Posttreatment imaging in patients with lung cancer: Adherence to surveillance guidelines is associated with improved survival in a longitudinal cohort.

OBJECTIVE

Surveillance imaging for survivors of non-small cell lung cancer may reduce mortality from recurrence and secondary primary tumors, but survival impact is difficult to assess because of confounding from symptom-driven imaging. We evaluated the association between active surveillance adherence (ASA) and survival in a longitudinal cohort.

METHODS

Patients with stage I-III non-small cell lung cancer who received curative-intent therapy and survived >6 months were identified within the Veterans Health Administration (2008-2016). ASA was defined using contemporaneous National Comprehensive Cancer Network guidelines and clinical chart abstraction. Time-to-event analysis incorporated time-varying ASA exposure, modeled as a continuous variable and as a percentage of time elapsed, with adjustment for clinical characteristics. Subgroup analysis was performed among patients with recurrence. Time to recurrence and postrecurrence survival were compared to evaluate potential lead-time bias.

RESULTS

The cohort included 5650 patients who were predominantly White (73%), male (97%), and with stage I disease (54%) treated with surgery alone (52%). ASA was associated with a reduced risk of death (hazard ratio, 0.92 per 6 months; 95% CI, 0.89-0.95, P < .001). Symptom-driven imaging was not associated with reduced risk of death (hazard ratio, 1.05 per 6 months; 95% CI, 1.00-1.11; P = .066). In patients with recurrence (n = 2199) median overall survival from treatment was 33.9 months [interquartile range, 32.6, 36.1] for surveillance-detected versus 27.1 months [interquartile range, 24.2, 30.0] for symptom-detected, P < .0001. Time to recurrence did not differ significantly.

CONCLUSIONS

ASA was associated with significant survival benefit compared with symptom-driven imaging that is not explained by lead-time bias, contrasting with previous reports failing to demonstrate benefits of surveillance after treatment for lung cancer.