Early tumor response to intraarterial or intravenous administration of carboplatin to treat naturally occurring lower urinary tract carcinoma in dogs

Veterinary Interventional Oncology

Interventional oncology (IO) is a rapidly growing field in veterinary medicine and has been accepted as a fourth pillar of treatment of neoplastic disease with other modalities including surgery, chemotherapy, and radiation therapy. The major categories of IO therapies in companion animals are focused on the use of locoregional therapies and stenting of malignant obstructions. Although significant assessment of veterinary IO techniques is still necessary, early evaluation of these varying techniques is demonstrating promising results.

Canine Prostate Cancer: Current Treatments and the Role of Interventional Oncology

Prostate carcinoma is one of the most common cancers worldwide in men, with over 3 million men currently living with prostate carcinoma. In men, routine screening and successful treatment schemes, including radiation, prostatectomy, or hormone therapy, have allowed for high survivability. Dogs are recognized as one of the only mammals to spontaneously develop prostate neoplasia and are an important translational model. Within veterinary medicine, treatment options have historically been limited in efficacy or paired with high morbidity. Recently, less invasive treatment modalities have been investigated in dogs and people and demonstrated promise. Below, current treatment options available in dogs and people are reviewed, as well as a discussion of current and future trends within interventional treatment for canine PC.

Efficacy and adverse reactions of intra-arterial chemotherapy in patients with bladder cancer: A systematic review and meta-analysis

This meta-analysis investigated the efficacies of intra-arterial chemotherapy (IAC) plus intravesical chemotherapy (IVC) versus IVC alone in patients with non-muscle-invasive bladder cancer (NMIBC), and preoperative IAC versus preoperative intravenous chemotherapy (IV) in patients with bladder cancer. We also assessed the adverse reactions (ARs) of IAC. We searched the PubMed, Embase, Cochrane Library, and Web of Science databases for English articles published before April 2021. The qualities of cohort studies and randomized controlled trials were analyzed using the Newcastle-Ottawa Scale and Cochrane risk-of-bias tool, respectively. Effect outcomes were computed by random-effects and fixed-effects models. Statistical analyses were conducted using Stata 16.0 and RevMan v5.3.0. A total of seven articles were included. The analysis revealed that IAC plus IVC significantly prolonged recurrence-free survival (RFS) (hazard ratio [HR] = 0.55, 95% confidence interval [CI] = 0.40-0.76, I² = 0%) and progression-free survival (PFS) (HR = 0.59, 95% CI = 0.37-0.97, I² = 0%) compared with IVC alone in NMIBC patients after transurethral resection of bladder tumor (TURBT), but had no effect on overall survival (OS), tumor recurrence interval, or tumor-specific death rate. Preoperative IAC had no significant OS benefit compared with preoperative IV in bladder cancer patients. Regarding ARs, patients treated with IAC were significantly more likely to develop grade 1-2 ARs, including nausea/vomiting (odds ratio [OR] = 26.38, 95% CI = 1.88-370.79, I² = 78%), neutropenia (OR = 10.15, 95% CI = 3.01-34.24, I² = 0%), hypoleukemia (OR = 5.49, 95% CI = 1.38-21.82, I² = 26%), and increased alanine aminotransferase (OR = 12.28, 95% CI = 2.24-67.43, I² = 0%), but there was no significant difference between grade 1-2 ARs and grade 3-4 ARs in terms of increased creatinine in patients treated with IAC. Therefore, administration of IAC plus IVC after TURBT improved RFS and PFS compared with IAC alone in patients with NMIBC. IAC was associated with mild ARs and was well tolerated by most patients.

Procedural description and prospective evaluation of short-term outcome for the use of prostatic artery embolization in dogs with carcinoma of the prostate

OBJECTIVE

To describe the procedure of prostatic artery embolization (PAE) in dogs with prostatic carcinoma and to evaluate the short-term outcome for treated dogs.

ANIMALS

20 client-owned dogs with prostatic carcinomas between May 2014 and July 2017.

PROCEDURES

In this prospective cohort study, dogs with carcinoma of the prostate underwent PAE with fluoroscopic guidance. Before and after PAE, dogs underwent CT and ultrasonographic examinations of the prostate, and each owner completed a questionnaire about the dog's clinical signs. Results for before versus after PAE were compared.

RESULTS

Prostatic artery embolization was successfully performed in all 20 dogs. Tenesmus, stranguria, and lethargy were significantly less common 30 days after PAE (n = 2, 1, and 0 dogs, respectively), compared with before PAE (9, 10, and 6 dogs, respectively). Median prostatic volume was significantly less 30 days after PAE (14.8 cm3; range, 0.4 to 48.1 cm3; interquartile [25th to 75th percentile] range, 6.7 to 19.5 cm3), compared with before PAE (21.7 cm3; range, 2.9 to 77.7 cm3; interquartile range, 11.0 to 35.1 cm3). All dogs had a reduction in prostatic volume after PAE, with a median prostatic volume loss of 39.4% (95% CI, 20.3% to 59.3%).

CONCLUSIONS AND CLINICAL RELEVANCE

Prostatic artery embolization was associated with decreased prostate volume and improved clinical signs in this cohort. The short-term response to PAE appears promising, and evaluation of the long-term impact on survival time is needed.

Prostate artery chemoembolization in prostate cancer: A proof of concept study in spontaneous prostate cancer in a canine model

PURPOSE

The purpose of this study was to assess the feasibility and efficacy of docetaxel-loaded bead chemoembolization in spontaneous prostate cancer in a canine model.

MATERIALS AND METHODS

Five pet dogs with histopathologically proven prostate cancer were referred for prostate artery chemoembolization (PACE). After PACE, all animals were followed, including pharmacokinetic study and clinical and biological evolution, until death. Pelvic contrast-enhanced computed tomography examination was performed at one and two months. Animals were subjected to pathological examination after death.

RESULTS

Both prostate arteries were successfully chemoembolized in all dogs. A median dose of 18 mg (Q1, Q3; 11.8, 20 mg) docetaxel loaded in 3 mL of 50-100 µm super absorbent polymer beads was injected into each dog. At one month, four of the five dogs were still alive and the median prostate volume was 51% lower (prePACE median prostate volume, 18.4 mL [Q1, Q3; 12, 32.1 mL] vs. postPACE median prostate volume, 6.2 mL [Q1, Q3; 6.2, 11 mL]). At two months, three dogs died because of disease progression. The two remaining dogs showed a 70% median decrease in prostate volume. Prostate pathological examination showed 73% of necrosis. No worsening of urinary symptoms was observed. Pharmacokinetic analysis showed limited systemic passage of docetaxel. All dogs died of metastatic spread at nine months.

CONCLUSION

This study suggests that PACE is feasible and safe for the treatment of spontaneous prostate cancer in a canine model and may provide a new approach to treat selected patients with prostate cancer.

A combined protocol with piroxicam, chemotherapy, and whole pelvic irradiation with simultaneous boost volumetric modulated arc radiotherapy for muscle-invasive canine urinary transitional cell carcinoma: First clinical experience

The aims of this pilot study were to evaluate the feasibility and efficacy of high-dose hypofractionated volumetric modulated arc radiotherapy (VMAT) applied to whole pelvic region radiotherapy (WPRT) with multilevel simultaneous integrated boost (MLSIB) combined with piroxicam and chemotherapy for the treatment of canine transitional cell carcinoma (TCC) of the lower urinary tract with muscle invasion TCC. Twelve dogs were enrolled, according to stage, in two groups: group 1, TCC confined to the urinary tract; group 2, TCC with metastasis. The planning target volume dose was tailored from 36 to 42 Gy in 6 fractions. All dogs were prescribed piroxicam and radiosensitizing carboplatin, and six received chemotherapy after radiotherapy. Serial follow-ups with computed tomography and magnetic resonance imaging were performed. Disease control and toxicity effects were evaluated according to the Response Evaluation Criteria in Solid Tumors and Veterinary Radiation Therapy Oncology Group criteria. The treatment was well tolerated, and no high-grade side effects were reported. The median overall survival times for groups 1 and 2 were 1,230 and 150 days, respectively. A considerable percentage of patients in group1 (50%) were still alive at the time of writing this paper, and a longer follow-up could enable a more accurate survival analysis. This preliminary analysis shows that VMAT applied to the WPRT with MLSIB is an effective and safe option for dogs with lower urinary TCC, although the presence of metastases worsens the prognosis.

Pilot study comparing serum chemotherapy levels after intra-arterial and intravenous administration in dogs with naturally occurring urinary tract tumors

The proposed advantages of intra-arterial chemotherapy (IAC) are based on the premises of local dose escalation to the tumor and reduced availability of systemic drugs. There is a lack of objective pharmacokinetic data to confirm the advantage of IAC in dogs with naturally occurring urogenital tumors. The objective of this study was to determine if IAC administration in urogenital tumors would result in decreased systemic drug exposure when compared to intravenous routes. Twenty-two dogs with naturally occurring urogenital tumors were enrolled in this prospective case-controlled study. Mitoxantrone, doxorubicin, or carboplatin were administered by IAC and intravenous routes [intravenous awake (intravenous chemotherapy - IVC) and under general anesthesia (IVGAC)] 3 weeks apart. Serum assays were used to determine the extent of systemic drug exposure. Dose-normalized peak systemic serum concentration (C_max) and area under the serum drug concentration-time curve (AUC) were used to quantify systemic exposure. A total of 26 mitoxantrone treatments were administered to 10 dogs. While there was no significant difference in C_max, the AUC was significantly lower after IAC compared with IVGAC. Ten doxorubicin treatments were administered to 5 dogs. There were no significant differences in C_max or AUC. A total of 14 carboplatin treatments were administered to 7 dogs. The C_max was significantly lower for IAC compared to IVC, while the AUC values were equivocal. This study demonstrates certain lower serum values may be achieved after IAC delivery of carboplatin and mitoxantrone. These chemotherapy agents may have a preferred pharmacological profile for regional chemotherapy delivery in dogs with urogenital tumors.

Lower Urinary Tract Neoplasia

Lower urinary tract neoplasia in companion animals is a debilitating and often life-threatening disease. Tumors of the bladder, urethra, and prostate often occur independently, although extension of these tumors into adjacent regions of the lower urinary tract is documented frequently. The most common lower urinary tract tumor in dogs and cats is transitional cell carcinoma (TCC). In both dogs and cats, TCC affecting the urinary bladder is generally considered to be highly aggressive with both local and metastatic disease potential, and this disease poses unique treatment challenges. Whereas much literature exists regarding the TCC disease process, treatment options, and prognosis in dogs, relatively few studies on feline TCC have been published due to the lower incidence of TCC in this species. Prostate tumors, most commonly adenocarcinomas, occur less commonly in dogs and cats but serve an important role as a comparative model for prostate neoplasia in humans. This article serves as a review of the current information regarding canine and feline lower urinary tract neoplasia as well as the relevance of these diseases with respect to their human counterparts.

Outcome and prognostic factors in medically treated canine prostatic carcinomas: A multi-institutional study

Literature describing medical treatment of canine prostatic carcinoma (PC) is sparse. The aims of this study were to assess outcomes, including time to progression (TTP) and median survival time (MST), of canine PC treated with non-steroidal anti-inflammatory drugs (NSAIDs) and/or chemotherapy, and to identify prognostic factors. Records from 8 institutions were searched for dogs with cytologically or histologically confirmed PC without bladder involvement: 67 dogs were included. Presenting signs were urinary (25), gastrointestinal ([GI], 11) and systemic (3); 16 dogs had GI and urinary signs, 7 dogs had systemic signs with concurrent GI or urinary signs and in 5 dogs the tumour was an incidental finding. Out of 27 dogs, 9 (33%) had positive urine culture. Metastases were identified in 26 dogs to lymph nodes (19), lungs (10), bone (2) and liver (1). Treatment included NSAIDs and chemotherapy (32), NSAIDs alone (31) and chemotherapy alone (4). The overall MST was 82 days (range 9-752) and median TTP was 63 days (range 9-752). Dogs receiving NSAIDs combined with chemotherapy experienced a significantly longer MST (106 vs 51 days; P = .035) and TTP (76 vs 44 days; P = .02) compared to dogs receiving NSAIDs alone. Intact dogs and those with metastatic disease had significantly shorter MST (31 vs 90 days, P = .018 and 49 vs 109 days, P = .037, respectively); intact dogs also had significantly shorter TTP (25 vs 63 days, P = .0003). This study suggests that a combination of NSAIDs and chemotherapy may improve outcomes in canine PC. Metastatic disease and being entire negatively influenced prognosis.