Prognostic value of 18F-FDG PET/CT metabolic parameters in patients with non-small cell lung cancer who achieved a pathological complete response after neoadjuvant chemoimmunotherapy.

BACKGROUND

Although pathological complete response (pCR) is generally associated with favorable survival outcomes, 10-15% of patients who achieve pCR after neoadjuvant chemoimmunotherapy still relapse within 3 years. This study aimed to explore the prognostic value of clinical features and metabolic parameters derived from 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT, hereafter referred to as PET/CT).

METHODS

We retrospectively analyzed 121 non-small cell lung cancer (NSCLC) patients with confirmed pCR of both primary tumors and lymph nodes after receiving neoadjuvant chemoimmunotherapy at Peking University Cancer Hospital. Univariate and multivariate Cox regression were used to identify prognostic factors, including clinical features, baseline (pre-neoadjuvant) and second (post-neoadjuvant) metabolic parameters on PET/CT-maximum standardized uptake value (SUVmax), peak standardized uptake value (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)-as well as their percentage changes prior to surgery.

RESULTS

During a median follow-up period of 26 months, 11 patients experienced recurrence or metastasis. The 1-, 2-, and 3-year disease-free survival (DFS) rates were 98%, 92%, and 88%, respectively. PET-defined N2 (HR = 10.32; 95%CI: 1.90-55.99; p = 0.007), squamous cell carcinoma histology (HR = 0.27; 95%CI: 0.07-0.97; p = 0.05), and baseline MTV (HR = 1.02; 95%CI: 1.01-1.03; p = 0.01) were all correlated with DFS among NSCLC patients attaining pCR. When metabolic parameters were dichotomized into high and low groups, those pCR patients with higher metabolic activity had significantly shorter DFS than those with lower activity did. The corresponding hazard ratios for baseline PET/CT parameters were as follows: SUVpeak, 10.17 (95% CI: 1.3-79.51); MTV, 4.26 (95% CI: 1.13-16.1); and TLG, 8.43 (95% CI: 1.08-65.9).

CONCLUSION

Among NSCLC patients achieving pCR after neoadjuvant chemoimmunotherapy, multivariable Cox regression analyses revealed that elevated baseline MTV and PET/CT-defined N2 status were independently associated with poor DFS, while squamous histology was associated with more favorable DFS. These findings highlight that even among pCR patients, baseline metabolic, histologic, and nodal staging characteristics retain important prognostic value.

CLINICAL REGISTRATION NUMBER: This real-world retrospective trial was registered at ClinicalTrials.gov on April 12th, 2025 (NCT06926179).