Can Cannabidiol (CBD) be used to treat carcinoma?

CBD for Carcinoma Treatment: Not Recommended as an Anticancer Therapy

Based on the most recent evidence from the American Society of Clinical Oncology (ASCO), CBD should not be recommended as a treatment for carcinoma due to lack of evidence-based data supporting its use as an anticancer treatment. 1

Current Evidence on CBD for Cancer Treatment

Lack of Evidence for Direct Anticancer Effects

• ASCO's 2024 guidelines explicitly state that clinicians should advise patients about the lack of evidence-based data supporting the use of cannabinoids and/or cannabis as anticancer treatments 1
• Despite some promising preclinical studies showing potential antitumor properties of CBD in laboratory settings 2, there is insufficient clinical evidence to recommend CBD for treating carcinoma in humans

Potential Risks with Immunotherapy

• Observational data shows poor clinical outcomes in adults receiving immunotherapy while using cannabis/cannabinoids 1
• CBD may interfere with immunotherapy effectiveness through:
  • Suppression of T-cell antitumor immunity
  • Inhibition of JAK/STAT signaling through cannabinoid receptor type 2 1
  • Possible interference with humoral immunity

Appropriate Uses of CBD in Cancer Care

While not recommended as a cancer treatment, CBD may have limited roles in supportive care:

For Chemotherapy-Induced Nausea and Vomiting

• CBD may be considered (typically in a 1:1 THC:CBD extract) for refractory nausea and vomiting from chemotherapy when standard antiemetics fail 1
• This is a weak recommendation with low evidence quality for THC:CBD extracts

Dosing Considerations

• Doses ≥300 mg/day of oral CBD are not recommended due to risk of reversible liver enzyme abnormalities 1, 3
• Lower doses may be safer but have limited evidence for efficacy

Case Reports vs. Clinical Evidence

Despite isolated case reports showing potential benefits:

• A case report of lung cancer regression with self-administered CBD oil exists 4, but single cases cannot establish efficacy
• Laboratory studies show CBD may inhibit cancer cell proliferation in various models including colon cancer 5 and cholangiocarcinoma 6
• These preclinical findings have not translated to proven clinical benefits in human trials

Practical Approach for Clinicians

1. Communicate openly with patients about cannabis/CBD use
2. Educate patients that:
   • No evidence supports CBD as a cancer treatment
   • Using CBD as cancer treatment may delay proven effective therapies
   • CBD may negatively impact immunotherapy effectiveness
3. Consider CBD only for symptom management in specific situations:
   • For refractory chemotherapy-induced nausea/vomiting
   • At doses below 300 mg/day to avoid liver enzyme abnormalities
4. Monitor patients who choose to use CBD for:
   • Potential drug interactions
   • Adverse effects including sedation, dizziness, confusion
   • Liver function abnormalities, especially at higher doses

Conclusion

While CBD shows some promise in laboratory studies and has generated interest for cancer treatment, current clinical evidence does not support its use for treating carcinoma. Patients should be advised to pursue established, evidence-based cancer treatments, with CBD potentially considered only as an adjunct for specific symptom management under medical supervision.