Recurrence patterns following curative therapy for stage I NSCLC.

Abstract

e21069 Background: Lobectomy remains the standard of care for definitive management of stage I non-small cell lung cancer (NSCLC). Stereotactic body radiation therapy (SBRT) is considered primarily for patients who were either unwilling to have surgery or deemed to be medically unfit for surgery. Current NCCN guidelines indicate the use of CT for surveillance following curative-intent therapies and recommend CT every 6 months for 2-3 years followed by CT annually without clear guidance on how long to keep doing annual CT scans. This study aims to evaluate the patterns of lung cancer recurrence within and beyond five years post curative therapy. Methods: Patients diagnosed with stage I NSCLC and treated with either curative surgery or SBRT from 1998-2016 at Mayo Clinic Florida were identified. Through retrospective chart review, data was collected on clinical and demographic features, surveillance imaging, pathology, time to recurrence or new primary lung cancer, and location of recurrence (loco-regional vs. distant). Statistical analysis with chi-square test was performed to identify risk factors associated with recurrence. Results: In total, 203 patients with stage I NSCLC were identified with most patients treated with surgery (n = 181) compared with SBRT (n = 22). Median time of follow up is 85 months. Overall, 48 patients (23.6%) developed a recurrence, with the median time to recurrence of 22.3 (3.9-69.8) months. Most recurrences were identified within 5 years from curative therapy (42/48) with 6 patients having a recurrence between 5 and 10 years post curative therapy. Of the 37 patients followed for more than 10 years, there were no recurrences. Twenty seven patients had new primary lung cancers identified and among them, 15 were found within 5 years, 10 found between 5-10 years and 2 found beyond 10 years. Median time to new primary lung cancer was 58.1 months. A positive smoking history and stage IB were found significantly associated with lung cancer recurrence (chi-square test P = 0.007 and P = 0.04 respectively), while age, gender, histology, grade, and treatment type had no association. Conclusions: In this study of 203 patients with stage I NSCLC treated with curative intention, there was no evidence of recurrent disease after 10 years following curative therapy, questioning the utility of continued annual CT surveillance once patients hit this milestone.