Assessing the pattern of recurrence in Danish stage I lung cancer patients in relation to the follow-up program: are we failing to identify patients with cerebral recurrence?

Background: There is paucity of evidence regarding the optimal follow-up (FU) regimen for lung cancer. Consequently, FU is organized differently across countries. The Danish FU regimen has short FU intervals with a computed tomography (CT) scan of the chest and upper abdomen every three months in the early phase (first 2 years), then every six months in the late phase of FU (3rd, 5th year). Characterizing recurrences missed by the FU program in terms of site, tumor histology, department, and phase of FU, could improve the FU program. Material and method: A case–control study of curatively treated stage I lung cancer patients who attended the Danish FU-program and had recurrence identified through the follow-up program (controls, FU group) or outside FU program (cases, symptomatic group). Results: Of 233 included patients with recurrence, the FU group constituted 85% (n = 197). Among the 15% (n = 36) in the symptomatic group, 53% had involvement of the central nervous system compared with 3% in the FU group. The unadjusted odds ratio (OR) for having an isolated brain recurrence (IBR) in the symptomatic group was 52.3 (95%CI: 15.1–181.4) as compared with the FU group. The OR for having a symptomatic recurrence in the early phase of FU was 2.5 (95%CI: 0.7–8.7) compared with the late phase. Conclusions: The FU program did not identify the majority of patients with IBR. Including cerebral imaging in the FU program may result in an earlier detection of brain metastases. These matters should be studied in a prospective setting.