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Canine Mast Cell Cancer

Here we go again, panic time. But this time, I'm gonna put all the links at the TOP of the page and spare you all from having to scroll scroll scroll through my ramblings like on the melanoma page. Check that page for more general info and skin cancer references, this will probably be more specific. These links will get more organized eventually.

Links have now been moved to Robin's Canine Cancer Files at:

Friday 9/20/02
I noticed a bump on Leilah's belly, below her spay scar. Ahhh, just a bug bit probably. About a week or two later, it bled, making me even more sure it's a pimple or bug bite. But, being the ultra paranoid dog mom I am, since it was no smaller, I took her in last Tuesday. I've learned that if my vet even slightly suggests additional tests, do it! It's paid off way too many times before. While writing the check for the needle biopsy, I was joking this would be the world's most expensive zit, I was 99% sure I was just being too paranoid this time.

Yesterday I got the results over my fax at work (my vet's office staff now automatically faxes me any test results). I burst into tears when I saw the words Mast Cell. Talked to the vet, surgery is next tuesday, appt with vet onco is in a couple weeks - the first day she's in town after we will hopefully get the full biopsy back. After the problems we had last time (granted, melanoma is tougher to diagnose), I've already requested that the sample get sent directly to the dermatopathologist. 

Last year was apparently a dry run, after all, the diagnosis did get revised from malignant melanoma to melanocytoma - a precancerous tumor that runs in Vizslas. (Leilah's mother is a purebred Vizsla and did have tumor problems, but I don't know what kind). So, I guess I'm probably a bit better prepared than most, already got the vet onco's # in my rolodex at work, etc... I know there's way worse cancers out there, even melanoma is usually more severe. But it's still scaring me out of my wits. 

The surgery will be the most major she's ever had. He needs a real wide margin for this one, at least 3cm (about 1 - 1 1/2"?), if not more,  in all directions. Gonna be quite a hole, I'm sure it will be at least slightly disfiguring. Because she's so skinny with a severe abdominal tuck up, there's almost nothing behind the tumor that's not major, getting 3cm there might be impossible. This may be a big problem. All I can do for now is read and panic.

My brain is racing mile a minute, thinking of all sorts of things, some important, some not. Managed to pull my entry from the trial in a week, they'll send me back my fees (thank you AVASA!). She's crate phobic so how am I gonna keep her quiet after surgery? Will my boss tolerate me bringing her with me every day? Gotta get the e-collar dusted off. 

Sunday 10/6/02
Oh man, what a couple weeks!

Leilah had her surgery on Tuesday the 24th. Because of the wide margins required, he took out a half pound of wonderpuppy. Turns out there was quite a layer of fat behind it so he was able to get the recommended margins all around. It included a lymph node and 2 mammary glands too. The incision is about 6 or 7" long, it's all quite a bit on a dog this size, but it looks like she'll probably only end up with a small divot in her belly when she's done healing and who counts mammary glands anyway?

Because of it being mast cell, she was given a dose of benadryl prior to surgery. We had taken presurgical xrays, and in the later shots you can see her spleen where you couldn't before. The vet said this is a normal reaction as the benadryl starts working, but we need to make sure anyone else who sees these films is aware of this. 

The first couple days were the roughest.  I had stayed with her through the whole thing. In recovery, she did not want to get up. I finally asked her to get up after almost 3 hours, and after one stumbling step she was walking pretty steadily. It was very difficult for her to assume the position to pee or poop, she didn't defecate at for almost 2 days. 

I did take her to work for the rest of that week, not only to keep her quiet, but also to keep clean the drains the vet put in her.  He had me use hydrogen peroxide for that. Fortunately everyone was real nice about her whining in the crate pretty well, since their shift ends within a half hour of when I start, they didn't have to put up with it much. I work 3pm to 11:30 pm and after a couple hours when it looked like no one from other departments would not come in,  I could let her out. She stayed quietly on a crate pad while I worked on a computer or just followed me around. I kept a lot of towels handy, not as much for dripping from the drains, but so she'd have a cleaner place to sit or lay down (the tile floors there are far from hygienic).  She was on keflex antibiotic, as well as codeine for pain and a half dose of acepromazine tranquilizer.  But since being buzzed and more pain free didn't seem to slow her down much, I stopped the codeine on Friday and the ace on Saturday. I could tell no difference in her behavior. 

I had been sleeping with her on a leash a lot, even having the leash wrapped around my wrist when asleep. Keeping her from jumping around is a very tall order. I built steps for her up to my bed, but she really didn't want to use them after the second day, I had to order her too use them. I had used cardboard to block off the bed and steer her towards the steps, ranging from 32 to 36" tall (she's 20" tall). On Thursday night (day 3), she'd jumped down over the barrier. On Friday night, she nicely jumped UP over it from a stand still on the floor, at the tallest part too, elizabethan collar and all. I think she may have been making a point.  Heck, I did have to go to the bathroom or take showers, that's why she was unleashed both those times when she looked asleep (but she sure wasn't asleep when I came back). The vet wasn't worried about it since the incision still looked real good on Saturday. At that point, having free access to jump onto my bed was less dangerous than going over the barriers, so down came the barriers, and the steps too since she was jumping over THOSE now. Not an easy patient!

The reports came back with great news! The pathologist called it a "complete local surgical cure". It was well differentiated with no mitoses (no dividing cells - it wasn't growing). Grade 1. The lymph node had no mast cells. The Buffy Coat Smear, a blood test, also came out negative for mast cells. It was  the best possible results!

There was one problem with one of the drains, not only was it not draining, but it seemed to be irritating the forward part of the incision. The drains came out on Saturday. By Wednesday, she had quite a pocket of something in that forward area, it hung way down too, very weird looking.  I didn't know if it was a hernia or fluid or what. It was just fluid, on Thursday the vet took out quite a bit and it's been much better since. He  thinks the stitches should stay in a bit longer since this was such a major surgery, but I'm not sure when this will be. We'll see him again on Tuesday, the 2 week point when the stitches would normally come out, and he'll drain it again if nothing else. He'll have a better idea then when it will be done. 

Later on Thursday, we saw the oncologist. I'd made the appointment immediately when I got the results of the needle aspirate biopsy. At this point, with all those great results,  I fully expected it to be completely uneventful. I was NOT expecting her to take a look at Leilah and say "chemo"! I was caught so off guard, I didn't ask very good questions. But her main concerns are the location and last year's benign tumor (see Melanoma). Mast cell tumors in the groin are considered more dangerous. It would be 10 sessions, 3 weeks apart, about 8 months total with vinblastin, cytoxin, and prednisone. We will do more tests, but she thinks Leilah should get chemo even if they are clean. This is what she'd do if Leilah were her dog.

I cannot find much in my reading  to support giving Leilah any chemo. The indications for further treatment are incomplete surgical removal, reoccurring tumor, any sign of spread in lymph nodes or anything else, or high grade/poorly differentiated. Location itself does not seem to be a criteria in anything I've found, unlike melanoma. The onco says it's a bad spot because of the way the lymph nodes drain there, but a lymph node removed from there was clean. Small Animal Clinical Oncology book (see above for book info) says it's because tumors there are often poorly differentiated. Leilah's was well differentiated. Recurrence is another maybe here too, how is that defined?. The literature I've found is referring to a recurrence of a mast cell tumor, usually mentioning that it's in the same location. While this is Leilah's second tumor, it's her first that's mast cell and it's not in the same location as the melanocytoma she had last year. So, depending on how you define recurrence, Leilah meets none of the criteria for further treatment so far. I realize medicine is often more art than science, but this is making me nuts.

I've spoken to my regular vet and am getting second opinions. He wouldn't do it. He also thinks it's debatable that this was actually in the groin area.  I think I should have taken a photo of it before surgery, but of course hindsight is 20/20. He's consulted with the onco guy at the local VCA  hospital (I've discovered it's apparently their flagship facility). Though not board certified, I've found he spent a few years at Tuft's vet onco dept. and has published on other cancers. The VCA vet wouldn't do it either, assuming all the rest of the tests come out clean, and he considers himself "aggressive" for treatment. We will see him next Tuesday and see if his opinion changes. I hope to get a third opinion from another board certified onco too, but if so, it will probably be a phone consult only. 

Of course there's always the matter of the further tests. Next Thursday, Leilah will get a spleen biopsy, an bone marrow biopsy, and ultrasound. If anything shows up on those, that may change things. The bone marrow biopsy is supposed to be more accurate than the Buffy Coat Smear for finding some problems beyond the initial tumor. They will give her a general for the marrow biopsy, this won't be something quick, so I've managed to get the day off (quite a feat too!). 

I've shed a lot of tears in the past few days over this. I feel damned if I do and damned if I don't. 

In the meantime, all I can do is let Leilah heal and continue reading things. She's not eating quite as much, but I think that's all behavioral. She can't do her "roman dog" nibbling while lying down with the elizabethan collar. Poor girl has to stand up to eat now if she wants to play "defend the bowl" with my other dog . He does not have access to her food since it's up to high for him, on my bed, but his proximity often triggers this. She's lost about a pound and a half including what he took from surgery but is still within normal limits for her, she was a little bit heavier than usual before the surgery, almost 34.5 lbs. She bashes that ecollar around like it's not there, and even gets it under the comforter. She can get it through the dog door I put in the new screen door too. I do take it off her for several hours every night , now that the incision isn't topmost on her radar. I hate that thing more than she does I think, she's always hitting me in the head with it too. What a way to wake up! Her style is only a little cramped, she's otherwise acting totally normally. 

Before the surgery, I had been asking around about prednisone, a steroid often used for Mast Cell, with or without other drugs, and it's a drug I find quite scary.  If Leilah was going to be given anything at all, it would be prednisone.

Tracy the Vet Tech had given me some good info, and she's given me permission to use it here.

NOTE: Predinsone is often NOT recommended for many cancers. It can make things worse. ALWAYS check with your vets. Mast cell cancer is often one of the exceptions.

Pred is a protocol approach in almost every case of tumor/cancer. Pred can greatly reduce inflammation and to some degree, reduce and shrink the tumor in cases where excisions are necessary. Pred also has the benefits of pain relieving, appetite enhancing, and nothing else can beat it's benefits.

Every drug has it's risks, every drug is a potential side effect. But, without it, a tumor will progress twice as rapidly, pain will be twice as much, and inflammation will always be there to cause worsening problems.

Your vet will take every precaution when prescribing prednisone for Leilah, he will perform regular blood profiling, (CBC's are imperative with pred treatment), and he will start her on a high-end dose, monitor her and will probably gradually decrease the dose to a maintenance schedule, or, based on Leilah's signs, CBC results, tumor progression, etc. 

Please try not to fear this medication as much as others would have you believe. Without prednisone, many cancer patients would never have extended lives and/or comfort levels. Used in combination with chemo gives many added benefits, just ask your vet, he is completely willing to discuss these issues with you, and he understands your apprehension and fears and concerns........................Traci


Because of the costs of chemo therapy or radiation therapy, many pet owners opt out of chemo therapy, therefore, prednisone becomes the main protocol in treatment. It is not a cure, it is an approach that has many benefits, as described earlier.

A biopsy helps with staging of the tumor. Staging tells your vet more about the dosing necessity of all meds or combo meds. If excision is preferable, even if the lump is small, it is best to excise when any tumor is less than 3 cm, ideal at first recognition. However, some vets choose to treat prior with prednisone to help shrink the tumor before removal. When in surgery, the vet can then get a wider margin and try to get all surrounding tissues out (encapsulization). Pred is continued to help both concurrent inflammation as well as help prevent matastisis or, slow the progression.

It wouldn't be unusual for 40 mgs BID (BID is twice daily, total of 80 mgs). In cats, we can go as high as 20 mgs daily, but usually, we maintain at 10 mgs. Your vet will want to start Leilah at a high dose to get the most added benefit and to gauge response, but will eventually taper it to a low dose for maintenance. Kevin Hahn's protocol is one of the most widely used in the nation, his and the U of Wisconsin and CSU (Colorado) are the only ones to my knowledge that share the same protocol, but they differ for each pet, as does chemo therapy. There are several protocols (as you've seen at Kevin's site), that can be applied, but your vet wants to tailor it to Leilah's individual needs. He will then closely monitor her, her response, the site of the tumor or excision site for any new development, and will want you in frequently to check her platelets and do a CBC while on pred OR chemo.

As for blood, your vet will be looking for high counts of blood cells or decreased/red blood cell production, indicating anemia or poor response to treatment. It's more risky with chemo, because chemo is actually a toxin that is used to destroy cancer cells and every protocol for chemo has it's risks and possible failures (side effects, over-toxicity, etc). Pred can actually help bring up platelet counts in some cases of anemia, making it a lifesaver, in other cases, pred must be ceased and an alternate med chosen along with other supportive care methods.

If your vet is contemplating surgery for Leilah, and subsequent chemo, he can consult with any of the veterinary universities mentioned for a protocol that will best benefit Leilah, but it may have to be modified based on her response, and pending any side effects and results of concurrent CBC's etc. If pred is going to be used without chemo, your safest bet is to start at a fairly high dose, get a blood panel done in a week or two, and take it from there. You'll want to carefully monitor her at home and watch for any signs of side effects such as decreased appetite, lethargy, fever, or infections that may or may not be associated with the tumor. With chemo, the side effects are numerous, but most patients tolerate it fairly well. It all depends on the stage of disease, and any associated conditions or internal problems.

To help calm your fears, ask your vet about a total blood profile that includes the thyroid function. Chances are, she is an ok candidate for prednisone therapy. Try not to fear so much, pred can be a lifesaver in cancer cases, and in many other cases of severe illness. That isn't to say it's a drug without caution, because it isn't, but the safety margin is fairly good for it's intended purpose.........................Traci 

I don't know which page on Kevin's site you were referring to, but he was probably basing the dose on a 50-100 lb dog. If Leilah is less than 50 lbs, the dose of course, will be smaller.

Just an example, for anti-inflammatory treatment, a 40-50 lb dog can tolerate median, 40 mgs per day. For immunosuppressive treatment (as in anemia, autoimmune), the median might end up at 90 mgs per day, depending on the urgency and situation.....As Davet said, it needs to be dosed carefully and used responsibly, but I'm confident your vet has had years of experience with this.....................Traci 

[note: I had been very worried about large doses of 40 mg that I saw on a doc's page, but it turns out Leilah would get 20 mgs at first then it would be dropped to 10]

On after care for the incision, I'd asked what to expect since I knew Leilah would be a tough patient.  Among other things, I had also asked about using betadine solution since I have a lot of it:
Betadine would be ideal to flush wounds with drains, but nolvasan is better for incision sites. Some pets have reactions to iodine-based products, so betadine should only be reserved for severe infections or flushing open wounds. Iodine can also harm sensitive tissues if used for a prolonged period of time. Your vet may actually use the betadine as a pre-surgical scrub before surgery, but just my opinion, I like nolvasan better.

Nolvasan is a surgical scrub, a fantastic aeseptic. It's mild and gentle on the skin and is effective for warding off infection at the incision site. Your vet will probably have Leilah on a short course of antibiotics or a good dose initially with Pen-G, so this will reduce the chance for infection.

I'm also not too hot on bandaging incision sites, but when necessary, they can be effective for obnoxious dogs. It also depends on the area, and how wide the incision is. If it's huge, then bandaging to protect the area would be fine as long as the bandage is cleaned and changed twice daily.

Again, I doubt she is going to feel too active after surgery, given the location, and that e-collar will be necessary to prevent her from licking the area, and from pulling out her sutures or staples. Your vet will want to remove her sutures in roughly 10 days, so at least it's not too long to have to keep an eye on it.

Jumping shouldn't be a problem, it's difficult to keep any dog from jumping, I'd simply suggest you keep pillows on the floor in the event she misses due to pain. Or, you can construct a doggie ramp using a simple step stool (I like rubbermaid's, they are one or two-steps, sturdy plastic and easy to store away when not in use)...........................Traci
 Thanks Traci!


Leilah had her biopsies this week. Tough day, I was not allowed to be present and I could hear her crying while I waited, but even tougher for her. She was very unhappy for about a half hour total, but I guess it was worth it. The tests told us that there's no sign of disease. She had a bone marrow and spleen biopsy, as well as ultrasound of the lymph nodes, and all looks good. The oncologist still wants to do chemo though. 

So far I've gotten several opinions from several vets. We did go to the one at VCA, who while an oncology specialist, he is not board certified. He does not think Leilah needs chemo, but it would be "safest". Chemo safe?? He consulted with the other specialist there and she agrees. My regular vet discussed this wth an "onco vet" at the lab, and that vet says the same, she probably doesn't need it. Add the holistic vet's opinion, and there's 5 vets who say she PROBABLY doesn't need it. Not definitely, and none of those vets are board certified like the first onco. The big problem is there's no studies for using chemo in this situation, this is where medicine is more art than science. Everyone has to go by experience and gut feeling. 

Since Leilah is not showing any sign of cancer now, this buys me a bit of extra time before I have to make a decision. My panic has settled down to a quiet roar. I am trying to contact a board certified onco vet in Houston, who is a friend of a friend, and get an opinion from him. In the meantime, I'm still trying to find numbers, odds, etc. Latest thing I've found is an abstract stating:

Recurrence rates and sites for grade II canine cutaneous mast cell tumors following complete surgical excision.
A retrospective study was performed on 31 dogs with completely excised, grade II, cutaneous mast cell tumors in order to determine recurrence rates and sites. Distant tumor recurrence developed in 22% of dogs, and local tumor recurrence developed in 11% of dogs; however, the vast majority of these animals were incompletely staged initially. Complete surgical excision of grade II mast cell tumors was associated with effective local control in 89% of these dogs. Therefore, adjuvant radiation therapy might not be indicated in the majority of dogs with complete surgical excision.

Unfortunately, I have not found what study this is from, it's for grade 2, not grade 1, and it's a rather small sample of dogs. The first oncologist says that there is a 15% chance that a dog may have some problem with chemo. But, the numbers for or against chemo seem like they're close no matter how I look at  them. The VCA onco specialist vet did say that in this location, he usually automatically notches it up a grade, but he also says Leilah's tumor truly is a grade 1 and it did not sound like he was comfortable assigning it the higher grade. The tests since then back that up too.

We also saw the new holistic vet this week for nutritional info. She recommended against chemo, no surprise there. She said Leilah's diet was already a great start, and added lots of supplements to it. It's gonna take some time to get it all in place, I can't give it to her all at once, but we're working on it. I'll make the update to Leilah's food page soon I hope. So far Leilah isn't complaining, if nothing else these cancer problems make what's in her food bowl more attractive! Poor Copper has been getting a bad deal here, I've been so distracted, I ran out of homemade food supplement for him. I tried a pre-packaged raw diet food for him, but it made him pretty sick even though it was only a fraction of his diet. He was fine after a few days and taught me to pay more attention to the freezer contents! 

Her incision looks much better, but my regular vet still mentioned correcting one area though he thinks in time it will go away. The top end of the incision is like a dressmaker's dart, there's a teeny little pucker there almost like a belly button. I couldn't care less how it looks, and I won't subject her to more surgery over it, just I'll have to keep it clean if it doesn't go away. I'm putting aloe on the scar, and vit E when I remember. he's not complaining, any excuse will do for a belly rub. The bone marrow site is bugging her a bit, but I think it's just itching - there is a small scab there. 

We're off to the dog park, we all deserve some fun about now! 

Oh man, I need to update here. I got too distracted last year. Leilah's been doing great, no signs of reoccurance. 

Every three months, she's gotten a blood panel, CBC and buffy coat smear, abdominal ultrasound, a spleen biopsy, as well as a checkup by both my regular vet and the oncologist. Everything's been normal. But what's been really cool is with her diet over the past year, her blood values have been the best they've ever been. While we still have her official one year checkup in a couple weeks, I don't expect anything unusual (famous last words!). After the one year onco checkup, I will also take her to the holistic vet for any diet modifications. 

I have also finally found docs who'll let me be present for her ultrasounds and spleen biopsies. As I suspected, with me present, there's no crying, no struggle, not even a blink. She does glare at me a bit when they insert the needle for the biopsy, but that's about it. The hardest part really is getting her upside down in that V shaped cushion they use, she does hate being picked up. The ultrasound is bascially a lubed belly rub and she has no problem with that part! 

Most vets won't let owners in with patients for procedures for various reasons. At least here in California, an owner can sue the vet if their own dog bites them while under duress during an exam, so it's a big liability risk for the vet. Also, many dogs and owners don't behave as well together as when separated. But with my regular vet willing to vouch that we are extremely bonded, we are well mannered during procedures, she's better when we stay together, which of course makes it easier for the vets, I did finally find someone who'll work on her with me there. Did I mention it's 40 miles one way in L.A traffic to see this doc? Definitely worth it  to not have to hear Leilah scream again.

My vet did go back and fix that "dart" when she had surgery on her foot to remove a suspicious lump that turned out to be nothing tumor related. It would have been difficult to keep it cleaned out and prevent skin problems. The shape of her belly in her lower abdomin isn't the same as before all this started of course, it's like she had a partial tummy  tuck, but it's not a problem. With the quarterly ultrasound shave, people keep asking if I just got her spayed. 

She turned 7 a couple months ago, my baby's growing up! Now her only limitations are from her ortho problems (tricky knees) and avoiding junk goodies. She's happy and healthy, blowing trials in the obedience ring like usual, plays with my chickendog aussie, and at the moment, she's snoring in my lap. 

Leilah has been doing very well, still no signs of recoccurance at all in 18 months. Her most recent cancer checkup was earlier this month, it included a full blood panel w/ buffy coat smear, abdominal ultrasound, spleen aspirate biopsy, and a full urinalysis (sterile sample). So far so good!! We'll do it again in 6 months. If all is still well at the 2 year mark, we'll then only have to do this checkup once a year. 


So far so good! She did have a mast cell re-occurance on her side in the summer of '04 at 7 years old. Again I found it very early when it was still very small. Surgery again was all she needed and it was a huge incision to get the margins, but you have to pretty much look for the scar. She goes for followups 2x a year. We've had a couple of false alarms that turned out to be lipomas or skin tags. Now 12, she still has fun in agility class every weekend.


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Last updated 6/3/09