Lung adenocarcinoma with malignant pleural effusion and an EGFR mutation
A 64-year-old woman who never smoked presents with two months of cough, fatigue and weight loss. Chest radiography shows a right pleural effusion. Computed tomography reveals a 3.2 cm right upper lobe mass, nodular pleural thickening, and a 1.5 cm right hilar node; there is no evidence of distant organ metastasis. Thoracentesis yields an exudate, and cytology confirms adenocarcinoma cells. Pleural biopsy shows adenocarcinoma with an epidermal growth factor receptor exon 19 deletion; ALK is negative and PD-L1 expression is 50%. She is performance status 1, has no brain symptoms, and asks whether she can have immunotherapy because a relative did well on it.
1. What is the stage, and which further staging investigations would you arrange?
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The malignant pleural effusion makes this stage IVA (M1a) disease in the eighth edition TNM classification, regardless of the small hilar node. Staging should include contrast-enhanced computed tomography of the chest and upper abdomen if not already complete, brain magnetic resonance imaging or contrast computed tomography, and fluorodeoxyglucose positron emission tomography-computed tomography to identify occult distant disease. Endobronchial ultrasound may characterise the hilar node and provide additional tissue, although it will not change the M1a stage. Baseline blood tests, liver and renal function, and molecular testing are needed before systemic therapy. Document performance status and pleural symptoms. Staging completeness matters because it defines prognosis and avoids inappropriate local therapy in metastatic disease.
2. What first-line systemic treatment would you recommend, and why not immunotherapy alone?
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Offer osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor, because the exon 19 deletion is a sensitising EGFR mutation. Osimertinib has superior progression-free and overall survival compared with earlier-generation inhibitors and good central nervous system penetration. Immunotherapy alone is inferior in EGFR-mutant non-small-cell lung cancer and can cause severe immune-related toxicity if combined with a tyrosine kinase inhibitor; the high PD-L1 score does not override the driver mutation. Start treatment after baseline electrocardiography, given the QT interval effect, and monitor for rash, diarrhoea, paronychia and interstitial lung disease. Continue until progression or unacceptable toxicity. Discuss the importance of adherence and avoiding drug interactions.
3. How would you manage her pleural effusion alongside systemic therapy?
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Assess whether the effusion is symptomatic and whether the lung re-expands after drainage. If symptoms recur, offer an indwelling pleural catheter or talc pleurodesis; an indwelling catheter is particularly useful if there is trapped lung or rapid reaccumulation. Systemic therapy may shrink the effusion, but do not delay symptom relief while waiting for a response. Avoid repeated large-volume thoracentesis without a definitive plan. Arrange district nurse support and education for catheter care, and monitor for infection. Reassess imaging after starting osimertinib and refer for palliative care support early. If the effusion is the dominant symptomatic problem, involve respiratory or pleural services promptly.