Efficacy of immunotherapy in obese patients with cancer

Obesity is a condition of excessive fat tissue and high body mass index (BMI ≥30), which is increasing worldwide. Excess body weight is associated with poorer results in cancer treatments; however, recent studies emphasized that elevated BMI was associated with improved outcomes in cases treated by immune checkpoint inhibitor (ICI) therapies, which is called the obesity paradox. In this review, we discuss the correlation between obesity and cancer immunotherapy, especially ICIs, the underlying mechanisms, and the outcomes in different types of cancers. In addition, we describe the occurrence of immune-related adverse events and the effect of gender in obese patients during immunotherapy using all relevant studies with available full texts.