Opioid-induced hyperalgesia (OIH) is most broadly defined as a state of nociceptive sensitization caused by exposure to opioids. In humans, the evidence of OIH is strong but conflicting. Previous clinical studies mostly used experimental or non-standardized surgical stimuli to assess OIH. We therefore sought to certify a presence of OIH using a standardized, clinical pain stimuli in cancer patients receiving opioid therapy and opioid-naive patients.

Inclusion Criteria:

• age 20-80
• cancer patient
• patient whom receiving opioid treatment, any acute or chronic pain condition amenable to a diagnostic/therapeutic nerve block or neuromodulation,and a regular analgesic regimen.

Exclusion Criteria:

• patient who has any change in opioid or other analgesic medications less than 14 days prior to the scheduled procedure
• an inability to understand English or adequately respond to the relevant questions