Primary pulmonary neoplasia in cats: assessment of computed tomography findings and survival

Retrospective study of 540 cats with respiratory diseases in Japan (2003-2020)

BACKGROUND

Few epidemiological studies on respiratory medicine and the relationship between clinical signs and various respiratory diseases in cats have been reported.

OBJECTIVES

This retrospective study aimed to investigate the prevalence and breed predisposition to feline respiratory diseases in Japan and determine the association between clinical signs, duration and type of respiratory diseases.

METHODS

The medical records of cats with feline respiratory diseases were examined to obtain information on age, sex, breed, final diagnosis, clinical signs and duration. The odds ratios (ORs) and 95% confidence intervals were calculated to evaluate breed predispositions. Mann-Whitney U, Kruskal-Wallis and Dunn's tests were used to assess the duration of clinical signs.

RESULTS

This study included 540 cats with 615 respiratory diagnoses. The American Shorthair breed was predisposed to bronchopneumonia (BP; OR: 5.0) and pulmonary tumour (PT; OR: 3.6), while the Russian Blue breed exhibited a predisposition to inflammatory lower airway diseases (OR: 3.4), BP (OR: 6.1) and interstitial lung diseases (OR: 11.1). Similarly, the Scottish Fold breed displayed predisposition to PTs (OR: 5.8). The duration of clinical signs among nasal diseases, nasopharyngeal diseases and lower tracheal/bronchial and pulmonary diseases differed significantly (p = 0.001, p = 0.012, p < 0.0001, respectively).

CONCLUSIONS

The results suggest that some popular breeds in Japan are predisposed to feline respiratory diseases, especially the American Shorthair, Russian Blue and Scottish Fold breeds. The characteristics of occurrence, clinical signs and duration of each disease will aid in diagnosing, treating, preventing and elucidating the pathophysiology of feline respiratory disease.

Feline pulmonary carcinoma: Gross, histological, metastatic, and immunohistochemical aspects

Feline pulmonary carcinoma (FPC) is an uncommon neoplasm with unique morphological features. We describe the gross, histological, metastatic, and immunohistochemical aspects of FPC, based on postmortem examinations from an 11-year retrospective study. Thirty-nine cases were selected. Predispositions were observed in senior (P < .001) and Persian (P = .039) cats. There were three gross patterns of the pulmonary tumors: (a) a large nodule and additional smaller nodules, (b) a solitary nodule, and (c) small, multifocal to coalescent nodules. Extrapulmonary metastases were present in 22/39 cases (56.4%), mainly in the regional lymph nodes (17/39, 43.5%), skeletal muscles (9/39, 23%), kidneys (6/39, 15.3%), and parietal pleura (4/39, 10.2%). The primary tumor size was correlated with the occurrence of extrapulmonary metastases (P = .002). Histologically, the tumors were classified as papillary adenocarcinoma (19/39, 48.7%), adenosquamous carcinoma (ADS) (8/39, 20.5%), acinar adenocarcinoma (6/39, 15.3%), solid adenocarcinoma (3/39, 7.6%), lepidic adenocarcinoma (2/39, 5.1%), and micropapillary adenocarcinoma (1/39, 2.5%). By immunohistochemistry, 39/39 cases (100%) were positive for pancytokeratin, 34/39 (87.1%) for thyroid transcription factor-1, and 8/39 (20.5%) for vimentin. Immunoreactivity for p40 was detected in the squamous component of all ADSs (8/8, 100%) and occasionally in the glandular component of adenocarcinomas (10/31, 32.2%). Napsin A expression was absent in all feline tissue tested. The results indicate that a modified and simplified histological classification based on current human and domestic animal systems is appropriate for cats. Additionally, this study highlights the utility of p40 as an immunohistochemical marker for the diagnosis of FPC with squamous differentiation.

Tolerability and outcome of palliative treatment for metastatic pulmonary carcinoma in cats

OBJECTIVES

Pulmonary carcinoma is uncommon in cats and reporting of outcomes following medical treatment is limited, especially in presence of metastases. The aim of this study was to describe the outcome of cats affected by metastatic primary pulmonary carcinoma and to evaluate the tolerability of palliative treatment in this patient population.

MATERIALS AND METHODS

Medical records were searched for cats with a cytological or histopathological diagnosis of primary pulmonary carcinoma and evidence of metastatic disease. Cats were treated with antineoplastic agents, corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs) or received no systemic treatment. Cases in which thoracic CT was not performed, and those lacking definitive diagnosis by cytology or histopathology or receiving curative-intent surgery were excluded.

RESULTS

Thirty-four cats were identified: 18 were treated with antineoplastic agents and 16 received corticosteroids, NSAIDs or no treatment. Presenting clinical signs included coughing (53%), tachypnoea (26%), gastrointestinal signs (35%) and lethargy (18%). CT scan identified metastases to the lung parenchyma in all cases and additional metastatic lesions in 10 of 34 (59%) cases; pleural effusion was detected in 11 cases (32%). The overall median survival time for all cats was 64 days [range 1-1352 days; 95% confidence interval (CI) 48-164]. Presence of respiratory signs at presentation was the only factor influencing survival in the multivariable analysis.

CLINICAL SIGNIFICANCE

Medical treatment was well tolerated and appeared to palliate clinical signs in cats with metastatic pulmonary carcinoma, albeit with a modest duration and short overall survival. The role and benefit of chemotherapy/antineoplastic agents versus conventional palliative drugs in this setting remains unclear.

Pulmonary adenocarcinoma in a captive ocelot (Leopardus pardalis): morphologic and immunophenotypic characterization - case report

ABSTRACT Pulmonary adenocarcinoma is a malignant epithelial neoplasia that usually arises from conducting airways or alveolar parenchyma. It has rarely been described in wild felids, with no previous reports in ocelots. In domestic cats it is a very aggressive neoplasm with a high metastatic rate that usually evolves to death. This report aimed to describe a pulmonary adenocarcinoma in a captive and senile ocelot (Leopardus pardalis), with a thorough morphologic and immunophenotypically characterization, evidencing the epithelial-mesenchymal transition (EMT) phenomenon in a high metastatic carcinoma, an important feature rarely described in veterinary medicine, even in domestic cats.

Review of Histological Grading Systems in Veterinary Medicine

Tumor grading is a method to quantify the putative clinical aggressiveness of a neoplasm based on specific histological features. A good grading system should be simple, easy to use, reproducible, and accurately segregate tumors into those with low versus high risk. The aim of this review is to summarize the histological and, when available, cytological grading systems applied in veterinary pathology, providing information regarding their prognostic impact, reproducibility, usefulness, and shortcomings. Most of the grading schemes used in veterinary medicine are developed for common tumor entities. Grading systems exist for soft tissue sarcoma, osteosarcoma, multilobular tumor of bone, mast cell tumor, lymphoma, mammary carcinoma, pulmonary carcinoma, urothelial carcinoma, renal cell carcinoma, prostatic carcinoma, and central nervous system tumors. The prognostic relevance of many grading schemes has been demonstrated, but for some tumor types the usefulness of grading remains controversial. Furthermore, validation studies are available only for a minority of the grading systems. Contrasting data on the prognostic power of some grading systems, lack of detailed instructions in the materials and methods in some studies, and lack of data on reproducibility and validation studies are discussed for the relevant grading systems. Awareness of the limitations of grading is necessary for pathologists and oncologists to use these systems appropriately and to drive initiatives for their improvement.

Usefulness of Chest Ultrasonography in Predicting Diagnosis in Non-emergency Small Animal Patients With Lung Parenchymal and Pleural Disease

Chest ultrasonography has become an indispensable tool for pulmonary specialists in human medicine, but its current use in dogs and cats is primarily for emergency. The diagnostic performances of various ultrasonographic features other than comet-tail artifacts are of limited information in veterinary literatures. Therefore, the aims of this retrospective study were to investigate ultrasonographic findings in feline and canine respiratory patients with lung parenchymal and pleural space diseases, and to assess how ultrasonographic features correspond to specific diagnoses. Sixty-five non-emergency cases with radiographically identified lung parenchymal and pleural space abnormalities were included. Medical records and ultrasound video clips were reviewed, and additional follow-up information was subsequently collected. Common findings such as comet-tail artifacts (87.7% of cases), consolidation (84.6%), and thickened/irregular pleura (69.2%) were not distinguishable for a specific diagnosis. The presence of nodular/mass-like lesion (OR = 212, p < 0.001) and consolidated lesion with heteroechogenicity (OR = 240, p < 0.001) was significantly associated with and strongly predictive of neoplasia after age, body weight and other sonographic findings were adjusted. The finding of nodular/mass-like lesion has the best diagnostic performance (AUC = 0.93) for neoplasia, with sensitivity of 91.7% and specificity of 93.6%. For predicting a diagnosis of pneumonia, although several sonographic features were found to be statistically associated with pneumonia, only a negative finding of nodular/mass-like lesion showed good diagnostic performance (AUC = 0.83, sensitivity 95.7%, specificity 71%). These findings demonstrate the value of chest ultrasonography in predicting diagnosis in non-emergency cases. The application of thoracic ultrasound in small animal respiratory patients as part of non-invasive assessment warrants further investigation.

Ecological level analysis of primary lung tumors in dogs and cats and environmental radon activity

Background

Epidemiologic studies suggest residential radon exposure might increase the risk of primary lung cancer in people, but these studies are limited by subject mobility. This limitation might be overcome by evaluating the association in pets.

Hypothesis

Primary pulmonary neoplasia (PPN) rate is higher in dogs and cats residing in counties with a high radon exposure risk (Environmental Protection Agency [EPA] zone 1) compared to zones 2 (moderate radon exposure risk) and 3 (low radon exposure risk).

Animals

Six hundred ninety client‐owned dogs and 205 client‐owned cats with PPN.

Methods

Retrospective review of medical records at 10 veterinary colleges identified dogs and cats diagnosed with PPN between 2010 and 2015. Each patient's radon exposure was determined by matching the patient's zip code with published county radon exposure risk. County level PPN rates were calculated using the average annual county cat and dog populations. The PPN counts per 100 000 dog/cat years at risk (PPN rates) were compared across radon zones for each species.

Results

The PPN rate ratio in counties in high radon zone (1) was approximately 2‐fold higher than in counties in lower radon zones for dogs (rate ratio zone 1 to 2, 2.49; 95% confidence interval [CI], 1.56‐4.00; rate ratio zone 1 to 3, 2.29; 95% CI, 1.46‐3.59) and cats (rate ratio zone 1 to 2, 2.13; 95% CI, 0.95‐4.79; zone 1 to 3, 1.81; 95% CI, 0.9‐3.61).

Conclusions and Clinical Importance

Exposure to household radon might play a role in development of PPN in dogs and cats.

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.

Unusual invasion of primary pulmonary adenocarcinoma in a cat

Case summary

An 11-year-old female spayed domestic shorthair cat was referred to the Foster Hospital for Small Animals, USA for suspected dysautonomia based on weight loss, vomiting and referral radiographs that showed severe dilation of the esophagus, stomach and entire gastrointestinal tract. After recheck radiographs revealed a decrease in gas compared with the referral images, persistently reduced gastrointestinal motility was deemed less likely; however, cardiomegaly and a soft tissue opacity overlying the esophagus were noted. Echocardiogram identified a pulmonary mass either impinging on or invading the local organs. At necropsy, gross pathology and histopathology showed an aggressive pulmonary carcinoma invading the heart, trachea and esophagus, resulting in a focal esophageal stricture. Gastrointestinal gas dilation was most likely secondary to aerophagia as a result of chronic partial esophageal obstruction.

Relevance and novel information

To our knowledge, this is the first reported feline case of invasion of the esophagus and heart by a pulmonary adenocarcinoma. Other than weight loss, the clinical signs for this invasive neoplasm were not evident until the cat was diagnosed with hyperthyroidism and prescribed oral medications. This reinforces the fact that pulmonary adenocarcinoma is difficult to detect clinically until secondary problems from the primary or metastatic neoplasm arise.

Strong associations of nine-point body condition scoring with survival and lifespan in cats

Objectives

The objective of the study was to investigate the associations of a nine-point body condition score (BCS) with survival time and lifespan in cats.

Methods

Electronic patient records from a cat-dominant primary practice in metropolitan Sydney, Australia, where the body condition of cats was regularly recorded using a nine-point BCS scale were obtained. The maximum BCS of each cat during the visits was used as the primary exposure variable. Two survival analyses were conducted to evaluate the associations of BCS with cats’ survival and lifespan.

Results

In total, 2609 cats met the selection criteria from 4020 cats screened. The median of the maximum BCS was 6 (interquartile range [IQR] 5–7). Compared with cats with a maximum BCS of 6, increased hazards of death were observed in cats with a maximum BCS of 3 (hazard ratio [HR] 4.67, 95% confidence interval [CI] 3.00–7.27), 4 (HR 2.61, 95% CI 1.95–3.49), 5 (HR 1.43, 95% CI 11.5–1.76) and 9 (HR 1.80, 95% CI 1.11–2.93). Median lifespan was 15.8 (IQR 13.5–17.6) years. Compared with cats reaching a maximum BCS of 6 in the same age group, cats reaching a maximum BCS of 4 (HR 4.15, 95% CI 1.26–13.67) or 5 (HR 1.75, 95% CI 1.07–2.85) between age 1 and 3 years, and a maximum BCS of 3 (HR 6.09, 95% CI 1.47–25.25) and 9 (HR 2.27, 95% CI 1.27–4.04) between the age of 3 and 11 years had shorter lifespans.

Conclusions and relevance

There are significant associations of nine-point body condition scoring with survival and lifespan, and BCSs <5 and of 9 were found to be negatively associated with both. The study yielded information regarding a desirable BCS for cat longevity that veterinarians could consult with.