Can Weight Changes Predict Renal Cancer Severity?

TOPLINE:

Patients with localized renal cell carcinoma (RCC) without obesity or with higher-stage, higher-grade tumours experience increased pre-diagnosis weight loss, ranging from 1.56 kg to 4.45 kg. Weight changes vary significantly by body mass index (BMI), with patients with normal weight and overweight showing notable pre-diagnosis losses that are partially regained after treatment.

METHODOLOGY:

• Researchers analysed 334 patients with localized RCC (median age, 62.3 years) from the prospective ReLife cohort between January 2018 and June 2021 in the Netherlands.
• Participants completed questionnaires 3 months, 1 year, and 2 years after diagnosis, providing data on body weight from 2 years prior to diagnosis to the end of follow-up.
• BMI categories were defined as underweight (≤ 18.5), normal weight (18.5-25), overweight (25 to ≤ 30), and obese (≥ 30), with 38.3% of patients classified as having overweight and 29.6% classified as having obesity at diagnosis.
• Researchers assessed weight at multiple timepoints and evaluated whether weight changes differed according to BMI at diagnosis, tumour stage, and tumour grade.

TAKEAWAY:

• Overall, patients experienced an average weight loss of 1.45 kg (95% CI, 0.84-2.06) 2 years prior to diagnosis but regained 0.78 kg (95% CI, 0.11-1.45) 2 years after diagnosis.
• Both patients with normal weight and those with overweight experienced significant weight loss before diagnosis; however, 2 years after diagnosis, a significant weight gain of 1.79 kg occurred in those with normal weight but not in those with overweight.
• Patients with stages II or III and grade 2-4 disease experienced pre-diagnosis weight loss ranging from 1.56 kg to 4.45 kg, with higher stages associated with greater weight loss.
• Among patients with normal weight or overweight, those with grade 3-4 disease experienced greater pre-diagnosis weight loss than those with grade 1-2 disease.
• By 2 years after diagnosis, significant weight gain was observed in patients with stage II-III and grade 3-4 disease.

IN PRACTICE:

“In conclusion, our study suggests that weight at the time of RCC diagnosis is not necessarily stable and for some patients is affected by pre-diagnosis weight loss. Pre-diagnosis weight loss was higher in non-obese individuals and in individuals with higher stage and grade tumours but was largely regained after treatment. This raises the possibility that the obesity paradox may be influenced by disease-related weight loss (ie, reverse causation),” the authors wrote.

SOURCE:

The study was led by Alina Vrieling, Radboud University Medical Center, Nijmegen, the Netherlands. It was published online on January 6, 2025, in Cancer Causes & Control.

LIMITATIONS:

The study’s relatively small sample size led to wide confidence intervals in subgroup analyses, particularly for patients with grade 4 disease. The use of self-reported body weight and height measurements may have introduced measurement error. Additionally, the pre-diagnosis weight data were collected retrospectively, whereas post-diagnosis weight data were collected prospectively, possibly affecting data accuracy. The researchers also noted uncertainty regarding the use of Fuhrman vs International Society of Urological Pathologists (ISUP) grading systems in tumour grade classification.

DISCLOSURES:

The Dutch Cancer Society provided funding for the ReLife study through grant KUN 2015-7948. Helena Furberg, PhD, received support through a National Cancer Institute grant and a Core grant to the Memorial Sloan Kettering Cancer Center. Linnea T. Olsson, PhD, received support through the T32 Cancer Health Disparities Training Grant from the National Cancer Institute. The authors reported no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.