CHAPTER 8 Anna C. Bibby, Nick A. Maskell and Rahul Bhatnagar Academic Respiratory Unit, University of Bristol, UK Malignant pleural effusions account for up to 70% of exudative effusions. They can be the result of primary tumours in the lung or pleura, or metastatic spread from distant malignancy. Lung and breast cancers are the most common underlying causes in men and women, respectively – together these two diseases account for over 50% of all malignant effusions. Lymphoma, ovarian and prostate cancer are also common pathologies (Figure 8.1). Figure 8.1 Site of primary tumour (%) of 2040 patients with malignant pleural effusions. (Adapted from BTS Guidelines for managing malignant pleural effusions, 2010.) Unfortunately, malignant pleural effusions are associated with a poor prognosis as their presence usually signifies advanced or metastatic disease. Median survival from diagnosis currently ranges from 3 to 12 months, depending on the underlying tumour type, with effusions related to lung cancer associated with the shortest survival times. Recently, a prognostic scoring system (the LENT score) has been developed and validated to help determine the predicted life expectancy of patients who present with malignant pleural effusions. Malignant effusions occur as a result of direct invasion of the pleural space by tumour; however, indirect tumour effects, such as blockage of pleural lymphatics or increased permeability of adjacent blood vessels, also contribute to fluid accumulation. The time taken for an effusion to develop varies between individuals and influences the degree and severity of their symptoms. Patients with malignant pleural effusions are usually symptomatic. Breathlessness is the most common feature, and is the result of reduced lung volumes caused by compression by fluid (Figure 8.2). The dynamics of the chest wall and diaphragm may be altered by pressure from the fluid, and this will contribute to the sensation of breathlessness. Pre‐existing respiratory conditions (e.g. chronic obstructive pulmonary disease (COPD)) or malignancy within the lungs will exacerbate the severity of this symptom. Figure 8.2 CT scan showing a large left‐sided pleural effusion (arrow A), causing complete compression of the left lung. Two pleurally based soft tissue masses are seen on the left (arrow B) with associated pleural thickening. Additional symptoms include a dry cough caused by pleural irritation, and chest wall or neuropathic pain resulting from tumour invasion. Systemic symptoms such as malaise, lethargy and anorexia are also common. In addition to symptoms from their effusion, patients may also have symptoms relating to their primary malignancy (e.g. haemoptysis), a breast lump or ‘B’ symptoms of lymphoma. The severity of symptoms does not always relate to the size of the effusion. For instance, a patient may have a large effusion that does not cause them significant symptoms. Alternatively, their functional status may be limited by comorbidities to such a degree that they do not exert themselves to a point where breathlessness occurs. Factors that contribute to symptom severity include the time the fluid has taken to accumulate and the patient’s underlying physiological reserve, including respiratory comorbidities. The most common options for managing malignant pleural effusions are shown in Box 8.1. Choice of intervention should be driven by two guiding principles: the need for diagnosis and the aim to improve symptoms. The wishes of the patient should be considered throughout the decision‐making process. Until the underlying malignant diagnosis is established, it is important that the chosen pleural intervention does not limit future investigations or treatment options. Simple pleural aspiration is an appropriate initial investigation, as it can transiently improve symptoms. Additionally, simple aspiration may yield a cytological diagnosis in a proportion of cases, although sensitivity is less than 60%. If pleural aspiration does not lead to a conclusive diagnosis, then a targeted biopsy will usually be necessary. This can be obtained surgically; using a radiologically guided technique; or by local anaesthetic thoracoscopy. Once the histo‐cytological diagnosis is confirmed, a definitive procedure to remove the fluid and prevent re‐accumulation can be undertaken. The appropriate definitive procedure should be adapted to each individual, with consideration given to the patient’s wishes, symptoms, physical fitness and prognosis. The goal of definitive pleural procedures is to control symptoms. Consequently, if a patient is asymptomatic, and the underlying disease is known, conservative management and watchful waiting may be entirely appropriate. Most patients will become symptomatic in time and at that stage further intervention can be decided on. For symptomatic patients, a decision on which definitive intervention to undertake should be made as soon as possible after obtaining the causal diagnosis. The different management options are described next, with consideration given to the benefits and disadvantages of each procedure. An approximate maximum of 1.5 L pleural fluid can be withdrawn via simple aspiration under local anaesthetic. It is a straightforward, rapid and effective way to relieve breathlessness. Patients can undergo a therapeutic procedure in clinic, and return home immediately. Additionally, simple aspiration can yield diagnostic information without compromising future investigations or treatment. Most patients will undergo simple aspiration at some point during their diagnostic and therapeutic pathway.
Management of Malignant Pleural Effusions
Pathophysiology
Symptoms
Management – general considerations
Simple pleural aspiration
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