Superior vena cava obstruction (SVCO) is a common complication of malignancy. Lung cancer accounts for approximately 50-70% of all cases of SVCO, with extrathoracic malignancies accounting for another 15-20% (1)(2)(3)(4). At some point during their disease course, approximately 10% of patients with small cell lung cancer, 2-4% of patients with non-small cell lung cancer (NSCLC), and 2-8% of patients with non-Hodgkin lymphoma will develop SVCO (1,2,5). The average life expectancy for patients who present with malignancy-associated SVCO is six to nine months, but there is wide variability depending on the type and stage of underlying cancer. Where clinical circumstances allow, decisions regarding management of patients with SVCO should be conducted in a multidisciplinary setting, with tissue diagnosis and completion of staging prior to institution of therapy.
The management of airway obstruction depends on many factors, including the urgency of presentation, tumour histology, stage, location, and performance status (PS) of the patient. Malignant airway obstruction is most commonly caused by direct extension from tumour in the mediastinum (i.e., lung cancer, thyroid, thymoma, esophageal) or a primary tumour of the head and neck 6. Lung cancer is the most common cause of malignant-associated airway obstruction. Airway obstruction occurs in approximately 20 to 30 percent of patients with lung cancer (6). Cancers which have metastasized to the lung or mediastinum can also cause airway obstruction (7).
Hemoptysis, or the expectoration of blood, can range from blood-streaking of sputum to gross blood or clots alone, in the absence of any accompanying sputum. Hemoptysis has a broad differential which includes metastatic cancer to the bronchus or trachea (most commonly from melanoma, breast, colon, or renal cell carcinoma), primary or secondary lung cancer, or terminal hematological malignancy, along with many non-malignant causes. Among patients with cancer, hemoptysis is most common in lung cancer, with approximately 20% of lung cancer patients experiencing hemoptysis during the course of their illness (8).
Recognizing that patients with SVCO, dyspnea and hemoptysis may benefit from a multidisciplinary palliative/supportive care team (including physiotherapy therapy/ occupational therapy/ psychosocial support/ speech-language pathology etc.), the intent of this guideline is to focus specifically on radiotherapy options. Whenever possible, participation in a clinical trial is strongly encouraged. Securing the opinion of an interventional respirologist or radiologist is recommended in certain circumstances (i.e. severe or life threatening SVCO, dyspnea or hemoptysis) (see: www.brit-thoracic.org.uk/documentlibrary/clinical-information/bronchoscopy/advanced-diagnostic-and-therapeutic-bronchoscopy/btsadvanced-bronchoscopy-guideline/).
The most common radiation approach to treatment is external beam radiotherapy (EBRT), in which radiation is delivered from a source external to the patient. Endobronchial brachytherapy (EBB) is a technique whereby radioactive seeds are positioned in close proximity to a malignant lesion to deliver high dose radiation with rapid dose fall-off. Photodynamic therapy (PDT) involves the use of an intravenous photosensitizing agent which is activated at the target location using a low-power laser, resulting in the generation of high-energy oxygen, which causes necrosis through a photochemical effect. Neodymiumdoped yttrium aluminum garnet (Nd:YAG) laser therapy vaporizes or coagulates tumour under direct vision with no mechanical stress to surrounding structures. Access to these treatment modalities varies geographically.

# GUIDELINE QUESTIONS
What are the recommended strategies for the management and treatment of adult patients with:

# SEARCH STRATEGY
For the 2016 update, the National Library of Medicine's Pubmed database was systematically searched (January, 2012 to December, 2014) using 2 independent searches (Full details in Appendix A). In brief, articles were excluded if they: were not written or translated into English, were case studies involving less than 10 patients, or if the study involved pediatric patients. The references cited in articles identified through the formal searches were also scanned for additional sources. In total,10 articles were identified and reviewed in detail for relevance to the guideline based on a title/abstract screen. During the production of this guideline, published literature was incorporated as it became available.

# TARGET POPULATION
Patients who are at least 18 years of age with malignant SVCO or airway obstruction, compression, or invasion, or those experiencing hemoptysis.

# Summary of Recommendations:
Superior vena cava obstruction: SVCO should be treated with chemotherapy and/or radiotherapy and/or stent depending on histology, urgency of presentation, and previous treatment, if any.

# Airway obstruction:
Radiotherapy is not routinely required in patients with minimal or no symptoms. However, those at risk of a serious impending event should be considered for upfront RT even in the absence of symptoms.
Depending on the primary histology, systemic therapy may be option for treatment.
Patients requiring immediate relief can be referred for consideration of bronchoscopic debulking or surgical resection.
If intrathoracic symptoms warrant palliative RT, a short course external beam multi-fraction approach alone is preferred over a single fraction. EBB could be considered in select patients who have previously been treated with EBRT and developed obstruction due to recurrent or progressive disease; however, this would require a referral to an out-of-province provider. Other potential treatment options in this situation include PDT, endobronchial debulking, Nd:YAG laser, or stenting, where resources allow.
Preferred treatment option depends on whether a causative lesion can be identified, whether other symptoms from intrathoracic malignancy also require palliation, severity of bleeding and whether the patient is cardiovascularly stable. In low volume bleeding, particularly where hemoptysis occurs coincident with other symptoms, EBRT should be considered. In higher volume or massive bleeding, interventional approaches under bronchoscopic or open surgical visualization may be required.

# I. SUPERIOR VENA CAVA OBSTRUCTION
- Typically, for patients with chemotherapy-responsive tumours such as SCLC or lymphoma, systemic therapy is recommended initially (provided the patient is a candidate otherwise), whereas patients with other primary histologies and metastatic lesions, EBRT is typically recommended first.
- While there is insufficient evidence to guide practice on RT dose fractionation, a retrospective review of SVCO due to any histology reported that an initial dose greater than or equal to 3Gy/fraction yielded a higher rate of symptomatic relief at two weeks than 2Gy/fraction (9).
- SVC stent insertion appears to provide rapid relief of symptoms, particularly for patients who fail to respond to chemotherapy or RT, patients with relapsed SVCO after initial treatment, and patients with NSCLC (5). The optimal timing of stent insertion is currently uncertain, and the role of RT postinsertion has not been defined, although should be considered especially if the patient is radiationnaive and the tumour is expected to be radiosensitive (5,10). The need for long-term anticoagulation therapy to prevent stent occlusion also remains unclear. In a prospective cohort study of 104 patients, the use of stents (n=11) for SVCO did not significantly affect survival (3).
- There is a lack of level one evidence to support the common practice of steroid use in the management of patients with SVCO (5). However, RT-induced edema can transiently exacerbate symptoms. Steroids may temporize this transient worsening of symptoms due to treatment, preventing a serious situation from becoming disastrous. However, consensus on dose and duration has not been reached, and should therefore be considered on a case-by-case basis.
- For patients with lung cancer, palliative intent chemotherapy or EBRT are effective in relieving SVCO in the majority of cases (11). A systematic review of 46 treatment studies documented symptom relief in 77-80% of patients with SCLC and up to 60% in patients with NSCLC treated with either chemotherapy and/or radiation (5).

# II. AIRWAY OBSTRUCTION
- There is no evidence to support delivery of immediate thoracic RT in patients with minimal to no symptoms secondary to incurable disease (12). RT could be deferred until symptoms warrant, unless a patient is at risk of a serious adverse outcome with disease progression, such as airway compromise. A randomized controlled trial by the Medical Research Council Lung Cancer Working Party reported that early treatment of minimally symptomatic patients with either 17Gy/2 fractions or 10Gy/1 fraction did not improve symptom control, quality of life (QoL), or survival when compared with instituting treatment when symptoms required (13). A Norwegian Lung Cancer Study Group trial which randomized stage III/IV patients between different dose schedules (17Gy/2 42Gy/15, 50Gy/25), also reported that immediate thoracic RT delivered to patients with minimal symptom burden did not prevent development of disease-related symptoms and actually diminished QoL due to treatmentrelated toxicity, compared to patients on active surveillance (14).
- When indicated to palliate intrathoracic symptoms such as airway compromise, short course external beam multi-fraction RT is preferred over single fraction treatment (15,16). A comprehensive metaanalysis reported that an RT regimen of 30Gy/10 fractions in NSCLC was associated with improved symptom palliation and survival, and minimized the need for further irradiation when compared with lower-or single-fraction regimens, but dose escalation beyond 30Gy did not appear to carry additional benefit (16). Patients treated with higher dose RT (>30Gy) compared to low dose RT (30Gy) had similar complete response rates (16.2% vs 10.0%, respectively; p=0.15) and similar overall survival (OS) at 2 years (8.1% vs 6.7%, respectively; p=0.84) (16). Various shorter EBRT dose/fractionation schedules (eg 20Gy/5, 17Gy/2, 10Gy/1) which provide good symptomatic relief with fewer side effects, can be used for patients requesting a shorter treatment course and/or with poor performance status 16. A more recent Cochrane review and meta-analysis found that when treating major thoracic symptoms, no strong evidence exists that any regimen gives greater palliation, and that higher dose regimens may give more acute toxicity than lower dose regimens (17).
- There is insufficient evidence supporting concurrent chemoradiotherapy as standard of care for patients with NSCLC treated with palliative intent (18). In a randomized study of RT alone versus RT plus continuous infusion fluorouracil, a statistically significant difference in response rates favouring the chemoradiotherapy group was reported; however this did not translate into significant differences in symptom control, overall survival, or progression-free survival (19). In addition, patients treated with chemoradiotherapy had higher rates of acute toxicity (19). In patients with stage III NSCLC with poor prognostic factors who cannot be treated for cure, a recent phase III trial investigated combined modality therapy which incorporated hypofractionated RT. 191 patients were randomized to concurrent chemoradiotherapy (42Gy in 15 fractions starting with cycle two of chemotherapy) versus carboplatin and vinorelbine alone. The combined modality arm had significantly improved median overall survival (12.6 vs 9.7 months) and long term QoL, but experienced more frequent hospital admissions (49% vs 25%; p<0.01) for treatment-related side effects including esophagitis and infection (20). However, due to the relatively small sample size, further data is needed before concurrent chemoradiotherapy can be recommended in this setting.
- EBB may be considered in patients with obstructing proximal airway tumours ( 21) with at least one retrospective study reporting improvements in dyspnea and cough (22). A randomized study reported improved symptom outcomes among patients with obstructing tumours in a mainstem bronchus treated with RT followed by EBB compared to RT alone (23). EBB was not associated with a higher risk of massive hemoptysis compared to RT alone provided fraction sizes were less than 7.5Gy to 10Gy (24). EBB may also be associated with improved QoL (25). A recent systematic review of high dose-rate EBB alone in previously untreated patients with NSCLC reported reasonable symptom palliation rates with a median survival of four to ten months (26). High-dose-rate EBB delivered in 3 fractions of 7.5Gy improved obstruction in 73.4% (27). A recent Cochrane review did not find conclusive evidence to support symptom relief or survival benefits associated with EBB plus EBRT over EBRT alone (28). However, EBB is unavailable in Alberta and therefore requires referral to an out-of-province provider.
- EBB may be used in the palliation of patients with NSCLC previously treated with EBRT who become obstructed due to recurrent or progressive disease (21,29). Access to EBB is unavailable in Alberta.
- Bronchoscopic management is an option for symptomatic central airway obstruction, and cases should be discussed with interventional radiology, respirology, or thoracic surgery (30,31).
- PDT, surgical or bronchoscopic debulking, Nd-YAG laser, and stenting may also be considered for symptom control related to airway obstruction, compression or invasion (12,28,32), with excellent relief of dyspnea demonstrated in retrospective studies of these interventions (33)(34)(35)(36). These local modalities should be strongly considered prior to institution of RT if the risk of acute RT-induced edema causing complete obstruction is considered high, and/or in the setting of recurrent or progressive disease post-RT. Antineoplastic modalities such as EBRT or systemic therapy should be considered subsequently, if clinically indicated (33).

# III. HEMOPTYSIS
- The preferred treatment for hemoptysis depends on whether a causative lesion can be identified radiologically or bronchoscopically, whether other symptoms from intrathoracic malignancy also require palliation, the severity of bleeding and whether the patient is cardiovascularly stable.
- In low volume bleeding, particularly where hemoptysis occurs coincident with other symptoms, EBRT should be considered. In patients with poor performance status and hemoptysis, a single fraction can be used (15). A recent meta-analysis of 13 randomized studies involving 3473 patients with symptomatic advanced lung cancer reported a greater likelihood of symptom improvement and one year overall survival associated with EBRT schedules of 30Gy/10 fractions versus lower doses (16).
The potential benefits associated with this higher dose must be weighed against the risk of higher toxicity and a greater investment of time, however (16). A more recent Cochrane review and metaanalysis found that when treating major thoracic symptoms, no strong evidence exists that any regimen gives greater palliation, and that higher dose regimens may give more acute toxicity than lower dose regimens (17).
- EBB is an option for managing bleeding in patients who are not eligible for more aggressive treatment and/or after maximal EBRT, where facilities and expertise exist (18,37,38).
- In higher volume or massive bleeding where a patient is unstable, interventional approaches under bronchoscopic or open surgical visualization are usually required.
- In large volume hemoptysis or in minor hemoptysis which persists or recurs following EBRT and when a central source is suspected, bronchoscopic management can be used. Alternative options include interventional radiology or thoracic surgery (39).

# GLOSSARY OF ABBREVIATIONS
This guideline will be reviewed annually for required updates; however, if critical new evidence is brought forward before that time, however, the guideline working group members will revise and update the document accordingly.