Malignant TOF
Malignant Tracheo-oesophageal fistula (MTOF)
What are the types of aero digestive tract fistulas?
Tracheo-oesophageal fistula (TOF)
Broncho- oesophageal fistula (BOF)
Oesophageal-lung parenchyma fistulas (rare)
What are the causes of these fistulas?
- These fistula’s develops either because of direct tumor invasion and subsequent perforation or after radiation, laser therapy, chemotherapy or pre-existing stents (primarily, oesophageal stents), or a combination of these.
- Approximately 77% of MTOF are related to oesophageal cancer, whereas approximately 16% originate from a primary lung neoplasm.
- Other tumours like malignant mediastinal nodal disease, thyroid, laryngeal cancer etc causes MTOF rarely
How common is it?
It develops in approximately 5%–15% of patients with an oesophageal malignancy and in less than 1% of those with bronchogenic carcinoma
What are the symptoms?
Intractable cough and repeated aspirations.
Autopsy data indicate a higher incidence of fistulas, thus suggesting that fistulas are more common in patients than is usually diagnosed. A history of repeated coughing associated with eating, drinking, or both, with an increase in dysphagia and dyspnea are highly suggestive of a fistula. Endoscopic findings are sometimes inadequate in demonstrating a fistula, in which case a water contrast swallow is required.
Lung abscess is the most frequent and severe complication of oesophageal-lung parenchyma fistulas. In this particular type of aero digestive fistula, stent placement may worsen the infectious problem by impairing natural drainage of the abscess.
In one study, lung abscesses decreased in size, but persisted even after stent placement. Concomitant abscess drainage procedures should thus be considered. Thus, oesophageal stent remains the accepted treatment for oesophageal-lung parenchyma fistulas (with percutaneous drainage of the abscess)
What is the prognosis?
Once a fistula (stage T4) develops, the tumour is incurable. The treatment is palliative to alleviate symptoms. Treatment should be begun immediately after the diagnosis is confirmed since the usual cause of death in these patients is pulmonary sepsis resulting from chronic aspiration through the fistula. In two, large series reports (4, 5), mean patient survival was reported to be 3.1-3.4 months. The usual causes of death are: massive bleeding, pneumonia or malnutrition
What are the treatment options?
Therapy is mainly directed to palliate symptoms and maintain quality of life.
- Unfortunately, at the time of diagnosis, the patient’s performance and disease status usually precludes aggressive palliative surgical therapy (oesophageal bypass using a gastric bypass and cardiostomy)
- Radiation therapy and chemotherapy are generally contraindicated due to the concern regarding fistula enlargement caused by tumor necrosis.
- Oesophageal or tracheobronchial stenting or both is the treatment of choice.
- Gastrostomy: Stenting however achieves better palliation of respiratory symptoms with a better quality of life.
Discuss selection of stent?
Several kinds of covered oesophageal stents are available (i.e., Ultraflex stent, Wallstent, and Z stent). However, there are no randomized or controlled trials to compare the outcomes of any of these stents when used to treat malignant aero digestive fistulas
Discuss the stenting area?
The selection guide for determining the stenting area could be summarized as follows:
- oesophageal stent placement if a patient has a stricture in the oesophagus,
but with no or only mild airway stricture since an oesophageal stent can successfully treat both oesophageal stricture and a fistula;
- airway stent placement if a patient has no or only mild stricture in the oesophagus, or has moderate to severe stricture in the airway, since an oesophageal stent migrates well when oesophageal stricture is absent or mild, and an airway stent can treat an airway stricture; or
- both the airway and oesophageal stent placement when a patient has moderate to severe stricture involving both the oesophagus and the airway, since both the airway and oesophageal stents are necessary to treat a stricture involving both the oesophagus and the airway.
- In case of a high (fistula at 18-20cm from incisor) tracheo-oesophageal fistula –oesophageal stent may be undesirable and a tracheal stent is the better option.
NB: Airway stent is preferred in malignant fistula developing after Ivor Lewis
Oesophagectomy (the replaced stomach or colon shows a large lumen compared
with the lumen of the original oesophagus). The larger lumen makes oesophageal stent migration (and hence uncovering fistula) easier.
Discuss double stenting i.e. both oesophageal and Tracheobronchial stent insertion?
Double stenting appear to provide more benefits than either oesophageal or respiratory stents alone in terms of palliation and safety. Double stenting is definitely indicated when fistula occlusion is not achieved by the oesophageal or airway stent alone. In cases of double stenting, airway stent should be placed first in order to avoid tracheal or bronchial compression secondary to the oesophageal stent.
Mechanical friction between the oesophageal and airway stents may cause pressure necrosis of the interposed tissue between the two stents, thereby possibly resulting in a fatal haemorrhage. Thus, parallel stenting should only be performed after thoroughly reviewing a patient’s clinical indications.
Discuss the success of oesophageal stenting?
- Oesophageal stenting is technically feasible in the majority.
- Oesophageal stent completely seals off the fistula in 60-100% of cases. Incomplete closure of the fistula caused by spillage of material through a gap between the proximal stent margin and the oesophageal wall (‘funnel phenomenon’). This is difficult to manage despite the insertion of additional stents or glue injection to seal the gap. An additional airway stent is usually required. Thus, a contrast swallow is obtained immediately after stent insertion to confirm the sealing of the fistula and subsequently allow a patient to eat a soft diet. If there is persistent leakage through the fistula, resulting from an incomplete stent expansion, a follow-up contrast swallow should be obtained 2-3 days after stent placement in order to confirm stent expansion before food intake is resumed.
- The fistulas may reopen/recur in 0-20% of cases. The reported causes of reopening following stent placement were stent occlusion (caused by tumor overgrowth or in growth, food impaction, or granulation tissue formation), stent migration, and stent covering disruption.
Does stenting have a survival advantage?
A recent study (3) compared treatment of MTEF in three groups: oesophageal stent group, gastrostomy group and control group (refused both stenting and gastrostomy).
There was no statistical difference in survival time (Average survival time for stent group was 93 days with a range of 44-165 days, gastrostomy group- 62 days, range 41-111 days and control group survival time was 66 days- range 20-119 days).
In two, large series reports (4, 5), mean patient survival was reported to be 3.1-3.4 months. In one of these reports (4), the survival benefit was significant in patients in the stenting group (3.4 months) compared with the gastrostomy group (1.1 months), and the supportive management group (1.3 months).
NB: It is very important to carefully evaluate the airway stenosis with CT scans or
bronchoscopy prior to oesophageal stent placement, since it is possible to develop tracheal compression caused by expanding oesophageal stents. Further, for airway
stenting, reconstructed CT images are very useful for measuring the distance between the fistula and a carina or vocal cord, in the determination optimal stent length.
References:
4. Balazs A, Kupcsulik PK, Galambos Z. Esophagorespiratory fistulas of tumorous origin. Non-operative management of 264 cases in a 20-year period. Eur J Cardiothorac Surg 2008;34:1103-1107
5. Shin JH, Song HY, Ko GY, Lim JO, Yoon HK, Sung KB. Esophagorespiratory fistula: long-term results of palliative treatment with covered expandable metallic stents in 61 patients. Radiology 2004;232:252-259
