“…Some studies cited in the CDC guidelines included data from the 1980s and 1990s, 18 For example, some studies included skin cancer patients but excluded patients with other types of cancer. 22,23,27,31 Previous studies have shown that White race is associated with a higher incidence of skin cancer, 54 pain, 55 receiving opioids, 56,57 and experiencing overdose. 36 Therefore, selective inclusion of skin cancers (or selective exclusion of other cancers) could lead to selection bias, threatening both internal and external validity.…”