Treatment Options for Stage IVa M1a Lung Adenocarcinoma

Essential First Step: Comprehensive Molecular Testing

The American Society of Clinical Oncology recommends biomarker testing with tissue and/or blood-based broad multi-gene panel and PD-L1 immunohistochemistry before initiating treatment for patients with stage IVa M1a lung adenocarcinoma 1
Testing for actionable driver alterations, including EGFR mutations, ALK rearrangements, ROS1 rearrangements, BRAF V600E mutations, MET exon 14 skipping mutations, RET rearrangements, NTRK rearrangements, and HER2 alterations, is crucial for treatment selection 1
The combination of blood and tissue testing maximizes detection of molecular alterations, though tissue testing allows histologic assessment and should be attempted when feasible 1
PD-L1 expression by immunohistochemistry guides immunotherapy selection, with a tumor proportion score (TPS) ≥50% indicating potential benefit from single-agent pembrolizumab, cemiplimab, or atezolizumab 1, 2

Targeted therapy with tyrosine kinase inhibitors should be offered as first-line treatment for patients with identified driver alterations, as these provide superior outcomes compared to chemotherapy, according to the National Comprehensive Cancer Network (NCCN) 1, 3
For patients with EGFR exon 19 deletion or L858R mutations, osimertinib is the preferred first-line agent, with alternative options including amivantamab plus lazertinib, or osimertinib plus chemotherapy 1, 3
For patients with ALK rearrangements, ALK tyrosine kinase inhibitors should be offered as first-line therapy, with crizotinib as an established option 1, 4, 5
For patients with ROS1 rearrangements, crizotinib should be offered 1, 4, 5
For patients with BRAF V600E mutations, dabrafenib and trametinib, or encorafenib and binimetinib, should be offered 1
For patients with MET exon 14 skipping mutations, capmatinib or tepotinib should be offered 1
For patients with RET rearrangements, selpercatinib should be offered as first-line therapy, with pralsetinib as an alternative option 1
For patients with NTRK rearrangements, entrectinib or larotrectinib should be offered 1

Treatment selection depends on PD-L1 tumor proportion score (TPS) and performance status, with immunotherapy-based regimens preferred for most patients, according to the American Society of Clinical Oncology (ASCO) 2
For patients with PD-L1 TPS ≥50%, single-agent pembrolizumab, cemiplimab, or atezolizumab should be offered, with alternative options including pembrolizumab plus carboplatin plus pemetrexed, or cemiplimab plus carboplatin plus pemetrexed 2
For patients with PD-L1 TPS 1-49%, pembrolizumab plus carboplatin plus pemetrexed, or cemiplimab plus carboplatin plus pemetrexed should be offered, with alternative options including atezolizumab plus carboplatin plus (nab)-paclitaxel ± bevacizumab 2
For patients with PD-L1 TPS <1% or unknown, pembrolizumab plus carboplatin plus pemetrexed, or cemiplimab plus carboplatin plus pemetrexed may be offered, with alternative options including atezolizumab plus carboplatin plus (nab)-paclitaxel ± bevacizumab 2

For patients with ECOG performance status 2, combination or single-agent chemotherapy or palliative care alone may be used, according to the NCCN 5, 4
Chemotherapy decisions should not be based on age alone, and for elderly patients (age 70-79 years) with good performance status and limited comorbidities, monthly carboplatin plus weekly paclitaxel is recommended 6

First-line cytotoxic chemotherapy should be stopped at disease progression or after four cycles in patients with nonresponsive stable disease, according to the ASCO 5, 4
For patients with stable disease or response after four cycles of pemetrexed-containing regimen, pemetrexed continuation maintenance may be used, with a strength of evidence rating of high 5, 4
Switch maintenance pemetrexed is suggested for nonsquamous NSCLC patients not experiencing disease progression after four cycles of platinum-based therapy (not including pemetrexed), with a strength of evidence rating of moderate 6

Patients with advanced lung cancer should be referred to interdisciplinary palliative care teams that provide outpatient and inpatient care early in the course of disease, alongside active treatment of their cancer, according to the ASCO and NCCN 1, 2, 8
Palliative care improves quality of life, mood, and potentially survival, with a strength of evidence rating of high 8

Stage IVa M1a disease includes separate tumor nodules in a contralateral lobe, or tumor with pleural or pericardial nodules or malignant effusion, according to the NCCN 9
Malignant pleural or pericardial effusion requires pathologic confirmation through thoracentesis or pericardiocentesis, with a strength of evidence rating of high 9
Local therapy for effusions (ambulatory small catheter drainage, pleurodesis, pericardial window) should be considered alongside systemic therapy, with a strength of evidence rating of moderate 9