Cannabis is a group of flowering plants that has been long used for industrial, recreational and medical purposes. When relating to its medical use, the terms "Medical Cannabis" or "Medical marijuana" has become prevalent. In this course we will use the term "Medical Cannabis". Nowadays, Medical Cannabis involves multiple medical disciplines such as neuroscience, pain, pharmacology, oncology, psychiatry and more. Moreover, it has cultural, agricultural and social, legal and political implications. This course will give you a solid ground to understand the whole picture. By completing this course, you will gain a broad understanding and knowledge base related to medical use of cannabis for pain control. You will be exposed to a wide range of topics such as historical use of cannabis in ancient times, botanic aspects of the plants, and potential benefits and risks associated with its medical use to both individuals and society.
Cancer pain
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From the course by Technion - Israel Institute of Technology
Medical Cannabis for Pain Control
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From the lesson
Effectiveness for pain
Meet the Instructors
Elon EisenbergProfessor of Neurology and Pain Medicine
Institute of Pain Medicine, Rambam Health Care Campus
Studies spanning the past three decades tell us that
some two-thirds of patients with advanced cancer suffer a moderate to severe pain.
In the vast majority of these patients,
pain is caused by the cancer itself,
by either direct invasion of surrounding tissues and nerves,
or through metastatic spread of the tumor to remote sites and commonly the bones.
Another major cause of pain in many patients is the cancer treatment itself.
There is a host of syndromes of treatment-induced pain.
Perhaps, most common is the syndrome of chemotherapy-induced painful neuropathy,
which is characterized by a burning, shooting,
and numb pain at a stockings and gloves distribution.
Another type of treatment-induced pain includes postoperative pain,
mostly caused by nerve injuries during cancer surgery.
A typical example, is chronic pain after breast surgery,
known as post-mastectomy pain syndrome.
But other types of surgeries also cause similar painful conditions.
Hormonal therapies may cause joint pain and radiation therapy especially,
if quad-ministered with chemotherapy,
may cause severe painful inflammation in the mouth,
urinary bladder, and rectum,
depending on the radiated body parts.
Importantly, due to advances in cancer therapy,
many patients recover from their cancer.
Unfortunately, a considerable number of these cancer free individuals have
a constant reminder of a very acute cancer in
the form of chronic pain which may last for months and even years.
Since moderate to severe pain is very common among cancer patients,
in the early 80's,
the World Health Organization published guidelines on cancer pain treatment.
Those guidelines principally indicate
that treatment has to be adjusted to pain intensity.
To that end, we needed to make a distinction between three levels of pain.
Mild, moderate and severe.
This incremental breakdown is often termed 'The Three Step Analgesic Ladder'. The W.H.O.
guidelines indicate that non-opioid analgesics should be used for mild pain.
Among these, we find acetaminophen and anti-inflammatory drugs.
For moderate pain, weak opioids such as codeine and tramadol can be added.
For severe pain, potent opioids such as morphine,
oxycodone and fentanyl are indicated.
Complimentary drugs for neuropathic pain can be added whenever it is diagnosed.
Another noteworthy point is that,
many studies have shown that adhering to
these guidelines results in
good pain control in most patients suffering from cancer pain.
So what does medical cannabis has to do with cancer pain?
In Israel, as I can't speak for other countries,
patients with cancer pain who requests medical cannabis,
get authorized quickly and receive treatment within a matter of days.
Whereas, authorization for other indications can take many weeks.
There are two reasons for this.
First, some patients with cancer,
especially those with advanced cancer,
may not survive many weeks,
and therefore need it right away.
The second reason, is that many people believe that medical cannabis is the solution for
otherwise unrelieved cancer pain and other symptoms at
all stages of the disease and are regarded as almost a panacea drug.
Well, is it?
A recent large scale study from Israel,
which included some 17,000 cancer patients,
found that less than two percent receive
authorization for cannabis use from an institutional Oncologist.
Most of these patients had metastatic disease, meaning advanced cancer.
By the end of their first months of medical cannabis use,
70 percent of users reported improvement in pain and in general well-being.
As I mentioned in the introduction to this module,
we need to look at clinical trials in order to assess
the effectiveness of medical cannabis for various types of pain.
So once again, I search Medline,
which as you will recall is a National Library of Medicine search engine.
I entered the terms cannabis and cancer pain,
and got nearly 120 results.
This is a considerable number of results.
I continued by searching for systematic reviews,
and found a recent one published in
The Journal of the American Medical Association in 2015.
28 tries related to cancer pain and cannabis were identified by the researchers.
12 of which were suitable for review,
and three provided quantifiable information.
These three studies showed attenuation in
pain intensity of a comparable magnitude for both cancer and non-cancer of pain.
The average reduction in pain intensity was
approximately half a point on a 10 point scale,
which is not a considerable change.
An earlier meta-analysis conducted by
a Spanish investigator group, produced similar results.
In more recent meta-analysis by a German group,
reported a much more meaningful analgesic effect reaching 30 percent.
However, there was no difference between medical cannabis and placebo,
questioning once again the effectiveness of cannabis per say for cancer pain.
To conclude, results of the published studies show that, first,
the average effect of medical cannabis on cancer pain does not appear to be a robust.
Second, a relatively small number of studies exist,
so drawing conclusions regarding the effectiveness
of medical cannabis for cancer pain is still difficult.
Third, when we refer to an average,
we are referring to a spectrum of responses.
So, while some patients do not benefit from a treatment,
others experienced dramatic pain reduction.
Indeed, in a recent article entitled,
Integrating Cannabis into Clinical Cancer Care,
a senior Oncologist at the University of California in San Francisco wrote; "Clinically,
I have observed that many cancer patients
benefit from adding cannabis to their pain regimen,
and some sorts of cancer-related pain appear to respond to medical cannabis".
When referring to patients at the most advanced stages of illness,
he adds; "patients who have been put on high doses of opiates at the end of their life,
by the whelming care team,
frequently feel totally unable to communicate with their loved ones
in their precious remaining time because of altered cognition.
Many have successfully winged themselves down or
off of their opiate dose by adding cannabis to the regimen".
So what do official organizations say about
medical cannabis in the context of cancer related to pain?
The NIH, National Cancer Institute states that,
cannabis and cannabinoids may have benefits in treating
the symptoms of cancer or side effects of cancer therapies.
The American Cancer Society affirms that a few studies have found that inhaled,
meaning smoked or vaporized marijuana,
can be helpful treatment of neuropathic pain.
It goes on and states that, for sometimes,
studies have shown that people taking marijuana extract
in clinical trials tend to need less pain medications.
A word of warning before ending these lesson.
Medical cannabis is available in a variety of forms.
Cookies, sublingual drops, vaporized mist,
cigarettes, pipes and so forth.
However, as with every herb,
various microorganisms are carried on the leaves and
flowers which when inhaled expose users in particular,
immunocompromised patients to the risk of opportunistic lung infections.
Primarily, from inhaled molds.
Such infections can be fatal for some patients.
Hence, immunocompromised patients should avoid using inhaled medical cannabis.
We'll discuss safety of cannabis use later in this course.
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