Probiotics in cancer care

Dr Linda Rogers explains what probiotics are, their benefits, and how they can support the body during chemotherapy.

What are probiotics?

Probiotics are live, healthy bacteria and yeasts which support the naturally occurring bacteria (microbiome) in the body. They are found in fermented foods like yoghurt and kimchi, as well as in supplements, and can be taken to help keep your immune system and digestive tract healthy, and to prevent infection with harmful organisms. Important well-known strains are Lactobacillus and Bifidobacterium.

When the microbiome is disrupted by illness, infection (gastroenteritis), or antibiotics, this can lead to unpleasant symptoms like diarrhoea or thrush, and in the long term can predispose you to other illnesses. 

It has been shown that women who have overgrowth of Gardnerella vaginalis in the vagina, leading to the condition known as bacterial vaginosis, have disruption of their normal vaginal lactobacilli, and this contributes to an increased risk of cervical cancer.

What is the difference between probiotics and prebiotics?

Prebiotics are non-digestible plant fibres that can feed and stimulate the growth of good bacteria (probiotics) in the gut microbiome. They are found in foods, such as garlic, onions, bananas, and oats, and can be used to improve digestive health and boost immunity. They may also help in the management of inflammatory conditions and obesity. 

Using probiotics during chemotherapy

Probiotics can be useful to manage the side effects of chemotherapy, particularly diarrhoea, abdominal pain, nausea, and vomiting, with studies showing a benefit in 85% of cases. They help restore gut microbiota which have been disrupted by treatment and can enhance immune function and quality of life. 

Probiotics can also decrease the severity  of inflammation or mucositis of the mouth and digestive tract. Some studies suggest that patients with lung and colorectal cancers have better quality of life when they use probiotics. 

Dr Nazia Fakie, an oncologist at Groote Schuur Hospital, advises that it’s vital that they are used under medical supervision.  She warns that patients who are severely immunocompromised, have a central venous catheter (port), or are critically ill should avoid certain probiotics. The risks and benefits of their use should be discussed with your oncologist. 

Certain probiotics like S. boulardii should be avoided if you’re receiving chemotherapy, while other strains like Lactobacillus rhamnosus GG may be safer and more beneficial.

Cisplatin

Cisplatin is a powerful chemotherapy drug, used particularly in gynaecological cancers and as a radiation-sensitiser (to make radiotherapy more effective). 

When used concurrently with radiotherapy, it has been shown to increase tumour responses and   prolong survival in advanced cervical and endometrial cancer. However, its use can be limited by the damage it causes   to patients’ kidneys, nerves, and hearing. This damage is caused by different processes, such as the inflammatory response, DNA damage, and oxidative stress. 

Studies suggest that this damage can be lessened by using probiotics, with their antioxidant and anti-inflammatory properties. Lactobacillus rhamnosus has shown promise in reducing the nephrotoxicity caused by cisplatin. It’s important to note, though, that there have been no randomised controlled trials to prove that probiotics are of benefit in this setting.

Medical supervision is a must    

Healthcare workers, such as nutritionists, dietitians, and doctors, advise taking probiotics (or prebiotics) due to their ability to prevent and treat diseases. It seems that they may be of benefit in reducing the side effects of chemotherapy too. Though, in this setting, medical supervision and individualisation of treatment are vital to avoid unwanted complications.

Dr Linda Rogers, a gynaecological oncologist, has worked as a senior specialist in the Department of Obstetrics and Gynaecology at the University of Cape Town (UCT) and Groote Schuur Hospital (GSH) since 2009. She is assistant editor of the South African Journal of Gynaecological Oncology (SAJGO) and is a member of the South African HPV Board.                                                                                                                                          

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