Page 1318 - Clinical Small Animal Internal Medicine

1256 Section 11 Oncologic Disease

survival time of 36 months. Local tumor recurrence was adjunct to surgery, a median survival time of 18–26 months
VetBooks.ir a more common cause of first treatment failure than is reported. A study completed in 2011 reported the out-
come in 29 dogs with oral fibrosarcomas treated with sur-
regional metastasis to lymph nodes. Dogs with T1, T2,
and T3 tumors had a progression free, one‐year survival
median survival time in this study was reported to be
rate of 89%, 83%, and 41% respectively, and a three‐year gical excision with or without adjuvant radiation. The
progression‐free survival rate of 74%, 53%, and 23%, approximately two years with a one‐ and two‐year progres-
respectively. A study of 14 dogs treated with full‐course sion‐free survival rate of 88% and 58%, respectively.
radiation therapy as the primary treatment modality
reported median disease‐free interval and survival of 12 Epulides
and 14 months, respectively. The median disease‐free The prognosis for dogs with epulides is excellent follow-
interval was 16 months in dogs 9 years or less, and seven ing treatment with either surgery or radiation therapy. In
months in dogs older than 9 years of age. contrast to fibromatous and ossifying epulides, wide
local excision of adjacent soft tissue and bone is neces-
Feline Squamous Cell Carcinoma sary for cure of acanthomatous ameloblastomas. Local
The prognosis for feline SCC is poor, as there is no recurrence rate following bone‐removing surgery is less
known consistent, effective treatment for gaining local than 5%.
control. In one series of 52 cats, the one‐year survival Radiation therapy is indicated for acanthomatous
rate was less than 10% with median survival times of ameloblastomas that are not curable with surgery alone.
three months for surgery, surgery and radiation therapy, In a prospective clinical trial, 47 dogs with acanthoma-
radiation therapy and low‐dose chemotherapy, and radi- tous ameloblastomas (39 dogs) or fibromatous or ossify-
ation therapy with hyperthermia. Other studies investi- ing epulides (eight dogs) were treated with 12 fractions
gating surgery alone, have reported median survival of 4 Gy, three times a week to a total dose of 48 Gy.
times of 5.5–7.5 months, but only tumors of the mandi- Clinical stage was the only significant prognostic factor,
ble were considered resectable. In a separate study the with dogs that had stage T3 tumors having a 7.9 times
combination of surgery and radiation reported a survival higher risk of tumor recurrence than dogs with stage T1.
time of 14 months. All cases were arising from the In a 2004 study of 57 dogs treated with radiation therapy,
mandible. the median overall survival time was four years.
Radiation therapy alone is generally ineffective in the Intralesional bleomycin has also been described for the
management of cats with oral SCC. However, the combi- treatment of acanthomatous ameloblastomas. With this
nation of radiation with radiation sensitizers or chemo- treatment, a complete response was sustained in all four
therapy has resulted in response rates from 70% to 100% dogs treated for greater than one year with no local
and median survival times of approximately 3–6 months. recurrence.
A recent prospective study including 31 cases of oral
SCC in cats evaluated the effectiveness of an accelerated
radiation therapy protocol and concomitant carboplatin Nasal Tumors
for treatment. Median survival for all cats in this study
was 5.4 months, while cats with tumors of tonsillar ori- Etiology/Pathophysiology
gin or cheek responded best to therapy with a mean sur-
vival of two years. Carcinomas, including adenocarcinoma, squamous cell
carcinoma, and undifferentiated carcinoma, comprise
Fibrosarcoma nearly two‐thirds of nasal tumors in the dog while sarco-
The prognosis for dogs with oral fibrosarcoma is guarded. mas, including fibrosarcoma, chondrosarcoma, osteo-
Multimodal treatment with surgery and radiation therapy sarcoma, and undifferentiated sarcoma, comprise the
of the local disease results in the best survival rates. bulk of the remaining tumors. In the cat, lymphoma and
Following maxillectomy or mandibulectomy alone, local carcinoma are the most common tumors of the nasal
recurrence is reported in up to 60% of dogs with a median cavity. It has been speculated that dogs living in urban
survival time of 10–12 months and a one‐year survival rate environments may be at higher risk for developing nasal
of 50%. Oral fibrosarcomas are considered to be radiation tumors, and some studies have also associated the expo-
resistant. A smaller tumor size improves the outcome fol- sure of environmental tobacco smoke as an increased
lowing radiation therapy, with the median progression‐free risk factor, but this finding is not consistent. Nasal lym-
survival time of 45 months for dogs with T1 tumors com- phoma in cats is typically feline leukemia virus (FeLV)
pared to 31 months and seven months for T2 and T3 antigen negative, and definite risk factors have not been
tumors, respectively. When radiation therapy is used as an reported.