Association of cancer mortality with postdiagnosis overweight and obesity using body mass index

Abstract

Although overweight and obesity increase cancer risk, it is still controversial with respect to cancer mortality. In the current study, we enrolled 2670 patients of 14 tumor types from the Cancer Genome Atlas (TCGA) project, to identify the prognostic role of overweight and obesity in cancer patients. After dividing the patients into different groups by the body mass index (BMI), we found significant lower mortality in the obesity group. In addition, we also treat BMI value as a binary categorical variable or continuous variable, respectively. We found significant lower mortality in the higher BMI group. Furthermore, when focusing on each tumor type, cervical cancer and bladder cancer showed lower mortality in the patients with higher BMI values. Taken together, our results demonstrate that postdiagnosis obesity might indicate a better prognosis in cancer patients. However, these findings should be interpreted cautiously because of small sample size.

Keywords: body mass index; cancer; obesity; overweight; prognosis.

Figure 1. Overall survival of 2670 cancer patients stratified by different BMI groups

A. overweight versus normal weight; B. Grade 1 obesity versus normal weight; C. Grade 2 and Grade 3 obesity versus normal weight; D. underweight versus normal weight; E. high BMI value versus low BMI value, with the BMI cutoff determined by ROC curve; F. high BMI value versus low BMI value, with the BMI cutoff determined by median value.

Figure 2. Hazard ratios for all-cause mortality relative to normal weight in different BMI groups in each cancer type

A. overweight versus normal weight; B. Grade 1 obesity versus normal weight; C. Grade 2 and Grade 3 obesity versus normal weight; D. high BMI value versus low BMI value, with the BMI cutoff determined by ROC curve; E. high BMI value versus low BMI value, with the BMI cutoff determined by median value; F. high BMI value versus low BMI value, with BMI as a continuous variable. UVM, Uveal Melanoma; UCEC, Uterine Corpus Endometrial Carcinoma; UCS, Uterine Carcinosarcoma; THYM, Thymoma; SKCM, Skin Cutaneous Melanoma; READ, Rectum adenocarcinoma; DLBC, Lymphoid Neoplasm Diffuse Large B-cell Lymphoma; LIHC, Liver hepatocellular carcinoma; KIRP, Kidney renal papillary cell carcinoma; ESCA, Esophageal carcinoma; COAD, Colon adenocarcinoma; CHOL, Cholangiocarcinoma; CESC, Cervical squamous cell carcinoma and endocervical adenocarcinoma; BLCA, Bladder Urothelial Carcinoma.