Cannabinoids and Cannabis for Cancer: Research Insights

Cannabinoids and Cannabis for Cancer: What the Research Says

Cannabinoids and Cannabis for Cancer: What the Research Says. Cannabinoids and cannabis are among the most widely discussed complementary therapies in cancer care. But what does the research actually show?

Can cannabinoids treat cancer? Laboratory and animal studies suggest that THC, CBD, and other cannabinoids may have anticancer effects. Still, there is currently insufficient clinical evidence to establish cannabis or cannabinoids as an effective cancer treatment. Cannabinoids do have an established role in managing some cancer-treatment side effects, particularly refractory chemotherapy-induced nausea and vomiting.

Cancer patients and survivors use cannabis and cannabinoid products for many reasons: chemotherapy-induced nausea, pain, appetite loss, sleep problems, anxiety and, in some cases, the hope that cannabinoids might directly slow or kill cancer cells.

The research is interesting—but it is also easy to misunderstand.

Laboratory studies have reported that cannabinoids can kill or slow cancer cells. Animal studies have produced similarly intriguing findings. However, evidence from human clinical trials is much more limited.

The most important distinction is this:

There is evidence that certain cannabinoid medications can help manage some cancer-treatment side effects. There is not yet sufficient clinical evidence to conclude that cannabis or cannabinoids are an effective cancer treatment.

The American Society of Clinical Oncology (ASCO) specifically recommends against using cannabis or cannabinoids as a cancer-directed treatment except in a clinical trial. ASCO does recognize a possible role for cannabinoids in refractory chemotherapy-induced nausea and vomiting when added to standard antiemetic therapy.

That distinction should guide how cancer patients think about cannabis.

I am a long-term survivor of an incurable blood cancer called multiple myeloma. My research and experience with evidence-based non-conventional therapies are the reason why I have lived in complete remission from my incurable blood cancer since achieving complete remission in early 1999. I have learned that the best way to manage cancer is to combine the best of conventional and evidence-based non-conventional therapies.

I have come to believe that therapy-induced side effects can be life-threatening while ruining quality of life. Consider therapies shown to reduce possible side effects.

Scroll down and post a question or comment if there’s anything you’d like to know about breast cancer.

Good luck,

David Emerson

Cannabis for Cancer: Symptom Relief vs. Wishful Thinking

Concepts Central to Managing Your Cancer

What Are Cannabinoids?

Cannabinoids are chemical compounds that interact with the body’s endocannabinoid system.

The cannabis plant contains more than 100 identified cannabinoids. The two most familiar are:

THC (delta-9-tetrahydrocannabinol) — the principal psychoactive cannabinoid responsible for the “high.”
CBD (cannabidiol) — a non-intoxicating cannabinoid that is being studied for a variety of potential therapeutic effects.

Other cannabinoids—including CBG, CBN and THCV—are also being investigated.

Cannabis products may contain different combinations and concentrations of these compounds.

That creates an important problem for patients trying to interpret research.

A study of pharmaceutical-grade THC is not necessarily evidence for a commercially available CBD oil.

Likewise, a laboratory study using a highly concentrated cannabinoid preparation does not prove that a cannabis product purchased by a patient will produce the same effect.

Can Cannabis or Cannabinoids Treat Cancer?

This is probably the most important question.

The short answer: We don’t know yet.

There is considerable laboratory research suggesting that cannabinoids may have anticancer properties.

Researchers have reported effects involving:

cancer-cell death
inhibition of cancer-cell growth
apoptosis
angiogenesis
invasion and metastasis
inflammatory signaling
cellular stress pathways
interactions with cannabinoid receptors

These findings have been reported in laboratory studies involving several cancers.

The National Cancer Institute notes that preclinical studies have found antitumor effects from cannabinoids in cell and animal models.

But there is a major difference between killing cancer cells in a laboratory dish and treating cancer in a human being.

A compound can destroy cancer cells in vitro and still fail as a cancer treatment because:

the required dose may be toxic to humans
the compound may not reach the tumor in sufficient concentration
cancer cells may become resistant
the compound may interact with other treatments
laboratory concentrations may be impossible to achieve safely in patients

This is why human clinical trials are essential.

What does the human evidence show?

At present, the clinical evidence is insufficient to establish cannabis or cannabinoids as effective cancer-directed therapies.

The 2024 ASCO guideline reviewed systematic reviews and clinical studies of cannabis and cannabinoids in adults with cancer. The evidence for most outcomes was considered low or very low certainty. ASCO concluded that cannabis and cannabinoids should not be used as cancer-directed treatment outside a clinical trial.

That does not mean the laboratory research is unimportant.

It means the research has not yet crossed the critical bridge from promising biological activity to proven clinical benefit in people.

Cannabis and Multiple Myeloma

Multiple myeloma is an especially interesting area of cannabinoid research.

Laboratory studies have reported that cannabinoids—including CBD and THC—can inhibit multiple myeloma cells.

There are also studies examining whether cannabinoids may work synergistically with conventional myeloma therapies such as bortezomib.

This is an area where the distinction between preclinical evidence and clinical evidence is extremely important.

A laboratory study showing that CBD kills myeloma cells—or makes myeloma cells more sensitive to bortezomib—is encouraging.

It does not establish that CBD treats multiple myeloma in a patient.

That is why I would encourage myeloma patients to read the research with both optimism and caution.

My own PeopleBeatingCancer discussion of this subject is:

Cannabinoids as Myeloma Therapy?

That article explores the laboratory research involving cannabinoids and multiple myeloma.

Cannabis for Chemotherapy-Induced Nausea and Vomiting

This is where the evidence becomes considerably more practical.

Chemotherapy-induced nausea and vomiting (CINV) can be one of the most difficult short-term side effects of cancer treatment.

Cannabinoids have been studied for decades as antiemetic therapies.

Two cannabinoid medications are particularly important:

Dronabinol — synthetic THC
Nabilone — a synthetic THC analogue

Both are FDA-approved for chemotherapy-induced nausea and vomiting in patients who have not responded adequately to standard antiemetic therapy.

This is very different from saying that cannabis is a cancer treatment.

What about CBD and THC combinations?

Research has also investigated combinations of THC and CBD.

A 2024 ASCO guideline concluded that cannabis and/or cannabinoids may improve refractory chemotherapy-induced nausea and vomiting when added to guideline-concordant antiemetic treatment.

A more recent systematic review examining 32 studies and 1,889 patients found that cannabinoids showed benefit in some comparisons, particularly versus older antiemetic approaches and placebo. However, the authors concluded that evidence remains insufficient for routine recommendation when modern guideline-based antiemetic therapy is considered, partly because of cannabinoid-related adverse effects.

The practical takeaway

Cannabinoids may have a role for refractory CINV.

They should not automatically replace modern antiemetic therapy.

Patients should discuss their use with their oncology team.

For additional information, see the PeopleBeatingCancer post:

Chemotherapy-Induced Nausea and Vomiting

Cannabis and Cancer Pain

Pain is another reason cancer patients turn to cannabis.

Unfortunately, the evidence here is much less encouraging than the laboratory research might suggest.

Cannabinoids affect pathways involved in pain perception, inflammation, and the nervous system. This provides a biologically plausible reason to investigate them for cancer pain.

But clinical trials have produced inconsistent results.

The Multinational Association of Supportive Care in Cancer (MASCC) reviewed randomized trials of cannabis and cannabinoids for cancer pain and concluded that high-quality evidence provides little support for cannabinoids as an effective analgesic or adjuvant treatment for cancer pain. The guideline recommends against using cannabinoids as an adjuvant analgesic for cancer pain.

That is an important reality check.

Biological plausibility is not the same thing as clinical effectiveness.

Patients experiencing severe cancer pain should not abandon proven pain-management approaches because cannabis has shown promising effects in laboratory studies.

For myeloma patients, I have written extensively about cancer and neuropathic pain, including:

Multiple Myeloma Pain

and

Neuropathic Pain Therapies

Cannabis and Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is another area of considerable interest.

CIPN can cause:

numbness
tingling
burning
shooting pain
sensitivity to touch
balance problems
difficulty walking

Cannabinoids have biological effects on the nervous system, and researchers have investigated whether cannabis might reduce neuropathic pain or even prevent nerve damage.

Some observational research is intriguing.

But observational studies cannot establish that cannabis caused the improvement.

For example, PeopleBeatingCancer has previously discussed research involving cannabis and oxaliplatin-induced neuropathy.

I would therefore classify cannabis for CIPN as an interesting but unproven complementary approach, rather than an established therapy.

For additional background:

Myeloma — Chemotherapy-Induced Peripheral Neuropathy (CIPN)

Cannabis, Appetite and Cancer Cachexia

Cancer patients sometimes use cannabis because they have difficulty eating.

THC and other cannabinoids can influence appetite, which has generated considerable interest in cancer-associated anorexia and cachexia.

But again, the clinical evidence is mixed.

A systematic review and meta-analysis found that the evidence for cannabinoids improving appetite, weight gain, and quality of life in cancer cachexia was low quality and did not demonstrate significant benefits.

Another systematic review of randomized trials found limited evidence that medicinal cannabis improves appetite-related outcomes in people with cancer.

This is an important distinction:

Feeling hungrier is not necessarily the same thing as reversing cancer cachexia.

Cancer-associated wasting is a complex metabolic condition involving inflammation, muscle loss, and altered metabolism. Simply increasing calorie intake may not solve the underlying problem.

Cannabis and Sleep

Many cancer patients report using cannabis to help with sleep.

This is plausible because THC and other cannabinoids affect the central nervous system.

However, cancer-specific clinical evidence is limited.

Patients may also develop tolerance, sedation or cognitive effects.

In other words, a patient may report:

“Cannabis helps me sleep.”

That is a legitimate patient experience.

But it should not automatically be interpreted as proof that cannabis is an effective long-term treatment for cancer-related insomnia.

Cannabis and Anxiety

Cancer can produce enormous psychological stress.

Patients may use cannabis to relax, reduce anxiety, or improve their sense of well-being.

The problem is that THC can affect people differently.

Some patients experience relaxation.

Others experience:

anxiety
dizziness
confusion
impaired concentration
paranoia
sedation

The dose, THC concentration, route of administration, and individual response all matter.

Patients should therefore approach THC-containing products cautiously, particularly when they are taking medications that already cause sedation or affect cognition.

CBD Is Not the Same as Cannabis

One of the most common misunderstandings surrounding cannabinoid research is treating CBD, THC, medical cannabis, and hemp-derived products as interchangeable.

They are not.

CBD does not produce the intoxicating effects associated with THC.

But CBD is still biologically active.

It can affect drug-metabolizing enzymes, including cytochrome P450 enzymes, which means concentrated CBD products may potentially interact with medications.

This is especially important for cancer patients because oncology treatment frequently involves multiple medications.

A patient should not assume:

“It’s natural, therefore it can’t interfere with my cancer treatment.”

Natural substances can have powerful pharmacological effects.

Can Cannabis Interact With Cancer Treatment?

Yes, potentially.

This is one of the most important reasons to tell your oncologist if you use cannabis or cannabinoid products.

Cannabinoids can affect liver enzymes involved in drug metabolism.

This creates a theoretical and sometimes clinically relevant possibility of altering the concentration of other medications.

The concern becomes particularly important when patients use highly concentrated CBD or THC oils.

The NCI specifically warns that concentrated CBD products may inhibit certain cytochrome P450 enzymes and could potentially alter the toxicity or effectiveness of drugs metabolized through these pathways.

Patients receiving:

chemotherapy
targeted therapy
immunotherapy
hormonal therapy
anticoagulants
sedatives
seizure medications
other medications metabolized through these pathways

should discuss cannabinoid use with their healthcare team.

Cannabis and Immunotherapy: A Special Concern

Immunotherapy adds another layer of uncertainty.

The immune system is one of the major biological systems affected by cannabinoids.

That creates an important research question:

Could cannabinoids alter the effectiveness of immune checkpoint inhibitors?

At present, the evidence is not strong enough to give patients a simple yes-or-no answer.

The MASCC cancer-pain guideline specifically highlighted the need to consider potential harms and adverse events, particularly in patients receiving checkpoint inhibitors.

This does not prove that cannabis makes immunotherapy ineffective.

It means that the interaction deserves careful consideration rather than being dismissed.

Patients receiving drugs such as pembrolizumab, nivolumab, ipilimumab or other checkpoint inhibitors should discuss cannabinoid use with their oncology team before beginning a concentrated product.

Smoking Cannabis Is Different From Using a Cannabinoid Medication

Another important distinction is route of administration.

Cannabinoids can be:

inhaled
eaten
taken as oils or tinctures
administered as capsules
delivered as pharmaceutical preparations
administered through oral sprays

Smoking cannabis introduces combustion products into the lungs.

That is different from using a standardized oral pharmaceutical.

For cancer patients—particularly those with lung disease or lung cancer—the method of administration deserves careful consideration.

What Does the Research Say?

Here is how I would summarize the current evidence.

Potential Use	Evidence	PBC Evidence Rating
Cancer treatment	Preclinical research is promising, but human evidence is insufficient	Low
Chemotherapy-induced nausea/vomiting	Evidence of benefit, particularly refractory CINV	Moderate
Cancer pain	Inconsistent clinical evidence	Low
CIPN/neuropathic pain	Interesting preliminary evidence; insufficient clinical proof	Low
Appetite/cachexia	Mixed/negative clinical evidence	Low
Sleep	Limited cancer-specific evidence	Low
Anxiety	Limited and inconsistent cancer-specific evidence	Low
Myeloma treatment	Promising laboratory research; insufficient human evidence	Preclinical

How to interpret this table

High-quality evidence: Multiple well-designed human clinical trials consistently demonstrate benefit.
Moderate-quality evidence: Human clinical evidence suggests benefit, but important limitations remain.
Low-quality evidence: Preliminary human studies, observational studies or inconsistent clinical findings.
Preclinical evidence: Laboratory or animal research that has not yet demonstrated meaningful clinical benefit in humans.

This distinction is especially important with cannabis.

A large number of laboratory studies does not automatically mean there is strong clinical evidence.

Why Patients Are Still Interested in Cannabis

If the evidence is limited, why are so many cancer patients using cannabis?

Because patients are experiencing real problems.

They are dealing with:

chemotherapy-induced nausea
neuropathic pain
cancer pain
insomnia
anxiety
appetite loss
treatment-related stress
chronic symptoms that conventional medicine does not always control adequately

The NCI reports that cannabis use is common among people with cancer. In a multicenter survey of more than 13,000 patients treated at NCI-designated cancer centers, about one-third reported cannabis use since their cancer diagnosis. Many users reported perceived benefits involving pain, sleep, nausea and appetite.

But the same research also illustrates a major problem:

Patients are using cannabis faster than the medical research is catching up.

Only a minority of patients in that survey reported discussing cannabis with their oncology providers.

That communication gap is not helpful to patients.

What Should Cancer Patients Ask Their Oncologist?

If you are considering cannabis or a cannabinoid product, consider asking:

Could this interact with any of my cancer medications?
Could this interact with my other medications?
Is THC, CBD or a combination more appropriate for my specific goal?
Could it worsen sedation, dizziness or cognitive problems?
Is there evidence for this particular symptom?
Should I use it in addition to—not instead of—my conventional treatment?
Would a standardized pharmaceutical cannabinoid be safer or more predictable than a commercial cannabis product?

Those questions turn cannabis from a controversial subject into what it should be:

A medical decision that deserves evidence and informed discussion.

Cannabis Is Not a “Cure”

Cancer patients are frequently exposed to claims that CBD oil, cannabis oil or concentrated THC products can “kill cancer.”

The laboratory research explains why those claims are attractive.

But laboratory evidence is not clinical evidence.

As of the current evidence base, cannabis and cannabinoids have not been established as a cure for cancer.

The FDA has not approved cannabis itself as a cancer treatment, and ASCO recommends against using cannabis or cannabinoids as cancer-directed treatment outside a clinical trial.

That does not mean cancer patients should ignore cannabinoid research.

It means we should ask a better question:

Where does the evidence actually support their use?

Right now, the strongest clinical case is for certain cannabinoid medications and formulations in the management of selected cancer-treatment symptoms—particularly refractory chemotherapy-induced nausea and vomiting.

The evidence for cannabinoids as direct anticancer agents remains an important area for future research.

The Bottom Line

Cannabinoids and cannabis are promising—but they are not proven cancer cures.

The research falls into three broad categories.

1. Symptom management

There is meaningful evidence that certain cannabinoid medications can help with chemotherapy-induced nausea and vomiting, particularly when standard antiemetic therapy has not been sufficient.

2. Supportive care

Research into cancer pain, neuropathy, appetite, sleep and anxiety is ongoing, but the evidence is generally limited or inconsistent.

3. Direct anticancer effects

Laboratory and animal research is intriguing, including research involving breast cancer, glioblastoma, lung cancer and multiple myeloma.

But these findings have not yet established cannabis or cannabinoids as effective cancer treatments in humans.

For me, this is exactly where an evidence-based complementary and integrative oncology approach belongs.

Patients should be allowed to investigate promising therapies without confusing promising research with proven treatment.

Cannabis and cannabinoids deserve continued cancer research.

They also deserve honest patient education about what we know—and what we don’t know yet.

PeopleBeatingCancer’s position is simple: investigate the science, understand the risks, don’t abandon proven cancer treatment, and talk openly with your oncology team about every complementary therapy you use.

Research Links

National Cancer Institute — Cannabis and Cannabinoids (PDQ), Health Professional Version
https://www.cancer.gov/about-cancer/treatment/cam/hp/cannabis-pdq
ASCO Guideline — Cannabis and Cannabinoids in Adults With Cancer
https://pubmed.ncbi.nlm.nih.gov/38478773/
Cannabinoids for Chemotherapy-Induced Nausea and Vomiting — Systematic Review
https://pubmed.ncbi.nlm.nih.gov/40797063/
MASCC Guideline — Cannabis for Cancer-Related Pain
https://pubmed.ncbi.nlm.nih.gov/36872397/
Cannabinoid Interventions for Cancer Cachexia — Systematic Review and Meta-analysis
https://pubmed.ncbi.nlm.nih.gov/34881518/
Medicinal Cannabis for Appetite-Related Symptoms in Cancer — Systematic Review
https://pubmed.ncbi.nlm.nih.gov/35360989/
Cannabinoids as Myeloma Therapy — PeopleBeatingCancer
https://peoplebeatingcancer.org/cannabinoids-as-myeloma-therapy/

For more information about Cannabinoids

I would make these contextual rather than simply placing them in a generic “related posts” section:

Our Mission