 Lung bronchoalveolar carcinoma BAC or adenocarcinoma in situ AIS continues to represent a poorly understood clinical entity. A frequent clinical dilemma in lung cancer care is the management of a documented or suspected invasive adenocarcinoma in the setting of multifocal ground glass opacity GGO consistent with multifocal AIS. These patients are typically classified as stage IV disease, and treated with palliative chemotherapy. No existing pathologic or molecular test is currently capable of making the distinction between independent primary versus metastatic tumors, a distinction for which substantial treatment impact exists. Many treating physicians suspect that outcomes for this specific patient subgroup are better than norms for stage IV disease, as such patients are frequently node-negative and without distant metastases despite multiple lesions present. To address this issue, we will evaluate a multimodality treatment protocol using aggressive local and targeted systemic therapy for multifocal lung adenocarcinoma, incorporating information from tumor genome sequencing for individualized treatment planning. The results will have significant impact in advancing the biologic understanding and treatment approach for lung adenocarcinoma in the setting of multifocal AIS. 