Topical THC and CBD balms were well tolerated for joint pain in breast cancer survivors on aromatase inhibitors | Research

The takeaway

A randomized trial of 21 breast cancer survivors found topical cannabis balms well tolerated for aromatase inhibitor-related joint pain, with 86% reporting improvement and THC balm showing a higher rate of substantial improvement (50% vs 18%) than CBD balm.

Breast cancer survivors on aromatase inhibitors, oncologists, pain management clinicians

86% of participants reported improvement; THC balm: 50% vs CBD: 18% with >50% improvement

What the researchers found

86% of participants reported improvement in hand-related symptoms from baseline to week 2. A higher percentage of THC balm users reported over 50% improvement compared to CBD balm users (50% vs 18%). Compliance was high, with 71% continuing an additional 2 weeks. Minor skin irritation occurred in 24%, and only one discontinuation was for cosmetic reasons ("greasy" texture). Nearly half of participants had never used cannabis before.

Why it matters

Nearly two-thirds of women on aromatase inhibitors experience joint pain and stiffness, leading many to stop a life-saving cancer medication. If topical cannabis can reduce these side effects, it could improve adherence to breast cancer treatment.

The numbers in context

21 women; mean age 54; 86% White; 48% no prior cannabis use; 43% received adjuvant chemo; 86% reported improvement; THC >50% improvement: 50% vs CBD 18%; 71% continued extension; 86% survey completion; 24% minor skin irritation; 1 discontinuation

How the study worked

Randomized open-label trial comparing topical CBD versus THC balms applied three times daily to hands for 2 weeks, with 2-week extension using balm of choice. 21 women with stage 1-3 breast cancer experiencing aromatase inhibitor-associated musculoskeletal syndrome (AIMSS). Used state-approved cannabis dispensaries.

What this study cannot tell us

Small sample (21 women). Open-label, no placebo control. 2-week primary period is short. Cannot determine if improvements are due to cannabis or placebo/natural fluctuation. Topical THC absorption and potential systemic effects were not measured.

How to read the evidence

Preliminary: small randomized trial without placebo control or blinding. Primarily a feasibility study with encouraging signals.

When this study was published

2026 publication from a randomized trial using state-approved cannabis dispensaries.

The bigger picture

Topical cannabis avoids the systemic effects and stigma concerns that may limit oral cannabis use in cancer patients. This approach targets local inflammation directly, which is particularly relevant for a condition that causes patients to stop beneficial cancer treatment.

Questions still open

Would a placebo-controlled trial confirm the THC balm advantage? Do topical cannabinoids produce detectable systemic levels? Could topical cannabis be used for joint pain from other causes? Would longer-term use maintain benefits?

Common questions

Can topical cannabis help with joint pain from breast cancer treatment?

This small trial found that 86% of breast cancer survivors reported improvement in hand pain and stiffness after 2 weeks of topical cannabis balm. THC balm appeared more effective than CBD balm, but a placebo-controlled trial is needed.

Is topical cannabis safe for cancer patients?

In this trial, both THC and CBD balms were well tolerated. Minor skin irritation occurred in 24% of users. No serious adverse events were reported, and nearly half of participants had never used cannabis before.

Read the original research

A Randomized, Open-Label Trial to Assess Feasibility and Tolerability of Topical Cannabis Balms for the Treatment of Aromatase Inhibitor-Associated Musculoskeletal Syndrome (AIMSS).

Cannabis and cannabinoid research, 11(1), 30-35

View on PubMed ↗Publisher’s paper ↗

Citation

Zylla, Dylan; Idossa, Dame; Borrero, Maria; Napurski, Char; Dahmer, Stephen; Cowger, Jordan; Gilmore, Grace; Luo, Xianghua; Birnbaum, Angela; Blaes, Anne H. (2026). A Randomized, Open-Label Trial to Assess Feasibility and Tolerability of Topical Cannabis Balms for the Treatment of Aromatase Inhibitor-Associated Musculoskeletal Syndrome (AIMSS).. Cannabis and cannabinoid research, 11(1), 30-35. https://doi.org/10.1177/25785125251398286