Gastric, Liver and Prostactic carcinomas, adenomas and Adenocarcinoma in dogs

Perianal Adenoma and Perianal Adenocarcinoma

Question: Dear Dr. Mike:

Just got back from seeing the oncologist as recommended by my vet. He also thinks I should have the liver biopsy but gave me his opinion about what he thought 99s liver mass could be. Unfortunately I can't find anything on your site about it or anywhere on the web. The oncologist states she has a rare condition either way and it is a unique case. He thinks she's got a primary liver tumor or sarcoma with insulin like pentacles secretions. After redoing her x-rays which confirmed there is nothing in the lungs, he said it's likely a hepatoma.

Is a hepatoma the same as hepatocellular adenoma and is primary liver tumor or sarcoma with insulin like pepticles secretions the same as hepatocellular carcinoma?

Would you be kind enough to let me know what you know about these conditions and where I might search for additional cases or articles concerning same. The only thing I can find information or related articles is osteosarcoma. That's involving the bones right. I can't find anything on canine liver sarcoma.

Thank you again for your valuable assistance. I really appreciate it. Sara

Answer: Sara-

If there is no evidence of a metastasis it is sometimes possible to remove hepatomas surgically. They often only involve one lobe of the liver and the remaining liver tissue is more than adequate for life after the removal of one lobe, if that is the case. Hepatomas have been reported to cause hypoglycemia due to the release of hormones (insulin like growth factors) which bind to the same receptors on the cell as insulin and thus block its function.

It is hard for me to tell you for sure what the relationship between hepatomas, hepatic adenomas and hepatocellular carcinomas is. It seems hard for pathologists to differentiate between hepatomas and low grade hepatocellular carcinoma based on a couple of pathology reports we have seen in which the pathologist listed both conditions as possibilities. In either case there is a chance that surgery could be curative because the hepatocellular carcinomas are supposed to be pretty slow to metastasize. I know that it is a really big decision to consider surgery, especially since it is probably best to seek out a surgical specialist, but this is a situation in which there is a possibility for a good outcome even with a large tumor (the largest I have heard of that involved one lobe and hadn't spread based on the dog's subsequent lifespan was 8 inches in diameter). We had a patient with one of these that was very close to that size. I think that a sarcoma would likely be a hemangiosarcoma or leiomyosarcoma, which would not have a good prognosis.

If you go to the PubMed web site http://www.ncbi.nlm.nih.gov and use the search term "dog hepatoma/ve" (the /ve is a "switch" to make it possible to sort out the articles of veterinary relevance), you can find a number of abstracts relating to liver tumors in dogs. There was a Clinics of North America issue in 1995 on liver disorders which had some information on liver tumors and the book "Textbook of Veterinary Internal Medicine, 5th Ed." has some information on these tumors.

It is really scary to contemplate removal of a large portion of the liver but there are enough success stories with this procedure to make it worth considering, if you would like to pursue all options.

Mike Richards, DVM 2/19/2001

Gastric adenocarcinoma

Question: I'll try to be brief but there is alot to explain. Our dog, Smokey, a collie/black lab mix, is 11 years old. Began vomiting everyday (in the morning upon waking and getting up) food from the previous day's meal, undigested. He's lost close to 20 lbs, going from 110 lbs. to 89 lbs. Our vet took blood and everything was normal; i.e., kidneys, liver, etc. Began feeding him small meals 4 times a day of a gruel, boiled hamburger and rice put throught the blender to be smooth consistency. He was able to hold down this. Vet suggested x-rays and possible GI series. He did an x-ray and stopped. Found a large mass (approximately softball size) in him. We were told either do an exploratory or assume the worse and let him go. We couldn't live with ourselves until we knew we'd done all we could. We got the opinion of another vet who suggested an ultrasound. This was done and confirmed the mass in the pyloric region. We talked to a surgeon who thought an exploratory would work because other than the vomiting, he was healthly. She also did a chest x-ray and found no obvious tumors in his lungs. His blood work was good and he is a strong dog both physically and in spirit. They did the surgury on July 18th.

The mass (per the pathology report) is adenocarcarcinoma, well differentiated, stomach. The surgeon said she had to remove the pyloric region but left the bile duct in tact. She said she got good margins. The biopsy says:

Sections of a gastric mass are examined on 8 slides. There is a partially delineated, discrete modular mass in the submucosa. It is composed of neoplastic epithelial cells that form acini and dilated ducts within a fibromuscular stroma. The cells have ovoid mulei with marginated chromatin, finely stippled chromatin. Nucleoli are small, but visible. The mitotic rate is low. The cytoplasm is abundant, polyhedral with distinct cell margins. The surgical margins examined are clear. The neoplasm in the gastric plylorus has apparently developed from submucosal glands (brunner's glands). The neoplasm is histologically well differentiated. This suggests a low grade of malignancy and a limited metastatic potential. Surgical excision appears to be complete but the prognosis is still guarded.

Small masses were found on the liver but are determined by the pathologist to be hepatic nodular hyperplasia; the vet said normal for an older dog and not of concern.

The surgeon consulted with an oncologist who says chemo and/or radiation would probably not be necessary nor is there any proof it would help. However, the surgeon and oncologist think there is a 50/50 chance the dog is cured. Our vet is not as optomistic. He said the likelihood is that the cancer will creep up elsewhere in the future. He said even though it is a slow growing cancer, that the size of the tumor indicates he's had it for a while. He also said even though the surgeon didn't find any other tumors on his liver, kidneys, stomach, etc. that we should not expect the dog to be completely cured. He tells us we might have a few months to a year with the dog. The surgeon says a year to two, maybe more. She took his staples out yesterday, said the area looks good; he hasn't vomited since the day of the surgury, had one small bout of diareaha and appears to be getting stronger by the day. She told us to only feed him canned food, no dry food, no table scraps, no bones. She explained that the pyloric valve she took out prevents any large pieces of food from entering the small intestine and that we should be careful with what he eats.

I'm sorry this is so long. Basically just want your opinion. Our vet is very pesimistic and the surgeon is very optimistic. We are confused. Give me your OPINION on how long Smokey is likely to live. If the cancer is still in him but in another area, what type of symtoms should we watch for. We are walking on egg shells now. Afraid to let him do the things he loves; hiking, swimming, running for fear he'll over do and get worse. The surgeon said he could swim in another week and do as much as he wants to do. What do you think?

Thanks for letting me write so much and for just being there for us devoted pet people who need advise.

Sincerely, Linda

Answer: Linda-

Gastric adenocarcinoma is best treated surgically. I can not find any research showing a benefit for chemotherapy and radiation therapy is not recommended due to complications in using radiation therapy for gastrointestinal problems. When the entire tumor is removed and there is no evidence of metastasis to surrounding lymph nodes or organs at the time of surgery the prognosis is still guarded, meaning that recurrence of the tumor is likely even in this case. The average life expectancy post surgery for this type of tumor is probably only six months to a year, but patients do seem to be comfortable most of that time, at least in the very small number of cases in which we have diagnosed this problem and attempted surgery. I found a couple of anecdotal reports in which remission periods of longer than a year were reported, though.

Surgeons tend to be optimistic by nature. It takes a certain amount of optimism just to do surgery, considering the risks of anesthesia and routine surgical procedures and then to want to take on the added risks of removing portions of vital organs just takes an attitude in which a person believes things will turn out OK. Vets who practice primarily medicine tend to be a little more pessimistic, especially about surgical outcomes. Oncologists tend to be somewhere between these extremes, so the fact that the oncologist feels that there is a 50 percent chance of a cure is pretty good.

Most older dogs recover pretty well from surgery, so the surgery itself doesn't impair their enjoyment of the remaining time they have, whether it is a short time or a long time. So I think that most owners don't regret attempting surgery, as long as the anesthesia and operation go OK, even if it doesn't turn out that it gives a long term cure.

The pathologist's report is very encouraging. I think it is reasonable to hope for a cure from the surgery, based on that. If lymph nodes from the region were removed and also found to be free of cancer, that would even be better. The lack of metastasis on the liver biopsies is also very good. I think it is reasonable to hope for a cure but it would be best to temper that hope with the realization that many of these tumors have spread by the time they can be diagnosed and removed. I would let him do all the things he likes to do, when your surgeon feels it is safe (usually two to three weeks after surgery). You should reintroduce him to heavy exercise slowly, though. Let him build up strength over a couple of weeks before allowing him the opportunity for uncontrolled exercise.

Good luck with this. I do all the surgery in our practice, so I have optimistic leanings --- so I'll hope that Smokey does really well.

Mike Richards, DVM 8/7/2000

Prostatic adenocarcinoma

Q: I have a four year old (neutered, yes neutered, when he was 14 months) Samoyed who has just been diagnosed with prostatic adenocarcinoma. My vet is currently--as I type--calling oncologists for help on treatments. I am told that this cancer is generally very resistant to treatment, that it moves very quickly and that most dogs are dead within three months of diagnosis. He is having difficulty urinating and defecating, so we do not have the luxury of time. Typical treatment is radiation and surgery. A complication is that his kidneys are not in good shape. The vet who did the ultrasound said that they look like the kidneys of a 10-11 year old dog. This dog has a history of an elevated BUN (usually 29-33), something we first noticed when he was nine months old, and have retested every six months or so. Last November, his BUN was at an all time low of 27. Last month when he was in for his annual checkup, it was 17. Today, it is 12. Urine looks fine, except that it is quite dilute. Creatinine is fine and always has been. Other than the BUN, he has been quite healthy, is in good physical condition. Unfortunately, his breeders lost interest in him as soon as the check cleared the bank and I do not know much about the longevity of the dogs behind him. His breeders are known (I know now) for producing very cutsey puppies who do all kinds of winning from the puppy classes and then aren't seen again. He matured very quickly, especially when compared to my younger dog, from different lines. I am just trying to get as much information about this type of cancer, possible treatments (allopathic and otherwise), etc. I'm wondering if there might be environmental factors in the onset of this? Genetic? Why does my young, neutered dog have it? Any info is greatly appreciated. Ann

A: Ann- Four years of age is pretty young for prostatic adenocarcinoma. It would also be young for the most common confusing differential, transitional cell carcinoma of the urethra. This can be confused with prostatic adenocarcinoma pretty easily if the biopsy to determine the cancer status was done by a fine needle aspirate. It is also possible to confuse rectal/colon tumors with prostatic tumors using fine needle aspirate biopsy techniques. Young large breed dogs are reported to be prone to rhabdomyosarcomas in "Small Animal Surgery" by Fossum. These are actually a bladder tumor most of the time but again, it is in the region of the prostate and perhaps could be present.

Neutering does not seem to protect dogs against prostatic adenocarcinomas. It does protect against problems with benign hypertrophy leading to problems urinating, etc.

Consulting with an oncologist (or more) is a good idea. The current thinking is that radiation therapy and perhaps concurrent chemotherapy offer the best hope for increasing survival times but surgery has some proponents and I vaguely recall hearing about a new surgical procedure --- but I can't even begin to think of where to look for that information. The oncologist is likely to be up on the latest information, though.

The current BUN values are normal. In a dog with a history of elevated BUN values it might be a good idea to check liver function before doing anything too invasive. When the liver fails the BUN drops because it produces the precursors to BUN. When the BUN value is less than 10 this has to be considered if there are any clinical indications to do so. It seems to me his history alone is sufficient reason.

I can not answer the questions regarding potential habitability, nor potential environmental influences. There is no mention of a genetic predisposition that I can find and no known environmental influences that I am aware of but that doesn't mean much. Mike Richards, DVM