evidence: 4.9.9 Anti-neoplastic properties - Pre-clinical studies suggest that certain cannabinoids (THC, CBD, CBG, CBC, CBDA) often, but not always block growth of cancer cells in vitro and display a variety of anti-neoplastic effects in vivo, though typically at very high doses that would not be seen clinically. - While limited evidence from one observational study suggests cancer patients use cannabis to alleviate symptoms associated with cancer (e.g. chemosensory alterations, weight loss, depression, pain), there has only been one limited clinical study in patients with glioblastoma multiforme, which reported that intra-tumoural injection of high doses of THC did not improve patient survival beyond that seen with conventional chemotherapeutic agents. [...] - Cannabis should be used with caution in patients with a history of substance abuse, including alcohol abuse, because such individuals may be more prone to abuse cannabis, which itself, is a frequently abused substanceReference 1078Reference 1359Reference 1360 (see Sections 2.4 and 4.9.5.4).