Palliative intracavitary carboplatin therapy in a cat with suspected pleural mesothelioma

Thoracoscopic Assisted PleuralPortTM Application in Seven Dogs Affected by Chronic Pleural Effusion

Chronic non-septic pleural effusion is a condition that frequently may occur because of lung or pleural neoplasia, or chylothorax refractory to surgical treatment, in dogs. Effusion management can be performed with multiple pleurocenteses or the application of chest drains. New modified vascular devices have been used for patients with chronic diseases; they offer the advantage of allowing home management and do not require hospitalization. Eight PleuralPort^TM devices were applied in seven dogs during thoracoscopic exploration and biopsy procedures; five were affected by mesothelioma; one by lung metastases from a mammary carcinoma; and one by chronic chylothorax. The median time of surgical procedure was 51 min; one developed pneumothorax post-operatively that resolved within 12 h after repeated drainage; one device was obstructed after 45 days and was successfully managed by flushing. All patients were discharged after 24 h. The median duration of port insertion in cancer patients was 5 months and those dogs were euthanized because of tumor progression; in the dog with chylothorax, the device was removed after 1 year when the effusion had resolved.

Evaluation of intracavitary carboplatin chemotherapy for treatment of pleural carcinomatosis in cats: a retrospective study of eight cases

OBJECTIVES

The aim of this study was to evaluate the benefit of intracavitary carboplatin chemotherapy in cats with malignant pleural effusion of epithelial origin.

METHODS

The medical records of cats with a cytological diagnosis of neoplastic pleural effusion of epithelial origin were reviewed at three referral institutions between January 2013 and June 2018. Only cats treated with intracavitary carboplatin chemotherapy were enrolled. Data collection included signalment, medical history, clinical signs, pleural effusion analysis, diagnostic imaging findings, intracavitary carboplatin chemotherapy protocol, adverse events, response to chemotherapy, outcome and underlying primary tumour, if possible.

RESULTS

Eight cats met the inclusion criteria. Three cats had previous surgical removal of a tumour, including a poorly differentiated primary lung carcinoma, a uterine adenocarcinoma and a benign mammary tumour. The main clinical signs were tachypnoea and/or dyspnoea, inappetence and weight loss. Thoracic radiographs revealed marked bilateral pleural effusion in all cats. Pleural fluid analysis was consistent with a modified transudate, with malignant epithelial cells on cytology, leading to a diagnosis of pleural carcinomatosis. All cats received only one cycle of intracavitary carboplatin chemotherapy at a dose of 200-240 mg/m2. Recurrence of pleural effusion was reported in 7/8 cats within 4-15 days of chemotherapy, and death was recorded in all cats within 5-16 days, owing to recurrent pleural effusion or poor general condition. The primary cancer was suspected to be of pulmonary, mammary and pancreatic origin in four cats, two cats and one cat, respectively, and of unknown origin in the remaining cat.

CONCLUSIONS AND RELEVANCE

In this study, intracavitary carboplatin chemotherapy seems ineffective in managing neoplastic pleural effusion of epithelial origin in cats with pleural carcinomatosis. Other cytotoxic drugs and/or techniques should be investigated in the future to improve the quality of life and survival of cats with pleural carcinomatosis.

A Review of 18 Cases of Feline Colonic Adenocarcinoma Treated with Subtotal Colectomies and Adjuvant Carboplatin

Feline colonic adenocarcinoma is a locally invasive, highly metastatic tumor that is most often treated with wide surgical excision (subtotal colectomy) and systemic chemotherapy either with or without nonsteroidal anti-inflammatory medications. In this retrospective study, the outcome of subtotal colectomy and adjuvant carboplatin in 18 client-owned cats is described. The median carboplatin dose was 200 mg/m2 (range, 200–254 mg/m2) q 4 wk with a median of five doses/cat (range was two to seven doses/cat). Limited toxicities were noted. Positive prognostic factors for the disease-free interval included cats that had weight loss as a presenting sign (P < 0.036) and negative prognostic factors for median survival included nodal and distant metastasis (178 versus 328 days and 200 versus 340 days, respectively). The median disease-free interval was 251 days (range, 37–528 days) and the median survival time was 269 days (range, 40–533 days). Subtotal colectomy and adjuvant carboplatin is a safe and potentially effective treatment for cats with colonic adenocarcinoma.

Pleural Effusion in the Cat: A Practical Approach to Determining Aetiology

Practical relevance Diverse disease processes result in sufficient fluid accumulation within the pleural space to cause respiratory compromise. Determining the underlying aetiology is key to appropriate management. This review outlines a practical approach to cases of pleural effusion, focusing on early recognition and confirmation of pleural space disease, stabilisation of the patient and logical diagnostic investigation. It emphasises the importance of a holistic approach, incorporating fluid analysis with other clinical data to determine the underlying aetiology.

Clinical challenges Cats with pleural effusion often have severe respiratory compromise at presentation. Careful handling and prompt and adequate stabilisation, incorporating supplemental oxygen and therapeutic thoracocentesis, is essential to avoid respiratory failure. The typical, stepwise approach to the case must be adapted and the clinician may have to proceed, at least initially, without the luxury of information gained from a full history and physical examination. The challenge is to juggle stabilisation, localisation and confirmation of pleural effusion, owner communication and minimally invasive examination while remaining vigilant for clues that allow ranking of the differentials to formulate a diagnostic plan.

Evidence base Appropriately designed studies to determine the utility of diagnostic techniques in cases with confirmed aetiology are limited. The evidence supporting this review is grade II, III and IV, comprising a small number of prospective studies, several case series, reviews, extrapolation from other species, pathophysiological justification and combined clinical experience of those working in the field.

Predominantly fibrous malignant mesothelioma in a cat

Malignant mesotheliomas are rare tumours in domestic cats. They occur within the abdominal or thoracic cavity and are regularly associated with pleural or peritoneal effusions. The histopathological diagnosis can be quite challenging, as these neoplasms may resemble other epithelial or mesenchymal neoplasms. However, differentiation can be achieved by immunohistochemistry in most cases. Here we describe the rare case of a malignant mesothelioma of the fibrous subtype in the thoracic cavity of a cat and discuss differential diagnoses and treatment options for this tumor type.

Evaluation of serum iohexol clearance for use in predicting carboplatin clearance in cats

OBJECTIVE

To determine whether a glomerular filtration rate (GFR) assay based on serum iohexol clearance can be used to predict carboplatin clearance in cats.

ANIMALS

10 cats with tumors.

PROCEDURES

GFR was measured concurrently by use of plasma clearance of technetium Tc 99m-labeled diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) to yield GFR(99mTc-DTPA) and serum clearance of iohexol to yield GFR(Iohexol). A single dose of carboplatin was administered IV as a bolus. Dose was calculated by use of a target value for the area under the plasma platinum concentration-versus-time curve (AUC(Target)) and estimation of platinum clearance (CL(PT)) derived from GFR(99mTc-DTPA) as follows: dose = AUC(Target) x 2.6 x GFR(99mTc-DTPA) x body weight, where AUC(Target) is 2.75 min.mg.mL(-1). Plasma platinum concentrations were measured via atomic absorption spectrophotometry. Values for GFR(99mTc-DTPA) and GFR(Iohexol) were compared by use of least-squares regression and Bland-Altman analysis. Least-squares regression was used to determine whether CL(PT) could be predicted from GFR(99mTc-DTPA) or GFR(Iohexol) (or both).

RESULTS

GFR(99mTc-DTPA) and GFR(Iohexol) were strongly correlated (r = 0.90), but GFR(Iohexol) values were significantly larger by a factor of approximately 1.4. Platinum clearance had a significant linear relationship to GFR(99mTc-DTPA) (CL(PT) = 2.5 x GFR(99mTc-DTPA)) and to GFR(Iohexol) (CL(PT) = [1.3 x GFR(Iohexol)] + 1.4).

CONCLUSIONS AND CLINICAL RELEVANCE

In cats, serum iohexol clearance was an accurate predictor of CL(PT) and can be used to calculate the carboplatin dose as follows: dose = AUC(Target) x ([1.3 x GFR(Iohexol)] + 1.4) x body weight.

Piroxicam and intracavitary platinum-based chemotherapy for the treatment of advanced mesothelioma in pets: preliminary observations

Malignant Mesothelioma is an uncommon and very aggressive tumor that accounts for 1% of all the deaths secondary to malignancy in humans. Interestingly, this neoplasm has been occasionally described in companion animals as well. Aim of this study was the preclinical evaluation of the combination of piroxicam with platinum-based intracavitary chemotherapy in pets. Three companion animals have been treated in a three years period with this combination. Diagnosis was obtained by ultrasonographic exam of the body cavities that evidenced thickening of the mesothelium. A surgical biopsy further substantiated the diagnosis. After drainage of the malignant effusion from the affected cavity, the patients received four cycles of intracavitary CDDP at the dose of 50 mg/m² every three weeks if dogs or four cycles of intracavitary carboplatin at the dose of 180 mg/m² (every 3 weeks) if cats, coupled with daily administration of piroxicam at the dose of 0.3 mg/kg. The therapy was able to arrest the effusion in all patients for variable remission times: one dog is still in remission after 3 years, one dog died of progressive disease after 8 months and one cat died due to progressive neoplastic growth after six months, when the patient developed a mesothelial cuirass. The combination showed remarkable efficacy at controlling the malignant effusion secondary to MM in our patients and warrants further investigations.