LDCT Spots Lung Cancer Recurrence Early, but Misses Brain and Bone

Most recurrences of lung cancer that are caught by low-dose computed tomography (LDCT) after curative surgery cluster within the first year after the operation, according to a retrospective cohort study published in BMC Surgery. Among 45 patients whose returning cancer was first detected on surveillance LDCT, 55.55% of recurrences appeared between three and twelve months after surgery, with further clustering within the first three years.

The study analyzed 150 patients who underwent radical lung cancer resection at a tertiary hospital between January 2018 and December 2023 and completed at least two years of postoperative LDCT follow-up. Patients whose first recurrence was an isolated brain or bone metastasis detected by other imaging modalities were excluded. The cohort was divided into a recurrence group of 45 patients and a non-recurrence group of 105. Because only LDCT-surveillance completers with LDCT-detected first recurrence were included, the findings describe recurrence patterns within this specific cohort rather than estimating the overall rate of recurrence after curative lung cancer surgery.

At the patient level, distant metastasis alone was the most common pattern, affecting 25 of 45 patients (55.6%), while purely locoregional recurrence occurred in 17 of 45 (37.8%). Three patients (6.7%) had synchronous locoregional and distant disease. Visually, recurrent lesions predominantly presented as solid nodules with lobulated margins on LDCT scans.

Quantitative imaging features separated the two groups clearly. In the recurrence group, the 95th percentile CT value was significantly higher than in the non-recurrence group, at 68.2 ± 18.7 HU versus 41.5 ± 8.3 HU (P < 0.001). Mean CT value moved in the opposite direction, lower in recurrences at 368.41 ± 90.17 HU versus 572.58 ± 165.42 HU (P < 0.001), and nodule volume was larger, at 2.08 ± 0.52 cm³ versus 1.47 ± 0.35 cm³ (P < 0.001).

Using Fine-Gray competing-risk models, which treated death without recurrence as a competing event, the researchers estimated a 48-month cumulative incidence of recurrence of 30.2% (95% CI: 22.1%–38.9%). Four independent predictors of recurrence emerged: a higher 95th percentile CT value (subdistribution hazard ratio 2.98, 95% CI 1.62–5.48), larger nodule volume (sHR 3.42, 95% CI 1.72–6.81), preoperative lymph node metastasis (sHR 2.67, 95% CI 1.48–4.82), and advanced TNM stage (sHR 2.38, 95% CI 1.39–4.07), all statistically significant at P < 0.05.

The model’s discrimination was quantified with an optimism-corrected concordance index of 0.815 (95% CI: 0.75–0.87) after 1000 bootstrap resamples, a form of internal validation. Penalized ridge regression with this bootstrap procedure was used to identify the predictors, meaning the performance estimate reflects the development dataset rather than an external, independent cohort.

The authors emphasize that LDCT is effective for detecting intrathoracic recurrence and some intra-abdominal sites, such as adrenal and liver deposits, but that it has an inherent blind spot: brain and bone metastases fall outside what chest LDCT can reliably visualize. They suggest that symptom- or risk-triggered dedicated imaging of the brain and spine should be considered for disease outside the chest, and that suspected vertebral disease should be assessed through SINS/NOMS-style multidisciplinary evaluation rather than routine dedicated spine imaging being inferred from this cohort.

Clinicopathological factors independently associated with recurrence in the analysis included a higher preoperative nodal metastasis burden, advanced TNM stage, and poor differentiation. The authors frame these results as supporting the hypothesis that risk-stratified, time-adapted surveillance strategies merit prospective evaluation, while explicitly cautioning that the findings should not be used as prescriptive clinical recommendations. As a single-center retrospective study of a selected surveillance cohort, the work identifies imaging and clinical patterns associated with recurrence, but prospective validation in broader populations would be needed before changing follow-up practice.

Subject of Research: LDCT imaging features and timing of recurrence detection after radical lung cancer surgery

Article Title: LDCT features and timing of LDCT-detected recurrence after radical lung cancer surgery

Article References: Gao, J., Zhou, Q., Gao, J., Huang, D., & Zhu, X. (2026). LDCT features and timing of LDCT-detected recurrence after radical lung cancer surgery. BMC Surgery. https://doi.org/10.1186/s12893-026-04283-3

Image Credits: AI Generated

DOI: 10.1186/s12893-026-04283-3

Keywords: lung cancer, LDCT, recurrence, computed tomography, surgery, surveillance, competing-risk models, distant metastasis, TNM stage, nodule volume, BMC Surgery, retrospective cohort