Prognosis of Patients with Pathological Stage I/II Lung Adenocarcinoma in Whom Diagnosis of Postoperative Recurrence Is Delayed after Initial Recognition of Elevated Serum Carcinoembryonic Antigen

Background: There are some postoperative lung cancer patients in whom the diagnosis of postoperative recurrence cannot be confirmed, despite steady increase of the serum carcinoembryonic antigen (CEA) levels over the normal range after surgery. It remains unclear if the prognosis of the patients might be affected by the interval from the first recognition of elevation of the serum CEA levels after surgery to confirmation of the presence of postoperative recurrence.Methods: We comparatively evaluated the overall survival (OS) after postoperative recurrence between pathological stage I/II lung adenocarcinoma patients with the interval of ≥4 months (long interval (LI) group, n = 14) and those with the interval of <4 months (short interval (SI) group, n = 14), as the median period of the interval was 3.9 months (range, 0-15.8 months).Results: There was no significant difference in the frequency of lympho-vascular invasion, proportion of patients receiving adjuvant therapy or with active epidermal growth factor receptor mutations and the disease-free survival period (24.6 months vs. 23.0 months, p = 0.772) between the LI group and SI groups. All the patients received anticancer therapy after postoperative recurrence. The OS in the LI group was not inferior to that in the SI group (43.0 months vs. 44.0 months, p = 0.887).Conclusion: A delayed interval between first detection of elevated serum CEA and the diagnosis of postoperative recurrence did not necessarily mean delayed diagnosis of postoperative recurrence.Ethics: Approval of the Institutional Review Board of Kumamoto Regional Medical Center (approval date, May 22, 2021; approval number, 21-07). Funding: NoneCompeting interests: None