LaRue

Canine urogenital tumors continue to present a therapeutic challenge. Invasive transition cell carcinoma, also referred to as invasive urothelial carcinoma (InvCU) is the most common cancer of the canine urinary system. Over the past decade, veterinary researchers added an important array of new information. Exquisite research by the Matthew Breen laboratory has provided us with an easy and accurate method for diagnoses (and please, is it possible to use this knowledge towards a targeted therapy?) Deborah Knapp’s laboratory continues to seek out drug alternatives literature and have expanded cell line capabilities. Urinary tract stents have become more available and continue to evolve and studies have provided information that these tumors may be more metastatic than previously believed. Michael Nolan’s work on image guided, intensity modulated radiation therapy set a landmark for survival, but a subsequent study did not show improvement and has opened questions such as “Why isn’t urinary incontinence on the VRTOG radiation effect scale?” and “How do we evaluate incontinence before and after treatment?” This integrated panel discussion should help us not only to better understand the disease, but to point us in the correct direction for improved treatment.

Four hundred thousand cases of human urothelial tumors are diagnosed each year. The majority (2/3) are non-invasive cancer treated with transurethral resection and intravesical therapy. InvUC make up the rest, and this group has a 50% mortality rate. Treatment of this disease includes cystectomy, radiation therapy, and chemotherapy with an average cost per patient of $150,000–$200,000. This is a serious disease, and serious treatment is required. Canine InvUC is important as a model for the human disease, and research in that direction should benefit our patients.

An important point to remember is that InvCU is a “solid tumor” implying that surgery and/or radiation therapy are the most appropriate treatments. For most solid tumors chemotherapy is primarily for prevention of metastatic disease. Interestingly, radiation therapy was the first reported treatment for canine urinary tract tumors. Alois Pommer, from the Austrian Veterinary College, wrote numerous publications from his thriving radiation practice, including bladder tumors. Anderson reported on late effects associated with lower abdominal radiation therapy. Numerous publications in the 1980s and 90s reported on cystectomies with alternative out paths for ureters, and of prostatectomy. Complications were numerous, and other than partial cystectomies, there was no further surgical progress, other than shunts. This provided a short term but not long-term treatment but can be successfully combined with radiation options.

We must recognize that medical therapy, surgical therapy, or radiation therapy alone is not enough to resolve this disease. We need to ask these questions. When combining radiation therapy and chemotherapy, is the chemotherapy to prevent metastatic disease or to help with local control? With the observation that there is more metastatic disease than expected, should chemo options be focused on metastatic disease? How can we better evaluate patients before and after treatment? How can we minimize late radiation effects? We need to recognize, like with the human counterpart, this disease will not be controlled without an aggressive, multimodality plan. So, let’s get serious, and collaborative about a serious disease.