Cancer in Animals
October 5th, 2011
Just like peopl
e animals get a wide variety of cancers. Since all cancers have variable signs and behave differently in every animal, your pet should be brought to your veterinarian if it is showing any problems of any nature. Three common cancers in animals are skin cancer, lymph node cancer, and spleen cancer.
Skin cancers vary greatly, from small and benign to malignant with serious additional problems. Of concern is a highly malignant skin cancer called a Mast Cell Tumor (MST). There can be a swelling or mass that comes and goes over several months as the only symptoms. If we find a growth or significant swelling we will perform an aspirate prior to any surgery and look at the cells in the mass for any signs of malignancy or cancer. If this aspirate gives us a good idea that cancer is present, and especially if the skin growth is getting larger or bothering your pet, we will remove it surgically for a definitive diagnosis and to stage it if it comes back malignant.
When we suspect a malignant cancer we remove all of it, in addition to healthy skin below and around it to make sure all of it is removed at the time of surgery. When we send the tissue in for diagnosis the pathologist can let us know if we removed all the cancerous tissue. Once we get this report we decide if further treatment, like radiation or chemotherapy is needed.
Lymph node cancer, called lymphosarcoma or malignant lymphoma, is a common cancer in dogs and cats. It is a cancer of the white bloods cells and lymph nodes, and affects many external and internal organs. Since it can affect many different organs the symptoms are variable, and cats and dogs tend to get different forms and have different causes.
On physical exam some pets will have enlarged external lymph nodes or skin masses. It can be diagnosed with a blood panel, checking for viruses in cats, and looking at the white blood cells in all species. This tumor can show up in any organ, so a radiograph and ultrasound are also commonly used in the diagnosis. Treatment ranges from surgery to chemotherapy, and the prognosis tends to be poor for the long term.
A tumor of the spleen, called hemangioma or hemangiosacroma, can also occur in the heart and liver less commonly. Symptoms can be subtle and easy to miss. Typically they might include lethargy, weakness, and weight loss. During an exam we might palpate an enlargement in the abdomen. This is confirmed with radiography and ultrasound. We can even do an ultrasound guided aspirate for more information.
Surgery is the treatment of choice in splenic hemangiosarcoma. These tumors can rupture and cause immediate collapse and even death so surgery should be performed soon after the diagnosis. Chemotherapy is after surgery in some cases.
(This picture is of one of my patients. It breaks my heart to see patients suffering from malignant cancers,but the number of patients is really increasing with cancers.)
Why to Spay a Dog?
July 23rd, 2010
Ovariohysterectomy or spaying,involves ligation of the ovarian veins & arteries and of the distal body of uterus & removal of uterus,fallopian tubes and ovaries as a unit.
Benefits of prophylactic ovariohysterectomy:
The three most common reasons for carrying out prophylactic OVH are prevention of misalliance,mammary tumours & pyometra.There are,however,even more reasons.Bitches on heat are often more reactive than they would be during anoestrus & this could lead to squabbles between dogs in the household.Bitches in heat can also cause serious fights between intact males through their mere presence in the neighbourhood.Less common physical problems associated with oestrogen include vaginal prolapse & Nymphomania and these are also prevented through removing the ovaries,the main source of oestrogen.
The link between mammary carcinoma and reproductive hormones is probably the most compelling reason for advising spaying in bitches.Most canine mammary carcinomas are oestrogen responsive and grow better when this hormone is circulating in the body.As a result,bitches sterilized before their first heat only have a 0.05% chance of developing mammary carcinoma at any stage in their life.If they are sterilized after first oestrus cycle,the risk increases to 8%,if after two heat cycles,risk increases to 26%.
Approx. half of the canine mammary carcinomas are malignant.