Cytoxan... how does it work?

When I started this blog, I wasn't sure if I was going to share it, I figured it would just be an outlet for how I was dealing with my best friends illness.  The more I thought about it, the more I realized that there are probably tons of owners out there that have no idea what chemotherapy is all about.  I mean, we all know that it is a cancer treatment, but what does it do to our pet's bodies?  How does it work?  Even though I have been in the veterinary field for almost 10 years now, I have only had one real encounter with chemotherapy prior to my own cat's diagnosis.  Needless to say, the treatment didn't work well and it was a long difficult battle for the cat that was fighting small cell lymphoma in his GI system.  When I was given my options for Stinky, I was at a loss.  I couldn't afford radiation, and doing nothing wasn't an option.  My decision to do chemo was a dedication to Stinky to do the best I could at helping him get through it, with his health being my priority.  This meant I was not going to just treat his cancer, but actually understand his treatments.  So, that's what lead me to sharing this journey.  I have the ability to just read veterinary journals, but I'd rather put what I find in terms for other owners to understand. 

Ok... so, what is Cytoxan??
Cytoxan, also known as Cyclophosphamide, is a chemotherapy drug belonging to a group of medications called Alkylating agents.  Apparently, this group of drugs have been around for a long time, being one of the first classes of drugs to treat cancer.  These alkylating agents work by reacting with the proteins that link up to make the DNA double helix.  The agents add an alkyl group to the proteins that bond together, preventing the normal proteins to link up like they should, causing them to break.  This leads to cell death.  Again, think back to high school biology...

G-C and A-T  (GCAT... that's how I remembered it)

Alkylation is a little more complex, but what we really need to know is that it causes the DNA helix to not coil or uncoil properly when replicating.  It is a mutation that leads to cancer cell death by taking away the ability for cancer cells to multiply.  Alkylating chemotherapy agents affect every life cycle of cancer cells, so they are quite common and effective in the treatments of many different cancers.

According to many sources that I've read, the biggest side effect in cats is inappetence, vomiting, or diarrhea (which we have been lucky not to experience).  Other side effects include bone marrow suppression between 5 and 14 post dose, and sterile hemorrhagic cystitis.  Some dogs may have alopecia (fur loss) and some cats may lose their whiskers. 

Fingers crossed!  Things are going well for Stinkeroo, lets hope it continues!

Cytoxan dose 1

Just a quick check-in... Stinky's neutrophil count was just about 8000 with a normal WBC count.  Hematocrit, hemoglobin, and RBC are still a little low, but like I said before, we are used to that... Its his normal.  Everything else looked awesome.  He is also back up to 10lbs 3oz.  All of this is really good news!   I gave him his first Cytoxan pill when I got home from a busy morning at work.  He held it down with zero problems and ate well this evening.  He is scheduled for his second dose on Monday.  Tomorrow I plan on posting a little about how this Cytoxan works in the body.  I hope everyone has a great weekend.  For all those following me that may be in the same boat, stay strong... You are your pet's most favorite thing in the world!  They want to live for you, so be their rocks.  I've seen some facebook posts about losing the battle.  For those friends, remember all the great times you had. Its not a battle lost... its relief gained.  Life is a battle that nobody will win.  Let memories comfort you until you meet your best friends again, they will be waiting for you at the Rainbow Bridge.



IN MEMORY OF THOSE WE'VE LOST



Just about 2 weeks in

Stink wasn't too happy about going to work with me today, but that made a quick 180 when he realized he was going to be treated like a king and showered with treats and a/d.  It's been 3 days since his antibiotic shot, and he looks great.  The lump under his nose is completely gone and his appetite is ravenous.  I've been cleaning his kitty acne with Pyoben shampoo, that seems to be helping too.  I'm hoping his follow up CBC shows a great neutrophil count.  I'm a little worried because Cytoxan is apparently pretty potent and can cause some serious bone marrow suppression.  The only good thing is that his neutrophils shouldn't bottom out for a couple weeks, which gives him some more time to rebuild.  Will touch base tomorrow on how well he tolerates the Cytoxan pills... please send us some good vibes!





Kitty acne clearing up

small scar under right nostril, but no lump!

End of Week 1

OK, so if you have been following, you know today was the big day as far as the CBC was concerned.  Well, the news wasn't great.  According to his oncologists, Stinky's neutrophil count needs to be at least a 2000, and his came back at just over 1300.  Mind you, when we started, his neutrophil count was just under 7000, which was only a week ago.  In addition, his hematocrit was only a 23%... we are used to him running low in that department, but not that low.  Somehow, his ridiculously high eosinophil count dropped to zero.  I'm not sure if this is a good thing or a bad thing.  Last week, Penn sent me home with his Cytoxin pills;  Stink was supposed to start these on Wednesday, but after taking to the onco's, we decided to start him on antibiotics and redraw the blood work on Friday.  With fingers crossed, hopefully he will be well enough to have his Cytoxin on Saturday.  Me, being a neurotic cat mom, drove all the way back to work to get him an injection of Convenia... this way I don't have to worry about shoving another pill down his throat.

I really admire cats because they never, ever, show us signs of weakness, but sometimes our jobs/lives would be so much easier if they did.  With the exception of a itty-bitty amount of tiredness, Stink has not expressed any feelings of not doing well.  He's eaten every meal, ran around with Penny every night, and comes running for treats (even though he knows about the pills before hand) with every shake of the bag.  He's always happy to see me and anyone else who wants to pay him some attention.  I love him so much that I'm borderline crazy... this cancer shit really sucks!

On the up side... HTTR!  We finally got one on the W side!

Day 5

Stinky has come back around.  Good appetite and good attitude.  Right before we started chemotherapy, I had noticed his right nostril was puffy and oozing plus a small bump developed right beneath his nose, next to his philtrum.  There was swollen tissue forming right where his nose connects to his face.  It was like they literally popped up over night!  Since his first injection, there hasn't been any advancement in the growths or swelling.  The areas have seemed to dry up some, so I will take that as a positive.

nasal growths in right nostril

 

Another thing I have noticed is his kitty acne is starting pop up.  I hope it doesn't get out of control...  Or be a sign of too many infection fighting cells dying.  Its supposed to be a beautiful weekend, so I plan on letting Stink lay in the open windows for as long as he so desires.

#stinkerooni

Day 3

It's Thursday, and it feels like it should be Friday.  It has been a very long week.  Being short staffed at work can really take a toll on a person, especially when it seems to be a never ending story.  Anyway, Stinky was a little stand offish this morning.  I've been feeding him a high calorie recovery diet, and he ate the small amount I put out before I left for work.  He usually doesn't get wet food in the morning, but I didn't see him much this AM since the dogs were too busy being brats outside.  Plus, he seemed to be a little off.  When I got home, he was waiting at the door, which is his norm.  As the night goes on, I'm noticing he's a little lethargic.  When he comes around, he's avoiding Penny and trying to stay close to me.  Once she gets too rough, he runs off to my room, making himself comfy on my too expensive mattress (that I'm still paying off 9 months later).  Today is the first time we've experienced a speed bump, hopefully things pick back up tomorrow.

Today at work, while assisting in surgery, I found myself discussing the chemo drugs Penn has chosen to use on Stinky.  I still haven't quite figure it out, but it consists of a combination of injections and pills.  We are staring with the COP Protocol which consists of:
Prednisone
Famotidine
Vinblastine
Cytoxin
Vincristine

None of us in surgery were absolutely sure how Vinblastine works.  So of course, the first thing I did was some research once I got home.  From what I understand, Vinblastine affects the microtubules that attach to chromatids during cell division, resulting cancer cell death/slowing of replication.  Sounds complicated, but we all sat through high school biology and remember mitosis...

courtesy of some website :)

 

 

My assumption is that the cells never get into Metaphase...

 

Anyway, tomorrow is FRIIIIDAAAY!  And I have a 11 hour work shift... cheers to it being a quick day!



Day 2

I woke up this morning and Stink wasn't next to me!  I got worried for second.  He was laying on the floor solo, which it not like him at all.  So I called him and he came running :)  nudding himself into my hair and rolling onto his back, looking for some belly rubs.
Day 2 seems to be off to an awesome start!  Stink has already been wrestling with Penny (shout out to my 3.5 legged chihuahua) and begging for treats.  I can't be anymore ecstatic... He seems to have a good appetite and attitude.  I'm not so nervous about leaving him at home alone all day while I go save other animal's lives :)