Association between values of preoperative 6-min walk test and surgical outcomes in lung cancer patients with decreased predicted postoperative pulmonary function

Objective: We retrospectively investigated the possibility that the 6-min walk test (6MWT) could predict surgical outcomes in lung cancer patients with decreased predicted postoperative (ppo) lung function. Methods: Patients were enrolled based on their preoperative spirometry: <60% of the ppo forced expiratory volume in 1 s (FEV_1.0) or < 60% of the ppo lung carbon monoxide diffusion capacity (DLco). Morbidity, oxygen inhalation required > 10 days, home oxygen therapy (HOT) requirement, unexpected readmission within 90 days, and 90-day mortality were included as surgical outcomes. The correlations with walking distance and the minimum SpO₂ (SpO₂min) and maximum decrease in SpO₂ (ΔSpO₂) during the 6MWT were analyzed using logistic regression analysis, adjusting for age, sex, and surgical procedure. Results: Altogether, 121 patients were analyzed. Logistic regression analysis revealed that higher ΔSpO₂ and lower SpO₂min were significantly correlated with a higher risk of prolonged need for oxygen inhalation and HOT, surgical morbidity, and 90-day mortality. Cut-off values of > 4% for ΔSpO₂ were significant for prolonged oxygen inhalation and surgical morbidity. Cut-off values of < 89–91% for SpO₂min were also significant for the need for prolonged oxygen inhalation, surgical morbidity, and HOT requirement. There were no significant correlations between walking distance and each surgical outcome. Conclusions: Oxygen desaturation during 6MWT was a good predictor for poor surgical outcomes in lung cancer patients with decreased ppo pulmonary function.