Last Modified: October 8, 2006
Dear OncoLink "Ask The Experts,"
My four-year-old black lab had her left kidney removed due to an abnormality on ultrasound, and at the time of surgery, a 3 cm tumor was found with pathology revealing a renal papillary adenocarcinoma. Radiographs were taken prior to surgery showing no apparent spread of the cancer, and she has showed 100% improvement, but they are recommending chemotherapy. I have not been able to find a lot of info about kidney cancer in dogs, and what I have found does not make chemotherapy sound very promising, so we are hesitant.
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
Renal (kidney) tumors are rare in dogs. The typical dog is middle-aged to older, and there is no breed or sex predilection. The exception is the German Shepard, which is predisposed to a syndrome of renal cystadenocarcinomas and nodular dermatofibrosis. The majority of primary renal tumors are carcinomas, but a variety of other types have been reported. In addition, some types of cancers can metastasize (spread) to the kidney from other locations.
Some dogs have no clinical signs associated with a kidney tumor. Others might have symptoms associated with the urinary tract, such as bloody urine or frequent urination. If the cancer has metastasized, which occurs in about half of dogs with renal carcinoma, there can be symptoms related to the organ or tissue that is involved.
A thorough staging evaluation is always indicated when a kidney tumor is detected. This includes chest radiographs (X-rays), abdominal ultrasound, and complete blood cell count and chemistry profile. The most common sites of spread are the lung, liver, and the linings of the abdominal cavity.
If there is no detectable evidence of cancer spread to other sites, if the uninvolved kidney has good function, and if the dog is in good enough health to tolerate surgery, then nephrectomy (removal of the affected kidney) is usually indicated. However, metastasis might still become evident weeks or months following surgery. Unfortunately, there is little evidence to indicate what type of chemotherapy might be effective in delaying or preventing this occurrence. In humans, this type of cancer tends to be resistant to chemotherapy.