Quantitative dual-layer spectral CT parameters associated with a continuous improvement response pattern to CAPTEM in advanced gastroenteropancreatic neuroendocrine neoplasms.

OBJECTIVES

To evaluate the prognostic significance of a dynamic continuous improvement (CI) response pattern in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) treated with capecitabine and temozolomide (CAPTEM), and to explore the association between baseline dual-layer spectral CT (DLCT) parameters and this favorable response trajectory.

METHODS

This single-center retrospective study (May 2016 - September 2025) analyzed 54 patients treated with CAPTEM. Cox proportional hazards regression models were used to identify prognostic factors affecting progression-free survival (PFS). Patients were stratified via 9-month landmark analysis into CI and non-continuous improvement (NCI) groups. PFS and Time to Nadir (TTN) were compared. Baseline DLCT parameters were analyzed for their association with the CI pattern.

RESULTS

54 patients (median age, 53 years; 29 men) were evaluated. Peritumoral tissue invasion was independent prognostic factor (p = 0.008; Hazard Ratio [HR], 4.604; 95% confidence interval: 1.495, 14.173). In the landmark cohort, post-landmark PFS was significantly longer in the CI (n = 9) than the NCI (n = 13) group (18.70 vs. 6.47 months; HR, 0.295; 95% confidence interval: 0.100, 0.876; p = 0.044), with a longer TTN (9.67 vs. 6.83 months; p = 0.021). Lower baseline nIC and Zeff values were significantly associated with the CI pattern (median Zeff 8.070 vs. 8.920, p = 0.008; median nIC 0.426 vs. 0.723, p = 0.030).

CONCLUSION

The continuous improvement response pattern was associated with prolonged PFS in GEP-NENs treated with CAPTEM. Baseline DLCT parameters may help identify patients likely to derive sustained benefit from CAPTEM therapy.