I have found this study to be one of the most interesting ones in 2023. It is a study from Yale as well as Dana-Faber/Harvard Cancer Center looking at the impact of exercise in nutrition on women undergoing adjuvant (after surgery) or neoadjuvant (before surgery) chemotherapy in women with a diagnosis of breast cancer. This LEANer study is a randomised controlled trial at the chemotherapy completion rates (RDI) as well as pathological complete rates (pCR) in those women who had neoadjuvant chemotherapy.

RDI is a measure of chemotherapy completion and is calculated as the ratio of the amount of chemotherapy delivered versus the amount initially prescribed. A lower RDI (<85%) is associated with worse chemotherapy effectiveness and prognosis. it is known that low RDI (<85%) is observed in a significant percentage of women receiving conventional and dose-dense chemotherapy regimens, primarily due to treatment side effects. It is estimated that 26% of women receiving conventional chemotherapy and 32% of women receiving dose-dense chemotherapy experience low RDI. The side effects of chemotherapy, such as fatigue, nausea, vomiting, and decreased appetite, can make it challenging for patients to maintain a healthy diet and engage in physical activity.

Women were included in this trial who were newly diagnosed with stage I-III breast cancer, undergoing chemotherapy, and willing to be randomly assigned to an intervention group or usual treatment care group. The intervention group received individualised counselling sessions focusing on adopting a healthy diet and meeting physical activity guidelines. The healthy diet was predominantly a plant-based diet. The counselling sessions were delivered by registered dietitians who were certified specialists in oncology nutrition. The intervention group received counselling sessions throughout the duration of chemotherapy, with the number of sessions varying based on the duration of chemotherapy.

173 women took part in this study. The results of the study showed that women in the intervention group were able to make significant improvements in exercise and diet quality during chemotherapy compared to the usual care group. The intervention group reported increased physical activity and improvements in fruit and vegetable intake and dietary fibre intake. However, there was no significant difference in RDI between the intervention group and the usual care group. There were only 72 women in the neoadjuvant chemotherapy setting. The study also found that women in the intervention group who received neoadjuvant chemotherapy had higher rates of pathologic complete response compared to the usual care group (53% vs 28%). These may be related to the impact of diet and exercise on immune and inflammatory pathways as well as the alteration of gene expression in breast cancers.

In conclusion, the LEANer study demonstrated that a home-based exercise and nutrition intervention led to improvements in exercise and diet quality among women with breast cancer undergoing chemotherapy. While the intervention did not significantly impact RDI, it showed promising results in terms of pathologic complete response rates. Further research is needed to explore the effects of exercise, nutrition, and body composition on RDI and other treatment-related outcomes in breast cancer patients.