Surveillance Imaging Findings of Lung Cancer Recurrence after Definitive Therapy

Lung cancer remains the leading cause of cancer-related mortality worldwide, and tumor recurrence following treatment with curative intent poses significant clinical challenges. Surveillance imaging with chest CT is essential for early detection of potentially curable recurrent disease. Recurrence may manifest locally, regionally, or distantly, depending on the mode of spread, and generally shares histologic and imaging characteristics with the primary tumor. The risk of recurrence varies on the basis of tumor histologic features and the treatment modality used. For example, adenocarcinoma with lepidic growth has a low risk of recurrence and a favorable prognosis, whereas adverse pathologic features, such as spread through airspaces, are associated with poor recurrence-free survival. Following curative lung resection, surveillance CT is used to assess the stability of surgical changes and detect new nodules at the surgical site that may indicate local recurrence. The type and method of delivery of radiation therapy influence the subsequent temporal and spatial posttreatment changes seen at CT, which can complicate detection of recurrent disease. Disseminated patterns of pulmonary tumor recurrence may manifest as aerogenous metastases, miliary metastases, pleural metastases, or lymphangitic carcinomatosis. Although posttherapy surveillance can be limited by image interpretation pitfalls, use of appropriate strategies can help overcome these challenges. Radiologists should recognize the imaging patterns of lung cancer recurrence to facilitate improved diagnostic accuracy and timely patient care. ^©RSNA, 2026 Supplemental material is available for this article. See the invited commentary by Vlahos and Shroff in this issue.