A recent meta-analysis of 34 studies found that cannabis use may decrease one’s risk of developing certain kinds of cancers.
For the research, Professor Thomas M. Clark at Indiana University in the US reviewed 34 studies that delved into the relationship between cannabis use and the risk of developing certain cancers.
In the end, he found that cannabis usage correlated with a reduction in several cancers, including those of the head, neck, and lungs, and those related to obesity. However, he also found that cannabis use was correlated with a slight increase in testicular cancer, although not by a significant amount.
While interesting results, Clark notes that they are not necessarily conclusive. This comes as his data sets had a high level of heterogeneity, and there was a lack of data for many cancer types.
Regardless, he found some other interesting correlations that may inform how cannabis usage reduces cancer risk. For example, he noticed that cannabis users tended to have lower rates of obesity- a well-established risk factor for many cancers.
He also noticed that cannabis users tended to have lower rates of inflammation- yet another risk factor for cancer. This finding is supported by previous research, having already established a link between the usage of cannabinoids and a reduced risk of inflammation.
Lastly, he found that cannabis users tended to have better insulin resistance and a lesser chance of having diabetes than non-cannabis users. This link may lend its hand to a reduced cancer risk too as diabetes and poorer insulin resistance are associated with a greater risk of cancer, as well as faster growth and aggressiveness of the disease, and thus increased mortality rates.
"The current analysis does not support average recreational levels of Cannabis use as an effective stand-alone cure for cancer. However, the results do suggest that, in addition to providing significant improvements in the quality of life of cancer patients, adding Cannabis therapy to established cancer treatment regimens may well improve treatment efficacy without stimulating tumor growth." writes Clark in the research.