Simba was referred to the renowned Southfields Veterinary Specialists, in Essex, suffering from right-sided heart failure causing severe abdominal swelling. James Elliott, head of radiation oncology at Linnaeus-owned Southfields, took charge of the challenging case and decided on a rare form of treatment to save Simba from the huge tumour found on his heart.
James, a dual specialist in medical and radiation oncology, explained: “We carried out a CT scan which revealed a very large mass arising from the heart, a marked compression of the large blood vessels and litres of fluid in Simba’s belly. There were also some suspicious lymph nodes in the chest which were concerning for tumour spread.
“The diagnosis was consistent with a type of tumour called chemodectoma, sometimes just called ‘heart base tumours’, so the oncology and radiation teams combined to discuss potential treatments.
“Needle aspiration can be performed to take some cells from these heart masses, though this isn’t commonly performed as they are very deep within the chest and so difficult to access. There are also risks associated with tumour sampling. Therefore, in most cases, the diagnosis is presumptive based on the tumour’s appearance on ultrasound/CT.
“There is a type of chemotherapy called toceranib phosphate (Palladia) which has provisionally been shown to be effective in stabilising these tumours, and reducing the fluid build-up associated with them. However, only in around 10 percent of cases do these tumours measurably shrink.
“For some dogs, this might not be an issue, but for Simba we really needed the mass to shrink significantly to take the pressure off the large and important blood vessels and reverse his heart failure. This is where radiotherapy can be so useful, although for most pets it needs to be given daily for two to four weeks. Each dose is given under a short and light general anaesthetic, which has to be taken into account.
“For most dogs, this is fine, but for Simba it could have proven much trickier or even life-threatening. We discussed it all with Simba’s owner who was very committed and wanted us to proceed with the course of radiotherapy.”
Southfields is one of only five dedicated veterinary radiotherapy centres in the UK and one of only two that could treat such a complex tumour as Simba’s.
It is also the only oncology service that has two, full-time dual specialists in both medical and radiation oncology, James and his colleague Sarah Mason, who is Southfields’ head of general oncology.
One important consideration for James and the Southfields team in Simba’s case was the sensitivity of the heart and lungs to radiotherapy, so treatment was planned with extreme precision and a lot of thought, to ensure the organs could cope.
James added: “Radiotherapy for heart tumours is almost never performed in the UK but we took extensive measures to devise a method specifically for Simba. He was medicated to help reduce the risk of his lungs being damaged by the radiotherapy and, with the expert support of our specialist cardiology and anaesthesia departments, he tolerated the treatment well.
“In Simba’s case, we decided on 10 treatments given over a two-week period (one treatment per day) with the heart tumour and the suspicious lymph nodes treated simultaneously. It was an intense period and extremely worrying for Simba’s owner, especially on one occasion during treatment when Simba had 11 litres of fluid drained from his abdomen.
“Fortunately, he had minimal side-effects and seemed to have responded well to the treatment, so we were pleased to allow him home and we were thrilled with a recent follow-up CT scan. This revealed the mass had shrunk by more than 50 percent in volume with no evidence of tumour spread to other organs.
“There has also been no further build-up of abdominal fluid and, happily, Simba is now enjoying an excellent quality of life at home where he is doing fantastically well.”
Simba’s successful treatment showcases Southfields’ multi-disciplinary expertise, with input from multiple specialists from medical and radiation oncology, diagnostic imaging, cardiology and anaesthesia helping achieve such a positive outcome.
Southfields, which is moving to a state-of-the-art new £16 million site in Basildon, Essex, later this year, offers a range of specialist-led services including anaesthesia and analgesia, cardiology, dermatology, exotics, internal medicine, neurology, oncology, radiotherapy, ophthalmology, orthopaedics and soft tissue surgery. This will include a Varian Truebeam linear accelerator, which will be the most sophisticated radiotherapy unit in the UK. For more information, visit their website or search for Southfields Veterinary Specialists on social media.
