Photodynamic therapy for squamous cell carcinoma and other tumors
Question: Why doesn't Dr. Mike advise owners of cats diagnosed with squamous cell carcinoma about the new photo dynamic therapy being used?? My cat has a small lesion on the tip of his nose and was taken to Oklahoma State University, where they are carrying out a clinical study on PDT with great success. (Other facilities around the country are also using PDT with success, as are human medical facilities.) It bothers me to read so many questions from owners with cats that have similar lesions and know that they are not being advised of this ground-breaking therapy that could save their cats lives!
Photodynamic therapy is a relative new procedure in veterinary medicine. It is considered to be promising for the treatment of superficial cancers, such as squamous cell carcinoma. Early studies of the response of cats with squamous cell carcinoma (SCC) to photodynamic therapy were only moderately successful (Peaston et. al., 1993) but more recent studies using newer photosensitizers seem to be more successful. This is an option for treatment of squamous cell carcinoma and other tumors, such as fibrosarcomas, that tend to occur on or near the skin surface.
Photodynamic therapy requires the use of specialized equipment and is not easily available in all areas of the country. It appears to be a viable option in areas in which it is available, though.
Mike Richards, DVM 9/14/2001
Squamous cell carcinoma of the esophagus - Radiation therapy
Question: Hi Dr. Mike,
I wrote you earlier this week about Cosmo the wonderful pet therapy cat. His biopsy came back indicating squamous cell carcinoma of the esophagus. According to the vet who did the endoscopy, chances of recovery through surgery or chemo are slim. She suggested exploring whether radiation is being done for this as it is in adult humans. Do you know? Also, is there a pain medication that he can be on while he's still eating that won't further irritate his GI tract? Karen
Answer: Karen -
According to Stephen Withrow in the book "Small Animal Clinical Oncology", radiation therapy of the esophagus for squamous cell carcinoma is possible if the tumor is in the portion of the esophagus between the mouth and the point where the neck meets the chest (the cervical esophagus). If the tumor is in the portion of the esophagus running through the chest, radiation therapy is not possible because the lungs and heart can't stand the amount of radiation necessary to treat the esophageal cancer. Dr. Winthrop agrees that chemotherapy and surgery are both poor choices, although surgical removal of the esophagus and implantation of a gastric feeding tube is possible. It just doesn't seem like a good long term solution due to the strong likelihood of complications developing with the feeding tube.
Fentanyl patches (Duragesic Rx) are very good for long term pain relief in cancer patients and since the medication is absorbed through the skin it shouldn't cause any complications with the esophageal cancer.
I wish that there was a better answer to your question.
Mike Richards, DVM 7/27/2001
Squamous cell carcinoma of nasal passages
Question: Dear DR:
My 18 and a half year old female kitty (Skeeze) was just diagnosed with Squamous Cell Carcinoma. Other than periodic weight loss with some vomiting and intermittent diarrhea over a 3 year period, she had exhibited no symptoms. As a full sister to my other kitty who has hyperthyroidism, my vet always did bloodwork to see if this was causing her to lose weight - but no problems ever came to light. 2 weeks ago, the right side of Skeeze's face appeared misshapen......seemingly overnight. Subsequent x-rays indicated extensive bone destruction of the upper right maxillary, the zygomatic arch (spelling?) etc. Additional radiographs done by the vet oncologist group showed no metastasis into her chest or abdomen, but her lymph nodes were not checked. Biopsies indicated SCC. Because of the large area affected, surgical excision is not an option. At this point in her life, neither is radiation and/or chemo since the most I could hope for after all that is another 4 to 6 months. We've elected to continue antibiotic treatment in conjunction with an opiate to alleviate her pain. Hopefully this won't make her a little zombie. When she stops eating or can no longer eat, it will be time to "let her go". I guess the reason I'm writing is to ask is there anything out there (other than a miracle - and I still hope) that could save her? I know I've had her for 18 1/2 years, but it seems like only yesterday. And my heart is breaking. Am I doing the right thing for her? Thank you......Paula
I do not know of any new treatment options for squamous cell carcinoma (SCC) of the nasal passages in cats. It is important to try for good pain relief and if there are secondary infections the antibiotics could help a lot. Radiation therapy can provide relief from pain associated with intranasal tumors but my understanding is that this treatment is less than reliable for SCC of the nasal passages in cats, helping some but not all cats. You may or may not be comfortable with implanting an esophageal feeding tube or gastric feeding tube, but oncologists really support the use of assisted feeding and report a great increase in comfort and general well being in patients with some sort of assisted feeding mechanism.
I wish that I did know something else you could do for Skeeze.
Mike Richards, DVM 11/4/2000
Squamous cell carcinoma
Question: Dear Dr. Richard's.
My cat Joe and I have been buddies for the past 9 years. I recently had him in to see the Vet for a check up and a teeth cleaning. The Vet pulled 2 teeth and discovered a tumor in Joe's jaw. The Vet did a biopsy and it came back as Squamous cell carcinoma. Could you please tell me if the are any types of treatments that are non-evasive that has been successful. Surgery is definitely out of the question. Joe still has huge appetite. But is starting to keep to him self. Joe weighs in at 17 lbs.
Thank you, Vincent
I think that the answer to your question depends on your definition of success and your definition of non-invasive.
Radiation therapy in combination with chemotherapy does seem to extend the lifespan while providing a reasonably good quality of life in cats treated with both therapies. The average lifespan is reported to be six or seven months with this sort of treatment (this is from some fairly old notes but I think it is still true). I think of radiation therapy as being invasive but if it is more acceptable to you than surgery, it is an option.
I wish that I could give you better news. This is a very devastating cancer. I have met a couple of oncologists who work (or worked) at the Animal Medical Center in Manhattan and they are very well respected in the veterinary profession, so you have a good referral center to get a second opinion from that isn't too far away. Oncologists obviously favor treatment for cancer in most cases, but they are also usually very careful to give clients a clear picture of what to expect, making it possible to judge whether or not the treatment seems appropriate for you and for Joe.
If Joe doesn't want to eat, it would be pretty important to consider assisted feeding at his weight. Cats that are overweight are a little more likely to develop hepatic lipidosis, a liver disease, if they don't eat for a few days than cats that are close to ideal weight. Your vet can help you find a way to do this that is acceptable to you, too. We have had a number of clients who were able to devote the time and effort to hand feed cats but a feeding tube is not a terrible option.
I hope that Joe is the exception to the rule and that he does well with whatever course of treatment you decide is best. If your vet, or an oncology specialist, recommends specific medications and you wish to get more information about them, I will be glad to look them up for you.
Mike Richards, DVM 4/29/2000
Squamous cell carcinoma
Q: Dear Doc:
My white cat was just diagnosed with squamous cell carcinoma of ear pinna and possibly in the area just above her eye and between her other ear. My vet wants to remove her ear. She said it could return on her other ear. She didn't say it could spread but I read in humans it can; can it in cats? Could it have spread internally and we don't know yet? She was a street cat that was here long before we took her into our life. So, she's about 8 year to 12 yrs. old.
Thank you for your thoughtfulness, Anjeanne
Squamous cell carcinoma (SCC) does sometimes spread to other areas of the body. It also seems to start at multiple sites so sometimes it is hard to tell if the cancer has spread or if new instances of cancer are occurring. This is especially true in white cats because they are very prone to SCC.
When squamous cell carcinoma is present on the tip of an ear it is best to amputate the ear, as far away from the tumor margin as is possible. It is a good idea to have a pathologist examine the amputated portion of the ear to be sure that the surgery did result in the removal of the entire tumor. If no tumor cells are in the margin of the amputated portion there is a very good chance that the tumor won't spread.
It is also important to consider at least a biopsy of the eyelid margin to be sure if there is squamous cell carcinoma there, as well. If there is and the tumor is very small, cryosurgery (freezing the tumor and surrounding area) may be effective in eliminating the cancer. If it is larger it may be necessary to remove a portion of the eyelid. This can usually be done without causing problems with the eye but large tumors may require surgery by a specialist -- either a surgical specialist or ophthalmologist.
In some cases the tumors can not be removed surgically due to location, size or other problems. In these cases radiation therapy may also be useful. Radiation is sometimes used as a follow-up treatment after surgery if there is any question about the tumor margins, too.
It is a good idea to take chest X-rays prior to surgery to check for spread of the tumor. This doesn't totally eliminate the possibility but the lungs are a common place for tumors to spread to and they are visible on X-rays of the lungs when present, most of the time, which isn't true of other tissues.
People worry about what their cat will look like with really short ears but they almost always look better than you think. In most cases it is possible to remove eyelid tumors or treat them with cryosurgery in such as way that the eye looks almost completely normal in appearance. If these tumors occur on noses surgical removal does change the look of the cat quite a bit but most people don't find the appearance too objectionable.
Your vet can help you decide the importance of all of these procedures. Good luck with this. I hope that it is possible to get good clean margins around the tumor at surgery and that this will turn out well.
Mike Richards, DVM 03/02/99
Squamous cell carcinoma in elderly cat
Q: My kitty is about 16 years old and has a cancer that is eating away at her nose. She is so old that radiation just might not be worth it but we are not ready to put her down is there anything that we can appaly to her open sores to help them heal. I know that this will not go away but I hope to make it look better. I am keeping her out of the sun. The sun tends to agrivate it. I would just like any help or suggestions that you might give me for my poor old cat. Other then her sores on her nose she is healthy. Thank you for any help that you can give me, Mapuana
A: Mapuana- I do not know if this will work for your cat, but injection of chemotherapeutic agents directly into the lesion can slow the progression of squamous cell carcinomas, the most common tumor that eats away at noses and ears. I think that cisplatin is used for this in cats but this would have to be checked out with an oncologist since I am repeating this from memory. Getting the sores to heal is very difficult (actually it has been impossible for me) because they are actually cancerous lesions in most cases. The only good thing about this tumor is that really appears to be non-painful despite the appearance.
I wish I could help more. It really might help to check out the intralesional use of chemotherapeutic agents since it bypasses the systemic effects of the agents and still may help. Mike Richards, DVM
Squamous Cell Carcinoma on ear tips
Q: Dear Sir, My family and I recently semi-adopted a stray cat. It is a beautiful pure white Tomcat. When he wandered on my deck in the middle of winter, the cat looked like he was starving and could just about walk. We fed him and I gave him a shelter (outside) with plenty of blankets and a good dry place (wooden crate). He has improved dramatically. He is allowing us to pet him now but scratches like crazy if someone tries to pick him up. The problem with this cat is that the top 3/4 inch of the cat's ears look raw and have what looks like scabs. No fur grows on this section of ear. Is there anything that I can put on them to help the ears heal and what causes this condition?? I would take him to a vet but it's not possible at this time since he doesn't like to be carried! Thanks for your help, J.
A: It is not possible to be sure "by computer" but I'd be willing to bet that your cat has squamous cell carcinoma on his ear tips. This is a form of cancer that is very common in white cats that spend much time outdoors. It causes exactly the signs you are seeing. Amputation of the ear tips with a good margin away from the damaged tissue is the best option. I know that it may be hard to get him to your vet but it would be a good idea. If this is squamous cell carcinoma it is a malignant cancer and will spread if left alone.
Mike Richards, DVM
Michal Response: If you don't have a crate or cat carrier you might try two laundry baskets tied together . One of our clients has done this for years..uses old socks as ties. Another client brings her cats in pillowcases..the cats don't seem to mind. I personally like the laundry baskets better.
Squamous Cell Carcinoma
Q: Last March, our then 16 year old grey tiger cat, developed a squamous cell carcinoma on her lower left jaw. A veterinary surgeon removed the jaw, from front mid point to the back hinge. Our cat adjusted well and, for several months, was able to manage using the right side of her jaws to eat. Since October, the lower right jaw has shifted slowly so that now, the center of the jaw, which was still in its original position, is almost touching what remains of the left hinge. It is almost impossible for her to eat and I fear it is blocking or will soon block her esophagus - we have to put her food in a blender and then add water to it so she may lap it up. Even then, she gets frustrated and is losing weight. We thought the tumor may be growing again, but she does not wince when we touch any part of her jaw or face. She is alert, purrs often, and her loving personality has not changed. Is there anything that has been surgically done in similar situations (if there are any similar situations) that could relieve and release the remaining right jaw bone from its current position? Our vet is scheduled to examine her again next week to see if he can spot anything to save her. I would appreciate going into that meeting with as much information as possible. Thank you for any help you may offer.
A: The mandibulectomy surgeries have been advocated for aggressive type tumors in dogs and cats for some time now. I practice in a pretty rural area and have not had a sufficient number of cases of mandibulectomies to be of much help to you. We have only referred two patients for this surgery. One was a dog and it did very well. This seems to be the standard experience in dogs -- they seem to have long term success. The other was a cat, which we recently referred to North Carolina State University for squamous cell carcinoma affecting the left side of the jaw. We expected that they would offer the hemimandibulectomy as a reasonable means of dealing with the cancer but they told the owner (and us) that their experience long term in cats had not been good. Apparently, they were having some cats with problems like you describe. In this cat, palliative radiation therapy was attempted but it only lived for 3 or 4 months after therapy.
I do not know if it would work for this condition, but a similar condition in the way the bones move might be pelvic injuries in which one side of the pelvis tends to swing into the midline and cause problems. In these cases it is sometimes possible to use transplanted bone to form a stabilizing bridge between the two halves of the pelvis. Perhaps some similar thing could be done with the jaw. I am just theorizing here -- I have no practical knowledge of how successful something like that would be.
In cases like this, the original surgeon is often the best person to consult. They tend to be the ones doing this type of surgery and therefore seeing the complications. Your vet may also have had more experience than I have with these and checking with him is a very good idea.
In a worst case scenario, we have had some success with surgically implanting stomach tubes for long term use to treat other conditions and perhaps that would be an option. Sorry I can't be more help. I hope that you find a solution to this problem.
Mike Richards, DVM
Cancer of Ear in Cat
Q: Dr. Mike: We have and use our very wonderful vet. About a month ago, we noticed that our cat's outer ear with somewhat inflamed. It didn't look serious and and her inner ear was not involved. About a week ago, we noticed that the outer ear of the cat (one side only) was much thicker and somewhat red. Still there was no inner ear inflamation. Went to vet. Put her on prednizone and clavamox. No response. The vet thinks it may be cancer and her outer ear may have to be removed next week. What can you tell me about this type of cancer. Thanks. PS her name is Katy, she is 10 years old and has never been ill.
A: Kty probably has squamous cell carcinoma affecting her ear. This is very common in cats with white ears and also occurs fairly commonly on the nose of white cats. On ear tips, the best treatment is to remove the external portion of the ear as far away from the cancer as is possible. Even though it radically changes the appearance of the affected cats, this is a fairly simple surgery and not very risky. It is worthwhile to consider this even if there is evidence of the cancer in other places, I think. There is some evidence that radiation therapy can be useful in slowing the progress of squamous cell carcinoma and if that is available in your area, you might consider it. Unfortunately, this is an aggressive form of cancer and often it will recur despite aggressive surgical removal of the visible tumor. Despite this, I really think it is worthwhile to follow your vet's advice and have surgery done if this is the cancer he or she suspects. It makes cats more comfortable and does seem to prolong their life.
Mike Richards, DVM
For more information and support for owners of cats with Squamous Cell Carcinoma a good site is http://www.geocities.com/feline squamous cell cancer/Last edited 01/30/05
Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...