founder investigates cannabis use to ease adverse treatment effects – Healio

November 19, 2020

3 min read


Disclosures: Weiss reports that the Survey was funded by Ananda Health. The funders did not have a role in the design of the study, collection of data, or the analysis and interpretation of data.

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Many patients with breast cancer use cannabis to help relieve treatment-related adverse effects, but there is a need for better data on its safety and efficacy and improved patient-physician dialogue, according to Marisa C. Weiss, MD.

“People who receive cancer treatment, especially people with breast cancer, end up going through a variety of treatments such as surgery, chemotherapy, targeted therapies and estrogen therapies, which can all go on for years,” Weiss, the founder and chief medical officer of and director of breast radiation oncology at Lankenau Medical Center in Wynnewood, Pa, told Healio.

Quote from Marisa C. Weiss, MDQuote from Marisa C. Weiss, MD

Weiss said that although these treatments are important in helping patients survive and manage their disease, each can have detrimental effects.

“The main focus of treatment is eradicating the cancer or limiting progression of disease to help patients live a long life with the best quality of life,” she said. “For patients to embrace the future fully, they need safe and effective solutions to help themselves get their lives back and live independently.”

According to Weiss, the most common adverse effects of breast cancer and its treatments for which patients use cannabis include pain, anxiety, insomnia, nausea and vomiting. Whereas nausea happens mostly during treatment, pain, anxiety and insomnia can continue for years after treatment.

Weiss has found that many patients prefer a “natural method” of treating these symptoms rather than leaning on more pharmaceuticals. They want to be able to use “something that feels more natural or holistic with fewer side effects and that they can manage on their own,” she said, which has led many patients to seek cannabis.

“A common symptom people struggle with is peripheral neuropathy after chemotherapy,” Weiss said. “In some patients, the pain and discomfort from this means they can’t even wear a regular shoe or stand on their feet for extended periods of time. Or, for those whose hands were affected, they cannot button a shirt or open a jar of peanut butter to make sandwiches for their kid’s lunch. The throbbing ‘pins and needles’ pain make each day a struggle and can also wake people up in the night.”

Weiss described the Coala-T-CBD study, an ongoing randomized controlled trial designed to test the efficacy of a medical-grade cannabidiol (CBD) gel cap in reducing the severity and duration of peripheral neuropathy in patients with breast, ovarian, uterine or colon cancer.

“This is the first study in the U.S. looking at using hemp CBD to treat this problem, but the idea for it came from listening to patients over the years speak about their struggles with this difficult, common side effect of the most commonly used chemotherapies,” she said.

Weiss also detailed results of a survey, conducted by, in which 42% of respondents with breast cancer reported using medical cannabis to manage their symptoms and treatment side effects. Of those, almost 80% used it during active treatment.

“Most people don’t report their cannabis use with their doctor,” Weiss said. “That raises concerns because both cannabis and many chemotherapies are metabolized by the p450 cytochrome system in the liver, and we don’t know if that’s safe or if it’s going to affect the efficacy of the chemotherapy.”

The survey also showed patients were disappointed with how little their physicians knew about medical cannabis. One obstacle to wider use is that cannabis is still illegal at the federal level, and although hemp-based products have been removed from Schedule 1 and are more regularly available, they are still not regulated. Additionally, the literature surrounding cannabis use for symptom relief is limited, and most studies are observational.

“ is focused on investigating the unmet needs of our audience so we can help them live full, active and long lives,” Weiss said. “The insights from our national survey study will equip patients with the information they need to better understand the safe and effective use of cannabis – and will promote the importance of shared decision-making with their doctors,”

For more information:

Marisa C. Weiss, MD, is a member of the Peer Perspective Board for Healio’s Women in Oncology. She can be reached at [email protected]


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