Herbal supplements for breast cancer “do more harm than good,” says expert

14 Nov 2019 --- Complementary breast cancer therapies – including garlic, ginger, gingko and turmeric supplements – are likely to cause more harm than good when used to treat skin lesions. This is according to Professor Maria João Cardoso, Head Breast Surgeon at the Champalimaud Cancer Centre and a teacher at the Nova Medical School in Lisbon, Portugal, who spoke at the Advanced Breast Cancer Fifth International Consensus Conference today. She is now calling for major investments in information and education for patients.

“The issue is mainly the consumption of complementary therapies. The doses we normally use in the diet are not a problem. It’s the use of higher dosing – as with supplementation – that can be problematic. However, for some products like grapefruit juice, tangerine, lime and red oranges, it can be an issue even with small doses. Ointments and creams may be a problem as well, but we have little evidence for either their harms or benefits,” Cardoso tells NutritionInsight.

Many herbal products and creams delay wound healing and interfere with systemic anti-cancer treatments, such as hormone therapy or chemotherapy, according to Cardoso. Examples that adversely affect clotting include green chiretta, feverfew, garlic, ginger, gingko, ginseng, hawthorn, horse chestnut and turmeric. Cardoso stresses that the number of herbal products available is huge and there is no available evidence for their efficacy.

She explains that many compounds are complex and some ingredients can delay healing and interfere with the efficacy of ongoing systemic treatments. Laboratory studies have shown that certain products can reduce the blood clotting process required for a wound to heal. If a patient has a bleeding wound, these compounds can have a strong, adverse impact on scarring and how well wound dressings work.

“Herbal products can interfere in the pharmacodynamics (PD) and pharmacokinetics of any drug. PD means competing with the desired effect of a drug (like soy and tamoxifen) or interfering with absorption in the gut, metabolism in the liver and excretion. Almost all drugs and herbs use the same enzymes in our body – the cytochromes P450 (CYP) complex. They can compete with each other, resulting in a reduced effect or attaining higher concentration, thus becoming more toxic,” she explains.

Cardoso proposes that education could take place through general, simple messages disseminated through media, as well as well-written leaflets and educational sessions. “Action in policy would also help, although different regulations in different countries make it more difficult. Currently, people are getting their information from social networks and word of mouth. In the vast majority of cases, it is not trustworthy.” 

A source of physical and emotional discomfort
Excluding skin cancer, around 5 percent of solid tumors can metastasize to the skin. Breast cancer is the most likely variety to do so, occurring in as many as 20 percent of cases. In addition, locally advanced, inoperable breast cancer and recurring cancer in the same area can result in clusters of cancer cells in the skin.

Cardoso emphasizes that there are some complementary therapies, including yoga, which can have a positive impact on patients’ quality of life.Skin lesions can cause discomfort and distress and are difficult to treat successfully. Topical treatments that can be applied directly to the lesion have become more popular, although they are successful in healing or controlling the wound in no more than 50 percent of cases, according to Cardoso. 

She explains that “the curse of the visible and disfiguring lesions, the pain, the smell and all the psychological impact on the patients and their loved ones must not be underestimated. In these circumstances, it’s not surprising that patients and their carers search for complementary or alternative treatments that might make a difference.”

However, Cardoso emphasizes that there are some complementary therapies that can have a positive impact on patients’ quality of life. These are therapies that aim to alleviate the psychological distress caused by having skin metastases and have no contra-indications, such as mindfulness to reduce stress, acupuncture, reiki and yoga.

Martin Ledwick, Cancer Research UK’s Head Information Nurse, notes that alternative therapies can be dangerous in various ways. These include interfering with any treatment someone is undergoing, reducing its effectiveness or causing patients harm, or people could choosing them instead of conventional medicine.

“They can also cost a lot of money, leaving patients and their families in a difficult position financially. There’s no strong evidence that herbal remedies can treat, prevent or cure any type of cancer, and we don’t advise patients to use alternative therapies that haven’t been approved by their cancer specialist doctor,” he adds. 

Earlier this year, a study found that the microalgae compound fucoidan may tackle cancer cells. The findings showed that fucoidan could limit cancer cells in their ability to make proteins, utilize energy and repair damage to themselves. 

Meanwhile, according to research from last week, vitamin D contributed to slowing the growth of melanoma cells and stopped their spread to the lungs of mice. 

Further studies have underlined the importance of a healthy lifestyle, with scientists finding that red meat consumption may increase the risk of breast cancer, whereas poultry consumption may diminish breast cancer risk. Additionally, obese women are at a higher likelihood of developing triple-negative breast cancer – an aggressive type of breast cancer that is particularly difficult to treat. 

By Katherine Durrell