Veterinary Society of
Surgical Oncology

GENERAL CONSIDERATIONS

Biologic Behaviour

  • esophageal tumors are very rare in both cats and dogs accounting for < 0.5% of all cancers
  • female cats are predisposed, but no known breed or sex predisposition in dogs
  • malignant tumors are more common and include SCC, leiomyosarcoma, FSA, and OSA
  • SCC is common in cats with the middle 3rd of the esophagus cranial to the thoracic inlet most commonly affected
  • neuroendocrine carcinoma and adenosquamous carcinoma reported in cats
  • sarcomas have been reported secondary to Spirocerca lupi infestation in indigenous areas such as Israel and SE USA
  • Spirocerca lupi-induced esophageal sarcomas include FSA, OSA, and undifferentiated sarcomas
  • locally invasive with metastasis to regional lymph node via direct extension or lymphatic or hematogenous routes
  • benign tumors include leiomyoma and solitary extramedullary plasmacytoma
  • solitary extramedullary plasmacytoma have a predilection for the terminal esophagus and cardia
  • paraesophageal (i.e., thymic, heart base, or thyroid) tumors can invade the esophagus
  • pulmonary and mammary carcinoma can metastasize to the esophagus
  • esophageal ADC is possibly associated with cholecystectomy in humans due to bile reflux

CLINICAL FEATURES

Clinical Signs

  • clinical signs are non-specific and include debilitation, regurgitation, hematemesis, weight loss, dysphagia, pain during swallowing, and aspiration pneumonia
  • regurgitation may be sporadic due to distensibility of esophagus and slowly progressive disease
  • hypertrophic osteopathy has been reported especially with Spirocerca lupi­-induced esophageal sarcomas
  • Spirocerca lupi-induced esophageal sarcomas are also associated with esophageal granulomas, aortic scarring and mineralization, and spondylitis of the caudal thoracic vertebrae (T6-T12)
  • esophageal tumors < 2 cm rarely cause clinical signs

Diagnosis

Survey Radiographs

  • survey radiograph findings include:
  • gas retention within esophageal lumen
  • esophageal dilation proximal to the mass
  • soft tissue mass displacing the esophagus or extending into the lumen
  • displacement of mediastinal structures
  • lumen irregularities

Contrast Esophagram

  • contrast esophagram can be performed ± fluoroscopy
  • esophagram findings include filling defect, stricture, or intraluminal mass

Esophagoscopy

  • esophagoscopy provides direct visualization of the mass and ability to collect biopsy samples
  • malignant tumors are usually ulcerated
  • leiomyoma appears as circumscribed submucosal mass movable beneath the mucosal layer
  • several biopsies should be taken due to prominent inflammation and necrosis, but representative samples are difficult to collect
  • iatrogenic perforation is rare with endoscopic biopsy

Other Diagnostic Techniques

  • plasma cell tumors may cause hyperproteinemia, hypercalcemia, and monoclonal gammopathy
  • fecal flotation test and examination for Spirocerca lupi ova
  • open surgical biopsy via either exploratory thoracotomy or cervical exploration

TREATMENT

General Considerations

  • treatment is complicated as the majority of cases are advanced at the time of diagnosis

Surgery

  • intrathoracic resection is difficult due to poor healing, large resection, anastomotic tension, and poor exposure
  • distal esophagus can be reconstructed with gastric advancement through the diaphragm
  • esophageal reconstruction has been reported with muscle flaps or microvascular transfer of colon or small intestine
  • results of esophageal reconstruction are variable
  • en bloc esophageal resection is associated with excellent local control and > 50% long-term survival
  • partial esophagectomy with primary esophageal closure has been reported in the management of 6 dogs with Spirocerca lupi-induced esophageal sarcomas with good postoperative recovery and function, and survival times ranging from 2 to > 20 months
  •     palliation with enteral nutrition (via E- or G-tubes) or self-expanding intraluminal stent

Radiation Therapy

  • indications: tumors of the cervical esophagus
  • intrathoracic esophageal tumors should not be irradiated due to poor radiation tolerance of the lungs and heart

Chemotherapy

  • unknown
  • doramectin (200 µg/kg q 2 weeks SC for 3 treatments) used successfully in dogs with Spirocerca lupi esophageal granulomas

Photodynamic Therapy

  • photodynamic therapy using photofrin as a photosensitizer has been described in the management of 1 dog with esophageal SCC with PR and 9-month survival time

Prognosis

  • prognosis is poor for malignant esophageal tumors due to difficult surgical resection and high metastatic rate
  • prognosis is good for benign lesions following complete resection
  • 5-year survival rate is < 20% in humans using a combination of surgery, radiation therapy, and chemotherapy

ESOPHAGEAL TUMORS

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