A recent paper published in the journal Lancet Oncology provides evidence that obese individuals with locally advanced or metastatic clear cell renal cell carcinoma (ccRCC) achieved longer overall survival than patients of normal weight. The study investigated select groups of ccRCC patients and evaluated overall survival and genetic differences in the primary tumour and the fat surrounding the tumour.
The study included 256 patients from the phase III COMPARZ study, 93 patients from The Cancer Genome Atlas (TCGA), and 129 participants from Memorial Sloan Kettering Cancer Center (MSKCC). The results of the analysis showed a longer overall survival in patients with a body mass index (BMI) of >30 kg/m² who were enrolled in both the COMPARZ study and in the TCGA cohort than patients of normal weight (BMI of 18.5–24.9 kg/m²). In the MSKCC cohort, there was no significant relationship between BMI and survival.
The development of new blood vessels (angiogenesis) by the tumour was impacted by BMI, and was increased in people who were obese compared with patients who were normal weight. However, there were no differences in the infiltration of immune cells into the tumour between patients with obesity and patients of normal weight.
The study was hypothesis-generating, and therefore, the results cannot be used in clinical practice. However, the investigators provided advice for moving this research closer to the clinical setting.
“Future studies should focus on the usefulness of body size (such as through BMI) or body composition measures as factors that are prognostic, in combination with clinicopathological and tumour-specific features (such as mutational status), and they should explore mechanisms of fat–tumour cross-talk that can be used to help improve patient outcomes,” the study authors wrote.
In conclusion, certain factors in the tumour microenvironment vary based on BMI and may be indicative of a survival advantage for patients with obesity over patients of normal weight.