Objective—To determine progression-free and overall survival times of cats with squamous cell carcinoma (SCC) of the nasal planum following treatment with a single fraction of strontium Sr 90 (90Sr).
Design—Retrospective case series.
Animals—49 cats with SCC of the nasal planum.
Procedures—Information including FIV infection status, diagnosis of SCC vs SCC in situ (ie, evidence that the tumor did or did not penetrate the epidermal basement membrane, respectively), 90Sr dose and number of probe applications, treatment-related response and complications, and recurrence of SCC and new lesion development was obtained from medical records. The relationships of these variables with calculated progression-free and overall survival times were assessed.
Results—Of 49 cats that underwent 90Sr plesiotherapy (median dose, 128 Gy), 48 (98%) had a response to treatment and 43 (88%) had a complete response. Median progression-free and overall survival times were 1,710 and 3,076 days, respectively. Treatment complications were infrequent (4 [8%] cats) and mild. Following treatment, the SCC recurrence rate was 20% (10/49 cats); 16 (33%) cats developed new lesions in other locations. Overall survival time was significantly longer for cats with a complete response to treatment than for those with a partial response. None of the other variables evaluated had a significant effect on progression-free or overall survival time.
Conclusions and Clinical Relevance—Treatment of cats with SCC of the nasal planum with a single fraction of 90Sr appeared to be effective and well tolerated. Initial response to treatment was predictive of overall survival time.
Objective—To assess the influence of tumor cell proliferation
and sex-hormone receptors on the efficacy
of megavoltage irradiation for dogs with incompletely
Design—Longitudinal clinical trial.
Animals—20 dogs with incompletely resected intracranial
Procedure—Dogs were treated with 48 Gy of radiation
administered 3 times per week on an alternateday
schedule of 4 Gy/fraction for 4 weeks, using bilateral
Results—Tumor proliferative fraction measured by
immunohistochemical detection of proliferating cell
nuclear antigen (PFPCNA index) ranged from 10 to 42%
(median, 24%). Progesterone receptor immunoreactivity
was detected in 70% of tumors. Estrogen
receptor immunoreactivity was not detected. An
inverse correlation was found between detection of
progesterone receptors and the PFPCNA index. The
overall 2-year progression-free survival (PFS) rate was
68%. The only prognostic factor that significantly
affected PFS rate was the PFPCNA index. The 2-year
PFS was 42% for tumors with a high PFPCNA index
(value ≥ 24%) and 91% for tumors with a low PFPCNA
index (value < 24%). Tumors with a high PFPCNA index
were 9.1 times as likely to recur as were tumors with
a low PFPCNA index.
Conclusions and Clinical Relevance—This study
confirms the value of irradiation for dogs with incompletely
resected meningiomas. Prognostic value of
the PFPCNA index suggests that duration of treatment
and interval from surgery to start of irradiation may
affect outcome. Loss of progesterone receptors in
some tumors may be responsible for an increase in
PFPCNA index and may indirectly affect prognosis after
radiation therapy. (J Am Vet Med Assoc 2000;216:
Objective—To determine quality and duration of progression-free survival (PFS) time in dogs with unresectable
thyroid carcinomas treated with definitive
megavoltage irradiation and analyze prognostic factors
of PFS and patterns of failure (local recurrence vs
Design—Prospective clinical trial.
Animals—25 dogs with locally advanced thyroid carcinomas
and no evidence of metastasis.
Procedure—Dogs were treated with 48 Gy during 4
weeks on an alternate-day schedule of 4 Gy/fraction.
Results—Irradiation was safe and effective for treatment
of large unresectable thyroid carcinomas.
Progression-free survival rates were 80% at 1 year
and 72% at 3 years. Time to maximum tumor size
reduction ranged from 8 to 22 months. Factors affecting
PFS were not found. Twenty-eight percent (7/25)
of dogs developed metastasis. Dogs with bilateral
tumors had 16 times the risk of developing metastases,
compared with dogs with a single tumor. Dogs
with no evidence of tumor progression had 15 times
less risk of developing metastases. Radiation-induced
hypothyroidism was suspected in 2 dogs 13 and 29
months after irradiation.
Conclusions and Clinical Relevance—Irradiation is
effective for local control of thyroid tumors, despite
their slow regression rate. Results provided evidence
that local tumor control affects metastatic
outcome in dogs with thyroid carcinomas and is a
strong basis for the development of new approaches
that include irradiation in the management of
dogs with advanced thyroid carcinomas. Improvements
in local tumor control alone may be
insufficient to improve survival times because of the
high risk of metastatic spread before an initial diagnosis
is made, which warrants initiation of early systemic
treatment. (J Am Vet Med Assoc 2000;216:
Objective—To determine the incidence of bovine
papillomavirus (BPV) type 1 or 2 in sarcoids and other
samples of cutaneous tissues collected from horses
in the western United States.
Animals—55 horses with sarcoids and 12 horses
Procedure—Tissue samples (tumor and normal skin
from horses with sarcoids and normal skin, papillomas,
and nonsarcoid cutaneous neoplasms from
horses without sarcoids) were collected. Tissue samples
were analyzed for BPV-1 or -2 DNA, using a polymerase
chain reaction (PCR) and restriction fragment
length polymorphism. The PCR products from 7 sarcoid-
affected horses were sequenced to evaluate percentage
homology with expected sequences for BPV-1 or -2.
Results—Most (94/96, 98%) sarcoids contained BPV
DNA. Sixty-two percent of the tumors examined had
restriction enzyme patterns consistent with BPV-2.
Thirty-one of 49 (63%) samples of normal skin
obtained from horses with sarcoids contained BPV
DNA. All samples subsequently sequenced had
100% homology with the expected sequences for the
specific viral type. All tissues from healthy horses,
nonsarcoid neoplasms, and papillomas were negative
for BPV DNA.
Conclusions and Clinical Relevance—Bovine papillomaviral
DNA was detected in essentially all sarcoids
examined. There appears to be regional variation in
the prevalence of viral types in these tumors. The fact
that we detected viral DNA in normal skin samples
from horses with sarcoids suggests the possibility of
a latent viral phase. Viral latency may be 1 explanation
for the high rate of recurrence following surgical excision
of sarcoids. (Am J Vet Res 2001;62:741–744)
Objective—To determine expression of a transforming
gene (E5) of bovine papillomavirus in sarcoids,
other tumors, and normal skin samples collected
from horses with and without sarcoids.
Sample Population—23 sarcoids and 6 samples of
normal skin obtained from 16 horses with sarcoids, 2
samples of normal skin and 2 papillomas obtained
from horses without sarcoids, and 1 papilloma
obtained from a cow.
Procedure—Protein was extracted from tissue samples
collected from horses and incubated with
agarose beads covalently coupled to Staphylococcus
aureus protein A and an anti-E5 polyclonal antibody.
Following incubation, proteins were eluted from the
beads and electrophoresed on a 14% polyacrylamide
gel and transferred to a polyvinylidene difluoride
membrane. The E5 protein was detected by use of
western blot analysis, using a chemiluminescence
Results—All 23 sarcoids had positive results for
expression of E5 protein. Quantity of viral protein
appeared to vary among sarcoids. All other tissues
examined had negative results for E5 protein. Highest
expression for E5 protein was observed in biologically
aggressive fibroblastic variants of sarcoids, compared
with expression in quiescent tumors.
Conclusions and Clinical Relevance—This study
documented that activation and expression of the E5
gene is evident in sarcoids obtained from horses.
These data support the conclusion that infection with
bovine papillomavirus is important in the initiation or
progression of sarcoids in horses. Treatment strategies
designed to increase immune recognition of
virally infected cells are warranted. (Am J Vet Res
Objective—To determine outcome associated with cutaneous tumors treated via intratumoral chemotherapy with cisplatin and identify risk factors affecting local tumor control and complications in equidae.
Design—Retrospective case series.
Animals—573 equidae with 630 cutaneous tumors.
Procedures—Medical records of horses, mules, donkeys, and ponies with cutaneous tumors treated via intratumoral chemotherapy with cisplatin were analyzed.
Results—549 horses, 13 mules, 8 donkeys, and 3 ponies with 630 histologically confirmed cutaneous tumors were included. Tumors included sarcoids (n = 409), squamous cell carci nomas (151), soft tissue sarcomas (28), cutaneous lymphomas (26), and melanomas (16). Overall cure rate, defined as local control at 4 years, was 93.3%. For all tumor stages combined, cure rates after 1 course of treatment were 96.3% for sarcoids, 96% for lym-phomas, 88% for squamous cell carcinomas, 85% for soft tissue sarcomas, and 81% for melanomas. Treatment protocol, tumor stage, and prior treatment were significant prog nostic factors for tumor control. Treatment efficacy was lower for large tumors, those with gross postoperative residual disease, and those that had been treated previously with other modalities. Treatment was well tolerated. Local reactions were more likely to occur and to be more severe after the third and fourth treatment sessions.
Conclusions and Clinical Relevance—Results confirmed the value of intratumoral chemotherapy with cisplatin for treatment of cutaneous tumors in equidae.The results cannot be extrapolated to other formulations of cisplatin or other protocols that might be used.