Ricerc@Sapienza

Small bowel adenocarcinomas (SBAs) are often associated with poor prognosis and have limited therapeutic options. Programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway blockade is an effective treatment in many microsatellite instability-high (MSI-H) solid tumors. We aimed at investigating PD-L1 and PD-1 expression in non-hereditary, non-ampullary SBAs, associated with celiac disease (CeD), Crohn’s disease (CrD), or sporadic, recruited through the Small Bowel Cancer Italian Consortium.

Rationale:Small bowel adenocarcinoma (SBA) is an uncommon gastrointestinal cancer, thus limited data about treatment for advanced disease are available. The lack of specific guidelines has justified the use of therapeutic protocols usually applied in advanced colorectal cancer.

To test the validity of the model and answer the second question by Wang et al.,2 considering the small sample of the population, we implemented the analysis including the cross-validation with bootstrapping. To quantify the discrimination performance of the model, Harrell’s C-index was measured. The model was subjected to bootstrapping validation (1000 bootstrap resamples) to calculate the optimistic corrected estimate of C-index. The C-index for OS models was 0.70 while the corrected C-index was 0.67. Despite the small sample, the conclusions of our model seem to be robust.