Excess adiposity and survival in patients with colorectal cancer: a systematic review
- 17 January 2014
- journal article
- review article
- Published by Wiley in Obesity Reviews
- Vol. 15 (5), 434-451
- https://doi.org/10.1111/obr.12140
Abstract
Excess adiposity is an established risk factor for incident colorectal cancer (CRC) but whether this association extrapolates to poorer survival is unclear. We undertook a systematic review to examine relationships between measures of adiposity and survival in patients with CRC. For distinction, we included pre-diagnosis exposure and CRC-related mortality. We performed dose-response meta-analyses and assessed study quality using eight domains of bias. Six study categories were identified based on (i) timing of adiposity measurement relative to survival analysis time zero and (ii) clinical setting. Several types of adiposity measurements were reported; body mass index (BMI) was the commonest. For pre-diagnosis cohorts, baseline BMI negatively impacted on CRC-related mortality in men only (risk estimate per 5 kg m(-2) = 1.19, 95% confidence intervals: 1.14-1.25). The other groups were pre-diagnosis BMI but diagnosis as time zero; population-based cohorts; treatment cohorts; observational analyses within adjuvant chemotherapy trials; patients with metastatic CRC - each had several biases (e.g. treatment selection, reverse causality) and sources of confounding (e.g. chemotherapy 'capping'). Overall, there was insufficient evidence for a strong link between adiposity and survival. These findings demonstrate an important principle: an established link between an exposure (here, adiposity) and increased cancer incidence does not necessarily extrapolate into an inferior post-treatment outcome.This publication has 71 references indexed in Scilit:
- Separate and combined associations of body-mass index and abdominal adiposity with cardiovascular disease: collaborative analysis of 58 prospective studiesThe Lancet, 2011
- National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9·1 million participantsThe Lancet, 2011
- Association of angiopoietin-2, C-reactive protein and markers of obesity and insulin resistance with survival outcome in colorectal cancerBritish Journal of Cancer, 2010
- Characterizing the profile of obese patients who are metabolically healthyInternational Journal of Obesity, 2010
- Survival of Women with Colon Cancer in Relation to Precancer Anthropometric Characteristics: the Iowa Women's Health StudyCancer Epidemiology, Biomarkers & Prevention, 2010
- Effect of comorbidity and body mass index on the survival of African‐American and Caucasian patients with colon cancerCancer, 2009
- Visceral fat area is an independent predictive biomarker of outcome after first-line bevacizumab-based treatment in metastatic colorectal cancerGut, 2009
- Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studiesThe Lancet, 2009
- Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studiesThe Lancet, 2008
- Cancer incidence and mortality in relation to body mass index in the Million Women Study: cohort studyBMJ, 2007