Page 1404 - Clinical Small Animal Internal Medicine

1342 Section 11 Oncologic Disease

Table 152.1 Modified World Health Organization TNM staging system
VetBooks.ir Stage 0 I II III

T = primary tumor No evidence of tumor Tumor less than 5 cm; Tumor 5 cm or greater Tumor invading
confined to primary site or ruptured; invading adjacent structures,
subcutaneous tissue including muscle
N = lymph nodes No lymph node Regional lymph node Distant lymph node
involvement involvement involvement
M = metastasis No distant metastasis Distant metastasis

Table 152.2 Chemotherapeutics commonly used for the treatment of hemangiosarcoma

Frequency/days given Unique
Drug Dose (every 3 weeks = 1 cycle) Use Route side‐effects

Doxorubicin 30 mg/m 2 Every 2–3 weeks (day 1 Single agent or combined Intravenous Cardiotoxicity
and day 14 or 21) with cyclophosphamide
+/‐ vincristine
Vincristine 0.75 mg/m 2 Days 8 and 15 Combined with doxorubicin Intravenous
Cyclophosphamide 100 mg/m 2 Day 1 (when with Combined with doxorubicin Intravenous Sterile
vincristine and alone or vincristine and or oral hemorrhagic
doxorubicin), days 3–6 doxorubicin cystitis
(with doxorubicin alone)
Dacarbazine 800 mg/m 2 Day 1 (same day as With doxorubicin Intravenous
doxorubicin) (constant
rate infusion)
Temozolomide 100–125 mg/m 2 Days 1–5 With doxorubicin Oral

Stage III (T2 or T3, N1 or N2, M1) describes a tumor ECG monitoring for a minimum of 24 hours postoper­
invading adjacent structures, lymph node involvement atively is recommended. Ventricular tachycardia,
(regional or distant), and/or distant metastasis. sustained tachycardia (180 beats per minute) with
When applied to the integumentary system, the paroxysmal runs of ventricular premature complexes
TNM classification can be utilized with the following (VPCs) or patients that are symptomatic for ventricular
additional location‐specific parameters: stage I, tumor arrhythmias can be treated with lidocaine boluses or
confined to the dermis; stage II, tumor extends into sub­ constant rate infusions. Most arrhythmias will resolve
cutaneous tissue, rupture not a consideration; stage III, within 24–48 hours.
muscular invasion has occurred. Patients with splenic hemangiosarcoma commonly
have evidence of liver metastasis at the time of diagnosis.
However, all hepatic nodules identified at surgery should
Therapy not be assumed to be malignant as benign conditions
such as nodular hyperplasia are also commonly found
in the aged animal. It is necessary to perform a biopsy
Surgery
of any suspicious lesion when removing an abdominal
Regardless of species and primary location, surgery mass.
along with adjunctive doxorubicin‐based chemotherapy Surgical excision of myocardial HSA is rarely per­
(Table 152.2) is the treatment of choice. Notable formed. Tumors in this location are a significant techni­
exceptions include small dermal lesions (stage I) and cal challenge and are seldom completely removed. For
conjunctival forms; these presentations may not require most patients, laparoscopic or open thorax pericardiec­
adjunctive chemotherapy as they carry a much lower risk tomy may be the only surgical option. Pericardiectomy
of metastasis. may provide palliation and short‐term survival gains as
Surgical mass removal is vital to minimize the risk it minimizes risk of pericardial tamponade. Owners
of fatal hemorrhage with splenic hemanigosarcoma. should be warned about sudden death from tamponade
Intraoperatively, arrhythmias are common, so continuous if removal or pericardectomy is not pursued.