells ‘gone bad.’ Normally, stem cells can develop into a variety of different cells within the tissues they reside to heal and repair the body. However, there is also strong evidence that stem cells are the cell-of-origin in cancer. These are the cells that grow uncontrollably once they have acquired genetic mutations.
There is the notion that cancer can be treated by differentiating the cells and not killing them. If the cancer is a stem cell that divides uncontrollably and the cell can be driven to differentiate, it’ll exit the cell cycle and stop dividing, alleviating the disease.
“In normal tissue, stem cells are resistant to injury and repopulate the tissue in the face of injury, which is a good thing,” says Lengner. “When you irradiate a colorectal tumor, by all measures it’s gone, but five or ten years later it comes back, and it comes back in the exact same place. Those cells need to be identified, purified, and studied, so that’s really what we’re interested in.”
Surgery Day
Steinman brought Dingus to Ryan Hospital for his surgery. Jantra Suran, Assistant Professor of Radiology, performed the CT scan which confirmed the solitary mass in Dingus’ right caudal lung lobe. The CT also confirmed that there were no signs of other lesions, metastasis, or fluid build-up.
Perry led the surgery, assisted by Ludwig and Intern Dr. Julie Pfeifer. Instead of cutting through the sternum, Perry was able to remove the affected lung lobe through the muscle between Dingus’ ribs. This approach reduced his pain, healing time, and hospital stay.
“Dingus did very well after surgery,” said Ludwig. “He was scarfing down food within hours after surgery. I removed his chest tube the next day and he was on his way home.”
“If you asked someone if they would consider going through the chest and removing a lung lobe from their 17-year-old cat, they’d realize age is not a big issue given how well Dingus recovered,” said Perry. “He’s just an awesome patient.”
The Penn Vet Cancer Center
The Penn Vet Cancer Center is a new initiative being launched this fall. It will bring together basic cancer research, clinical trials, and patient care into one centralized location at Ryan Hospital. In this state-of-the-art facility, scientists and clinicians will be able to bring research breakthroughs directly to patients. (Learn about the Cancer Center’s inaugural Symposium here.)
Lengner hopes there will be a push, for example, to bring molecular diagnostics into a clinical setting with the intent of identifying genetic mutations within companion animals, particularly as it relates to cancer.
“If we knew the genetic basis of a lot of these cancers that occur in companion animals, we could easily start testing these next generation drugs under development for human cancer, including many coming out of Penn Medicine’s Abramson Cancer Center,” said Lengner. “Hopefully Penn Vet’s new Cancer Center will embrace all the knowledge from the human side and try to translate it into companion animals. This is a personal thing for me.”
Perry echoed those sentiments. He would like to see more clinical trials and translational therapies available to cats.
“A lot of the initial translational therapies were developed in dogs,” said Perry. “We’re starting to see a transition to cats, so hopefully they’re not the lost soldiers in all of this research.”
Follow-Up
Dingus recovered well from surgery at home, but removal of the tumor hasn’t resolved his occasional vomiting. He’ll need to return to Ryan for more testing.
“His intestines looked normal on the ultrasound, so something else is going on,” said Lengner. “That’s going to remain a mystery for awhile.”
“Dingus is the nicest, sweetest cat,” said Callan. “I can understand why they love him so much.”
