Impact of Body Mass Index and Lipid Metabolism on Anti-PD-1 Immunotherapy Outcomes in Colorectal Cancer

This retrospective observational study investigates the prognostic value of body mass index (BMI) and dyslipidemia in colorectal cancer (CRC) patients treated with anti-PD-1 immune checkpoint inhibitors (ICIs). A total of 142 patients were included, all of whom received at least two cycles of PD-1 inhibitors, including Camrelizumab, Nivolumab, Pembrolizumab, Sintilimab, Tislelizumab, or Toripalimab, at Sun Yat-sen University Cancer Center between January 1, 2019, and December 31, 2022.

The primary objective of the study was to evaluate progression-free survival (PFS) stratified by BMI and lipid profile status. Patients were grouped by BMI into normal (<24 kg/m²) and overweight (≥24 kg/m²) categories, based on WHO standards for the Chinese population. Dyslipidemia was defined according to standard lipid thresholds. Kaplan-Meier and Cox proportional hazard models were used for survival analysis. Additionally, a subset of 12 patients underwent pre-treatment serum lipidomic profiling using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to explore potential metabolic mechanisms contributing to differential responses.

Inclusion criteria

Age ≥ 18 years at time of diagnosis

Histologically confirmed colorectal adenocarcinoma

Received at least two doses of anti-PD-1 immune checkpoint inhibitor therapy (e.g., Camrelizumab, Nivolumab, Pembrolizumab, Sintilimab, Tislelizumab, or Toripalimab)

Availability of baseline body mass index (BMI) and lipid profile within 30 days prior to ICI initiation

Adequate clinical records for retrospective data collection

Signed informed consent for data usage (if applicable to retrospective cohort)

Exclusion criteria

Participation in another interventional clinical trial during the study period

Incomplete PD-1 treatment (< 2 cycles)

Severe immune-related adverse events leading to early discontinuation of immunotherapy

Missing or incomplete BMI or lipid profile data

Loss to follow-up prior to outcome assessment