Targeting probiotic modulation of gut microbiota for postoperative depression management in patients undergoing gastric cancer surgery

Table 1 Integrated probiotic-antidepressant treatment protocol

Phase	Timeline	Intervention components	Clinical and microbiome monitoring	Quality control measures
Preoperative baseline	2 weeks pre-surgery	Comprehensive gut microbiome profiling (targeted 16S rRNA sequencing). Standardized psychometric assessment (HAMD-17, SDS). Nutritional status evaluation	Alpha/Beta diversity indices. Baseline depression severity. Serum inflammatory markers (interleukin-6 and C-reactive protein)	Standardized stool collection protocol. Blind-rated psychological assessments
Perioperative initiation	Day 0-1 (surgery)	Single-dose probiotic loading (B. longum R0175 2 × 109 CFU). Anesthesia protocol optimization (vagus nerve-sparing techniques)	Surgical stress biomarkers (cortisol, norepinephrine). Acute pain scores	Probiotic viability testing. Surgical team training
Active treatment	Weeks 1-8 post-op	Pharmacotherapy: Mirtazapine titration (15→30 mg/day); Bifidobacterium triple viable (2 g bid). Adjuncts: Weekly cognitive behavioral therapy sessions; Mediterranean diet protocol	Weekly: Depression scales (HAMD/SDS), gastrointestinal symptom diary. Biomarkers: Monthly serum brain-derived neurotrophic factor, serotonin; Stool microbiome (Weeks 4,8)	Pharmacy-compounded probiotics. Medication adherence monitoring
Maintenance and transition	Months 3-6	Probiotic tapering (50% dose reduction monthly). Monthly booster psychotherapy. Personalized exercise prescription	3-month microbiome stability. Quality of life (EORTC QLQ-C30). Depression relapse rates	Telehealth follow-ups. Digital symptom tracking

HAMD-17: Hamilton Rating Scale for Depression; SDS: Self-Rating Depression Scale.