Page 1342 - Clinical Small Animal Internal Medicine

1280 Section 11 Oncologic Disease

needle aspirate cytology is diagnostically accurate in up The role of radiation therapy, interventional radiology,
VetBooks.ir to 90% and 100% of dogs and cats with pulmonary and regional chemotherapy remains relatively unexplored
for veterinary patients with pulmonary neoplasia.
tumors, respectively. Ultrasound and/or CT‐guided aspi­
ration has been described, as well as techniques utilizing
thoracoscopic or keyhole lung biopsy methods.
Prognosis
Most information regarding prognosis for animals with
Therapy
pulmonary tumors is derived from the behavior of epi­
Surgery is the treatment of choice for solitary pulmonary thelial tumors.
tumors in dogs and cats. For unilateral tumors, surgery can The median survival time of 24 beagle dogs diagnosed
be performed through either an intercostal thoracotomy or with pulmonary carcinomas treated with symptomatic
median sternotomy approach. Thoracoscopic and keyhole care alone was 10 months (range five days to 42 months).
techniques have also been described. Complete lung lobec­ The prognosis for dogs with pulmonary tumors treated
tomy is the preferred surgical approach, but techniques for surgically is variable and depends on a number of fac­
partial lung lobectomy are described. The use of automatic tors, some of which can only be determined postop­
stapling equipment allows for decreased surgical time with eratively (e.g., histologic grade and completeness of
minimal complications, but is more difficult in small excision). An older study reported a median survival
patients. It is important to note that biopsy of hilar lymph time of 13 months with lung lobectomy alone. For dogs
nodes at the time of thoracic surgery should be performed with incompletely excised tumors, median survival time
to complete staging. was only about 1–2 months compared to 11 months for
Pneumonectomy is considered for lesions that have completely excised tumors.
extended to all lobes of one lung while the contralateral Several specific prognostic factors have been identified
side is unaffected. The resulting physiologic alterations in dogs with pulmonary tumors (Table 140.1). Tumor stage
are much greater than performing a single lobectomy. is prognostic: T1 (solitary tumor) = median survival time
Dogs can survive a 50% decrease in lung volume, but not of 26 months, T2 (multiple tumors) = median survival time
75%. Therefore excision of all lung tissue on the left side seven months, and T3 (invasive into surrounding tissue) =
can be tolerated since it represents less than 50% of total median survival time of three months. The presence of
lung volume. metastatic disease within intrathoracic lymph nodes is a
There is little information regarding the utility of negative prognostic factor for dogs with primary lung
chemotherapy for treating primary lung tumors in dogs tumors (11–15 months if no metastatic disease present;
and cats. In dogs, doxorubicin and mitoxantrone have 1–2 months if metastases are detected). The presence of
been shown to provide little to no response. Two of seven clinical signs at the time of tumor detection is also a nega­
dogs with measurable pulmonary tumors showed a par­ tive prognostic factor: 18 months with no clinical signs
tial response to treatment with vinorelbine. Single‐agent compared to eight months when clinical signs are present.
vinorelbine was also evaluated in the microscopic dis­ Tumor size and location are also prognostic. Dogs with
3
ease setting in three dogs, and survival time for those tumors <100 cm and those with peripherally located
patients was 112, 169, and >730 days. tumors have longer survival times compared with dogs
3
Inhalational therapy has also been evaluated in dogs, with tumors >100cm or encompassing entire lung lobes.
resulting in complete and partial responses for dogs with Histologic grade is a prognostic factor for both dogs
metastatic tumors compared to stable to progressive dis­ and cats. The median survival time for dogs with well‐
ease for dogs with solitary ones. differentiated, moderately differentiated, and poorly dif­
Intracavitary chemotherapy with cisplatin, carbopl­ ferentiated tumors was 28 months, eight months, and
atin, or mitoxatrone, as well as sclerosing agents such five days, respectively. The median survival time for cats
as talc, has been used to treat malignant effusions with well‐differentiated tumors treated surgically was 23
in dogs. months, compared to 2.5 months for cats with poorly
In people with non­small cell lung cancer, treatment differentiated tumors. Other prognostic indicators for
benefits have been obtained using targeted therapy cats include the presence of clinical signs (median sur­
with either monoclonal antibodies or tyrosine kinase vival time of 4 days if present vs. 78 days if not), pleural
inhibitors directed against cell signaling pathways. The effusion (median survival time 2 days vs. 31 days), and
role of such targeted therapy in veterinary patients is the presence of metastatic disease (median survival time
unknown. 3 days vs. 60 days.)