Bone Cancer - Osteosarcoma


Hemimandibulectomy - Ear problems and weight loss following surgery

Question: Dear Dr. Richards: I wrote to you in September 1999 after our ten year old Rottweiller was diagnosed with a bone tumor in his lower right jaw. He underwent a hemi-mandiblectomy, and he is doing fine. The surgery took about three hours, twice as long as the surgeon had estimated. This was most attributable to Nikoli's being a Rottie and to Rottie bone structure. (Underneath this loveable pooch is one tough puppy! I certainly never gave the strength of his jaws, muscle and bone, much thought.) Nikoli spent three nights in the surgical hospital; we took him home on Day Four which happened to be a Friday. My husband and I both got the day off from work, so we were able to spend three full days and nights with him before he had to be left alone during the day. The surgeon gave us three prescriptions: Rimadyl (100 mg); Cephalexin (500 mg) and Torbugesic drops. The first couple of days at home, Nikoli just wanted to sleep and relax. The right side of his face was bristling with stitches and a couple of drains. He was still bleeding and draining a lot, and I was concerned that he would tear his stitches or worse, so the first day or two I literally hand fed him soft, canned food. But as Nikoli began feeling better and his appetite increased, he started eating for himself. A week (or maybe two weeks) later he went back to the surgeon for a follow up and got gold stars for his progress (best of all, he didn’t need any restitching). Within a few more weeks he was pretty much back to his old self. The muscles on the right side of Nikoli's face have atrophied. The bones on the right side of his face have become very pronounced, especially the bone over his right eye. The bones on the left side of his face have become somewhat more pronounced as well, but they aren’t as noticeable visually. His mouth on the right side looks normal, but of course the lips were sewn together up to a point to help hold his tongue in place and to help him eat. But unless you are petting him on his face you don’t really notice it. Still there is nothing like a dog’s very own jaw to keep a dog’s tongue up in his mouth ­ yes, Nikoli’s drops out when he is relaxed. We try not to laugh in front of him. Nikoli takes much longer drinks than he did before, but I believe this is because he is unable to lap up as much water in a single gulp as he used to. He backwashes significantly more since his surgery, so we are changing his water every day or every other day, because it gets “dog mouth gunk” in it and begins to smell. And he also has a serious post-drinking dribble problem. Outdoors this is no big deal. But inside, I have begun keeping the mop next to his water station in the kitchen. It’s that bad. He has dropped some weight. Before the surgery Nikoli’s normal adult weight was 85 pounds. At the vet’s yesterday he was down to 75 pounds. Our vet would like to see him gain back that ten pounds . After he recovered from surgery we switched Nikoli from a diet of soft, canned food back to his usual dry kibble with occasional table scraps (we don’t do a lot of home cooking, so scraps really are occasional). Now we are thinking of incorporating a least a can of soft food a day. (I have a question about this, but I will try to lump my questions together at the end of this letter, so they don’t get lost in my ramblings.) The only other problem that Nikoli has now is a chronic (I think that’s the word) ear infection. It gets better; it gets worse, but it doesn’t seem to go away. This past week, I tried home remedies including hydrogen peroxide and Monostat 7. Neither seemed to help, so it was back to the vet’s. The vet examined his ears and took another culture. She confirmed that the deeper, lower parts of his ear canals were very dirty. The culture revealed no yeast (so the Monostat apparently did its job - maybe), but there were several different types of bacteria thriving. After flushing Nikoli’s ears, she sent us home with a couple of prescriptions and advised that we stop home flushing his ears for now as this seems to be keeping them wet while not really affecting the bacteria. Nikoli is now taking Clavamox (250 mg tablets, 2/am, 2/pm) and Tresaderm drops in both ears (am/pm). He seems better today, but that may be due mostly to the thorough ear flushing he got at the vet’s. It’s probably too early to tell if the other stuff is working. He has a follow-up visit in two weeks. If this treatment plan doesn’t seem to work, the vet suggests we try a different type of culture that will allow her to isolate the kinds of bacteria that are in his ears and allow us to treat for resistant bacteria if we need to. The right ear structure is more closed than it was before the surgery. The loss of bone and muscle has apparently changed the way the ear is supported. This makes things a little more challenging, but Nikoli had this problem before his surgery. So this is not something that has come up unexpectedly as a result of his operation. Well, maybe I should summarize: Ears Previous Treatment: Chlorhexi Derm Flush with Otomax Otic (can’t they design a container that will make it easier to judge how much Otomax you’re squeezing out of the tube and into the ear?) Current Treatment: Clavamox and Tresaderm Questions: Would Witch Hazel make an effective ear flush? I dropped by and read up on ear problems. After reading your comments on home remedies, I realize that I should have been diluting the hydrogen peroxide (ooops). I didn’t think about vinegar, but I was wondering if witch hazel (which has an astringent quality) would be effective. By the way, when I tried the Monostat I did realize that it would only affect yeast (if it was present), not bacteria. I cannot say for sure that there was yeast in Nikoli’s ears before the Monostat, but the vet said she didn’t find any when she tested for it. However, given that the Monostat didn’t and can't solve Nikoli's ear problem, I don’t see any reason to use it again. What is the best way to feed Nikoli and get him back, closer to or at his old weight? We currently feed him Kibble-N-Bits. We switched a few years ago after reading a pet food comparison study done in Consumer Reports. Up until then we had always fed him a “premium” dog food. As a puppy he started on Science Diet, later we tried Iams and others (Nikoli’s “dad” usually bought the food, and I think he got whatever sounded good to him ­ even though he wouldn’t be eating it. My husband would adamantly deny this, of course.) In the Consumer Reports study, Kibble-N-Bits stacked up well against the premium stuff: same nutrition, but lower fat, lower price and increased availability. So we switched. But now he seems to be losing weight. The vet suggested adding canned food to his diet. We have two theories on canned food. 1) mix it with the dry and he will eat more over all; 2) feed him the canned separately and let him “top off” with the dry. The down-side to Theory 1 seems to be that Nikoli might still eat less; instead of finishing his dish, he might leave behind both the canned and the dry. The down-side to Theory 2 seems to be that he will finish the can, but won’t top off with the dry, so he is still eating less. We haven’t tested either of the theories on Nikoli (but I have seen dogs in the past practically lick the canned food off the dry kibble, leaving it right there in the bowl otherwise untouched.) While he was on a soft food diet, he was eating about three large cans a day. Now I am thinking one can a day along with the dry food would be a good supplement. Is one can a day enough? Should we look for a dry food with more fat in it? (Nikoli has always been a very fit dog, never, ever fat, in part, because we never neutered him ­ I could not get my husband on board with that one. I must add that to our knowledge our dog is still a virgin even at the ripe age of 10 years. I could not and would not stand to be responsible for even one more litter of pups, planned or unplanned, in this over-populated world, so we have been very careful to keep Nikoli away from temptation. --still a virgin and always a very docile and gentle dog, contrary to the usual unneutered male expectations.) What can we expect related to Nikoli’s upper right jaw now that it no longer has its lower chewing surface? Tooth decay comes to mind, since these teeth will get none of the cleaning benefit of dry, crunchy food. Should we start brushing his teeth? What are your recommendations regarding toothpaste, etc.? Will his upper teeth grow longer with not lowers to grind them away (that sounds more like a rat problem than a dog problem)? Are you aware of anyone doing post-mandiblectomy studies on dogs? I would be interested in finding out more about how dogs get along after the surgery. Well, thanks for your patience. This note has turned into a bit of an ear bender. Thanks for listening. We're looking forward to your comments and thoughts. Lisa Answer: Lisa- I am pretty sure I'm going to miss some of your questions, so please feel free to resend any that don't get answered. The simplest way to add calories to a dog's diet is to add a tablespoon or two of oil to the food. This adds a lot of calories without changing the dietary balance of vitamins and minerals much. This works with either canned or dry food. If additional calories beyond this are necessary you can get them by feeding either canned or dry food in whatever quantity it takes to support a weight gain. Then you need to cut back when Nikoli gets close to his optimal weight so that his weight levels off rather than continuing to increase. Ordinarily there is no particular advantage that I can see to premium dog foods but they are helpful in situations like yours in which a dog needs to gain additional weight and where it may be helpful to feed lower volumes of a premium food rather than adding additional cups or cans of a non-premium food. I would consider this if you think that Nikoli won't eat larger amounts of food or can't eat more food comfortably. Teeth problems associated with hemimandibulectomies tend to be problems with the bite on the opposite side being affected by the surgery because the mandible becomes less stable on that side. Most of the time this isn't a severe problem but sometimes there is enough impingement on the gums or palate to cause problems based on literature references. We have had two or three patients who have had this procedure and I don't recall any major problems with tartar on the upper teeth on the side that the jaw was removed nor do I recall serious bite problems on the opposite side. I hope that is your experience, too. Witch hazel is OK to use in ears. It just stings if there is any ulceration of the ear canal and should be discontinued if signs of pain occur when using it. Diluted vinegar can also sting but is a little less likely to do so. I suspect that you are correct that the ear problems are related to changes in the ear canal, or possibly middle ear drainage or pressure equalization, postsurgically. It may be necessary to use antibiotics or topical therapy on a semi-regular basis to control this problem in the future, if these changes make it easier for bacteria or yeast to grow in the ear. It is OK to do this, if necessary. I am not a big fan of ear cultures but lots of vets believe they are helpful and I do find myself doing them occasionally, too. Using something to keep the ear environment unfriendly to yeast and bacteria can help prolong the interval between infections. Witch hazel and vinegar/water combinations should be helpful. I think it is worth doing these things since I think that the benefits outweigh the risks but your vet may have different clinical experience with this. I can't say I can prove scientifically that I am right, it is just an observation based on my patients. Hope this helps. Mike Richards, DVM 2/11/2000

Bone cancer (osteosarcoma) or Bone infection (osteomyelitis) and Rapid respiration

Question: Hi Dr. Mike, I am a subscriber who wrote you about a month ago about my large mixed breed (90 lb male 10 years old (lab, border collie, newf?) dog (Noah) who was having rapid respirations (avg. 60 to 70 per minute; has been as high as 90 and as low as 40) but no other symptoms. At the time we thought it was bronchitis. This has been going on for about 10 weeks. Tests have ruled out Cushings. Low thryoid problems were found (very very low according to our vet) and he has been put on thyroid medication but this has not done anything to help respirations. Please note, he is not panting. These rapid respirations occur whether awake or asleep with mouth closed. He can't tolerate exercise and gets tired very easily. We went to a specialist last Thursday. He said x-rays clearly showed lung disease but not bronchitis but problems with the connecting tissue of the lung. He also noted a possible problem with the breastbone that showed up on the x-rays (3 sets taken about 2-3 weeks apart). He thought perhaps there was infection going on or possible cancer. (In the bone sections which were squard off, there was a section that was rounded and smaller than the others.) A bone marrow biopsy was done along with a bronchial wash. We will get the results by September 12th. In the meantime Noah has been put on 3000mg per day of Keflex. He is still showing no signs other than the rapid respirations and being tired all the time. Oh, and high akaline phophostates (?) - not new, he has had this problem off on on for about two years. Can you give us any idea what might be in store for us? Infection or worse yet, cancer. Treatment advise, etc. Other info we can find on bone infection talks about long term recovery, high fevers, vomitting, etc. so we are concerned. Your information is always wonderful and I am very grateful that you provide this service. Any information or thoughts you could give would be very much appreciated. Thank you. Brenda Answer: Brenda- There are two likely possibilities suggested by the specialist, bone infection and bone cancer. If the first set of X-rays did not show a problem or if they showed a problem that is worse on the second set of X-rays, then there is no need to consider the other possibility that I can think of, which is a birth defect that hasn't been detected until this time because it wasn't causing any problems. There are several possible bone cancers and the prognosis is quite different, depending on which one is present. The most common form of bone cancer is osteosarcoma. These are very invasive and highly malignant tumors that usually occur in the bones of the legs but can occur in any bone. Approximately 90% of bone cancers are osteosarcomas. The second most common form of bone cancer is chondrosarcoma. This tumor usually occurs in flat bones, such as the ribs. This is the form of bone cancer that has the best prognosis. If it is possible to remove the affected bone and a wide margin around it, the long term survival rate after surgery is pretty good, an average of three years or so. Even though this tumor represents less than 10% of the bone cancers it may be more likely in this case, due to the location. There is a pretty rare form of bone cancer known as a multilobular osteochondrosarcoma that usually affects the skull bones. This type of cancer often recurs at the site that it is removed and can metastasize to other tissues but most dogs that have these tumors live for a two to three years after surgical removal. The other cancers that involve bone are tumors that arise in other tissues and then spread to the bone. Tumors that can do this include hemangiosarcoma, lymphoma and fibrosarcomas. These tumors tend to be identified in other tissues prior to showing up in bone but we have seen one case of lymphoma where the first sign of problems was lameness from bone invasion and a couple of fibrosarcomas that seemed to arise directly from bone or from tissue very closely associated with bone. Bone infections are not common, but do sometimes occur. We sometimes see bone infections underlying areas in which there is a lot of pressure on the skin when dogs lay down, leading to skin sores, such as the elbow region and sternum. Bone infections are best treated by culturing the infected area, identifying the bacteria involved and determining which antibiotics are likely to work by doing sensitivity testing. Once this lab work is done, an appropriate antibiotic is given for 4 weeks or more (sometimes three or four months) until the bone has healed. If there appears to be bone death (necrosis) from the infection, it is usually necessary to remove the dead bone surgically prior to using antibiotics, in order to get a cure. Most of the cases of bone infection (osteomyelitis) will respond to antibiotics and surgical debridement but there are times when this is a frustrating condition that requires a lot of effort to resolve. In areas in which fungal infection of bone occurs, that has to be ruled out, as well. I think you have to wait to see what is found before getting too far into exploring options. It is likely that you will have viable options for treatment of whatever is identified, based on the location of the problem or even that treatment won't seem necessary after the results are in. There are a lot of problems that can lead to rapid respiratory rates. Upper airway disorders such as nostrils that are too narrow, obstructions in the nasal cavity, pharyngeal disorders, laryngeal paralysis, tracheal collapse and tracheal parasites can cause rapid respiratory rates. Lower airway disorders such as bronchial constrictions (allergic, asthmatic, etc) can also do this. Heart and circulatory disorders such as heartworms, anemia and bleeding disorders can lead to increased respiratory rates. Injuries to the chest, ribs, sternum (including congenital defects) or the abdominal cavity which cause pain or bleeding can lead to increased respiratory rates. Things that cause fluid to accumulate in the chest cavity (cancer, heart disease, heartworms) can raise respiratory rates. I think that pain alone can do this and that stress probably can. Infections such as pneumonia, septicemia and probably osteomyelitis can do this. At this time, many of these problems have probably been ruled out --- but if one of them seems possible to you, it would be a good idea to ask your vet about it. I hope this helps in thinking over the possible problems. Mike Richards, DVM 9/10/2000

Bone Cancer - Dilantin and phantom pain

Q: Dr. Mike, My dog is a 12-yr old, 65 lb. mixed breed who underwent amputation of her right front leg due to bone cancer in August, 1996. She recovered nicely but about 6 months after the surgery she began licking her remaining front leg, esp. in the early morning. She has lately been intensifying her efforts, and sometimes the urgent licking is accompanied by little yelps or groans, and she has also begun working on her hind legs, and sometimes also on her bedding fabric. Our vet (the one who did the surgery) thought that she might have some arthritic pain and prescribed anti-inflammatory medication last March. This didn't really have any effect, and after another visit last week, after consulting with a fellow clinic vet, he suggested that we put her on Dilantin, 100 mg, 3 tab BID. He also took chest x-rays and one rear leg x-ray and at this time there still is no evidence of the cancer having spread to the lungs. He said that the Dilantin might help if her condition is related to a phantom nerve condition brought on by the amputation. After researching Dilantin, I am concerned because it seems to be used largely to treat epileptic seizures. I am wondering if you have had experience with this type of reaction in dogs with limbs removed, or if there is any other kind of care or consultation that we might look into. Thank you, Cathy A: Cathy- I can not find any information on the use of phenytoin (Dilantin Rx) for phantom pain in dogs but that doesn't mean your vet doesn't know something I don't. There are a lot of anecdotal uses for various medications that may appear in just one or two references --- or none at all. I have not seen this type of reaction after an amputation. Given the reason for the amputation I think I'd still be really suspicious of metastasis of the cancer even though it is not seen on the X-rays. Unfortunately I do not have any better suggestions for treatment. I wish I could help more. Mike Richards, DVM


Q: I recently wrote to you regarding my parent's german shephard with a diaphragmatic hernia. Thank you for your response. Unfortunately when they opened her up to repair the hernia they discovered instead a large 20cm tumor between her heart, diaphragm and lungs. She tolerated the surgery and is recovering well. We bring her home tomorrow. Unfortunately it is malignant. It is a osteosarcoma. Do you know anything about this type of tumor? Further histology is being done, but apparently it contained bone, fiber, and cartilage cells. The vets feel it probably started in utero as she was developing. They say they have not run into this type of tumor in a dog before and are not sure of the prognosis, except that it is probably poor. Do you have any further information or know of any sources? Thank you. m- A: Osteosarcomas are a bone origin tumor, usually. German shepherds have a predilection for these tumors,, along with St. Bernard's, great Danes, golden retrievers and Irish setters. These tumors are most common in bone but they have been reported as a primary lung tumor and definitely can metastasize to the lung region from a site in the bone. When this type of tumor is found in the lungs it is a good idea to try to find a primary site in the bone. The major sites these are found are the wrist, shoulder, hock, stifle and hip region. I wish I knew of a good treatment, but I do not. It is important to be sure of the type of tumor, through histopathology (examination by a pathologist) if at all possible. This has probably been done already but it is good to check. Some tumors are more treatable than osteosarcomas. There are veterinary cancer specialists and it is worth asking for referral to one for the most definite answer as to treatment. They usually know the most up-to-date information on this.


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...