"A growing number of restrictions on opioid prescribing are already impacting these patient populations."

According to a survey conducted for the American Cancer Society Cancer Action Network and the Patient Quality of Life Coalition:

Patients answering yes to "Has your doctor indicated his or her treatment options for your pain were limited by laws, guidelines, or your insurance coverage?"
Patients Being Treated For Cancer: 48%
Patients Being Treated For Chronic Pain: 40%
Patients Being Treated For Other Serious Illnesses: 56%

"There has been a significant increase in cancer patients and survivors being unable to access their opioid prescriptions since 2016, when the Centers for Disease Control and Prevention (CDC) finalized opioid prescribing guidelines."

Percent of cancer patients and survivors who report being unable to get opioid prescription pain medication because the pharmacy did not have the particular drug in stock:
December 2016: 16%
May 2018: 41%

"The opioid epidemic is a public health crisis that is at least partially driven by harms associated with POM [Prescription Opioid Medication] use. States are passing laws allowing use of MC [Medical Cannabis] and patients are using MC, but currently there is little understanding of how this influences POM use or of MC-related harms. This literature review provides preliminary evidence that states with MC laws have experienced reported decreases in POM use, abuse, overdose, and costs.

"Opioid medications also have a potential for abuse (a discussion of this important issue is in the Executive Summary and Section III of the Evaluation Guide 2013). Consequently, opioid analgesics and the healthcare professionals who prescribe, administer, or dispense them are regulated pursuant to federal and state controlled substances laws, as well as under state laws and regulations that govern professional practice.^70;71 Such policies are intended to prevent illicit trafficking, drug abuse, and substandard practice related to prescribing and patient care.

"Pain is a significant public health problem. Chronic pain alone affects approximately 100 million U.S. adults. Pain reduces quality of life, affects specific population groups disparately, costs society at least $560-635 billion annually (an amount equal to about $2,000 for everyone living in the United States), and can be appropriately addressed through population health-level interventions."

"The information reviewed above indicates that cannabis has a long established history of efficacy in migraine treatment. Clinical use of the herb and its extracts for headache has waxed and waned for 1200 years, or perhaps much longer, in a sort of cannabis interruptus. It is only contemporaneously that supportive biochemical and pharmacological evidence for the indication is demonstrable.

"• Cannabinoids, the active components of Cannabis sativa and their derivatives, act in the organism by mimicking endogenous substances, the endocannabinoids, that activate specific cannabinoid receptors. Cannabinoids exert palliative effects in patients with cancer and inhibit tumour growth in laboratory animals.