Charles S. Cleeland, PhD, formed the Pain Research Group (PRG) at the University of Wisconsin in 1979. The PRG relocated to The University of Texas M. D. Anderson Cancer Center in 1996, and has enjoyed significant visibility and support as part of this internationally recognized cancer center. The PRG has been supported by competitive grants from several NIH institutes, the World Health Organization, and private foundations including the Robert Wood Johnson Foundation and the American Cancer Society. It has also been supported by unrestricted educational grants from the pharmaceutical industry.

The PRG is probably best known for interdisciplinary research focusing on cancer pain and its treatment. Its first efforts were to develop the Brief Pain Inventory (BPI) for the rapid assessment of cancer pain and its impact on patients. The BPI has been used in the United States and around the world to document the proportion of cancer patients who experience pain that is severe enough to impair their function. To date, the BPI has been translated and validated in seventeen languages.

Since 1987, the PRG has collaborated with the Eastern Cooperative Oncology Group (ECOG) on studies of symptom prevalence, severity, and treatment. ECOG is one of the two major cancer clinical trials groups in this country, involving thousands of oncologic specialists and tens of thousands of cancer patients. Through this research, specific barriers to symptom management have been identified, and interventions have been planned to reduce these barriers.

From its inception, the PRG has had an international interest. Since 1987, the PRG has been designated a WHO Collaborating Center, and has conducted studies of the prevalence and severity of cancer pain in China, Mexico, Thailand, the Philippines, and Vietnam using the BPI.