Weight loss of 5% or more after lobectomy for lung cancer via minimally invasive approaches is associated with poor prognosis

Introduction: We analyzed the association between postoperative weight loss (WL), preoperative body mass index (BMI), and prognosis in patients with lung cancer who underwent lobectomy using minimally invasive approaches.Methods: Weight change in 325 patients who underwent radical lobectomy for non-small cell lung cancer was assessed at 3, 6, and 12 months postoperatively and compared to preoperative weight. Patients were divided into three groups according to their preoperative BMI interquartile range: low BMI <= 20.3 kg/m(2), middle BMI 20.4-24.4 kg/m(2), and high BMI >= 24.5 kg/m(2). Postoperative WL >= 5% was evaluated with reference to frailty.Results: There were no significant differences in pathological findings, postoperative complications, or postoperative hospital stay among the three groups. Thirty all-cause deaths and 39 cancer recurrences occurred. Within the first year after surgery, WL of any grade was observed in 229 patients (70.5%) and WL >= 5% in 86 patients (26.5%). Postoperative WL of any grade within 1 year after surgery was not associated with OS and RFS (both p > .05). However, WL >= 5% within 1 year after surgery was associated with worse OS and RFS (p = .007 and .006, respectively). WL >= 5% within 1 year after surgery was more common in the low BMI group (p = .045). There was no difference in OS and RFS among the BMI groups in patients with WL >= 5% and those without WL >= 5% (all p > .05).Conclusion: WL >= 5% was associated with poor prognosis after lobectomy via minimally invasive approaches. Weighing is a useful prognostic marker that can be easily self-checked.