Non-small Cell Lung Cancer in Metastatic Renal Cell Carcinoma Patients.

INTRODUCTION: Renal cell carcinoma (RCC) most commonly metastasizes to the lungs and shares risk factors with lung cancer. However, primary lung cancer in patients with metastatic RCC is underrecognized and poses diagnostic and therapeutic challenges. PATIENTS AND METHODS: We retrospectively identified patients at UT Southwestern Medical Center with both metastatic RCC and primary non-small cell lung cancer (NSCLC). Individuals with ICD codes for RCC and lung cancer between October 2006-September 2024 were reviewed and adjudicated by a multidisciplinary team. RESULTS: Among 60 patients with both diagnoses, thirteen (22%) developed metastatic RCC preceding the diagnosis of NSCLC and are the focus of this report. Most patients were male and had a history of smoking (77%). Median age at RCC diagnosis was 61 years and 71 years at NSCLC diagnosis. Ten patients (77%) had stage I NSCLC and received curative-intent treatment with surgery or stereotactic radiation therapy. NSCLC diagnoses were pathologically confirmed and supported by radiographic features suggestive of a primary lung malignancy (e.g., spiculation, cavitation), discordant treatment responses, and, in select cases, FDG PET/CT findings. CONCLUSION: Primary NSCLC can occur in patients with metastatic RCC and is underrecognized. Increased clinical awareness and careful evaluation of pulmonary lesions may enable earlier detection and curative-intent treatment.