Follow-up is not justified in patients with typical lung carcinoids without lymph node involvement treated with curative intent: A Danish Multi-ENETS Center of Excellence Study

Typical carcinoids (TC) are neuroendocrine malignancies of the lung with low risk of recurrence and a favorable prognosis. It is unclear whether lymph node status and tumor size affect the recurrence risk. Following radical surgery, current guidelines recommend comprehensive follow-up including regular computed tomography (CT) imaging. We aimed to estimate the risk of recurrence in curatively treated patients with TC and to discuss the justification of the current comprehensive follow-up program. We identified all patients diagnosed with TC from 2009 to 2020 at Aarhus University Hospital, Denmark and Copenhagen University Hospital, Rigshospitalet, Denmark. Patients without distant metastases (M0) who underwent radical surgery (R0) were included in the analysis. The risk of recurrence was estimated using the Aalen-Johansen method treating death as a competing risk. Fine-Gray models were used to evaluate the effect of lymph node status and tumor size. Three-hundred and thirty patients were included in the analysis, of whom 40 had lymph node involvement and 290 did not. During a total follow-up time of 2806 years across all patients, with an individual median of 8.1 years (IQR: 5.9–11.2), 10 patients had recurrence: four in the node-negative group and six in the node-positive group. The 10-year cumulative risk of recurrence for all patients was 3.4% (95% confidence interval (CI): 1.7–6.0), for patients without lymph node involvement 1.6% (95% CI: 0.5–3.8), and for patients with lymph node involvement 15.6% (95% CI: 6.3–28.8). Of the four recurrences in the node-negative group, one led to re-resection with curative intent. Patients with TC without lymph node involvement have a very low risk of recurrence. Thus, we recommend tailoring the follow-up program based on lymph node status, with node-negative patients being excluded from regular follow-up programs.