Abstract
Image-guided cryoablation has low procedure-related morbidity and mortality rates, with the complications usually being self-limiting. The most common complications include pneumothorax, hemoptysis, pleural effusion, cough, phrenic nerve injury, and tumor implantation. Bronchopleural or bronchocutaneous fistula formation is a rare but severe complication of lung cancer ablation. We report a patient with non–small cell lung cancer who developed a bronchocutaneous fistula, persistent empyema, and chest wall abscess a month after cryoablation. With this case report, we aim to sensitize physicians to such complications.
Keywords: Bronchocutaneous fistula, empyema, lung cancer, multifocal pneumonia, percutaneous cryoablation, pneumothorax
Only 20% of all diagnosed lung cancers are suitable for curative resection. Percutaneous cryoablation of lung cancer is a minimally invasive procedure utilized in the treatment of early stage lung cancer that is deemed inoperable.
CASE PRESENTATION
A 76-year-old man had known stage IB non–small cell lung cancer of the right lung, diagnosed 3 years earlier and initially treated with radiation. The tumor recurred a year earlier, and the patient was receiving maintenance immunotherapy and chemotherapy and underwent elective cryoablation of the right lung tumor. A month after the cryoablation, the patient presented with purulent sputum, cough, and dyspnea of 3 days’ duration. Computed tomography (CT) showed subcutaneous emphysema, empyema, and intrapulmonary abscess involving the right lung with a likely bronchial perforation and a bronchocutaneous fistula (Figure 1a, 1b). Blood and sputum cultures grew methicillin-sensitive Staphylococcus aureus. Thoracic surgery decided against surgical correction of the fistula at that time, and instead interventional radiology inserted a 14F Wayne chest tube. The patient also underwent subcutaneous decompression via placement of a subcutaneous drain. The chest tube was maintained to suction and intravenous cefazolin was started. The subcutaneous drain was removed after 2 days. Repeat blood cultures were sterile, and the patient completed a 14-day course of cefazolin.
Figure 1.
The patient’s CT scan on (a) presentation showing subcutaneous emphysema; (b) presentation, showing mediastinal/peritracheal emphysema; and (c) day 19, showing the presence of a bronchocutaneous fistula with a chest tube in the left abscess cavity and diffuse pulmonary opacities suggestive of multifocal pneumonia.
On hospital day 19, the patient became acutely hypoxemic, requiring emergent intubation and transfer to the medical intensive care unit. Emergent CT angiography of the thorax showed development of multifocal pneumonia (Figure 1c). Chest tube output grew Pseudomonas, and the patient was started on piperacillin-tazobactam infusion. Repeat blood cultures were negative. He remained febrile, and repeat CT of the thorax on hospital day 22 again showed a persistent right lower lobe intrapulmonary abscess associated with a bronchocutaneous fistula and multifocal pneumonia. A new abscess cavity developing within the right lateral chest wall was also noted, requiring placement of another drain. The patient developed septic shock requiring vasopressors and continued to deteriorate with inability to wean off mechanical ventilation. His family decided to transition him to comfort measures only, and he died 2 days later. The family declined an autopsy.
DISCUSSION
Surgical resection of early stage lung cancer with or without chemotherapy is considered a gold standard treatment for achieving cure, but only 20% of all diagnosed lung cancers are suitable for curative resection.1 Techniques such as radiofrequency ablation, microwave ablation, and cryoablation are being utilized more frequently and are considered safe and effective for the treatment of inoperable lung cancer. Cryoablation offers the advantage of visualization of the ablation margin due to formation of an interstitial infiltrate or visible ice and allows for a complete ablation while avoiding adjacent normal tissues.2,3 Cellular destruction is caused by production of lethal cold temperatures inducing tissue ischemia, protein denaturation, microvascular thrombosis, and cellular osmotic shifts.4
Cryoablation-related complications are usually mild and self-limiting with a low local failure rate, and the overall survival rates are comparable to those achieved with sublobar resection.5,6 Pneumothorax is the most common complication and occurs in 12% to 62% of patients, with 0% to 12% of patients requiring a chest tube.7 Other complications include persistent cough, hemoptysis, pleural effusion, skin injury, phrenic nerve injury, and tumor implantation. Using higher numbers and larger-sized cryoprobes causes a higher risk of complications.8 Pneumothorax, pleural effusion, and hemoptysis are common self-limiting complications of cryoablation, but formation of bronchopleural and/or bronchocutaneous fistulae is a rare and serious complication. The estimated incidence of bronchopleural fistula formation after radiofrequency ablation is 0.6%, but no clear incidence rates have been documented with cryoablation.9
Mechanisms for fistulae formation following lung cancer ablation include direct injury to the pleura and adjacent lung tissue, breakdown of the necrotic tissue, and superimposed infection of the ablated zone, among others. The diagnosis is made using a combination of clinical, radiographic, and bronchoscopy findings.
Bronchial fistulae are associated with high morbidity and mortality.10 Management involves both conservative and surgical interventions, including chest tube insertion, antibiotics for infection control, and obliteration of the residual pleural cavity. A bronchial fistula with an associated empyema usually requires surgical therapy such as debridement, surgical closure of the tract, and/or resection. Bronchoscopic interventions such as endobronchial occlusion can be performed with coils, fibrin glue, Oxycel cotton, cyanoacrylate, or other embolic agents.10
Our case illustrates the importance of careful monitoring for postprocedure complications in patients undergoing lung cancer ablation.
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