The 58-Year-Old with a 3 cm Lung Nodule and a Previous Breast Cancer
A 58-year-old woman, former smoker (20 pack-years, quit 10 years ago), is referred with a 3.0 cm spiculated right upper lobe nodule found on a CT performed for persistent cough. She had breast cancer 8 years ago treated with lumpectomy, radiotherapy and tamoxifen, now completed. She is otherwise well. PET-CT shows the nodule is FDG-avid (SUVmax 9.2) with no mediastinal or distant uptake. Her staging CT shows no mediastinal lymphadenopathy by size criteria. The respiratory team asks you to advise on the next step: biopsy, resection, or something else.
1. How would you approach the diagnosis and staging of this nodule?
Read the worked answer
A 3 cm spiculated FDG-avid upper lobe nodule in a former smoker is lung cancer until proven otherwise, but the prior breast cancer means metastasis is a real differential.
Diagnosis:
- Tissue diagnosis is required before definitive treatment. Options are CT-guided percutaneous core biopsy (preferred for a peripheral upper lobe lesion, gives histology and molecular testing), bronchoscopic biopsy with EBUS if centrally located, or surgical resection if the lesion is small and easily accessible and the patient is fit.
- Do not rely on PET alone. SUVmax 9.2 is highly suspicious but not specific; infection, inflammation and some metastases also avidity. A negative PET would not exclude malignancy either.
- Immunohistochemistry (TTF-1, napsin A, GATA3, ER/PR, HER2) will distinguish primary lung adenocarcinoma from breast metastasis, which changes management completely.
Staging:
- CT staging of chest, abdomen and pelvis; brain MRI if there is any neurological symptom or if curative-intent treatment is planned (some protocols routinely image the brain in stage III).
- EBUS-TBNA or mediastinoscopy if mediastinal nodes are borderline or if the PET shows any mediastinal uptake; size criteria alone under-stage.
- PET-CT is already done and shows no distant disease, which is encouraging for curative intent.
2. What would you advise if the biopsy shows metastatic breast carcinoma rather than a primary lung cancer?
Read the worked answer
This is a pivotal result and changes the entire pathway.
- Re-stage the breast cancer. Request the original breast histology and receptor status (ER, PR, HER2). Metastatic breast cancer 8 years after treatment is a systemic disease; management is driven by receptor status and symptoms, not by surgery to the lung.
- Systemic therapy is the mainstay. Depending on receptor status: endocrine therapy ± CDK4/6 inhibitor for hormone receptor-positive disease, HER2-directed therapy for HER2-positive disease, or chemotherapy for triple-negative disease. Refer to medical oncology urgently.
- Do not resect the lung lesion unless it is solitary, the patient is fit, and the multidisciplinary team agrees that oligometastatic disease warrants local therapy - and even then, systemic therapy usually comes first.
- Look for other sites of disease with a full staging CT and bone scan or PET, and a brain MRI if symptomatic.
- Communicate clearly with the patient. The earlier assumption of a new primary lung cancer was reasonable but wrong; explain the change and the new plan, and involve the breast multidisciplinary team.
- Consider the possibility of a second primary - a lung primary can coexist with a breast metastasis - so molecular testing and expert pathology review are essential before committing to systemic therapy.