Veterinary Oncology: The Lumps We Hate To Treat Michelle Turek, DVM, DACVIM (Oncology), DACVR (Radiation Oncology) College of Veterinary Medicine University of Georgia Athens, GA
Veterinary Oncology Veterinary Oncologists American College of Veterinary Internal Medicine 313 Veterinary Radiation Oncologists American College of Veterinary Radiology 86 Vet Rad Onc Facilities US: 77 (20 academic, 57 private practice) Canada: 4 (2 academic, 2 private practice) Europe: 12 (UK, Italy, Switzerland, Germany, France)
CT based planning 1980s Megavoltage 1950s Stereotactic Radiosurgery Emerging therapy Image-Guided Radiotherapy State of the art Intensity Modulated Radiotherapy Current 3D Conformal Radiation Therapy 1990s
Veterinary Radiation Therapy Centers USA Courtesy Dr. Susan LaRue, CSU
Veterinary Radiation Therapy Centers - IMRT Courtesy Dr. Susan LaRue, CSU
Veterinary Radiation Therapy Centers - IGRT Courtesy Dr. Susan LaRue, CSU
Canine Cancer Statistics 62% of American households have a pet 78 million pet dogs in US 86 million pet cats in US 6 million dogs diagnosed with cancer each year Cancer affects 1 out of 3 dogs Half will die of cancer Breed predispositions
Comparative Oncology The Dog As A Model For Human Cancer www.behance.net
Common Companion Animal Cancers Non-hodgkin s lymphoma Osteosarcoma Lung cancer Breast (mammary) carcinoma Prostate carcinoma Brain tumors Melanoma Intra-nasal carcinoma Thyroid carcinoma Anal sac adenocarcinoma Mast cell tumor / Soft tissue sarcoma Feline oral squamous cell carcinoma Feline vaccine associated sarcoma
Common Companion Animal Cancers Non-hodgkin s lymphoma Osteosarcoma Breast (mammary) carcinoma Melanoma Intra-nasal carcinoma
Common Companion Animal Cancers Melanoma Intra-nasal carcinoma Anal sac adenocarcinoma Feline oral squamous cell carcinoma Feline vaccine associated sarcoma
Nasal Tumors 10% of all neoplasms evaluated by radiation facilities 5 th most common tumor tx Epistaxis or nasal discharge Facial deformity Breathing noise Sneezing
Stage 2 Stage 3 Stage 4
Nasal Tumors: Radiation Therapy RT is not curative but offers local control Goals for therapy are Tumor control (curativeintent) Palliation With no therapy, median ST for carcinomas is 4 months
Radiation Therapy Palliation: 6-8 Gy X 4 weekly fractions 4 Gy daily X 5 days 70-100% rate of clinical sign resolution Median duration 120-300 days Curative-intent: 4.2 Gy X 10 days = 42 Gy Median survival time = 14-19.7 months Stage 4: 6 months
Veterinary Radiation Oncology at UGA Siemens mevatron linac 6 MV X-ray (10 MV disabled) Various electron energies 58 leaf MLC Varian s Eclipse and Aria 3D RT Advanced imaging: CT and MRI
3D RT with MLC
KCS Conjunctivitis Corneal ulceration Cataracts Ocular Effects
Acute Side Effect Oral Mucositis
Radiotherapy is the art of sparing normal tissue 100 100 Tumor Control Therapeutic Ratio Complications % COMPLICATIONS 0 Dose 0
Advanced IMRT w/ On-Board Imaging = Image Guided RT Varian Trilogy Cyberknife
Courtesy Dr. Susan LaRue, CSU
Dosimetric comparison 3D IGRT (Trilogy) Courtesy Dr. Susan LaRue, CSU
IGRT Dosimetry (Tomotherapy)
Patient Immobilization
Positioning Verification
Ocular Toxicity - IGRT Minor ocular toxicity despite severe periocular tumor extension 5 months Mild conjunctivitis Mild keratitis
Anal Sac Gland Adenocarcinoma www.vestvetstore.com www.veterinarypracticenews.com
Highly metastatic to regional LN
2.7 Gy X 18 daily fractions = 48.6 Gy
Radiation skin effects Fraction 18 1 month post RT
Chemoradiation for ASAC Mitoxantrone or carboplatin Median survival time with chemoradiaton >1000 days Timing of chemotherapy vs. radiation is controversial
Melanoma Oral tumor in dogs Highly metastatic Lymph node and pulmonary metastasis Size matters for prognosis Death within 6-8 months due to metastasis Immunotherapy breakthrough
Hypofractionated protocols Oral melanoma is radioresistant Coarse-fractionated protocols are believed more effective than standard fractionation 8 Gy X 3 weekly 6 Gy X 6 weekly 9 Gy X 3 weekly 10 Gy X 3 weekly
Coarse Fraction Protocols: Overall response rate 80-90% Complete response rate 50-70% Pre-RT Month 4 Week 3
Biological therapy: Therapeutic tumor vaccine
Xenogeneic DNA Immunization Canine Differentiation Antigen Human Differentiation Antigen Immunity Bergman, PJ., Wolchok, J.D. Reproduced with permission.
VRTOG: Evaluation of ONCEPT and course fraction RT in canine oral melanoma
Manual Treatment Set Up
Base of tongue necrosis 6 months post coarse fraction RT
Radiation Skin Effects Fraction 4 10 mo post RT 4 mo post RT
Tumor response to radiation Fraction 1 Fraction 4 1 year post RT
Vaccine-associated sarcoma Highly invasive SQ tumors Related to vaccination Inflammation malignant transformation
Vaccine-associated sarcoma Treatment of choice : radiation and surgical resection
Vaccine-associated sarcoma
Prevention = Thoughtful vaccination Avoid interscapular region All other vax R shoulder Left = Leukemia Distal Right = Rabies Distal
Pre-operative radiotherapy RT SX sterilized cancer cell
Electron beam therapy
4 months post RT
Feline Anesthesia Challenge Daily propofol causes Heinz-body anemia
Pituitary Tumors Tumors we like to treat Most tumors are nonfunctional Dogs present with neurologic signs No radiation side effects Excellent progressive tumor response and clinical improvement
2.5 Gy X 20 daily fractions = 50 Gy
Feline Oral Squamous Cell Carcinoma
Feline Oral Squamous Cell Carcinoma Early detection is critical to a favorable outcome Courtesy Dr. Kai-Biu Shiu, WI
Strontium-90 Ophthalmic Applicator Sr-90 is a radioactive isotope that emits beta particles 90 38 Sr 90 39Y + β - Shallow penetration Physical half life = 30 yrs
Sr-90 = Superficial irradiation
Indications for Sr-90 plesiotherapy SUPERFICIAL TUMORS: Feline cutaneous mast cell tumor Feline nasal planum squamous cell carcinoma Superficial ocular tumors
Challenges in Veterinary Radiation Oncology Advanced tumors Large incisions Anesthesia requirement Increases risk Slows throughput Rush to use of SRS/SRT Limited info about normal tissue tolerance Inconsistent reporting standards
Thank you for your interest! Questions?