Page 800 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

778 PART IV Specific Malignancies in the Small Animal Patient

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TABLE 34.2 Outcomes for Dogs Treated for Splenic MST of almost 4 months. There is also some evidence to suggest
Hemangiosarcoma that systemic therapy may offer some benefit to patients with other
forms of advanced and inoperable HSA. One study evaluating the
VetBooks.ir Treatment MST Reference combination of DOX and deracoxib reported an MST of 149
a
(days)
days for dogs with stage III splenic HSA, which was similar to the
Splenectomy 19–86 2,3,8 MST of 150 days for dogs of all stages combined. 107 Dogs with
advanced stage HSA treated with a DAV protocol had a response
Splenectomy + MBV 91 3 rate of 47% and median time to progression of 101 days. 104 Simi-
Splenectomy + MBV + VMC 117 3 larly, dogs with stage III HSA treated with a VAC protocol had an
MST (195 days) that was similar to that of dogs receiving the same
Splenectomy + A 172–210 b 100,109
treatment for stage I/II disease (MST 189 days). 133
Splenectomy + AC 140 –180% 101,121
c
Splenectomy + AC + L-MTP-PE 277 121 Feline
Splenectomy + A + VAX 182 120 In cats, the prognosis for visceral HSA is poor. Most cats die from
recurrence of the primary tumor or metastasis, and MSTs are generally
Splenectomy + A/DER 150 107
short (77–197 days), owing to metastasis. 59,134 On the other hand,
Splenectomy + A/IFOS 123 105 cats with cutaneous and subcutaneous HSAs that are treated with
aggressive surgery have reported MSTs of approximately 9 months
Splenectomy + A/DTIC >550 d 106
to 4 years. 11,58 Similar to those in dogs, feline HSAs with subcutane-
Splenectomy + A + TOC 172 126 ous involvement are associated with higher rates of incomplete exci-
Splenectomy + VAC 140–145 8,103,133 sion (50%–94%) and local recurrence (50%–80%). 11,55,56,58
Splenectomy + MET 1 178 113 Conclusion
Splenectomy + DOX + MET 2 NR 114
In summary, HSA remains one of the most aggressive cancers in
Splenectomy + DOX + MET 3 134 115 dogs and cats and the longterm prognosis for most forms is generally
Splenectomy + EPI 144 111 poor. Surgery still offers the best approach to treat HSA even though
it is typically only palliative; standard DOX-based chemotherapy has
Splenectomy + DOXIL (IV) 166 109
led to incremental improvement in prognosis. New approaches to
Splenectomy + DOXIL (IP) 131 110 treatment using combinations of surgery, conventional chemother-
apy, metronomic and antiangiogenic therapy, immunotherapy, and
Splenectomy + IFOS 147 108
targeted agents are needed to improve the outlook for this disease.
Splenectomy + PSP 117–199 3
Comparative Aspects
Splenectomy + eBAT + DOX 258 127
a Not separated by stage of disease. In humans, a spectrum of endothelial tumors, including heman-
b Data for stage II splenic HSA only. gioma, hemangioblastoma, Kaposi’s sarcoma, hemangioendothe-
c 15/18 had splenic HSA. lioma, and AS, is seen. AS is extremely rare in humans and can be
d 5/9 had splenic HSA. a late sequela to RT in women treated for breast cancer. 135 With
A, Adriamycin (doxorubicin); C, cyclophoshamide; DER, deracoxib; DOXIL, pegylated liposomal this exception, it has a lesion distribution and behavior similar to
encapsulated doxorubicin; DTIC, dacarbazine; eBAT, bispecific Egf-urokinase angiotoxin; EPI, canine HSA. As in dogs, metastasis is frequent and adjuvant che-
epirubicin; HSA, hemangiosarcoma; IFOS, ifosfamide; L-MTP-PE, liposome muramyl tripep- motherapy provides minimal benefit.
tide phosphatidylethanolamine; M, methotrexate; MBV, mixed bacterial vaccine; MET 1 , met-
ronomic cyclophosphamide/etoposide + piroxicam; MET 2 , metronomic cyclophosphamide +
thalidomide; MET 3 , metronomic cyclophosphamide +/– nonsteroidal antinflammatory; MST, SECTION B: THYMOMA
median survival time; PSP, polysaccharopeptide (Coriolus versicolor); TOC, toceranib phos-
phate; V, vincristine; VAX, tumor lysate vaccine.

CARLOS H. DE MELLO SOUZA
tumors responded sufficiently to allow for complete resection.
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Traditionally, the prognosis for cardiac HSA is considered poor. Incidence and Risk Factors
Without treatment, most dogs succumb to the disease within 2
weeks. In the rare case where surgical removal of cardiac HSA is Thymoma is an uncommon cranial mediastinal tumor in dogs and
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possible, survival times generally range from 1 to 3 months. 25,94,95 cats, but is the second most common cranial mediastinal tumor
In a small group of dogs receiving adjuvant chemotherapy after sur- in both species. Thymomas can occur at any age, but they usu-
gical tumor removal, an increased MST (175 days) was reported. ally affect older patients. The mean age at presentation in dogs
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Although pericardiectomy (via thoracotomy or thoracoscopy) can and cats is 9 and 10 years, respectively. 136,137 A breed predisposi-
be considered as a palliative measure, it does not appear to improve tion has not been clearly identified, but in a recent retrospective
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survival by itself, with reported MSTs of 2.7 to 4 months. Che- multiinstitutional study, 38% of 116 dogs with thymoma were
motherapy appears to offer some benefit, as a retrospective study Labrador retrievers and golden retrievers. 138 A sex predisposition
evaluating the use of DOX chemotherapy for dogs with presump- has not been identified. 136–138 Risk factors predisposing animals
tive cardiac HSA documented a 41% objective response rate and to thymoma have not been identified.