• In cases with severe CAO, endotracheal intubation may be required to secure the patient’s airway and to provide positive pressure ventilation.

• Flexible bronchoscopy can then be performed after patient is intubated.

• If patient has an obstructive pneumonia, empiric antibiotic therapy should be initiated.

• Bronchoscopy is an important diagnostic tool and can be used to evaluate and possibly treat the cause of obstruction.

• Bronchoscopic management of airway obstruction is palliative.

• A single institutional study revealed 42% of patients required more than one procedure to maintain airway patency [25].

• There are two types of bronchoscopy

 The flexible fiber optic bronchoscopy is used widely in evaluating and diagnosing diseases of the airway due to its relative ease of use, and lack of a need for general anesthesia.

 The rigid bronchoscope is often preferred by interventional pulmonologists given its superior control when managing difficult airway conditions.

– In a severely obstructed airway, the beveled edge of the rigid bronchoscope can be used to shear large pieces of the endobronchial tumor and ventilation through the bronchoscope can be used to ventilate the distal airway.

– Additionally, the large bore of the rigid bronchoscope can accommodate larger caliber suction catheters and larger biopsy forceps.

 The rigid bronchoscope is more unwieldy than the flexible bronchoscope and requires greater training [26].

• Bronchoplasty or balloon dilation can be utilized to dilate a stenotic airway.

• Rigid dilators or sequential balloons may be passed through a stenotic segment of a central airway to dilate the stenosis.

• For balloon dilation, a series of dilations are performed with increasing balloon diameter to reduce risk of tracheobronchial rupture.

• Irrespective of the method of dilation, bronchoplasty provides immediate relief of extrinsic and intrinsic lesions, but the results are temporary.

 Granulation tissue may form after bronchoscopy and cause recurrent stenosis due to mucosal tears from the procedure.

 Often airway stents are placed for more durable results.

• Airway stents may be used to maintain patency of the airway, and may be placed via flexible or rigid bronchoscopy.

• Metal and silicone stents may both be used.

 Covered metal stents are most often used for malignant obstructions

– Prevent tumor ingrowth and provide a larger internal: external diameter ratio compared to silicone stents.

– Difficult to remove.

 Silicone stents

– More easily removed if the obstructing mass responds to chemotherapy and/or radiation therapy.

– Smaller diameter, which leads to a higher rate of migration.

– Require a rigid bronchoscopy for placement.

• Argon Plasma Coagulation (APC) is a noncontact electrocoagulation therapy applied via rigid bronchoscopy.

• A 5000–6000 V spark formed at the tip of a tungsten electrode ionizes argon gas, which then coagulates adjacent tissues causing them to undergo coagulative necrosis.

• Coagulation occurs 2–3 mm deep and there is very little risk of airway perforation [27].

• Can treat lesions lateral to probe or areas inaccessible by laser therapy making this therapy useful for hemorrhages.

• Does not vaporize tumor and some authors recommend repeat bronchoscopy 1–3 days after APC procedure to debulk the necrotic tissue.

• Lasers have been used for debulking since 1975.

• The Nd:YAG laser is most commonly used today. It can be used via a flexible bronchoscope and can achieve a tissue penetration of up to 10 mm [28].

• Laser photoresection has been used extensively for both benign and malignant airway lesions.

 Malignant lesions have the best ablation rates with laser therapy alone;

 Benign lesions were best managed by laser therapy and mechanical rigid dilation [29].

• Success can depend on location.

 Tumors located in the trachea, right mainstem bronchus, and bronchus intermedius were treated successfully 97%, 94%, and 90% of the time;

 Tumors in the left mainstem bronchus and left upper lobe were more difficult, but treated successfully in 86% and 58% of the time, respectively [30].

• Laser resection has a greater than 90% success in reestablishing patency in endobronchial masses that are central, intrinsic, and less than 4 cm in length [30,31].

• The most common reported complications from laser resection are bleeding (2.5%), and hypoxia (1.8%) [32].

• Endobronchial cryotherapy destroys tumors with cytotoxic effects of rapid freezing (–100°C/minute) and slow thawing of tissue.

 The freezing creates intracellular ice crystals that expand in the cell causing cell membrane and organelle damage resulting in direct cell death.

 Additionally, the freezing causes thrombosis of the microvasculature to the tumor [33].

• Using a flexible cryoprobe, adjacent tissue is frozen to extremely low temperatures (below −20°C to −40°C) [34].

• The role of cryotherapy for management of CAO is limited due to its delayed effect and the need to undergo multiple bronchoscopies to remove debris [35].

• For patients with a localized tumor encasing a major bronchus, and who cannot tolerate a pneumonectomy, a tracheobronchial sleeve resection may be considered for both curative and palliative intent.

 Helps preserve native lung function.

 Associated with lower mortality rates than pneumonectomy [36].

• Tracheostomy can be performed to bypass a large obstructive neoplastic lesion proximal to the larynx and prevent respiratory compromise.

 Patients can function with a temporary or permanent tracheostomy.

 The side effects from tracheostomy are increased risk of infections, and perceived social stigma.

• The primary goal of palliative chemotherapy is to prolong survival and ease the symptoms by reducing the burden of disease.

• Each patient must be carefully evaluated and his or her goals of care must be known before deciding on pursuing palliative chemotherapy.

 The American Society for Clinical Oncology guidelines recommend palliative chemotherapy only for solid tumor patients with good Eastern Cooperative Oncology group (ECOG) performance status (ECOG <3) [37].

 Prigerson et al. showed that chemotherapy-refractory metastatic cancer patients with good ECOG performance status who received additional palliative chemotherapy will have significantly worse quality of life at the end of life than those who did not receive chemotherapy [38].

• If the patient has not received chemotherapy before, or their cancer has had previous response to the chemotherapy, palliative chemotherapy may be an option.

 Standard doublet therapy with cisplatin or carboplatin and a second agent such as a taxane is superior to single-agent therapy [39].

 In a Phase III RCT, cisplatin and pemetrexed was found to be more active in patients with nonsquamous histology, while cisplatin and gemcitabine were more active in squamous histology [40].

• Palliative radiotherapy has a role in treatment of symptoms including cough, shortness of breath, hemoptysis, bronchial or tracheal obstruction, or superior vena cava obstruction.

• Many randomized trials have assessed palliative dose fractionation for locally advanced lung cancer, though many of these studies were completed before wide use of modern CT simulation and computerized treatment planning [41–43].

 The studied regimens have ranged from as short as a single 10 Gy fraction to as lengthy as 50–60 Gy in 25–30 fractions.

 Though there is not a single defined optimal dosing schedule, shorter fractionation schedules (10 Gy in 1 fraction, 17 Gy in 2 fractions over 2 week, and 20 Gy in 5 fractions) are equally efficacious in providing palliative relief with fewer side effects (1991; 1992) (See Table 8.3).

 Palliative improvement with either short- or longer-course radiation has been shown to improve dyspnea (40–97%), hemoptysis (77–92%), cough (60–91%), superior vena cave syndrome (51–96%), and pain (70–78%).

 When deciding on the most appropriate fractionation scheme, a patient’s age, performance status, pulmonary function, presence of pleural effusion, and metastatic disease burden should be taken into account [42].

• Radiation for collapsed lung

 71% of patients who received 30–60 Gy to the obstructive tumor in the mainstem bronchus within 2 weeks after radiological evidence of atelectasis had complete reexpansion of their lungs, whereas only 23% of patients who received radiation greater than 2 weeks had reexpansion [49].

 If there are plans for definitive radiation, then large dose per fraction (3–4 Gy/fraction) should not be pursued since it will limit the radiation dose for future treatment. If the lesion is amenable to endobronchial management (debridement, stent, or even brachytherapy), this should be considered first. Some patients have collapsed lobe on imaging but are asymptomatic (especially if both ventilation and perfusion are affected, i.e., a “matched defect”).

 If patient is neutropenic, consider prophylactic antibiotic due to risk of sepsis after reexpansion of lung.

• Radiation for intubated patient

 Intubated patient with near complete consolidation due to either intrinsic or extrinsic airway obstruction (i.e., endobronchial disease, or hilar LN or mass that is central enough to compress on the airway) should be managed endobronchially first if there is endobronchial disease, since patient is already intubated. Debridement would have more immediate benefit than stent. If stent is placed, palliative dose would be the same even if no stent is present.

 The addition of concurrent chemotherapy with external beam radiotherapy does not improve symptom improvement and may add unwanted toxicity [42].

• The use of highly conformal therapy such as stereotactic body radiotherapy (SBRT) for locally advanced lung cancer holds promise, but has not yet been extensively studied [42].

 Single institution trials of SBRT showed no benefit in overall survival.

 Approximately 25% of patients have partial or complete bronchial strictures resulting in secondary loss of normal lung volume [50].

• Side effects associated with palliative radiation therapy

 Worsened fatigue, dysphagia, and esophagitis resulting in weight loss.

 Increase shortness of breath with radiotherapy to the lung in patients with preexisting chronic obstructive pulmonary disease.

 Patients should be counseled regarding the potential acute effects of radiation against benefits.

• Supportive care for intubated patient

 In an intubated patient in the ICU, all options could be considered to determine what might be most effective to alleviate obstruction. Possibilities might include trial of bronchoscopy with cryotherapy or laser therapy, possible stent placement, or XRT. Decision about whether or not to proceed would depend on location of obstruction, acuity, and patient’s overall prognosis and goals of care.

• High dose rate (HDR) endobronchial radiation can be used as an adjuvant therapy following stenting procedures to delay regrowth of the obstructive mass.

 Polyethylene afterloading catheters are positioned in place with flexible or rigid bronchoscopy.

 Intraluminal brachytherapy is limited to smaller tumors [51].

– The effective dose distance of endochronichial HDR brachytherapy is 0.5–2 cm from the source.

 Typical doses prescribed are 20–30 Gy total dose at 2 cm.

• Intraluminal brachytherapy is considered for symptomatic recurrence of intraluminal disease that has previously been treated with EBRT [42].

• The addition of endobronchial brachytherapy to external beam radiotherapy has not been shown to significantly add to symptom control.

• Heliox is a helium–oxygen gas mixture that reduces work of breathing by decreasing airway resistance by decreasing turbulent flow and thereby decreasing airway resistance.

• Has been used in multiple medical situations including postextubation laryngeal edema, tracheal stenosis, and angioedema [52].

• Two case studies demonstrated the use of the helium/oxygen mixture to manage severe upper-airway obstruction associated with tumor [53].

• Improvement in breathing and dyspnea is only temporary (CAO is still present).