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Czar's Medical Updates

Concerned about our Siberian Tiger, Czar? Read below for all the latest information.

10/11/99
"Czar", the Oregon Zoo's 15 year old Siberian tiger, was anesthetized last week to examine a mass that had been noticed in his mouth. Czar's keepers first noticed the mass the week before.
Biopsy results indicated that the mass is probably a malignant melanoma. Although this type of cancer can be very serious, we do not yet know its extent in Czar. Further testing (to be done soon) will help us determine this, and help us to decide on the best course of treatment.
Czar is currently acting normally, eating and playing as usual, and he is on exhibit as usual.
10/16/99
Ultrasound examination of various lymph nodes and abdominal organs has not found any evidence of development of other large melanomas in Czar's body. This is good news for Czar's current status, but he does still have cancer and his future prognosis is extremely serious.
We must now try to decide, with the help of many veterinary specialists and zoo employees, what the best plan should be for Czar. We will let you know when new information is available.
10/21/99
The veterinary staff met with two veterinary oncology specialists today to try to plan out how we can best manage Czar's malignant melanoma. Unfortunately this type of tumor carries a grave prognosis and has usually metastasized to the lungs or other tissues by the time the tumor is detected. Three options were considered:

" no treatment;
" radiation therapy of the primary tumor site (gingiva above the upper incisors) and associated lymph nodes;
" hemi-maxillectomy (removing the bone and oral tissues of the front part of Czar's snout).

After consulting with the oncology specialists and discussing Czar's case with his keepers and zoo curatorial staff, it was decided that a course of radiation therapy was the best option we had. Treating Czar's tumor with radiation is not expected to effect a cure, but potentially it will accomplish a couple of things which we felt warranted the risk and trauma of repeated anesthesias. The main objective in using radiation therapy will be to control pain associated with bone invasion by the tumor. If the tumor proves to be radiation sensitive, its expansion into the bone should be checked by the radiation. Radiation will have no effect on distant metastases, but it is expected to extend his life because it will allow him to remain pain-free for a longer period of time. The demonstration of signs of pain associated with tumor growth will be used for the end point of therapy at which time Czar will be euthanized.
It is impossible to accurately predict how much time using radiation therapy will buy Czar, but we speculate that if the tumor is radiation sensitive it will extend his life by at least three months and possibly much longer. If the tumor is not radiation sensitive this therapy will have no significant effect. We will monitor the tumor for its sensitivity to radiation and will discontinue radiation therapy if it appears to not have the desired effect. Czar's well being is the primary concern of us all and we will monitor him closely to evaluate how he is doing throughout this process.
We are planning on performing 4 radiation treatments approximately one week apart starting next Thursday (10/28).
10/28/99
Czar was anesthetized and taken to the hospital for his first radiation treatment (4 are scheduled). The 2 hour anesthesia went very well and the radiation treatment went without a hitch. The hospital staff were great to work with (i.e., they fed us chocolate) and did a real good job with what was for them a very large and orange patient. A big part of the treatment was determining the areas to irradiate and calculating doses and subsequent treatments should go more quickly. We did pick-up a fairly significant weight loss since the last anesthesia and we will try to keep as much weight on Czar as we can. Weight loss is frequently associated with cancer and may be a negative prognostic indicator.
As of this morning Czar was looking good and just a little grumpy toward the guy that darted him. We'll keep you all posted as things go.
11/4/99
Czar underwent the second of 4 scheduled radiation treatments at the hospital today. As before, the anesthesia and procedure went well. There were no signs of tumor re-growth at the original site, no signs of metastases to the lungs and no signs of side-effects from the previous radiation therapy. Czar continues to do well, is eating and is otherwise behaviorally normal. We were concerned about his weight from the last time we had him down, but this week's weight is right back up where we'd expect it to be for him. We're thinking the low weight from last week was erroneous due to scale error (not to worry, because of a generous donation from a wonderful friend of the zoo, we will have a new, much more reliablenot to mention portablescale in the very near future!). At any rate, old Czar is hanging in there and seemed to be enjoying the brief sunshine today and was out gnawing on a huge beef shank bone.
Next week is a scheduled "rest" week for Czar, so he will not have to be anesthetized again until the week after next (11/17). He'll have another treatment about a week after that one and then we will go into wait and watch mode. So far, so good. We'll keep you posted as things develop.
11/17/99
Today was Czar's third radiation treatment for the malignant tumor discovered on his gingiva on October 6. Overall, the procedure went very smoothly. As before, Czar handled the anesthesia well and recovered quickly when it was all over. There was a very strong media presence waiting for Czar at the hospital today, but everyone behaved themselves and the treatment went very quickly.
From the time Czar was initially darted with anesthetic drugs to the time he was standing and partially recovered from the anesthesia was less than three hours.
Czar is showing mild signs of inflammation on his hard palate due to the previous radiation treatments and it is believed that this will persist and may worsen following this treatment and the next one. Thus far, Czar is not exhibiting signs of discomfort associated with this inflamed area (so far, it is less than what would happen to you if you ate pizza which was too hot). His weight has increased in response to the additional calories the keepers have been giving him and his attitude appears to be holding up despite the frequent interruptions to his usual life style.
Next Wednesday (11/24) will be the final scheduled radiation treatment. We will radiograph his chest again to check for signs of tumor metastases and draw blood to see how well his other organ systems are holding up. After next Wednesday's treatment most of the follow-up monitoring will be done with the help of the keepers and behaviors that they've trained Czar to do. Through the use of training we should be able to inspect his oral cavity without anesthetizing him.
11/24/99
Czar underwent his final radiation treatment today for the malignant melanoma tumor discovered in his mouth in October. Aside from being stuck in a major traffic jam on Highway 217 on the way to the hospital, the procedure went very smoothly. The tumor site in his mouth is showing no signs of regrowth and there was again very little inflammation at the sites of radiation. Czar continues to eat well and gain weight. He will be closely monitored by the keeper and veterinary staff for any signs of discomfort, distress, or tumor regrowth. We are all happy to give him a break from the almost weekly anesthetizations; probably none so much as he.
2/5/00
Czar, continues to eat well. His whiskers are growing back in, all short and stubby. Only one whisker remains from before radiation. His gums look pink.
4/14/00
Following keeper reports of inconsistent training and appetite and the observation by keeper Diana Bratton of unusual red streaks on the roof of his mouth, we anesthetized Czar, the zoo's only Siberian (a.k.a. Amur) tiger for a recheck examination last Tuesday (4/11). The examination consisted of a physical examination, radiographs of his head and chest, and blood work. Czar had been diagnosed with oral malignant melanoma 6 months ago and underwent radiation therapy to try to slow the spread of the tumor.

On oral examination we confirmed Diana's observation of the red streaks which looked like two linear ulcerations running along either side of the roof of his mouth. It looked like he had swallowed a sharp rock or eaten too-hot pizza. Dr. Harrenstien biopsied these lesions and we submitted the biopsies to a zoo pathologist for histological examination. Czar also had moderate gingivitis, but the original tumor site looked normal.

The pathologist's preliminary report was e-mailed to me today and indicates that the oral lesions represent local extension of the original oral tumor. This is sad news for Czar and the rest of the zoo. There really is no further treatment we can recommend for Czar at this point. The veterinary staff will work closely with the curatorial and keeper staff to monitor Czar's level of comfort. When we all agree that Czar's quality of life has diminished to an unacceptable level he will be anesthetized one last time and euthanized.

It is difficult to predict how much time Czar has left. His body condition is excellent (his weight is at an all time high) and he shows no radiographic signs of spread of the tumor to his skull (which is painful) or to distant organs (lungs, especially) so it really depends on how quickly the tumor grows from here on out and how Czar responds to its growth.

We will continue to keep you updated as new information is available.

Learn more about Czar and other Siberian (a.k.a. Amur) Tigers.