Anesthetic opiates may interact with the immune system in negative ways.

[kainasar]

"Up to 80% of oncological patients receive anesthesia and/or analgesia for diagnostic, therapeutic or palliative interventions. Therefore, anesthesiologists are asked to administer drugs such as opiates and volatile or intravenous anesthetics, which may determine different effects on immunomodulation and cancer recurrence. For instance, some studies suggest that intravenous drugs, such as propofol, may inhibit the host immunity to a lower extent as compared to volatile anesthetics. " - F. Longini et al. Cancer Manag Res. 2020; 12: 931–940.

ncbi.nlm.nih.gov/pmc/articl...

also, pubmed.ncbi.nlm.nih.gov/293...