What are the benefits and risks of using medical marijuana for cancer related symptoms?

The 2020 ASCO Antiemetic guidelines state that the evidence remains insufficient to recommend medical marijuana for either prevention or treatment of N/V in patients receiving chemotherapy or radiation therapy.

There is insufficient evidence to recommend inhaled cannabis for cancer-related side effects due to inadequate trial design (observation, non-RCT) or small sample size. There are ongoing trials evaluating oromucosal administration of cannabis plant extract - mostly in Canada and Europe.

There is stronger evidence for the use of cannabinoids (dronabinol and banilone) on Chemo-induced N/V compared with placebo, and it does have an FDA label, though it should only be used after failure of conventional anti-emetics.