Synopsis
Interpret suspected secondary lung disease in its oncological context, distinguish mimics and second primaries, and select proportionate systemic, local or supportive management.
- Pulmonary metastasis is a route and pattern of cancer spread, not one disease; prognosis and treatment are governed mainly by the primary tumour biology, distribution, tempo and patient fitness.
- Haematogenous deposits often appear as multiple rounded nodules of varying size, but solitary nodules, miliary disease, cavitation, endobronchial lesions, lymphangitic carcinomatosis and pleural spread also occur.
- A new pulmonary nodule in a person with cancer is not automatically metastatic: infection, inflammation, treatment toxicity and a synchronous primary lung cancer remain important alternatives.
Key red flags
Progressive dry cough and marked breathlessness with smooth or nodular interlobular septal and peribronchovascular thickening, preserved architecture and small effusions suggest lymphatic tumour spread. Hypoxaemia can progress rapidly.
Investigation priorities
Characterise lung lesions and establish extracranial disease distribution.
Management branches
One or more pulmonary lesions appear during or after treatment of a known malignancy.
- Retrieve the primary pathology, treatment history and serial imaging, then have thoracic radiology describe morphology, distribution and growth rather than accepting the report label alone.
- Stage the rest of the disease with tests selected for that primary and discuss whether confirming lung histology would materially change systemic therapy or local intent.
Key medicines
Primary-specific systemic anticancer therapyUse only the live site-specific oncology protocol, incorporating histology, molecular results, organ function, performance status and previous treatment.
Opioid for cancer-related cough or painBegin with a low protocol-approved dose and titrate to symptom benefit, prior exposure, frailty and renal function.