Medical Marijuana Lowers Opioid Distribution, Hospital Encounters in New Cancer Diagnoses

Results from a cross-sectional study, published in JAMA Oncology, suggest that the legalization of medical marijuana reduced opioid dispensation and pain-related hospital visits among adults newly diagnosed with cancer.

Investigators from Weill Cornell Medicine sourced data for this study from the Health Care Cost Institute claims database dated between 2012 and 2017. Adults (N=58,195) younger than 65 years with newly diagnosed breast (n=38,189), colorectal (n=12,816), or lung (n=7190) cancers were evaluated for opioid dispensations, total morphine milligram equivalents (MMEs) doses, and pain-related emergency department (ED) visits or hospitalizations within 6 months of diagnosis. Outcomes were compared between 34 states that did not have legal medical marijuana with 14 states that did allow marijuana use for cancer-related pain.

The mean age of the breast, colorectal, and lung cancer cohorts ranged from 55 to 64 years; prior to cancer diagnosis 12.4%, 13.7%, and 19.4% received opioids; 64.8%, 71.4%, and 81.9% received chemotherapy; 48.2%, 32.2%, and 60.1% received radiation; and 12.5%, 57.1%, and 23.6% underwent cancer resection surgery, respectively.

Stratified by cancer type and whether the patient had a recent precancer history of opioid use, the patients with a recent opioid history were more likely to receive opioid prescriptions (88.3%-89.6% vs 32.9%-37.9%), long-acting opioids (5.6%-30.2% vs 0.5%-7.0%), higher MME doses (mean, 2211.3-7870.9 vs 558.9-3475.8 mg), and to have more ED and hospital encounters (8.0%-19.4% v s 5.0%-13.5%) compared with those who had no recent opioid history, respectively. In general, patients with lung cancer were more likely to receive long-acting opioids, they received the highest MME dose, and they had the most pain-related health care encounters.

Legalized medical marijuana was associated with a 5.6% reduction in the rate of opioid prescription days among patients with breast cancer and a recent history of opioids (P =.001), a 4.9% reduction among patients with colorectal cancer and a recent opioid history (P =.03) and a 6.5% reduction among patients with lung cancer and no recent opioid history (P =.02). Medical marijuana also decreased long-acting opioid prescription days by 9.4% among patients with lung cancer and a recent history of opioids (P =.03).

Pain-related ED or hospital encounters decreased by 6.3% in medical marijuana states for patients with lung cancer and a recent opioid history (P =.03).

Overall, these significant trends were not observed until the end of the first to the fourth year after legislation, depending on the outcome.

The findings of this study may not be generalizable for older populations or for other types of cancers.

These data indicate that legislation permitting marijuana use for cancer-related pain likely decreased opioid dispensation and hospital encounters for pain among patients with newly diagnosed breast, colorectal, and lung cancers. However, the study authors caution, “As medical marijuana legalization expands, research will need to evaluate the safety, effectiveness, and therapeutic benefits of marijuana for patients with cancer with opioid or other substance use disorders.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.