Surviving Oral Melanoma TUMOR TIDBITS, A BIWEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 84; January 17, 2003. ======================================================================= THIS WEEK'S TUMOR TIDBIT: Surviving Oral Melanoma. ======================================================================= THIS WEEK'S ANNOUNCEMENTS We're adding a third day of clinical service in San Antonio in March! Dr. King returns to San Antonio for consultations in Radiation Oncology. Please call our reception desk at the Broadway Clinic at 210-822-1913 to see Drs. Hahn, Carreras and King in San Antonio Tuesdays through Thursdays. Please call our Clinical Trials Assistant, Ms. Kelly Griffice, if you have questions about pet eligibility for our ongoing clinical trials. ======================================================================= Everyone knows the prognosis for a dog with oral melanoma is bad right? Well it still isn't stellar but in this week's Tidbit, we present a short overview from our just- published study (in the Journal of Veterinary Internal Medicine, 2003;17:96-101) by our own Dr. Freeman on the therapy of oral melanoma in dogs following incomplete surgical removal. In short, without chemotherapy the one-year survival rate is less than 10-20% with most dogs developing systemic metastatic disease and complications from tumor regrowth in the oral cavity. With weekly low-dose chemoradiation the recurrence rate is <15%, the metastatic rate is 50%, one-year survival rate is 50% and the two-year survival rate is 40%! In the study published by Dr. Freeman, 39 dogs with incompletely resected oral melanoma were examined to determine the efficacy of hypofractionated radiation therapy and platinum-containing chemotherapy. All dogs were completely staged, with the majority of dogs classified as stage I (tumors <2 cm maximum diameter). Dogs received six weekly fractions of 6 Gy megavoltage irradiation using a Cobalt-60 Unit or 4 MeV Linear Accelerator. Dogs received cisplatin (10 to 30 mg/ m2 IV) or carboplatin (90 mg/ m2 IV) chemotherapy 60 minutes prior to radiation delivery. Duration of local control, metastasis free survival time, and overall survival time were recorded. Using the Kaplan-Meier method, 15% of dogs had local recurrence of their disease. Fifty-one percent of dogs developed metastatic disease during the first year. Median survival time for all 39 dogs was 1 year (range 1 month to 5 years) with 40% surviving 2 years or longer. The protocol as described in this report provided a low rate of local recurrence, prolonged control of metastatic disease, and a survival time comparable to previous reports for dogs with incompletely resected oral malignant melanoma. This protocol was well tolerated by patients and no treatment delays secondary to radiation therapy effects or chemotherapy were reported. Acute grade I radiation side effects of the oral mucosa were noted during weeks 3 or 4 of therapy, but resolved following completion of therapy. Chronic radiation reactions included alopecia and dermal thinning from 1 to 12 months following completion of the radiation protocol. Because chemotherapy was given well below the maximum tolerated dose, no side effects were observed. SO WHAT DO WE DO AT GULF COAST? * First, we recommend immunohistochemistry on all dogs who have oral malignancies suspected as high grade sarcomas or amelanotic melanomas to determine if this weekly protocol is warranted. * Second, we begin therapy once weekly (chemotherapy first, radiation following) for a total of 6 times. * Third, we consider after therapy the use of other adjuvants that have improved survival time in dogs with melanoma including the melanoma vaccine available from the University of Wisconsin as well as daily Piroxicam and Doxycycline as antiangiogenic/antimetastatic care. ======================================================================= As always, we hope this info helps and don't hesitate to call or email us Gulf Coast Veterinary Oncology! Kevin A. Hahn, DVM, Phd, Diplomate ACVIM (Oncology), drhahn@gcvs.com Janet K. Carreras, VMD, Diplomate ACVIM (Oncology), drcarreras@gcvs.com Glen K. King, DVM, MS, Diplomate ACVR (Radiology & Radiation Therapy), drking@gcvs.com Gulf Coast Veterinary Diagnostic Imaging & Oncology 1111 West Loop South, Suite 150, Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 W: www.gcvs.com