Is it better for cancer patients to be fatter or thinner?

Author: Wu Yinfan, Intermediate Nutritionist at Fudan University Cancer Hospital

Reviewer: Ling Yiqun, deputy chief physician, Fudan University Cancer Hospital

Greedy tumor cells will frantically absorb nutrients in the human body. Some people want to eat less to "starve" the tumor, but the result is counterproductive, causing themselves to be malnourished and even further aggravating their condition...

Figure 1 Copyright image, no permission to reprint

Some people, in order to enhance their immunity to fight against tumors, eat chicken, fish, meat, and eggs like crazy, and gain a lot of weight in just a few months. However, the doctor tells them to lose weight quickly...

Figure 2 Copyright image, no permission to reprint

Is it better for cancer patients to be fatter or thinner? Scholars are still arguing about this question, and have even mentioned the concept of the "obesity paradox" [1].

Viewpoint 1: Cancer patients should be fatter

Since tumors can cause a series of problems in patients, such as increased consumption and insufficient intake, the vast majority of cancer patients will experience weight loss. As the disease progresses, it may also cause severe malnutrition or even cachexia, which will greatly reduce the survival rate of cancer patients.

Figure 3 Copyright image, no permission to reprint

On the contrary, if patients are given adequate energy and nutrition during cancer treatment, and their weight is maintained or increased appropriately, the efficacy and survival rate of patients may be improved. For example, a study published in JAMA Oncology, a top international oncology journal,[2] revealed that non-small cell lung cancer patients with a higher body mass index (BMI) (overweight or obese) are more sensitive to immunotherapy. In layman's terms, being a little fatter may improve the efficacy of treatment and reduce mortality to a certain extent.

Viewpoint 2: Cancer patients should not be too fat

Being overweight or obese means that there is too much fat accumulated in the body, which will not only aggravate the inflammatory response in the body, but also promote blood vessel proliferation (which helps tumor cells to absorb nutrients), increase insulin secretion (promote tumor cell proliferation), increase estrogen secretion (the "culprit" of breast cancer)... In addition, if the cancer patient is too fat, it will also limit the application of treatment methods such as surgery and chemotherapy, and increase the risk of postoperative complications and infection.

Figure 4 Copyright image, no permission to reprint

Taking breast cancer as an example, a large amount of research data [3-4] shows that the incidence of overnutrition in postmenopausal breast cancer patients exceeds 50%, which can cause adverse consequences such as physical damage, decreased quality of life, increased treatment-related adverse reactions and persistent psychological problems. Active weight loss in breast cancer patients will bring obvious health benefits.

Whether you are fat or thin, it is safest to maintain a healthy weight

From the perspective of a nutritionist, the question of "Is it better for cancer patients to be fatter or thinner?" should be analyzed specifically based on the specific problems of the cancer patients.

(1) If you have recently experienced a significant weight loss (e.g., weight loss >5% in one month), or if you have difficulty eating due to illness, treatment, or other issues, you should increase your nutritional intake through a variety of methods (e.g., oral nutritional supplements or tube feeding) to slow down the weight loss trend as much as possible, or even gain weight appropriately to avoid symptoms such as emaciation and sarcopenia.

(2) If you have recovered well after surgery or chemotherapy and the tumor development has been effectively suppressed, it is recommended not to over-supplement nutrition. Some overweight or obese cancer patients (especially breast cancer patients) are advised to lose weight by properly controlling their diet and increasing their exercise appropriately, thereby reducing the health hazards caused by obesity.

(3) For most cancer patients, maintaining an appropriate body weight, that is, 18.5 kg/m2＜BMI＜23.9 kg/m2, is most conducive to disease treatment and recovery. In addition, we should also pay more attention to changes in body composition, especially skeletal muscle mass, intracellular and extracellular water content, body fat percentage and other indicators, which can be professionally tested and consulted in the hospital's nutrition department.

References:

[1]Slawinski CGV, Barriuso J, Guo H, et al. Obesity and Cancer Treatment Outcomes: Interpreting the Complex Evidence. Clin Oncol, 2020, 32(9): 591-608.

[2]Kichenadasse G, Miners JO, Mangoni AA, et al. Association Between Body Mass Index and Overall Survival With Immune Checkpoint Inhibitor Therapy for Advanced Non-Small Cell Lung Cancer. JAMA Oncol, 2020, 6(4): 512-518.

[3]Strulov Shachar S, Williams G R. The Obesity Paradox in Cancer-Moving Beyond BMI. Cancer Epidemiol Biomarkers Prev, 2017, 26(1): 13-16.

[4]Reeves M, Winkler E, Mccarthy N, et al. The Living Well after Breast Cancer™ Pilot Trial: a weight loss intervention for women following treatment for breast cancer. Asia Pac J Clin Oncol, 2017, 13(3): 125-136.