Results of frequent CT surveillance on recurrence detection and survival after radical resection for non-small cell lung cancer.

Introduction: Non-small lung cancer (NSCLC) carries a substantial risk for recurrence even after complete resection. Evidence regarding the survival impact of post-resection surveillance strategies remains limited. Danish guidelines for lung cancer recommend contrast-enhanced computed tomography (CE-CT) every 3 months for the first 2 years and every 6 months for the subsequent 3 years, a frequency twice that of major international guidelines. This study retrospectively assessed the outcomes of this high-frequency CT surveillance in Denmark, specifically focusing on recurrence detection within two years post-surgery, the potential for renewed curative-intent treatment, and post-recurrence prognosis during this initial period. Method: A cohort of 1079 patients who underwent resection for NSCLC in the period 2019-2020 was identified from the Danish Lung Cancer Registry (DLCR). Detailed information regarding new diagnoses of lung cancer, offered treatments, and mortality was extracted from patients' medical records. Results: Within two years following resection, 20% of patients developed a new diagnosis of lung cancer. Of these, 28.5% presented with localized disease (stage I-II), 26% with locally advanced disease (stage III), and 45% with metastatic disease. Recurrence frequencies ranged from 13% for pathological stage I (pStage I) to 44.5% for pStage III. Forty-eight percent of patients were offered renewed curative-intent treatment, demonstrating a 2-year post-recurrence survival of 78%. In contrast, patients offered palliative care or no treatment had a 2-year post-recurrence survival of 40%. Conclusion: The proportion of recurrences presenting with metastatic disease was lower than reported in cohort studies with less frequent surveillance. A further notable finding was the high proportion of patients offered curative-intent treatment for recurrent disease, exceeding previously reported rates. These patients demonstrated a 2 year post-recurrence survival comparable to that observed following a primary NSCLC diagnosis. The presence of symptoms at the time of recurrence was a negative prognostic indicator, even among patients receiving palliative treatment.