Association Between Pretreatment Fusobacterium Nucleatum And Cancer Pain At Six Months Postsurgery In Newly Diagnosed Colorectal Cancer Patients: Results From The Colocare Study.

3581 Background: Pain is a prevalent, debilitating symptom in more than half of cancer patients. Accumulating evidence suggests a bi-directional relationship between gut microbiota and pain, potentially via inflammation and oxidative stress. Fusobacterium nucleatum (Fn), a pro-inflammatory anaerobic bacterium, is frequently detected in colorectal cancer (CRC) patients. To date, no study has identified a relationship between Fn and cancer pain in CRC patients. We investigated the associations between pre-treatment Fn and cancer pain at 6 months post-surgery in CRC patients. Methods: We utilized pre-surgery stool samples collected from 80 prospectively followed, newly diagnosed CRC patients recruited from the German site of the international ColoCare Study. Eligible patients were neo-adjuvant treatment naïve and did not use antibiotics for at least 1 month before stool collection. Fn DNA was assessed via quantitative real-time polymerase chain reaction. Patients were median split into Fn-high (>17.27; n=40) or Fn-low (≤17.27; n=40). Cancer pain was assessed using the 2 pain symptom items from the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core-30 (lower score=lower pain) at pre- and 6 months post-surgery. Results: Before surgery, 48% of all patients reported any pain. At 6 months post-surgery, we observed a decrease in cancer pain by 33% for Fn-low, while there was an increase in cancer pain by 41% for Fn-high. After controlling for pre-surgery cancer pain in ANCOVA model, we observed significantly higher mean cancer pain at 6 months post-surgery in the Fn-high group vs. the Fn-low group (24.07 vs. 13.44; effect size, ES=0.45; p=0.04). These results were maintained even after controlling for age, sex, tumor stage and site, adjuvant chemotherapy, BMI, physical activity, and any pain medications (29.11 vs. 16.55; ES=0.53; p=0.03). Conclusions: These findings suggest that high Fn is an independent predictor of cancer pain at 6 months post-surgery in colorectal cancer patients. Further research is needed to confirm and understand the mechanisms of these results. Funding: NCI U01 CA206110.