# Dynamic variation in a combined inflammation–tumor marker index during neoadjuvant chemotherapy and its value for organ-preservation decisions in gastric cancer

## TL;DR

A new index tracking changes during chemotherapy helps predict treatment response and supports decisions to preserve organs in gastric cancer patients.

## Contribution

A dynamic inflammation–tumor marker index (ΔCITI) is proposed as a novel biomarker for assessing neoadjuvant chemotherapy response in gastric cancer.

## Key findings

- A ≥1-point decline in ΔCITI was observed in 53.1% of patients during neoadjuvant chemotherapy.
- Favorable ΔCITI was associated with higher pathologic complete response and improved overall survival.
- ΔCITI complements imaging and biopsy for assessing treatment response and guiding organ preservation decisions.

## Abstract

We evaluated whether on-treatment change in a Combined Inflammation–Tumor Marker Index (ΔCITI) signals chemosensitivity during neoadjuvant chemotherapy (NAC) for gastric cancer and can support selective organ preservation. Of 179 patients, 158 (88.3 %) completed planned NAC, 164 (91.6 %) underwent resection, with pathology evaluable in 163. A ≥ 1-point ΔCITI decline occurred in 53.1 % (95/179) as cohort means fell from 4.3 to 3.2. Among resected patients (evaluable n = 163), favorable ΔCITI was associated with higher pCR (22.5 % vs 9.8 %), R0 resection was achieved in 148/163 (90.8 %). In multivariable Cox models adjusting for regimen (FLOT vs SOX), baseline CITI, and clinicopathologic factors, favorable ΔCITI predicted improved overall survival (adjusted HR 0.62, 95 % CI 0.43–0.91) and showed a directionally favorable disease-free survival (adjusted HR 0.76, 95 % CI 0.55–1.06). A multidisciplinary pathway identified 15/179 (8.4 %) candidates for organ preservation, 11 proceeded, and 2/11 (18.2 %) experienced local regrowth, both salvaged. Given the small size and limited follow-up of this subgroup, these findings are exploratory. ΔCITI ≥ 1 offers a simple, dynamic indicator that complements imaging and endoscopy/biopsy for NAC response assessment and cautious MDT-guided de-escalation. Prospective validation and head-to-head comparisons with established indices are warranted.