Minimally invasive technique a successful option in cancer surgery

There are many treatment options available at the Ontario Veterinary College’s (OVC) Mona Campbell Centre for Animal Cancer for companion animals in their fight against cancer. The recent addition of a specialist in surgical oncology provides one more opportunity to enhance those treatment plans.

Often there is a misconception that surgery for cancer has to be invasive, but that doesn’t always have to be the case, says Dr. Michelle Oblak, who joined OVC in September as an assistant professor of small animal surgery with a focus on surgical oncology. 

Oblak completed her veterinary degree, internship and surgical residency at OVC before going on to a surgical oncology fellowship at the University of Florida College of Veterinary Medicine. This position is one of only two surgical oncology fellowships in North America recognized by the American College of Veterinary Surgeons.  Her research focuses on osteosarcoma in dogs.

“I’m excited to be back in Guelph and to see a strong surgical oncology caseload, as well as work with other members of the soft tissue surgery service to provide cancer surgery for pets, says Oblak.

She points out there are options for minimally invasive surgery in cancer treatment that reduce recovery time, pain and enhance the pet’s opportunity for a full recovery.  “As long as these techniques don’t compromise our ability to get a cure, we are always looking for ways to decrease the impact of surgery in our patients, especially those with cancer,” says Oblak.

Case in point – Joey, a nine-year-old Border Collie, who first came to OVC through emergency services.  He was having difficulty breathing and had fluid in his chest, which upon testing, turned out to be blood.  The immediate concern was Joey had encountered some sort of toxin that was causing the bleeding, says Oblak.  He had a blood transfusion and was kept in the hospital’s intensive care unit until he was stabilized.  Working with the radiology service, the internal medicine service determined he had a tumour in his chest, but further diagnosis was required to determine what type of tumour and what was being affected.  They also evaluated him for any evidence of spread to other parts of his body and Joey appeared to be otherwise in great health. He was stabilized enough to return home and then returned to OVC the following week for a CT scan and biopsy. 

The CT scan confirmed a cranial mediastinal mass in his chest that had likely eroded through a small blood vessel, causing the initial bleeding.

“ It was determined that the tumour was relatively small and discreet – we had expected a larger tumour based on his history,” says Oblak.  

Typically this type of surgery requires an open chest procedure, which results in a longer recovery time and increased need for postoperative pain medication.  Based on the discreet nature of Joey’s tumour, the surgery team determined that he was a candidate for a less invasive technique. By using thoracoscopy, Oblak and Dr. Ameet Singh, another faculty surgeon, were able to avoid cutting bone and the majority of the surgery was done inside his chest while working with instruments from the outside.

“In this situation, since a large margin of tissue cannot be removed around the tumour, the image we get with minimally invasive surgery is actually even better than what we can see with our own eyes. Based on this view and the major advantage of decreased pain, whenever possible we hope to use this technique for these types of tumours” says Oblak.

Three small incisions were made, including one slightly larger incision on the side of the chest instead of cutting through the sternum.  The anesthetist had to collapse one lung to allow more space for the surgeons to dissect the tumour. They were then able to remove the tumour through an incision between two ribs. “It was definitely a team effort to make sure everything went smoothly,” adds Oblak.

“We are very fortunate that OVC has the expertise and the equipment to do this type of surgery,” says Oblak. These types of tumours are not often removed in this way and there aren’t many veterinary hospitals in Canada performing this type of technique, she adds. This is the first time this technique has been used at OVC to remove a mediastinal tumour, although it has been used several times to remove both lung and intraabdominal tumours. 

Oblak spoke to the owners prior to the surgery and discussed that they might have to go to an open chest procedure if the tumour was too invasive or there was a risk of bleeding. Fortunately, neither was a problem.

Joey required two days of recovery in the hospital, but could have gone home one day after surgery, says Oblak.  He also required little pain medication. 

As well, Joey only needed to be quiet for about two weeks post-surgery, as opposed to a month with open chest surgery. And, he’s recuperated well.

Joey’s tumour is suspected to be Thymoma, which is a locally aggressive tumour that rarely metastasizes. While rare percentage of dogs have a local reoccurrence with this type of cancer – most go on to live long lives, adds Oblak.  That’s the hope for Joey as well.

Dr. Michelle Oblak returned to OVC in 2013 after completing a prestigious surgical oncology fellowship at the University of Florida.