One in Three Cancer Patients in a Memorial Sloan Kettering Survey Used Cannabis After Diagnosis
A survey of 1,258 adults treated for cancer at Memorial Sloan Kettering Cancer Center found that nearly one in three reported using cannabis after their diagnosis. The study, published in 2023 in Supportive Care in Cancer, examined patients’ reasons for using cannabis, their perceptions of its benefits and harms, and whether they discussed it with members of their healthcare team.
Researchers surveyed adults with nine types of cancer who received treatment at Memorial Sloan Kettering between March and August 2021. Participants lived in New York, New Jersey, or Connecticut, where medical and nonmedical cannabis use was legal at the time. Of the 3,837 patients invited to participate, 1,258 completed the survey, representing a 35% response rate.
Overall, 31% of respondents said they had used cannabis since their cancer diagnosis. Reported use varied by cancer type, ranging from 25% among patients with lung cancer to 59% among those with testicular cancer. Younger age and lower educational attainment were associated with greater use in some analyses, but the strongest predictor was cannabis use during the year before diagnosis.
Patients most often reported using cannabis to address difficulty sleeping, cited by 48% of users. Other common reasons included stress, anxiety or depression, at 46%, and pain, at 42%. Eating cannabis products was the most common method of consumption, followed by smoking. Many users obtained cannabis through friends, family members, or other community contacts rather than through their oncology teams.
Among respondents who used cannabis specifically to improve symptoms, 70% to 90% said their symptoms improved, while fewer than 5% said that any symptom became worse. These figures describe patients’ perceptions, however, rather than results from a controlled treatment trial. The study did not establish that cannabis caused the reported improvements, and symptoms may also have changed because of cancer treatment, other medications, or the natural course of illness.
The survey also identified a significant communication gap. Only 25% of respondents said they had discussed cannabis with a healthcare provider, and the proportion who discussed it with an oncologist was even lower. About three-quarters said they would feel comfortable talking with a provider about cannabis, suggesting that limited communication may reflect a lack of routine guidance rather than unwillingness to have the conversation.
The findings are important because patients may use cannabis alongside chemotherapy, immunotherapy, prescription medications, or other supportive treatments. Cannabis products can vary considerably in their concentrations of tetrahydrocannabinol (THC), cannabidiol (CBD), and other compounds, and potential side effects and drug interactions depend on the product and the patient’s health. Memorial Sloan Kettering’s clinical overview of cannabis notes that oncology guidelines do not recommend cannabis or cannabinoids as a cancer-directed treatment outside a clinical trial.
Evidence for symptom relief is mixed. The National Cancer Institute’s evidence summary on cannabis and cannabinoids reports the strongest established role for cannabinoid medicines in treating chemotherapy-induced nausea and vomiting when standard treatments have not worked. Research into pain, sleep, appetite, anxiety, and other symptoms remains limited or inconsistent. A 2023 systematic review of cannabis-based medicines for cancer pain also concluded that the available randomized evidence was insufficient to determine whether these products provide meaningful benefits for most patients.
The Memorial Sloan Kettering study had several limitations, including its 35% response rate, reliance on self-reported cannabis use, and the absence of information about cancer stage and prognosis. Its participants also came from a single cancer center and states where cannabis was legal, so the results may not apply to all people with cancer.
Even so, the survey shows that cannabis use is common across a broad range of cancer patients and often occurs without oncologist involvement. The researchers argue that oncology teams should be prepared to ask about cannabis use, discuss possible benefits and harms, and help patients consider potential interactions with their treatment. Open, nonjudgmental communication can help patients make safer and better-informed decisions while the clinical evidence continues to develop.
