During cancer treatment, adequate nutrition and exercise are key components during cancer care to promote weight maintenance, retain physical function, decrease side effects of treatment, and negate or improve the signs and symptoms of malnutrition.¹ With the use of a multidisciplinary team to aid in the treatment and recovery of cancer, healthy lifestyle factors including nutrition and exercise are encouraged. Diet, exercise, and healthy weight management during cancer treatment may result in improved quality of life, treatment toxicity, and cancer control. However, weight change recommendations vary widely by provider, cancer type, and stage of treatment.

Ligibel et al. aimed to provide evidence-based recommendations for oncology clinicians to use in practice for patients during cancer treatment via three guideline questions: (1) Does exercise during cancer treatment safely improve outcomes related to quality of life (QoL), treatment toxicity, or cancer control? (2) Does consuming a particular dietary pattern or food(s) during cancer treatment safely improve outcomes related to QoL, treatment toxicity, or cancer control? (3) Do interventions to promote intentional weight loss or avoidance of weight gain during cancer treatment safely improve outcomes related to QoL, treatment toxicity, or cancer control?

A panel of oncology physicians, dietitians, and researchers reviewed the current literature and provided recommendations. This review combined over 20 years of oncology research regarding exercise, diet, and weight loss during cancer treatment. Unfortunately, some questions remain unanswered and further research is needed. Limitations of the review included that population characteristics were widely varied. A variety of cancer stages were included. Some individual studies included only certain malignancies.

Exercise guidelines were extracted from a robust literature base. Specifically:

1. Oncology providers should recommend aerobic and resistance exercise during active treatment with curative intent to mitigate side effects of cancer treatment.
2. Oncology providers may recommend preoperative exercise for patients undergoing surgery for lung cancer to reduce length of hospital stay and postoperative complications.

These recommendations provide insight on the positive effects of cardiovascular exercise during cancer treatment. Exercise has a myriad of benefits before, during, and after cancer treatment. In most cases it is both safe and beneficial for patients to exercises, even during active treatment.

There is insufficient evidence regarding the use of many popular dietary interventions during cancer treatment, including fasting, low-fat, and ketogenic diet plans. A lack of randomized trials and reviews (9 reviews, 8 randomized control trial (RCT)) with outcomes that provided data on QoL, treatment toxicity, or cancer control limited conclusions regarding specific diets. Instead, we recommend including oncology dietitians as key members of multidisciplinary care teams to provide individualized recommendations for patients before, during, and after cancer treatment.

The neutropenic diet is a popular intervention to limit infection during cancer treatment, often consisting of limitations in fresh fruit and vegetable consumption, and avoidance of rare or uncooked egg and meat products. The summation of the RCTs reviewed uncovered higher infection rates with use of a neutropenic diet compared to a general healthy diet! This is potentially due the fact that neutropenic diets often restrict fresh produce, leading to the lack of important micronutrients found in fruits and vegetables.

The literature regarding the effects of weight loss during cancer treatment was also limited. Like the evidence for most dietary interventions, weight change also used reviews and RCTs that didn’t focus on cancer outcomes and instead analyzed the quantity of weight change. Due to this, the panel was unable to provide a recommendation for or against weight changes during treatment. To date, while we are unable to make strong recommendations, it appears that weight loss may be harmful in particular malignancies such as lung cancer, and head and neck cancer, while modest weight loss may be beneficial for patients who have colorectal, breast or prostate cancer. Oncology providers should continue to encourage weight maintenance during treatment and refer to the clinical dietitian for specific guidelines. Dietitians use clinical judgement on a patient-to-patient basis based on the available data and patient-specific characteristics.

As this review had mentioned, there is a critical need for additional research regarding many dietary interventions and weight change during cancer treatment. Specifically, more research is needed that analyzes cancer specific outcomes such as tumor response and survival in relation to dietary and weight changes. The inclusion of additional malignancies outside the most common (breast, prostate, colorectal, lung), patients receiving immunotherapy, and patients with metastases is needed to generalize results to a greater number of patients. Including nutrition as an aspect of cancer trials is vital to solidify recommendations and avoid complications.

Even if this review was not able to provide the desired recommendations that some oncology providers would hope for, the expert panel was able to include some valuable information regarding the benefits of exercise and debunking the use of neutropenic diets during cancer treatment, exercise recommendations, and highlight areas of needed research for the future of oncology treatment.

References

1. Ligibel Lifestyle Factors in Cancer Survivorship. J Clin Oncol. 2012;30(30):3697-3704. DOI: 10.1200/JCO.2012.42.0638.