Usefulness of transnasal volume-reduction treatment for nasal tumors by ultrasonic emulsification suction in 2 dogs

Abstract

Intranasal tumors in dogs are rare neoplastic diseases with obvious clinical signs, such as epistaxis, nasal congestion, and facial deformity. Radiation therapy is the treatment of choice but is not always accessible due to geographical location, logistics, or financial constraints. Other treatments may not be used because of various restrictions. We performed transnasal intranasal tumor volume reduction in 2 dogs with intranasal tumors; 1 dog had an adenocarcinoma and the other had a fibrosarcoma. In both cases, improvement in the quality of life (QOL), including reduced clinical signs and increased activity, was observed ~1 wk after treatment. No obvious complications were associated with this treatment. Although tumor recurrence was noted in both cases, this treatment could be applied multiple times. In conclusion, transnasal nasal tumor volume reduction is a palliative method that contributes to improvement of clinical signs and QOL.

Key clinical message:

We report palliative treatment of intranasal tumors in dogs. The treatment described in this report is available to most veterinarians and helps improve the QOL of dogs with nasal tumors, including improving respiratory status.

Nasal tumors account for 1 to 2% of canine tumors (1). Clinical signs include nasal discharge, epistaxis, sneezing, and reverse sneezing, and are initially mild (2,3), leading to delayed diagnosis. However, as tumors progress, dyspnea, facial deformity, and exophthalmos may develop, and quality of life (QOL) declines. Reported median survival rates are 3 to 5 mo without aggressive treatment and 8 to 25 mo with radiation therapy or surgery (1,2). Surgical treatment is seldom recommended due to the high incidences of postoperative complications and mortality (3,4). The result may also be esthetically undesirable. Radiation therapy is the gold standard for treatment of intranasal tumors (2), but it has limited availability, is generally costly, and may cause toxicity and esthetic changes.

Ultrasonic emulsification suction devices are popular in human medicine (5). These devices use ultrasound waves generated from a titanium tip to crush (cavitate) tissue with high water content and irrigate and aspirate it with a handpiece. In dogs, their use has been reported for liver and prostate tumors (6,7), and thus it was suggested that volume reduction could also be achieved for intranasal tumors by crushing of tumor tissue, perfusion, and aspiration. Therefore, this technique was used in the cases reported herein.

CASE DESCRIPTIONS

Case 1

A 7-year-old spayed female toy poodle dog weighing 2.6 kg had a 2-month history of epistaxis from the left nostril when it sneezed. Epistaxis was relieved by medical treatment (tranexamic acid: 10 mg/kg, PO, q12h) by the referring veterinarian, but the dog had another episode of epistaxis from its left nostril and was referred to us. The dog had sneezing, reverse sneezing, and nasal discharge, though no apparent external factors, such as trauma to the nose or bleeding disorder, were suspected. Laboratory tests indicated a mild decrease in white blood cell count, an increase in C-reactive protein, and a mild increase in alkaline phosphatase (Table 1). However, blood coagulation system tests indicated no abnormalities.

TABLE 1.

Results of laboratory blood tests.

Item	Result		Reference interval
	Case 1	Case 2
White blood cells (/μL)	4900	26 200	6000 to 17 000
Red blood cells (×106/μL)	7.52	5.72	5.5 to 8.5
Hemoglobin (g/dL)	16.8	11.7	12.0 to 18.0
Platelets (×103/L)	401	40.4	2200 to 500
Blood urea nitrogen (mg/dL)	18.0	21.1	9.2 to 29.2
Creatinine (mg/dL)	0.6	0.6	0.4 to 1.4
Alanine aminotransferase (U/L)	31	33	17 to 78
Alkaline phosphatase (U/L)	404	374	47 to 254
Calcium (mg/dL)	10.1	11.1	9.3 to 12.1
C-reactive protein (mg/dL)	6.9	0.9	0.0 to 1.0

Radiographs revealed increased radiopacity in the left nasal cavity but no osteolysis of the nasal septum. Computed tomography (CT) revealed a space-occupying lesion (SOL) with a contrast-enhancing effect on the caudal side of the left nasal cavity and part of the frontal sinus. The SOL did not extend to the left ventral nasal meatus, and the respiratory tract to the pharynx was maintained. In addition, the SOL was confirmed to be ~40 mm caudal to the external nostril. No other findings suggestive of osteolysis, such as nasal septum, lamina cribrosa, or orbit, were detected, and no swelling or distant metastasis of the regional lymph nodes were observed. Therefore, the lesion was designated a Stage-1 lesion, based on the modified Adams staging system (8).

A biopsy of the SOL was obtained using endoscopic biopsy forceps and was subjected to histopathological examination. The dog was diagnosed with intranasal adenocarcinoma. The owner declined surgery or radiation therapy and elected to start the dog on medical treatment with piroxicam (0.3 mg/kg, PO, q48h). After 4 mo, clinical symptoms such as worsening of the respiratory condition at bedtime, open-mouth breathing, and nasal-obstruction sounds apparent even while the dog was at rest became remarkable. When CT was repeated, the tumor in the nasal cavity had increased and extended to the left abdominal nasal passage, and osteolysis of the orbit and right displacement of the nasal septum were observed (Figure 1 A, B, C). According to the modified Adams staging system, the lesion was designated as Stage 3.

FIGURE 1.

Computed tomographic (CT) evaluation of transnasal volume-reduction treatment for nasal tumors in dogs (Case 1, both pre- and posttreatment images). A — Transverse (pre-treatment); B — Sagittal (pre-treatment); C — Coronal (pre-treatment); D — Transverse (1 mo post-treatment); E — Sagittal (1 mo post-treatment); F — Coronal (1 mo post-treatment). Pre-treatment, the tumor in the nasal cavity had increased and extended to the left abdominal nasal passage, and osteolysis of the orbit and right displacement of the nasal septum were observed (A to C). Post-treatment, the nasal tumor was reduced in size, although complete disappearance was not achieved (arrows in D to F).

Ca — Caudal; Cr — Cranial; L — Left side; Post — CT image at the posttreatment checkup (1 mo after treatment); Pre — CT image just before treatment.

The owner was offered a more aggressive treatment option but did not consent. Instead, a transnasal volume-reduction treatment for nasal tumors was proposed and accepted. Under general anesthesia, CT was used to determine the distance from the external nostril on the rostral side to the site of tumor development, and the degree of lateral and ventral-dorsal extension of the lesion. Next, an ultrasonic suction device (SonoSurg-IU; Olympus Medical Systems, Tokyo, Japan) was inserted through the rostral nostril, and the volume of the tumor was reduced while using CT images as a guide. The most important precautions were the distance and angle from the external nostril to the cribriform plate area and from the external nostril to the orbit, so that the tip of the ultrasonic suction device did not enter the skull from the cribriform plate or the orbit. The distance and angle were measured in advance, and the volume was reduced with great care.

Although total removal of the intranasal tumor was not possible, the volume reduction of the intranasal tumor was sufficient, as evidenced by CT 1 mo after treatment (Figure 1 D, E, F). Epistaxis was a postoperative complication but subsided within ~7 d with no medical treatment. A few days postoperatively, the dog showed much improvement in QOL compared to preoperatively, including a stable respiratory condition (stable sleep, disappearance of open-mouth breathing and nasal congestion at rest) and increased appetite.

The dog was monitored for clinical signs of recurrence, and a CT scan was done every 2 mo to monitor recurrence of the intranasal tumor. Over time, the size of the intranasal tumor gradually increased. In addition, epistaxis was sometimes observed approximately once per week; however, after medical treatment (tranexamic acid), it was no longer observed.

Six months after the volume-reduction treatment, the intranasal tumor had grown to ~60 to 70% of its pretreatment size, and the nasal bone was substantially reduced. Therefore, transnasal volume-reduction treatment was performed again. After the second volume-reduction treatment, the tumor volume was reduced to the same extent as after the first treatment. The dog continued to live without obvious clinical deterioration except for occasional epistaxis. Thereafter, volume-reduction treatment was performed approximately once every 6 mo and, apart from occasional epistaxis, no obvious progression of intranasal tumors was observed. No major complications other than epistaxis were observed after additional treatment. No change in appearance was observed due to progression of the intranasal tumor, and the dog died for reasons unrelated to the intranasal tumor > 5 y after diagnosis.

Case 2

A 12-year-old female Shiba Inu dog weighing 8.4 kg had experienced increased sneezing and a blood clot expelled from the nasal cavity ~1 mo earlier. After medical treatment (antibiotics, antihistamines: details unknown) by the referring veterinarian, the dog exhibited nearly constant epistaxis and was referred for further examination. Laboratory tests indicated an elevated white blood cell count and mild elevation of alkaline phosphatase (Table 1), but blood coagulation system tests indicated no abnormalities.

Head CT revealed an SOL in the left nasal cavity with a poor contrast-enhancing effect (Figure 2 A). In addition, the nasal septum had partial osteolysis on the right side, but no infiltration of the lamina cribrosa or orbit was observed. No other findings suggestive of metastasis were observed. The nasal lesion was classified as Stage 2 according to the modified Adams staging system. Histopathological examination revealed that the intranasal tumor was a fibrosarcoma.

FIGURE 2.

Computed tomographic (CT) imaging of a dog with an intranasal fibrosarcoma (Case 2). A — Dorsal (pre-treatment); B — Dorsal (3 mo post-treatment); C — Dorsal (7 mo post-treatment). The left nasal cavity and turbinate were partially lysed (arrow in A). At 3 mo post-treatment, the nasal tumor was reduced (B). At 7 mo post-treatment, the nasal tumor recurred (C).

L — Left side; Post — CT image at the posttreatment checkup; Pre — CT image just before the start of treatment.

Based on these results, a transnasal volume-reduction treatment of the nasal tumor using ultrasonic emulsification suction was performed. Following the procedure, the dog had epistaxis that subsided within 7 d with no medical treatment, but no other major complications were observed. Neither epistaxis nor nasal discharge were observed at an examination 3 mo after treatment, and the dog’s general condition was good. Although CT revealed an intranasal tumor near the lamina cribrosa, the overall volume was reduced (Figure 2 B).

At 7 mo after treatment, CT indicated a clear recurrence of the tumor in the left nasal cavity (Figure 2 C). The tumor in the nasal cavity was removed using an ultrasonic emulsification suction device. The dog was subsequently untreated and died 7 mo after the second treatment.

DISCUSSION

In the cases reported herein, an ultrasonic emulsification suction device was used to reduce the volume of an intranasal tumor from the rostral side. Although it is necessary to identify the site of the intranasal tumor using CT, this approach enables volume reduction of the intranasal tumor from the rostral side while using the CT image as a guide. Compared to general surgical procedures, the approach is minimally invasive, does not require skin incisions or removal of the nasal bone, and can be completed easily — all major advantages. The only postoperative complication of this procedure was epistaxis for ~1 wk in both cases. It was noteworthy that both dogs had substantial posttreatment improvement in their respiratory function and QOL.

This treatment was not intended to be a substitute for radiation therapy but was limited to palliative volume reduction, and relapse of clinical signs occurred. The interval from treatment to relapse (asymptomatic period) was 6 to 7 mo; the length of this interval may depend on the type of intranasal tumor. This treatment has potential as part of a multimodal approach with radiation therapy and/or toceranib (9), or after relapse, to extend survival, but further investigation is needed.

For this technique, CT was necessary to determine the location of the lesion and the insertable range of the ultrasonic emulsification suction device. Intranasal tumors may cause changes in the appearance of the head, by causing osteolysis of the surrounding bones (e.g., nasal bone and maxilla) as the tumor grows. Some owners have difficulty accepting this change in appearance. Although there was osteolysis around the tumor in both cases we report, treatment prevented further progression and did not alter the head’s appearance. Therefore, this technique was also considered effective from an esthetic perspective.

A challenge of our volume-reduction treatment would be its application in cases of intranasal tumor arising in the frontal sinus or from the cribriform plate. The frontal sinus is likely inaccessible to ultrasonic emulsification suction devices owing to its anatomic angle and depth. The cribriform plate is adjacent to the brain and, even if the location and angle of nasal tumor development have been determined via CT, sufficient care must be taken. Therefore, we inferred that this method may be most appropriate for treatment of nasal tumors arising in the nasal cavity and nasopharyngeal regions other than the frontal sinus.

In Case 1, deemed Stage 3 based on the modified Adams staging system, the nasal adenocarcinoma that had invaded the orbit disappeared after treatment. This suggested that ultrasonic emulsification suction may have successfully removed the tumor that had invaded beyond the orbital bone. Our method in Case 1 did not involve aggressive treatment in the orbital direction. One possible reason for the disappearance of the orbital lesion was that the ultrasonic emulsification treatment-induced hyperthermia may have been effective. However, the actual temperature and range of heating by the equipment were not known, and aggressive use of this treatment for orbital lesions may cause ophthalmologic problems. Therefore, this treatment should not be used in modified Adams Stage-3 or Stage-4 cases and may be feasible for patients at modified Adams Stage 1 or Stage 2.

In conclusion, this transnasal volume-reduction treatment has a limited therapeutic effect and should be regarded as a palliative treatment. However, the treatment was easy to perform, and improvements in QOL, such as respiratory conditions, were promptly observed. Therefore, it should be considered an effective treatment option for intranasal tumors.