This phase I trial tests whether fluoxetine (prozac) works to modify the tumor immune cells before surgery in patients with colorectal cancer. Fluoxetine is a commonly used selective serotonin reuptake inhibitor (SSRI) prescribed for major depressive disorder and generalized anxiety. Giving fluoxetine may modify the immune cell composition in the tumor and its microenvironment and may induce changes in body's immune system and may interfere with the ability of tumor cells to grow and spread in patients with colorectal cancer.
Male or female ≥ 18 years of age at visit 1
Previously untreated cytologically or histologically confirmed colorectal adenocarcinoma that will not need neoadjuvant therapy
Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study
World Health Organization (WHO) Eastern Cooperative Oncology Group (ECOG) performance status 0-2
Presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the participant or the quality of the data
A diagnosis of metastatic colorectal adenocarcinoma
Individuals who have received neoadjuvant chemotherapy prior to the planned colon cancer resection
Individuals with absolute or relative contraindications to fluoxetine