Systemic Inflammation Response Index and weight loss as prognostic factors in metastatic pancreatic cancer: A concept study from the PANTHEIA-SEOM trial

BACKGROUND The prognostic value of the Systemic Inflammation Response Index (SIRI) in advanced pancreatic cancer is recognized, but its correlation with patients´ nutritional status and outcomes remains unexplored. AIM To study the prognostic significance of SIRI and weight loss in metastatic pancreatic cancer. METHODS The PANTHEIA-Spanish Society of Medical Oncology (SEOM) study is a multicentric (16 Spanish hospitals), observational, longitudinal, non-interventional initiative, promoted by the SEOM Real World-Evidence work group. This pilot study sought to analyze the association between weight loss and inflammatory status as defined by SIRI. The cohort stems from a proof-of-concept pilot study conducted at one of the coordinating centers. Patients with pathologically confirmed metastatic pancreatic adenocarcinoma, treated from January 2020 to January 2023, were included. The index was calculated using the product of neutrophil and monocyte counts, divided by lymphocyte counts, obtained within 15 days before initiation chemotherapy. This study evaluated associations between overall survival (OS), SIRI and weight loss. RESULTS A total of 50 patients were included. 66% of these patients were male and the median age was 66 years. Metastasis sites: 36% liver, 12% peritoneal carcinomatosis, 10% lung, and 42% multiple locations. Regarding the first line palliative chemotherapy treatments: 50% received gemcitabine plus nab-paclitaxel; 28%, modified fluorouracil, leucovorin, irinotecan and oxaliplatin, and 16% were administered gemcitabine. 42% had a weight loss > 5% in the three months (mo) preceding diagnosis. 21 patients with a SIRI ≥ 2.3 × 103/L exhibited a trend towards a lower median OS compared to those with a SIRI < 2.3 × 103/L (4 vs 18 mo; P < 0.000). Among 21 patients with > 5% weight loss before diagnosis, the median OS was 6 mo, in contrast to 19 mo for those who did not experience such weight loss (P = 0.003). Patients with a weight loss > 5% showed higher SIRI levels. This difference was statistically significant (P < 0.000). For patients with a SIRI < 2.3 × 103/L, those who did not lose > 5% of their weight had an OS of 20 mo, compared to 11 mo for those who did (P < 0.001). No association was found between carbohydrate antigen 19-9 levels ≥ 1000 U/mL and weight loss. CONCLUSION A higher SIRI was correlated with decreased survival rates in patients with metastatic pancreatic cancer and associated with weight loss. An elevated SIRI is suggested as a predictor of survival, emphasizing the need for prospective validation in the upcoming PANTHEIA-SEOM study.