Mediterranean diet associated with better response to immunotherapy in patients with advanced melanoma

These findings were brought to light by a study led by researchers at the UMCG (Laura Bolte, Johannes Björk, Geke Hospers, Rinse Weersma) in collaboration with Kings College London (Karla Lee, Veronique Bataille, Tim Spector). The results of their study were published today in the scientific journal JAMA Oncology.

The use of immunotherapy with checkpoint inhibitors is one of the latest and most successful therapeutics for treating severe forms of cancer. Checkpoint inhibition therapy functions to boost the immune system, enhancing the recognition, clearance and destruction of cancer cells. However, some patients do not respond to immunotherapy. Interestingly, new evidence points to the influence of diet as a player in the effectiveness of immunotherapy. 

Diet of 91 patients with melanoma

In the present study, the researchers assessed the diet of 91 patients with advanced melanoma. All patients were treated using checkpoint inhibitors. Checkpoint inhibitors trigger immune activity to become heightened, enabling immune cells (T cells) to recognise and attack cancer cells. Throughout the study, CT scans were used to measure and determine the effectiveness of the medication. The effect of medication on patients was followed over a period of 12 months. Additionally, the researchers also looked at the progression-free survival of the treated group of patients after one year. 

Better efficacy of immunotherapy

Their study showed that a Mediterranean diet was significantly associated with a better response to immune checkpoint inhibitors. A Mediterranean diet contains unsaturated fats from olive oil, nuts and fish and antioxidants, polyphenols and fibre from vegetables, fruits and whole grains. The researchers also found that patients that consumed a Mediterranean diet had a better survival rate after 12 months. 

Importance of diet

According to researchers Laura Bolte, Geke Hospers and Rinse Weersma of the UMCG, the current study highlighted the potential importance of diet in cancer patients starting immunotherapy: “Immunotherapy has contributed to a kind of revolution in the treatment of different types of advanced cancer. This study suggests that a patient's diet plays a role in improving treatment outcomes and patient survival.” In earlier work, the research group demonstrated that the composition of the gut flora could also affect the efficacy of immunotherapy treatment. In light of this, the researchers aim to conduct more in-depth studies on whether diet impacts clinical response directly or if diet influences treatment response indirectly by altering the gut microbiome, which might behave as a mediator.

Also in other cancers?

The study's findings suggest that diet may play an essential role in the success of immunotherapy. Therefore, in the subsequent phases of the study, the researchers aim to determine whether the impact of diet is also applicable to patients with other forms of cancer. According to Laura Bolte, the connection between immunotherapy response, diet and gut bacteria is promising to improve treatment outcomes. Bolte: “Clinical intervention studies investigating the effect of a high-fibre diet, a ketogenic, low-carbohydrate diet and additional administration of omega-3 are ongoing. As treatment with checkpoint inhibitors is extended to several tumour types, including gastrointestinal cancers, these studies could provide treatment benefits for a large group of cancer patients in the future.” 

Read the publication in JAMA Oncology here.