Preliminary clinical observations on the use of piroxicam in the management of rectal tubulopapillary polyps

Submucosal resection via a transanal approach for treatment of epithelial rectal tumors - a multicenter study

OBJECTIVE

To report complications and long-term outcomes after submucosal resections of benign and malignant epithelial rectal masses.

STUDY DESIGN

Retrospective multicentric study.

SAMPLE POPULATION

Medical records of 93 dogs at 7 referral hospitals.

METHODS

Records were reviewed for surgical time, diagnosis, margins, complications, and recurrences. Survival of dogs was evaluated based on tumor types, categorized as benign, carcinoma in situ, and carcinoma. The Kaplan-Meier survival curve and Cox proportional hazards analysis were used to determine the association of a range of variables with recurrence and survival time.

RESULTS

Duration of follow up was 708 days (range, 25-4383). Twenty-seven dogs (29%) developed complications. Recurrence was identified in 20/93 (21%), with 12/20 recurrent masses treated with repeat submucosal resection. Median survival was not reached in any group. The 1-,2-, 5-year survival rates for carcinomas were 95%, 89%, and 73% respectively. However, overall survival was longer for benign tumors than carcinomas (P = .001). Recurrence was more likely when complications (P = .032) or incomplete margins (P = .023) were present. Recurrence was associated with an increased risk of death (P = .046).

CONCLUSION

Submucosal resection of both benign and malignant rectal masses was associated with a low rate of severe complications and prolonged survival in the 93 dogs described here.

CLINICAL SIGNIFICANCE

Submucosal resection is a suitable technique for resection of selected rectal masses.

Immunohistochemical expression of β-catenin, Ki67, CD3 and CD18 in canine colorectal adenomas and adenocarcinomas

Background

Inflammation is believed to influence human colorectal carcinogenesis and may have an impact on prognosis and survival. The mucosal immunophenotype in dogs with colorectal cancer is poorly described.

The aim of this study was to investigate whether the density, distribution and grade of tumor-infiltrating immune cells (TIIs) are different in normal colonic tissue vs benign stages (adenomas) and malignant stages (adenocarcinomas) of canine colorectal carcinogenesis, and thus, whether they can be considered as prognostic factors in dogs.

This retrospective case-control study was performed on formalin-fixed, paraffin-embedded tissue samples from dogs with histologically confirmed colorectal adenoma (n = 18) and adenocarcinoma (n = 13) collected from archived samples. The samples had been collected by colonoscopy, surgery or during postmortem examination. Healthy colonic tissue obtained post mortem from dogs euthanized for reasons not involving the gastrointestinal tract served as control tissue (n = 9).

Results

The tumor samples had significantly lower numbers of CD3+ T-cells in the epithelium compared to controls (adenocarcinoma vs control, Kruskal-Wallis test, p = 0.0004, and adenoma vs control, p = 0.002). Adenomas had a significantly lower number of CD18+ cells in the lamina propria, compared to control samples (Kruskal-Wallis test, p = 0.008). Colonic samples from control dogs had uniform staining of β-catenin along the cell membrane of epithelial cells. Compared to normal colonic cells, the expression levels of cytoplasmic β-catenin were significantly higher in adenomas and adenocarcinomas (adenoma vs control Kruskal-Wallis test, p = 0.004, and adenocarcinoma vs control, p = 0.002). None of the control samples showed positive staining of β-catenin in the nucleus of colonic cells. In contrast, adenocarcinomas and adenomas showed moderate to strong staining of the cell nucleus. The nuclear β-catenin expression (signal strength and distribution) was significantly higher in adenomas compared to adenocarcinomas (Kruskal-Wallis test, p < 0.05).

Conclusions

β-catenin and Ki67 were not useful markers for demonstrating tumor progression from adenomas to adenocarcinomas. The lower presence of CD18 and CD3+ cells in colorectal tumors compared to controls indicates a reduced presence of histiocytes and T-cells, which may have implications for the pathogenesis and progression of colorectal cancer in dogs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02829-6.

Endoscopic Biopsies and Histopathological Findings in Diagnosing Chronic Gastrointestinal Disorders in Dogs and Cats

Nowadays, endoscopic examination is a diagnostic tool gaining popularity in the management of gastrointestinal disorders in dogs and cats. Direct accessibility of the lumen of gastrointestinal tract combined with the mucosal biopsy provides a great diagnostic potential. Using endoscopy and endoscopically guided biopsy, one can conduct both macro- and microscopic assessment of lesions and perform many specialist adjunct examinations. Histopathological examination of mucosal biopsy specimens collected from the stomach and intestines allows us to distinguish between types of inflammations and to diagnose ulcerative, polypoid, and cancerous lesions.

Combination of radiation therapy and firocoxib for the treatment of canine nasal carcinoma

Carcinomas represent two-thirds of canine nasosinal neoplasms. Although radiation therapy (RT) is the standard of care, the incidence of local recurrence following treatment is high. Cyclooxygenase-isoform-2 (COX-2) is expressed in 71-95% of canine nasal carcinomas and has been implicated in tumor growth and angiogenesis. Accordingly, COX-2 inhibition seems rational to improve outcome. Dogs with histologically confirmed, previously untreated nasal carcinomas were randomized to receive the combination of a selective COX-2 inhibitor (firocoxib) and palliative RT (Group 1) or RT and placebo (Group 2). Patients were regularly monitored with blood tests, urinalysis, and computed tomography. Pet owners were asked to complete monthly a quality-of-life questionnaire. Twenty-four dogs were prospectively enrolled. According to Adams modified system, there were five stage 1, five stage 2, three stage 3, and 11 stage 4 tumors. Two dogs had metastases to regional lymph nodes. Median progression-free interval and overall survival were 228 and 335 days in Group 1 (n = 12) and 234 and 244 days in Group 2 (n = 12). These differences were not statistically significant. The involvement of regional lymph nodes was significantly associated with progression-free interval and overall survival (P = 0.004). Quality of life was significantly improved in Group 1 (P = 0.008). In particular, a significant difference was observed for activity and appetite. Although not providing a significant enhancement of progression-free interval and overall survival, firocoxib in combination with RT is safe and improved life quality in dogs with nasal carcinomas.

Polypoid adenomas secondary to inflammatory colorectal polyps in 2 miniature dachshunds

Two miniature dachshunds, a 7-year-old neutered male and an 8-year-old male, presented with chronic hematochezia and tenesmus. A solitary pedunculated or multiple diffuse colorectal polyps were identified by colonoscopy and resected by polypectomy. Inflammatory colorectal polyps (ICRPs) were diagnosed according to histopathological findings. Both cases were treated with immunosuppressive therapy, and the clinical signs were resolved, although the colorectal polyps remained to some extent. Several months after the initial diagnosis, both cases presented with recurrence of hematochezia and enlargement of the polyps. A second colonoscopic polypectomy was performed, and adenoma was diagnosed histopathologically in both cases. ICRPs are a nonneoplastic disease, but their long-term prognosis is unknown. Careful follow-up seems to be important, and repetitive biopsy is recommended when growth of polyps is identified in miniature dachshunds with ICRPs.

A novel surgical stapling technique for rectal mass removal: a retrospective analysis

Both benign and malignant rectal masses occur in dogs. The mainstay of treatment is surgical excision with adjuvant therapy based on histopathological diagnosis and completeness of removal. Location of the mass within the rectum helps dictate the approach used. This paper describes the use of a novel technique for removal of rectal masses involving the distal third of the rectum in seven dogs. To perform this technique, the rectum is prolapsed and stay sutures are placed to maintain prolapse. A thoracoabdominal stapling device is placed at the base of the mass with a minimum of 0.5- to 1-cm margins, and the mass is amputated. Mean time to veterinarian follow-up was 564 days, and no dog had recurrence of disease during this time.

Evaluation of transanal endoscopic treatment of benign canine rectal neoplasia

OBJECTIVES

To evaluate transanal endoscopic treatment in the management of benign canine rectal neoplasia.

METHODS

A retrospective study was carried out to evaluate the response to transanal endoscopic treatment in 13 dogs with extensive rectal neoplasia that was considered inoperable by conventional surgical techniques but was indicated as benign by previous biopsy.

RESULTS

Tumours affected the lengths of rectal mucosa varying from 2 to 13 cm. Between 25 and 100 per cent of the rectal circumference was affected in each case. Transanal endoscopic treatment of canine rectal neoplasia was curative in five dogs, palliative in three and associated with a poor result in the remaining five. Complications of the technique included rectal perforation, leading to peritonitis and death.

CLINICAL SIGNIFICANCE

Transanal endoscopic treatment can be recommended as an alternative to radical, full-thickness rectal excision for the management of extensive but benign canine rectal neoplasia. Owners should be informed that the treatment may be palliative rather than curative and that complications, if they occur, can be fatal. Dogs should be hospitalised for at least five days after treatment and observed for signs of potentially fatal complications such as rectal perforation.

Antineoplastic effect of the cyclooxygenase inhibitor meloxicam on canine osteosarcoma cells

A decisive role in cancer development has been attributed to cyclooxygenase-2 (COX-2) activity, but the significance of COX-2 inhibitors in cancer treatment still needs to be thoroughly investigated. We studied the influence of meloxicam, a non-steroidal antiinflammatory drug with preferential inhibitory effects on COX-2 compared to COX-1, on canine osteosarcoma (D-17) cells. We demonstrated that D-17 cells expressed mRNA and COX-2 protein. Treatment with meloxicam induced a time- and dose-dependent inhibition of cellular growth. To determine if apoptosis plays a role in meloxicam-induced cell death, we performed agarose gel electrophoresis and found a DNA-ladder pattern, typically seen in apoptosis, as well as early apoptotic changes by Annexin V tests. Furthermore, electron microscopy revealed ultrastructural alterations typical of apoptosis. Quantification of apoptotic cells by immunohistochemical staining of caspase 3 confirmed the results. However, further studies with meloxicam are necessary to assess its potential use for treatment of osteosarcomas in dogs.

Cohort study of COX-1 and COX-2 expression in canine rectal and bladder tumours

OBJECTIVES

To determine the role that cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) play in malignant transformation in canine transitional cell carcinoma and rectal tumours.

METHODS

Histological sections of 21 canine rectal adenocarcinomas and 18 canine transitional cell carcinomas were stained for COX-1 and COX-2. Mann-Whitney non-parametric tests were applied to determine if there was any relationship between the percentage of cells expressing COX-1 or COX-2, and between COX-1 and COX-2 staining intensity and age, breed or sex.

RESULTS

For rectal adenocarcinomas, 19.0 per cent of the sections were negative for COX-1 and COX-2. A further 38.1 per cent of the sections were negative for COX-2 but positive for COX-1, and 38.1 per cent of the sections had rare or occasional single cells positive for COX-2. No significant differences were found in COX staining when compared with age, breed or sex. For transitional cell carcinomas, all of the sections were positive for COX-1 and COX-2. For COX-2 staining, 16.7 per cent had more than 30 per cent positive cells. For COX-1 staining, 38.9 per cent had more than 30 per cent positive cells. There was a significant increase in the percentage of COX-1 positive cells in small breed dogs (P = 0.0337).

CLINICAL SIGNIFICANCE

The variations in COX expression reported in this study may explain the differences in the clinical response of transitional cell carcinomas and rectal adenocarcinomas following treatment with non-steroidal anti-inflammatory drugs.

In vitro effects of meloxicam with or without doxorubicin on canine osteosarcoma cells

Cyclooxygenase (COX) inhibitors, already widely used to reduce fever, inflammation and pain, are under increasing consideration as potential agents for the prevention and treatment of neoplasia. As COX-2 was detected in human and canine osteosarcomas, we have evaluated the effect of the preferential COX-2 inhibitor meloxicam on an established D-17 canine osteosarcoma cell line, which expressed, as well as COX-1 and COX-2 also COX-3 (as demonstrated by Western blot). An XTT proliferation kit was used to assess surviving cells after drug treatment. At low concentrations (1, 2, 4 and 10 microm) meloxicam caused an increase in cell numbers while a marked anti-proliferative effect was observed at higher concentrations (100, 200 microm) after 3 days and also 3 weeks of incubation. The chemotherapeutic drug doxorubicin showed a cytotoxic effect at all concentrations (60-1920 nm). Exposure of tumour cells to combinations of meloxicam and doxorubicin revealed synergistic effects (with 240 nm doxorubicin), as well as sub-additive and antagonistic results, especially if combined with concentrations of meloxicam typically found in serum. Care should be taken in concluding, on the basis of one in vitro study, that meloxicam does not have a role in the treatment of canine osteosarcomas given that the results from in vivo studies may differ.

The in vitro effects of piroxicam and meloxicam on canine cell lines

OBJECTIVES

To analyse the direct antiproliferative effects of both piroxicam and meloxicam at a variety of concentrations on a series of canine cancer cell lines and the mechanism of cell death.

METHODS

The in vitro effects of piroxicam and meloxicam at various concentrations on canine cell cultures (Madin-Darby canine kidney cells, osteosarcoma, mammary carcinoma, and lymphoma) were assessed with respect to proliferation inhibition and apoptosis induction. Western blot analysis of cyclooxygenase-1 and cyclooxygenase-2 expression was performed on all cell lines.

RESULTS

All cell lines used in this study were cyclooxygenase-1 and cyclooxygenase-2 positive apart from Madin-Darby canine kidney cells which were negative for both cyclooxygenase-1 and cyclooxygenase-2. Both meloxicam and piroxicam were able to inhibit proliferation in cell lines in a dose-dependent manner. However, the drug concentration required for a given effect was cell line dependent.

CLINICAL SIGNIFICANCE

The results suggest that significant inhibition of proliferation and induction of apoptosis would only occur when drug concentrations were in excess of those that can be achieved in vivo following maximum recommended dose rates. It is possible, however, that local or topical treatment or altered dosing regimens may offer alternative approaches to the use of these drugs as antineoplastic agents.

Improved Survival Associated With Postoperative Wound Infection in Dogs Treated With Limb-Salvage Surgery for Osteosarcoma

BACKGROUND

Limb-salvage surgery and adjuvant chemotherapy are performed as a treatment of appendicular osteosarcoma in dogs. Approximately 50% of dogs that undergo limb-salvage surgery develop postoperative surgical wound infections. Postoperative surgical infections may affect survival in cancer patients. The purposes of this study were to examine the effect of surgical wound infection on survival, local recurrence, and metastasis in relation to other prognostic factors for dogs with spontaneous osteosarcoma treated with limb-salvage surgery.

METHODS

Forty-seven client-owned dogs with osteosarcoma of the distal radius were treated with limb-salvage surgery and adjuvant chemotherapy--either carboplatin or carboplatin and doxorubicin. Hazard ratios were estimated by using the Cox proportional hazard model, and survival functions were estimated by using the Kaplan-Meier product-limit life-table method.

RESULTS

Of the 47 dogs in this study, 32 (68%) developed a postoperative wound infection. Infection, dog weight, and extent of the primary tumor (percentage of length) significantly affected survival, and infection and percentage of length significantly affected time to metastasis. None of the variables considered in this study affected local recurrence. Dogs that were diagnosed with an infection were less likely to die (hazard ratio, .446), and dogs with greater body weight and greater percentage length involvement were more likely to die (hazard ratios of 3.37 and 3.66, respectively).

CONCLUSIONS

In dogs with osteosarcoma treated with limb-salvage surgery, infection has a positive influence on survival, as does a smaller initial length of radius involved and lower body weight.

Single dose pharmacokinetics of piroxicam in cats

Piroxicam (PIRO) is a nonsteroidal anti-inflammatory drug (NSAID) recognized for its value as a chemopreventative and anti-tumor agent. Eight cats were included in this study. PIRO was administered in a single oral (p.o.) and intravenous (i.v.) dose of 0.3 mg/kg. The study was designed as a randomized complete crossover with a 2-week washout period. Serial blood samples were collected after each dose and plasma was analyzed for PIRO. Pharmacokinetic parameters of PIRO were determined using noncompartmental analysis. PIRO is well absorbed in the cat with a median bioavailability (F) of 80% (range 64-124%). The median i.v. t1/2 was 12 h (range 8.6-14 h). The median Cmax was 519 ng/mL with a corresponding Tmax of 3 h. PIRO appears to be rapidly absorbed following p.o. administration in cats with a higher Cmax and AUC than in dogs.

Neutrophilic leucocytosis in a dog with a rectal tumour

A nine-year-old cocker spaniel was presented with a three-year history of intermittent haematochezia and a palpable rectal mass. Routine haematological examination revealed a marked mature neutrophilia (86.04 x 10(9) neutrophils/litre). A friable mass in the middle portion of the rectum was detected on colonoscopy. Histopathological examination of mucosal pinch biopsies collected from the mass confirmed a diagnosis of adenomatous tubulopapillary polyp. Some evidence of malignant transformation was observed. Palliative treatment with piroxicam suppositories at a dose of 1.4 mg/kg administered rectally every third day was instituted. On re-evaluation, 47 days after starting medical therapy, the owner reported a significant reduction in haematochezia and tenesmus; however, frequency of defecation had remained unaltered. Routine haematology revealed a reduction in the mature neutrophil count (33.67 x 10(9) neutrophils/litre). This report describes a case of a rectal tumour associated with a neutrophilic leucocytosis, which responded to palliative therapy with piroxicam suppositories.