A BOOST TECHNIQUE FOR IRRADIATION OF MALIGNANT CANINE NASAL TUMORS

Eighteen dogs with malignant nasal cavity tumors were treated with rad iation therapy, including a boost technique. Three 3.0 Gy boost doses were added to a treatment protocol consisting of sixteen 3.0 Gy daily fractions, bringing the total dose to 57 Gy. This boost technique was implemented without an associated increase in overall treatment time b y giving the boost doses on a twice-a-day basis. Boost doses were give n during the first half of the radiation therapy period. The treatment was completed as planned in 16 of the 18 dogs; two dogs received lowe r doses (51 and 54 Gy). Median survival was 177 days, poorer than in s ome other reported studies of nasal tumor irradiation. Acute effects w ere unacceptable, with 11 of the 18 dogs developing severe mucositis, desquamation, edema, swelling, and pruritus. The extensive nature of t he acute reactions compromised assessment of the effect of the increas ed radiation dose on the tumor. Although there is justification for as sessing more aggressive radiation protocols in canine nasal tumor pati ents, total doses approximating 60 Gy can not be given as described be cause of the inability of acutely responding normal tissues to compens ate.