OncoVet Survivor Story: The Mystery of Mast Cells

Author: Nicole Kraft
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It was a lump, marble sized and firm to the touch, that changed my dog's life forever.

Could be a bug bite, mused the vet. It might be a splinter trying to work its way out. It could be a cyst or a skin irritation. It could, of course, be a tumor, but that was pretty unlikely.

How unlikely, though, she couldn't say, and when the lump was still there six weeks later, we opted for surgical removal. The result: a grade II mast cell tumor that, without quick action, would likely metastasize and kill what had up that moment been the healthiest dog I had ever known.

Cody is 6 years old, a handsome black Lab with a sable coat, bright eyes and the energy to run 10 men into the ground. He is ever smiling, ever playing, ever making those around him happy. At the time we had found him roaming the streets at the age of 12 weeks, I considered him a gift from above. In the ensuing years he had been the picture of perfect health-his only emergency vet visit coming when he had gotten into his bag of dog food and gorged.

At 90 pounds he was a dog who had never missed a meal, who frolicked happily every day of his life and could gallop fast enough to give racing greyhounds a go.

But then we discovered the lump.

There were actually two lumps I had uncovered, one on his right flank and one on the outside toe of his left hind foot. Dogs get lumps all the time, I was certain, and they rarely meant anything.

I nearly had heart palpitations when our vet called on a Sunday evening, almost two weeks after surgical removal. Her news: Cody's lumps were malignant mast cell tumors-the flank a Grade I-the lowest and least invasive-and the toe a Grade II. I would need to see a specialist the next afternoon to determine a course of action.

Failure to act, she assured me, would be Cody's death sentence.

Making Sense of Mast Cells

Mast cell tumors are the most common skin tumors diagnosed in dogs. They can occur anywhere, and look and feel like anything. They can be small and wart-like, spongy like cysts or hard like marbles. They can appear alone or in clusters, above the skin or below it. They can grow slowly or spread like kudzu.

Most of them are seen on the trunk and hindquarters, although they can also appear on the legs, head and neck-and certainly feet. They range in size from a few millimeters to several centimeters.

The fact that dogs develop mast cells tumors is probably not that surprising, considering they regularly have mast cells floating about their system. They are a type of blood cell, which is involved in the body's inflammatory response system. Allergies, skin irritations, wounds, tick bits all generate mast cell response.

And just like any other cells in the body, sometimes they go out of control and become what we know as cancer.

Just as mast cells are the most common skin tumors, so is the skin the most common site for mast cell tumors. But undetected, they don't usually stop at the skin level. Their aggressive nature means they can invade the body quickly, heading out to the lymph nodes, bone marrow and spleen, taking over before they have barely been detected.

They key to how fast they will move comes in the grading of the tumors by a pathologists to determine how it will behave. Grade I is a slow-growing tumor that responds well to surgical excision. Grade IIs involve an aggressive tumor often which may spread to the lymph nodes and beyond, requiring more treatment than just surgery. Grade IIIs are highly aggressive tumors with the greatest spread potential.

Excising mast cell tumors is made difficult by the necessity of getting complete "margins," not the easiest of tasks. Experts say a three-centimeter area around the tumor is required to get all the mast cells. Leaving the cells behind means leaving the tumor tentacles from which to grow back. Those margins might not be so hard to accomplish on a flank-as Cody's Grade I tumor was easily extracted. However, when you consider that the foot is a mere three centimeters wide on either side of the tumor, the challenge becomes greater.

The question became: What do I do now?

Questions & Options

Armed with as much information as I could gather in a day and more fear than I thought my chest could hold, Cody and I headed on the afternoon after diagnosis to MedVet, a veterinary specialization clinic just minutes from our Columbus, Ohio, home. Our first step after diagnosis was to determine our starting point: Had there been any spread or could we still contain the tumor where it lay?

Called staging, it consisted of leaving Cody for two hours while he underwent a battery of tests including a chest X-ray, bone marrow and lymph node aspirates, abdominal ultrasound and a buffy coat smear to find any circulating mast cells.

The news that afternoon was a mixed bag. On the positive side, Cody test results were negative, save for a small nodule they uncovered in his spleen, which the doctors felt was neither impacting him nor related to the tumor. However, the recommended course of action was rather radical-amputate his leg to the hip.

It was, the doctors said, the only way of ensuring the entire tumor was removed. There was no way to take only Cody's toe to get the required three-centimeter margins. There was no way to just take his foot or part of his leg. It was all or nothing.

There is no way to tell how a person will react when faced with a life-altering decision, especially one we must make that will alter the life of another forever. I sat looking at my friend for hours at a time, trying to envision his life without a limb and wondering how I could make this choice for him.

He would be fine, everyone assured me. Three-legged dogs get around quite well. But for someone whose life revolved around chasing Frisbees, sticks and balls, I wondered it that could possibly be true.

An alternative presented itself in the most casual manner, when a passing comment from a neighbor who happened to be a veterinary oncologist sent us on a new and uncertain path. "Have you thought about radiation," she asked casually.

Radiation had been mentioned briefly as an alternative, but there were significant obstacles. For one, the course of treatment takes place often daily and lasts about a month. Radiation is not offered at every veterinary facility-even one as large as nearby Ohio State University-and the closest recommended site for radiation treatments was north of Detroit, a distance of about five hours each way. In addition, the course of treatment costs at least $2,000-often beyond-which may be an insurmountable barrier to many pet owners.

When we figured, however, that amputation was going to cost about $1,000 and have a life-altering impacts, radiation looked a bit more feasible. And when my mother who lives in Philadelphia volunteered to take Cody for treatment at the University of Pennsylvania, it suddenly looked imminently doable.

Several phone calls later we had an appointment at the University's west Philadelphia facility for a course of treatment I had barely heard of--and prayed that it would be our salvation.

The Roots of Radiation

When cancer treatments are discussed, the three most frequently mentioned are surgery, chemotherapy and radiation. Radiation therapy, quite simply, is the use of high levels of radiation directed at a cancer site to kill diseased tissue.

Radiation is used often in conjunction with surgery, specifically when surgeons feel they have been unable to get all of the cancerous tissue. It may also be used to shrink a large tumor before surgery or even to provide an extended quality of life when "cure" is not available. With Cody we were looking at this treatment as a means of eradicating the margins of the tumor which could not be excised through surgery.

After an eight-hour drive across Ohio and Pennsylvania, Cody and I arrived at University of Penn for the first of what would amount to 14 visits to the hospital over the next month. The purpose of visit one: to find out just what we were in for and evaluate Cody for acceptance into the program.

They told me before we arrived that not all animals were cut out for the radiation protocol, and after discussing the matter further with veterinary oncologist Dr. Lili Duda, I could see why.

At Penn, radiation treatments are given in 12 small doses every other day, usually Monday, Wednesday and Friday. Other facilities will give treatments five days a week, and some four days. Sessions may range from a dozen to more than 20, depending on the size of the tumor. Weekends are given off to allow the tissues to heal and the animal to recuperate.

The radiation machine directs a beam toward the cancer and some normal tissue around it, with Penn using orthovoltage [relatively low energy] radiation, although megavoltage [high energy] is used at some other facilities. Patients may stay in the hospital for the week or be brought back and forth for each treatment, as would be done with Cody.

The animal is put under anesthesia for each treatment, which in Cody's case would last about seven minutes-there is a wide range of treatment times, depending on a variety of factors-so they may be groggy afterward. Their energy level may wane significantly by the end of the protocol as the constant drugging takes its toll. Feeding schedule must be carefully regulated before every treatment day; there may be no food intake less than 12 hours before a session.

Upon the completion of the protocol, animals suffer a radiation dermatitis, which resembles a bad, blistering sunburn. Considering the spot to be radiated was Cody's foot, he would likely lose his footpads and possibly a nail or two. Keeping dogs from licking the area is often the biggest challenge and requires long-term usage of an Elizabethan collar-a cone-like device that fits around the neck and spreads out wide all around the face. Hair loss is common, but regrowth likely would occur.

Everything Dr. Duda told us in her soothing way we knew we could live with. Once we had agreed with the necessary signatures, Cody went off for his first evaluations-a reaspiration of his lymph node and an ultrasound. Treatments would begin the following day.

The first glitch came that evening, when Dr. Duda called to say that mast cells had been discovered in Cody's lymph node-"Not a ton, but more than a few," she told us. In other types of cancer, this may have been evidence of spread. But we had to remember that mast cells are inflammatory cells, and Cody had just undergone surgery and aspirates of the lymph node. There was bound to be inflammation; there were bound to be mast cells. Our course of action would be to radiate the site, ultrasound the next set of lymph nodes in his groin to exam for signs of inflammation, and see what happened.

Treatment One

Those pet parents, who have never been in an environment such as the Veterinary Hospital of the University of Pennsylvania, should consider themselves both fortunate and deprived. Certainly it is good fortune to never have a pet suffering from a condition that must be addressed by specialists at one of the world's foremost vet hospitals. However, to never see the level of caring and professionalism in a hospital of this nature is a shame.

Truth be told, hospitals like Penn may be overwhelming on many fronts. There is constant activity, animals everywhere-people are scared, crying, or trying to do homework or business while they await life and death word regarding those they love so much.

It was into this environment we brought Cody at 12:15 a.m. on Sept. 14 for his first session. Dr. Duda's technician, Cassie Schmidt, took him from us that first day and recommended we be back in two hours. The first session is always the longest, for it takes time to line up the radiation site and mark it accordingly with the semi-permanent ink that will guide future sessions. We went to lunch, walked the campus, and came back to wait.

And wait. And wait.

All told Cody was behind the walls at Penn for four hours that day. The lymph nodes in his groin had been untrasounded and appeared normal. He had endured his first radiation session without complications, although he had been more sensitive to the anesthesia than expected. He came out groggy and stumbling. It would take some time to regulate his doses, they told me.

Just before we left I paid a $500 deposit on what would be about a $2,000 bill. We were on our way.

At my mother's house, I examined his foot, and could only see the purple ink marks that outlines the three-inch square radiation site. The foot might have been a bit warm to the touch, but he seemed comfortable and happy as he slept off his experience.

The diarrhea came the next day, Thursday, as Hurricane Floyd pounded the East Coast. It was not expected, but did occur, Dr. Duda told me. Rice and sweet potatoes became part of Cody's diet to settle a stomach upset by stress and bodily invasion.

Treatment two came on Friday. We brought him down, dropped him off, went to lunch and walked the campus. We tried to pretend we were simply a mother and daughter out for an afternoon, but Cody invaded much of our conversation and nearly all of our thoughts. He had become a focal point for a family that had been together more often in good times than bad.

We picked Cody up in three hours this time, and I stroked him as we drove through the Philadelphia rush hour. He was less groggy and had hopped easily into the car. We had a few laughs as we drove home. Maybe this whole experience wouldn't be so bad after all.

After the weekend off, it was back for treatment three, they one that would be the hardest for me. I had a life I had to return to while Cody stayed in Philadelphia. He would be my mother's responsibility from this point forward, as she and the Penn staff worked to assure us a future together.

He was extremely agitated as we waited for Cassie to take him back, no doubt feeling the anxiety I couldn't hold back. Nine more treatments seemed so long to go. There was too much uncertainty still ahead.

But he was, I knew, in the best and most caring hands. He was, I knew, where he needed to be to get well.

The reports from subsequent treatments came to me both verbally from my mother and in Dr. Duda's written discharge slips.

Each message ended with the same kind comment: "Cody was a good patient today!"

In session four they aspirated Cody's incision site because it appeared swollen. Nothing out of the ordinary appeared, but he was started by session five on a course of prednisone, working as both an anti-inflammatory agent and chemotherapy for the mast cell tumor. His dose was high: 60 mg once a day for two weeks; 40 mg once a day for two weeks; 20 mg one a day for two weeks; then 20 mg every other day for 18 weeks.

Some side effects included an increase in appetite and thirst, which, not surprisingly, meant Cody had to get up at least three times a night to go outside. And a dog who normally charted the passage of his life by every meal now became completely obsessed by every morsel, his stomach never satisfied.

By session six the swelling was nearly gone and Tagamet was added to Cody's diet to help protect his stomach against the prednisone. Sessions, seven and eight went normally, although Judi noticed a cough by session nine. After an exam, it was deemed likely allergies, as was regular licking he was doing to his front paw.

By session 10, heat had started to build significantly in Cody's foot, and it was now time for the Elizabethan collar. For every session Dr. Duda had warned against letting him lick, and a sock did the trick for weeks. However, as the heat built up and the internal blister began to form, the desire to lick would be too strong.

There were few things Cody hated more than his cone-like collar, but as with every part of his treatment, Cody got used to it.

It was amazing to me to hear the reports of my small black friend's behavior through these weeks of prodding and poking and needles and cages and cold metal tables. The dog who would growl whenever he faced our regular vet would bound into the Penn hospital. Once behind the clinic doors he would follow Cassie along like her own dog, would walk up the stairs to the treatment table and hold out his paw for the IV needle. He would position himself so that his afflicted foot hung in the proper position and wait for his nap to come.

Only when he started to awake from his anesthesia did Cody make specific wishes known: He would howl like he was being tortured until Cassie offered him something to eat.

By treatment 11 the burns began to show themselves on the top side of his foot, and Cody wore the collar night and day. He still ran on his foot, but he was a little slower, a little gentler.

Treatment 12 came on Oct. 8 at 10:15 a.m. By 12:15 he was out the door and heading home, well stocked with supplies. My mother would have to wash his foot three times each day as the burns broke through and spread.

Since we had failed to notice any significant burn in the days following his final treatment, I had hopes that maybe Cody would be the lucky one and he would avoid the painful dermatitis. Dr. Duda assured me he would have a burn-and if he didn't that was a bigger problem. A failure to burn meant the treatment had likely not been done properly.

By the Sunday after his last treatment, Cody had flecks of redness atop his foot. By Tuesday he would no longer walk on the foot as the fire erupted.

I flew into Philadelphia to retrieve my friend on Thursday, Oct.14. Upon calling my mother from the airport train station she told me his foot pads had that day begun to come off. I burst into tears on the train platform.

Those tears flowed again when I arrived at my parents home and found Cody, his eyes still bright, his coast still shiny, hopping on three legs to greet me at the door. The foot looked nasty, I will admit. It was red and pulpy on the top, and sticky with discharge on the bottom. His pads had begun to separate and a whitish marbled material appeared underneath.

But if all had gone well, the tumor was no more. If all had gone well, our mission was accomplished.

My parents and I drove Cody home to Ohio that Saturday. Pain relief came from a carefully calculated dosage of Tylenol with codein, as Tylenol may only be given for short periods of time and under the right circumstances. Further pain relief came from a sampling of homeopathic tablets and an aloe-based topical gel. He was well stocked with antibiotics to fight infection in the foot, as well as homeopathic drops to fight the effects of radiation, Chinese herbs to help his body deal with the prednisone and herbal supplements to boost his immunity.

He was restless when he got home, almost not sure where was home anymore. But when my parents got ready to drive back to Philadelphia on Monday and asked Cody if he wanted to take a ride, he huddled down in his bed and simply went to sleep. He had clearly had enough activity for a while.

What's Next

Cody hopped for about a week before he began to put weight on regenerating foot pads. The pads never did come off-they receded and grew new underneath. He wore his collar for another three weeks while we tried to keep him from licking, before progressing to dog booties and baby socks. He ultimately lost the nail on the outside of his foot, but it was growing back a month later.

Except for the shaved marks that lasted months after from his surgeries and ultrasounds-a side effect of the prednisone-Cody reassumed normal life within two months after his treatment's completion. His foot is still naked and his new pads still tender, but he can catch a Frisbee with the best of them and is still a rocket whipping through the park.

Sometimes if I suspend my conscious thought, I can imagine we are back at a time before I had ever heard of mast cell tumors or radiation, or ever considered his life without a limb.

But we are not at that point.

Six weeks after returning home I found a lump on Cody's back. We hustled off to MedVet where an aspiration revealed a fatty tumor, totally benign. But in the hours before I knew the diagnosis, I was faced with another surgery, the possibility we had metastasized, and the chance that the radiation had been for naught.

Radiation, we hope, took care of the one tumor, and we have heard several stories of people who keep having the tumors taken off and their dogs live happy, normal lives.

We also hear stories of people whose animals become overwhelmed by the tumors and ultimately succumb.

We have heard of those who never see another mast cell tumor again.

No matter how badly I wish to be in the latter group, I am aware of all the possibilities, so as I pet Cody I still feel for lumps, and I will never look at any mass the same.

Our lives have, indeed, been changed forever. But as I look at him in health, I appreciate even more every moment I spend with him. I relish each walk, play ball when I just want to watch TV, go for a walk when I would normally have sent him to the backyard, and take the extra moment to stroke his satiny ears before I leave for work.

Our lives may have been forever altered, but living through something like this has, in many ways, made it change for the better.



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