Public health scientists at Fred Hutch Cancer Center dug into cannabis and alcohol use among their cancer patients with two recent studies.

A study published in the journal Cancer Causes & Control used the cancer registry for the Pacific Northwest region to identify 1,515 patients who’d been diagnosed from April to December 2020. They then had these patients complete a questionnaire outlining demographics, medical history and cannabis and other substance use.

Results, per lead author Mimi (Trucmai) Ton, MPH, were surprising. More than 40% of the patients reported cannabis use after their cancer diagnosis, she said.

Patients in chemotherapy often use anti-nausea drugs, but may supplement with cannabis if these drugs prove ineffective. In addition, cannabis is sometimes used as a way to stimulate appetite in patients or to help with insomnia (cancer medications often include steroids which can cause sleeplessness). 

The researchers found most patients used edibles (60.5%) or smoked it (43.8%). The most frequent reason for use cited in the survey were sleep (54.5%); mood, stress, anxiety and depression (44.3%); pain (42.3%); and recreation (42.3%).

“About half of those who used cannabis after their cancer diagnosis reported using it at least several times per week during cancer treatment,” Ton said.

Co-author Jaimee Heffner, PhD, director of Fred Hutch’s TReHD (Tobacco-Related Health Disparities research group), said the results were unexpected.

“The overall prevalence of cannabis use was a little eye opening,” she said.

In the U.S., cannabis for medical use is legal in 38 of 50 states; cannabis for recreation is legal in 24 states. In 2012, Washington state passed Initiative 502, which allows adults over the age of 21 to purchase the drug in various forms. Cannabis is still illegal under federal law but there are several bills before Congress proposing changes to this.

‘Risky’ alcohol use in nearly a third of patients

The same team also published an analysis of alcohol use by people who’d been diagnosed with cancer, publishing their results in the journal Cancer Epidemiology, Biomarkers & Prevention.

They again used the cancer registry for the Pacific Northwest region to identify people ages 21 to 74 diagnosed with any type of cancer within the last 6 to 17 months between April and December 2020.

Surveys were sent to these patients with questions about their demographics, substance use, mental health and cancer. Approximately 1,500 patients responded and the researchers divvied them up into three groups: any drinking; drinking that exceeded cancer prevention guidelines (1 drink/day for women or 2 drinks/day for men) and hazardous drinking, defined as engaging in a pattern or frequency of alcohol use that is likely to lead to harmful consequences.

Weighted prevalence of alcohol use was 71% for “any drinking”; 46.2% for “drinking exceeding cancer-prevention guidelines” and 31.6% for “hazardous drinking.”

The team, which in addition to Heffner and Ton included Fred Hutch’s Salene Jones, PhD, Polly Newcomb, PhD, MPH, Stacey Cohen, MD, and Rachel Malen, MPH, found patients who earned more money and who also used cannabis were more likely to drink. Least likely to drink were patients with poor quality of life due to their physical health; patients with gastrointestinal cancer and patients who’d received chemotherapy within the last month.

Heffner was again surprised by the findings, especially as the prevalence of drinking was higher than in previous studies of cancer survivors.

“It suggests drinking may be increasing over time among cancer survivors, potentially putting them at higher risk of cancer recurrence, developing new cancers, and developing other alcohol-related physical and mental health problems,” she said.

Heffner said a limitation of the two studies was that the data were collected during the early period of the COVID-19 pandemic, which did impact people’s behavior in many ways, including the use of alcohol and other substances.

“Since this was a cross-sectional study where we were just looking at what was happening at a single point in time, we don’t know how COVID-19 may have impacted survivors’ use of alcohol and cannabis and whether, if there were any changes, they were more time-limited,” she said. “We don’t know if they continued beyond that early pandemic period.”

The public health researchers said the findings do emphasize the importance of incorporating universal screening and intervention for alcohol use into cancer care settings.

“The fact that risky or hazardous alcohol use is so prevalent among cancer survivors and that many people are not even aware that alcohol is a carcinogen demonstrates how important this is,” she said, adding that she’s currently working with patient advocates and a multidisciplinary group of researchers to create potential interventions.

Many cancer centers have tobacco cessation programs, the researchers point out in their paper, but “counseling services for alcohol use [is] far less common.”

This story was published by Fred Hutch News Service on April 5, 2024. It is republished with permission.