Very little is known about how cannabis is absorbed and metabolized in cancer patients

A systematic review of medicinal cannabis pharmacology in oncology found only 18 relevant studies and virtually no data on absorption in cancer populations, revealing a critical gap in dosing knowledge.

RTHC-01961Systematic ReviewPreliminary Evidence2019RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Systematic Review
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

Of 18 selected articles (10 RCTs, 2 experimental, 2 retrospective cohort, 4 case studies), only 4 reported absorption data and only 1 drug interaction study was identified. There is almost no evidence on the pharmacokinetics of medicinal cannabis specifically in cancer patients.

Key Numbers

18 articles selected: 10 RCTs, 2 experimental, 2 retrospective cohort, 4 case studies. Only 4 reported absorption data. Only 1 drug interaction study found.

How They Did This

Systematic literature review across six databases for studies reporting pharmacological data on medicinal cannabis in oncology.

Why This Research Matters

Without absorption data, cannabis dosing in cancer patients is essentially guesswork. Cancer patients may metabolize cannabinoids differently due to their disease, other medications, and compromised organ function, making this gap particularly dangerous.

The Bigger Picture

Cannabis is increasingly used by cancer patients, but the pharmaceutical basics, how much gets absorbed, how it interacts with chemotherapy, and how disease state affects metabolism, are almost entirely unknown. This is remarkable for a substance used by millions of patients.

What This Study Doesn't Tell Us

Systematic review can only identify what has been studied. The lack of pharmacokinetic data may partly reflect the difficulty of conducting such studies in cancer populations and the challenges of cannabinoid analytical methods.

Questions This Raises

  • ?How do cancer-related changes in liver and GI function affect cannabis absorption?
  • ?What are the drug interactions between cannabinoids and common chemotherapy regimens?
  • ?Should dosing be adjusted based on cancer type or treatment?

Trust & Context

Key Stat:
Only 4 studies had absorption data
Evidence Grade:
Rated preliminary because the review reveals a near-total absence of pharmacokinetic evidence rather than providing positive findings.
Study Age:
Published in 2019. Some additional pharmacokinetic research may have been conducted since.
Original Title:
Pharmacological evidence of medicinal cannabis in oncology: a systematic review.
Published In:
Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 27(9), 3195-3207 (2019)
Database ID:
RTHC-01961

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Analyzes all available research on a topic using a structured method.

What do these levels mean? →

Frequently Asked Questions

Do we know how cannabis works in cancer patients?

Barely. This review found almost no data on how cannabis is absorbed in cancer patients, meaning dosing recommendations lack a pharmacological foundation.

Why is this gap important?

Cancer patients often have altered metabolism from disease and treatment. Without knowing how cannabinoids are absorbed and processed in this population, effective and safe dosing cannot be determined.

Read More on RethinkTHC

Cite This Study

RTHC-01961·https://rethinkthc.com/research/RTHC-01961

APA

Brown, Danielle; Watson, Michael; Schloss, Janet. (2019). Pharmacological evidence of medicinal cannabis in oncology: a systematic review.. Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 27(9), 3195-3207. https://doi.org/10.1007/s00520-019-04774-5

MLA

Brown, Danielle, et al. "Pharmacological evidence of medicinal cannabis in oncology: a systematic review.." Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 2019. https://doi.org/10.1007/s00520-019-04774-5

RethinkTHC

RethinkTHC Research Database. "Pharmacological evidence of medicinal cannabis in oncology: ..." RTHC-01961. Retrieved from https://rethinkthc.com/research/brown-2019-pharmacological-evidence-of-medicinal

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.