Endometriosis is a notoriously painful condition affecting up to 10% of women. It is characterised by the presence of endometrial tissue, which should only be found inside the uterus, in other areas of the abdomen.
Despite extensive research, the causes and mechanisms behind endometriosis are still unclear. While none have been entirely proven, several theories exist including a kind of reflux of endometrial tissue into the abdominal cavity, immune dysfunction with the lymph dispersing tissue or even the process of metaplasia – where a normal type of cell transforms into another cell, out of place in its environment.
The presence of endometrial tissue or lesions outside of its normal environment does not exclude it from reacting to hormonal fluctuations of a woman cycle. As these lesions react to changes in hormones, they slough off creating debris or cysts in the abdomen (including the bladder, bowel and ovaries) which in turn can activate inflammatory immune responses.
The combination of lesions and the immune response can cause severe and chronic pain- one of the main complaints of endometriosis patients, other symptoms include dysmenorrhoea, heavy or irregular bleeding as well as gastrointestinal discomfort.
The endocannabinoid system (ECS) is made up of receptors and cannabis-like compounds that the body innately produces (endocannabinoids). There are two types of cannabinoid receptors in the body, CB1 receptors are primarily found in the brain and central nervous system, however also expressed notably in the uterus. CB2 receptors are largely dispersed in the immune system and gastrointestinal tract but can also be found in the female reproductive organs.
Levels of endocannabinoids are known to vary throughout a woman’s menstrual cycle particularly around ovulation. Signalling within the ECS is also thought to be important in pregnancy, with ECS dysfunction associated with early miscarriage.
The ECS is also strongly implicated in pain management which is a major aspect of women’s reproductive healthcare. In 2016, a study showed endometriosis patients exhibited lower levels of CB1 receptors than control subjects, which was inferred to be impairing mediation of pain sensation.
CBD and THC have been investigated for their anti-inflammatory properties. In relation to endometriosis, THC is known to act on CB1 and CB2 receptors, which may have huge implications on inflammation and pain for these patients.
CBD has also been shown to aid in alleviating chronic and severe pain. Instead of engaging the ECS, CBD acts on the same pathways as non-steroidal anti-inflammatory drugs (NSAID), like ibuprofen which is commonly prescribed for endometriosis-related pain. Fortunately, CBD appears to lack some of the negative gastrointestinal side effects that are commonly caused by NSAIDs.
Sufferers considering CBD as a treatment alternative should discuss its use and possible side-effects with their GP for their specific condition.
In Australia, a recent survey of 484 women, 13% used cannabis to manage endometriosis pain. Of all of the pain management strategies assessed, women self-medicating with cannabis reported the greatest relief in symptoms.
While this survey was subjective and by no means gold-standard research, it is pleasing to see foundational information like this being gathered locally, with potential for Australian-based clinical trials in the future.
Cannabinoids have also been researched for their impact on the processes of angiogenesis, a key aspect of the pathology of this condition.
By inhibiting endometrial lesions from creating new vessels to feed their growth and nervous innovation there is potential for managing both pain and disease progression.
CBD has also been shown to block migration of endometrial cell lines. This is exciting information for endometriosis research: such investigations are still isolated to the Petri-dish yet it is promising information that will inform future investigations and treatment plans.
As it stands, there is still insufficient evidence to proclaim medical cannabis could mitigate disease progression in patients with endometriosis. However, animal and human trials have showcased enough positive evidence to definitely warrant further investigation.
In the meantime, the positive impacts of medical cannabis on pain are potent enough to consider medical cannabis as a pain management option, adjunct to current treatments. For those patients with severe chronic pain requiring opioid medications, the potential of medical cannabis as an opioid-sparing agent has not gone unnoticed, but as always, it’s a good idea to consult with your doctor about the most appropriate path forward.