Evaluation of outcomes and radiation complications in 65 cats with nasal tumours treated with palliative hypofractionated radiotherapy

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.

Clinical presentation, treatment and outcome in 23 cats with laryngeal or tracheal lymphoma

OBJECTIVES

Feline primary laryngeal or tracheal lymphoma (PLTL) is an uncommon extranodal presentation. Information on long-term survival is scarce, although some small case series describe this being achieved with multiagent protocols; an accurate outcome for cats with PLTL is yet to be determined. The aim of this study was to gather information on the clinical presentation, response to treatment and outcome in a large case series of feline PLTL.

METHODS

This retrospective multicentre study included cats with a cytological or histopathological confirmation of PLTL. Histopathology samples, when available, were reassessed for grade and immunophenotype. Clinical (age, signalment, retroviral status, presence of anaemia, clinical signs, location and therapy type) and outcome (response, progression-free survival [PFS] and overall survival [OS]) variables were recorded. Survival analyses to assess the impact of variables on PFS and OS were performed.

RESULTS

Twenty-three cases were included; cats had a median age of 11 years (range 2-16) and the male:female ratio was 3.6:1. Common clinical signs at presentation included increased respiratory effort (74%) and abnormal upper respiratory tract sounds (48%). Immunophenotyping was performed in 48% of cases and all were B cell. Debulking surgery was performed in 26% of cases. All cats received chemotherapy, COP (cyclophosphamide, vincristine and prednisolone; 39%), CHOP (cyclophosphamide, vincristine, doxorubicin and prednisolone; 44%) and other protocols (17%); 35% had a partial response and 65% a complete response. Median PFS and OS were 909 days (range 23-1484) and 909 days (range 23-2423), respectively. Complete response was associated with longer PFS (P <0.001) and OS (P = 0.012). Pretreatment with steroids was associated with longer OS (P = 0.003). No other variable was found to be significant.

CONCLUSIONS AND RELEVANCE

PLTL in cats is mostly of a B-cell phenotype, could be of a low-to-medium grade, and may respond to surgical and medical treatment with a longer survival time than has previously been reported.

Successful rescue treatment using chlorambucil for presumed recurrence of sinonasal lymphoma in a cat

Case summary

A 12-year-old male neutered domestic shorthair cat presented with a 2-week history of serous unilateral nasal discharge, swelling of the nasal bridge and sneezing. Whole-body CT revealed a mass filling the entire right nasal cavity with lysis of the cribriform plate. The cat was diagnosed with sinonasal large-cell lymphoma based on cytopathological analysis, with PCR-based lymphocyte clonality testing showing a monoclonal population with rearrangement of the immunoglobulin heavy chain gene. The cat received radiotherapy with a dose of 30 Gy in seven fractions given three times weekly, and then cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP)-based chemotherapy was initiated soon after completion of the radiotherapy schedule. Despite this treatment, CT performed 4 months after radiotherapy revealed enlargement of the lesion in the right nasal cavity consistent with presumed progression of the cat’s lymphoma. The cat then received rescue chemotherapy with chlorambucil, which markedly reduced the size of the disease burden in the nasal and frontal sinus without severe adverse effects. At the time of writing, the cat was receiving chlorambucil for 7 months without any clinical signs suggestive of tumour relapse.

Relevance and novel information

To our knowledge, this is the first case of feline sinonasal lymphoma with chlorambucil used as rescue chemotherapy. This case indicates that chemotherapy with chlorambucil may be a useful treatment option for cats with relapsing sinonasal lymphoma following radiotherapy and/or CHOP-based chemotherapy.

Use of a cyclical hypofractionated radiotherapy regime ('QUAD shot') for the treatment of feline sinonasal carcinomas

OBJECTIVES

Radiation therapy is the treatment of choice for cats with sinonasal carcinomas. Different protocols have been described in the literature, though a clear consensus regarding the optimal protocol is lacking. The aim of the study was to describe the tolerability, efficacy and outcome of cats treated with a cyclical hypofractionated protocol.

METHODS

Cats with histologically diagnosed sinonasal carcinomas in a single institution were retrospectively included. All patients were treated with a cyclical hypofractionated protocol ('QUAD shot' regime). Cats were treated with 4 Gray (Gy) delivered in four fractions within 48 h, with a minimum of 6 h between two treatments, and repeated every 3-4 weeks for a total dose of 48 Gy in three cycles.

RESULTS

Seven cats met the inclusion criteria. Nasal discharge and sneezing were the most common presenting complaints. All cats presented with advanced stage of disease with CT examination (three with modified Adams stage 3 and four with stage 4). Clinical improvement was seen in six cats. Five cats had a follow-up CT; one had a complete response, two had partial responses, one had stable disease and one had progressive disease. Two cats were still alive at the time of writing while four were euthanased owing to tumour-related causes. The median overall survival time was 460 days. The 1-year survival time was 80% and the 2-year survival time was 0%. Severe acute or late toxicity was not reported.

CONCLUSIONS AND RELEVANCE

This is the first report of a cyclical hypofractionated protocol in the veterinary literature that can provide prolonged survival in cats with advanced stage sinonasal carcinoma. Its use should be considered in patients when prolonged hospitalisation can be detrimental to quality of life, while still delivering a therapeutic total dose of radiation therapy.

Combined Hypofractionated Radiotherapy and Chemotherapy Versus Hypofractionated Radiotherapy Alone for Cats with Localized Sinonasal Lymphoma

Despite considering hypofractionated radiotherapy (HRT) a useful treatment option for feline localized sinonasal lymphoma (stage I), the benefits of additional chemotherapy remain controversial. This retrospective cohort study evaluated the efficacy of the early initiation of chemotherapy in combination with HRT (HRTC) to prolong the progression-free survival (PFS) and overall survival (OS) in cats with localized sinonasal lymphoma compared with HRT alone. While 24 eligible cats received HRT alone (HRT group), 18 received HRTC (HRTC group). The total median administered dose was 35 Gy, with one fraction per week, for a median of five fractions. In the HRTC group, the chemotherapy protocol was cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-based and cyclophosphamide, vincristine, and prednisolone (COP)-based in 14 (78%) and 4 cats (22%), respectively. Cats in the HRTC group had significantly longer PFS (677 versus 104 days; P = .04) and OS (983 versus 263 days; P = .04) than those in the HRT group. Considering the poor outcome in the HRT group despite the cats having received rescue chemotherapy for progressive disease, the early initiation of additional chemotherapy along with HRT may be recommended for feline localized sinonasal lymphoma.

Single-modality palliative radiotherapy versus palliative radiotherapy after chemotherapy failure for cats with nasal lymphoma

Published studies describing outcomes for cats with nasal lymphoma (NLSA) receiving first-line palliative radiation (PRT) versus PRT after chemotherapy failure are currently lacking. The aims of this retrospective observational study were to compare outcomes for cats with NLSA that were treated with these two methods. A total of 48 cats were included in analyses; 32 receiving PRT alone and 16 receiving PRT after chemotherapy failure. The treatment response, progression-free survival (PFS), disease-specific survival (DSS), overall survival (OS), and incidence rate of systemic disease were compared between the two groups. The overall response rate (ORR) was calculated from the same target lesions between pre-RT (within a week before starting PRT) and post-RT (on date of PRT completion) by computed tomography (CT) imaging. The ORR was 94% in cats that received PRT alone, 13 had a complete response (CR) and 17 had a partial response (PR). The ORR was 88% in cats that received PRT after chemotherapy failure, with five having CR and nine with PR. There were no significant differences in the ORR between the two groups. The PFS, DSS, and OS significantly increased in the cats that received PRT alone compared to the cats that received PRT after chemotherapy failure (median PFS: 336 vs 228 days, P = 0.0012, median DSS: 360 vs 242 days, P = 0.0025, median OS: 346 vs 242 days, P = 0.0036, respectively). The incidence rate of systemic disease significantly increased in 75% (12/16) of cats receiving PRT after chemotherapy failure compared to 41% (13/32) of cats receiving PRT alone. The results suggested that clinical outcomes may improve in cats with NLSA with first-line PRT compared to PRT after chemotherapy failure.

Retrospective evaluation of intranasal carcinomas in cats treated with external-beam radiotherapy: 42 cases

Background

Little is known regarding the comparative efficacy of various irradiation strategies used to treat intranasal carcinomas (INC) in cats.

Objectives

Investigate outcomes and prognostic factors associated with survival for cats with INC.

Animals

Forty‐two cats with INC that underwent radiotherapy (RT).

Methods

Single‐arm retrospective study. Medical record review for cats with INC that underwent RT at 1 of 7 veterinary RT facilities. Irradiation protocols categorized as: definitive‐intent fractionated RT (FRT), definitive‐intent stereotactic RT (SRT), and palliative‐intent RT (PRT). Median overall survival time (OST) and disease progression‐free survival (PFS; documented by advanced transverse imaging, or recurrence of symptoms) were calculated. Associations between tumor stage, RT protocol/intent, and adjunctive treatment usage and outcome were calculated.

Results

Cats underwent SRT (N = 18), FRT (N = 8), and PRT (N = 16). In multivariate modeling, cats received definitive‐intent treatment (DRT; FRT/SRT) had significantly longer median PFS (504 days, [95% confidence interval (CI): 428–580 days] vs PRT 198 days [95% CI: 62–334 days]; p = 0.006) and median OST [721 days (95% CI: 527–915 days) vs 284 days (95% CI: 0–570 days); p = 0.001]). Cats that underwent second DRT course at time of recurrence lived significantly longer than cats that received 1 RT course (either DRT or PRT [median OST 824 days (95% CI: 237–1410 days) vs 434 days (95% CI: 277–591 days); p = .028]).

Conclusion

In cats with INC, DRT is associated with prolonged OST and PFS as compared to PRT. If tumor progression occurs, a second course of DRT should be considered.

Efficacy of chemotherapy and palliative hypofractionated radiotherapy for cats with nasal lymphoma

Nasal lymphoma (NL) is the most common nasal tumor in cats, and radiotherapy, chemotherapy, or a combination of these treatments have been described as the treatment for this disease. However, the previous studies included various machines and protocols of radiotherapy. Therefore, we aimed to retrospectively compare the prognosis among cases treated with palliative hypofractionated radiotherapy, chemotherapy, and a combination of them with united machine and protocol of radiotherapy. When compared overall survival and progression free survival, there was no significant difference among these three groups. The data of this study suggested that similar efficacy could be achieved by palliative hypofractionated radiotherapy, chemotherapy, or a combination of them.

Clinical response and survival time of cats with carcinoma of the nasal cavity treated with palliative coarse fractionated radiotherapy

OBJECTIVES

Carcinoma is the second most common tumour of the nasal cavity in cats. Few studies assessing the response and survival of cats with carcinoma of the nasal cavity treated with palliative coarse fractionated radiotherapy have been published.

METHODS

Twenty-eight cats were diagnosed with histologically confirmed carcinoma of the nasal cavity. All patients treated with a coarse fractionated radiotherapy protocol were retrospectively reviewed.

RESULTS

Improvement of the clinical signs were reported in 24 cases; median survival time (MST) was 342 days; and cats with Adams modified stage IV and facial deformity had a significantly reduced MST of 152 days (P = 0.0013) and 67 days (P = 0.0002), respectively. Severe radiotherapy-related clinical signs were not reported and alopecia and leukotrichia were the most common side effects reported in ten cases.

CONCLUSIONS AND RELEVANCE

Coarse fractionated radiotherapy treatment for carcinoma of the nasal cavity in cats is effective in relieving clinical signs. Long survival times can be achieved, in particular in cases with a less advanced stage of the tumour.

Hydropulsion as Palliative, Long-Term, Last-Resort Treatment of Nasal Carcinoma in a Dog and a Cat

An 8 yr old spayed female domestic shorthair and an 8 yr old neutered male Polish Lowland sheepdog were evaluated for a 3 wk history of sneezing and a 5 day history of left epistaxis, respectively. In both cases, computed tomography revealed a voluminous nasal mass, which was later histologically identified as carcinoma, without cribriform plate involvement. Nasal hydropulsion was performed in both animals in sternal recumbency under general anesthesia. A Poole suction tip was inserted into the orad esophageal opening and adequacy of the endotracheal tube cuff inflation was checked. Sterile saline was forcefully infused into the obstructed nasal cavity to dislodge the tumor. Both patients had temporary resolution of clinical signs. Nasal hydropulsion was repeated as a palliative last-resort treatment at each clinical relapse (four times in both animals over ≥1 yr), allowing long-term survival. Minor complications included a self-limiting retrobulbar and oropharyngeal swelling in the cat and self-limiting epistaxis in both animals. Although this technique is not intended to represent an equivalent alternative to radiation or surgical therapies, nasal hydropulsion may represent an appropriate palliative, last-resort treatment in case of obstructive nasal tumors in dogs and cats, when radiation therapy or surgery is not affordable, available, or desired.

Definitive-intent radiotherapy for sinonasal carcinoma in cats: A multicenter retrospective assessment

Treatment of epithelial sinonasal tumours in cats is not commonly reported. In the newer reports, palliative radiation protocols have been described more often than definitive-intent protocols. In this multi-institutional retrospective study, we included 27 cats treated with single-modality radiotherapy. Cats were irradiated using 10 daily fractions of 4.2 Gy. Three cats (11.1%) experienced a complete clinical response and 17 (63%) had a partial clinical response. Stable clinical disease was noted in three cats (11.1%). Four cats (14.8%) showed progression within 3 months following treatment. The median time to progression for all cases was 269 days (95 % confidence intervals [CI]: 225; 314). The proportion of cats free of progression at 1 and 2 years was 24% (95% CI: 22%; 26%) and 5% (95% CI: 5%; 6%), respectively. None of the prognostic factors evaluated were predictive of outcome (anaemia, tumour volume at the time of staging, modified Adams stage, intracranial involvement, facial deformity, epistaxis, inappetence or weight loss). Median overall survival (OS) for all deaths was 452 days (95% CI: 334; 571). The proportion of cats alive at 1 and 2 years was 57% (95% CI: 37%; 77%) and 27% (95% CI: 25%; 29%), respectively. Surprisingly, cats with epistaxis had a longer median OS of 828 days (95% CI: 356; 1301) compared to 296 days (95% CI: 85; 508) in cats without epistaxis, (P = .04, Breslow). Radiation therapy used as a single modality for the treatment of feline sinonasal carcinoma improved clinical signs and was well tolerated but progression within a year was common.

Nasal adenocarcinoma as a suspected secondary malignant neoplasm in a cat previously treated for nasal lymphoma

Case summary

A case of nasal adenocarcinoma as a suspected secondary malignant neoplasm following definitive radiation therapy and multiagent chemotherapy for nasal lymphoma is described. An 11-year-old spayed female domestic shorthair cat was presented for a 3-week history of progressive facial swelling located over the nasal planum and extending to the medial canthus of the right eye. The cat was previously diagnosed with nasal lymphoma and treated with chemotherapy and definitive radiation 2.5 years prior. Although a definitive diagnosis could not be obtained via cytology, recurrent lymphoma was suspected based on the cat’s history and recurrent clinical signs. A lymphoma-directed chemotherapy protocol was attempted, but no clinical response was achieved. The cat was euthanased owing to progressive clinical signs and a diagnosis of nasal adenocarcinoma was made on necropsy examination. Both the original diagnosis of nasal lymphoma and the secondary diagnosis of nasal adenocarcinoma were confirmed with immunohistochemistry.

Relevance and novel information

Secondary malignant neoplasm following radiation therapy is infrequently reported in the veterinary literature. In the few reports that exist, most have described sarcoma development in the dog following radiation therapy. In the present report, we describe a cat with a suspected radiation-induced nasal adenocarcinoma that developed 2.5 years after definitive radiation treatment for nasal lymphoma.

Radiation-induced sarcoma in a cat following hypofractionated, palliative intent radiation therapy for large-cell lymphoma

Case summary

A 5-year-old female spayed domestic shorthair cat was presented with a 4.5 × 3 cm ulcerated cutaneous mass on the nasal bridge with extension into the nasal cavity. Tissue biopsy was obtained and a diagnosis of large-cell lymphoma was confirmed on histopathology. The cat was started on prednisolone and injectable chemotherapy; however, only a partial response was observed. A CT scan revealed a highly infiltrative mass with extensive subcutaneous involvement, extending into the nasal cavity, resulting in lysis of numerous nasal and facial bones. The cat received hypofractionated, palliative intent radiation therapy (four fractions of 8 Gray) and a complete clinical response was achieved. Nine months after radiation therapy, minimal residual intranasal disease was observed on advanced imaging. Sixty-nine months after the completion of radiotherapy, a mass was observed dorsal to the right eye within the previous radiation field. CT scan revealed a mass associated with the right frontal sinus with extension throughout the nasal cavity and facial bones. Histopathology was consistent with a moderately differentiated sarcoma. Seventy-one months post-radiation therapy, the cat developed neurologic clinical signs and was humanely euthanized. Radiation-induced sarcoma was suspected based on human criteria, which included history of irradiation and tumor development within the irradiated field, a latent period after irradiation prior to the development of the second tumor and histopathologic confirmation of a different malignant neoplasm at the irradiated site.

Relevance and novel information

To our knowledge, this is the first report of a malignant radiation-induced sarcoma in a cat. Based on this case, radiation-induced sarcomas should be considered as a late-term side effect associated with radiation therapy in cats.

Prognostic factors for cats with squamous cell carcinoma of the nasal planum following high-dose rate brachytherapy

OBJECTIVES

The aim of the study was to investigate retrospectively the prognostic impact of variables such as sex, neuter status, breed, age, number of lesions, location and size of the tumour, tumour extension beyond the nasal planum, ulceration and lymph node status, among others, in a population of cats treated with high-dose rate brachytherapy.

METHODS

This study reviews the outcome of 58 cats with cytologically and/or histologically confirmed squamous cell carcinoma of the nasal planum, treated at the Clinic Alliance (Bordeaux, France) with high-dose rate brachytherapy from 2010-2016. The total radiation dose delivered was 30 Gy, administered in two different schedules: five fractions of 6 Gy for a period of 4 days (Tuesday-Friday) or four fractions of 7.5 Gy for a period of 3 days (Tuesday- Thursday). Data were collected from cats' clinical records.

RESULTS

Complete response was achieved in 72% (n = 36) of the cats, partial response in 24% (n = 13) and 2% (n = 1) did not respond. Median progression-free survival and overall survival times were 316 and 835 days, respectively.

CONCLUSIONS AND RELEVANCE

Results indicated that sex (P = 0.045), extension of the tumour from the nasal planum to the upper lip (P = 0.015), tumour size (P = 0.015; P = 0.001), the existence of a previous treatment (P = 0.043) and the tumour response to high-dose rate brachytherapy (P = 0.038; P <0.001) are prognostic factors for cats with squamous cell carcinoma of the nasal planum following high-dose rate brachytherapy.

Outcome and failure patterns of localized sinonasal lymphoma in cats treated with first-line single-modality radiation therapy: A retrospective study

Failure rate and site are not well defined in localized sinonasal lymphoma in cats treated with radiotherapy. In this study, we describe (a) failure pattern, (b) outcome, (c) influence of previously reported prognostic variables on the outcome in cats with suspected localized sinonasal lymphoma. In this multi-institutional retrospective study, we included 51 cats treated with single-modality radiotherapy. Cats were irradiated using 10x4.2Gy (n = 32), 12x3Gy (n = 11) or 5x6Gy (n = 8). Regional lymph nodes were prophylactically irradiated in 24/51 cats (47.1%). Twenty-five cats (49.0%) developed progressive disease: progression was local (nasal) in five (9.8%), locoregional (nodal) in two (3.9%), local and locoregional in three (5.9%), systemic in nine (17.6%) and both local and systemic in six cats (11.8%). No cat receiving prophylactic nodal irradiation had progression in the locoregional lymph nodes. The median time to progression was 974 days (95%CI: 283;1666), with 58% and 53% of cats free of progression at 1 and 2 years, respectively. Median overall survival was 922 days (95%CI: 66;1779) with 61% and 49% alive at 1 and 2 years, respectively. Half of the cats that died of relapse/progression (13/26) died within 6 months of treatment, suggesting possible shortcomings of staging, rapid dissemination of disease or sequential lymphomagenesis. None of the prognostic factors evaluated were predictive of outcome (prednisolone use, anaemia, nasopharyngeal involvement, modified canine Adams tumour stage, protocol, total dose). Radiotherapy is an effective treatment for localized sinonasal lymphoma with a long time to progression. However, in one-third of the cats, systemic disease progression occurs soon after radiotherapy.

Dynamic pharyngeal collapse in three cats with different pharyngeal pathology

Dynamic pharyngeal collapse (PC) is a rarely reported condition in cats defined as the partial or complete collapse of the pharyngeal lumen during inspiration. Herein, we report the imaging findings and clinical features of three cats with dynamic PC. Lateral radiograph of the head was insufficient to detect dynamic PC, but fluoroscopy in conscious cats revealed dynamic PC. Magnetic resonance imaging was not helpful to reveal dynamic PC and underlying diseases. We obtained biopsy samples from the irregular nasopharyngeal mucosal membrane through endoscopy in two of the three cases and high-grade B-cell lymphoma was histopathologically diagnosed. In feline cases with abnormal upper respiratory sounds, dynamic PC should be considered, and fluoroscopy is the imaging technique of choice to diagnose the condition.

Novel Treatments for Lymphoma

Lymphoma is a common disease in companion animals. Although conventional chemotherapy has the potential to induce remission and prolong life, relapse is common, and novel treatments are needed to improve outcome. This review discusses recent modifications/adjustments to conventional standard of care therapy for canine and feline lymphoma, as well as cutting-edge immunotherapy and small-molecule-based approaches that are in varying stages of regulatory approval.

FePt nanoparticles: a novel nanoprobe for enhanced HeLa cells sensitivity to chemoradiotherapy

The present work exhibited high therapeutic efficacy of FePt nanoparticles in combination with radiotherapy without apparent cytotoxicity, suggesting the potential of FePt nanoparticles as a promising nanoprobe in improving the outcome of tumor chemoradiotherapy.