Impact of Obesity on Cancer Survivorship and the Potential Relevance of Race and Ethnicity

Abstract

Evidence that obesity is associated with cancer incidence and mortality is compelling. By contrast, the role of obesity in cancer survival is less well understood. There is inconsistent support for the role of obesity in breast cancer survival, and evidence for other tumor sites is scant. The variability in findings may be due in part to comorbidities associated with obesity itself rather than with cancer, but it is also possible that obesity creates a physiological setting that meaningfully alters cancer treatment efficacy. In addition, the effects of obesity at diagnosis may be distinct from the effects of weight change after diagnosis. Obesity and related comorbid conditions may also increase risk for common adverse treatment effects, including breast cancer-related lymphedema, fatigue, poor health-related quality of life, and worse functional health. Racial and ethnic groups with worse cancer survival outcomes are also the groups for whom obesity and related comorbidities are more prevalent, but findings from the few studies that have addressed these complexities are inconsistent. We outline a broad theoretical framework for future research to clarify the specifics of the biological-social-environmental feedback loop for the combined and independent contributions of race, comorbid conditions, and obesity on cancer survival and adverse treatment effects. If upstream issues related to comorbidities, race, and ethnicity partly explain the purported link between obesity and cancer survival outcomes, these factors should be among those on which interventions are focused to reduce the burden of cancer.

Comorbidities and Their Management: Potential Impact on Breast Cancer Outcomes

“…Specifi c comorbidities have been shown to increase adverse effects of breast cancer therapy although most of this research has focused on the effects of obesity and related cardiovascular risk factors (Schmitz et al 2013 ). Diabetes for instance is a risk factor for paclitaxel neuropathy and increased risk of neuropathic pain following breast surgery (Lee and Swain 2006 ;Wilson et al 2013 ).…”

“…Diabetes for instance is a risk factor for paclitaxel neuropathy and increased risk of neuropathic pain following breast surgery (Lee and Swain 2006 ;Wilson et al 2013 ). Hypertension and obesity are risk factors for development of heart failure with trastuzumab, and development of postoperative lymphedema, fatigue and worse functional health (Schmitz et al 2013 ;Helyer et al 2010 ;Perez et al 2008 ).…”

Weight gain during adjuvant endocrine treatment for early-stage breast cancer: What is the evidence?

“…Weight gain after breast cancer diagnosis has also been associated with hot flashes [13], physical function limitations [14], pain [15], and lower quality of life [16,17]. Weight change in breast cancer survivors is complex and influenced by the interaction of individuallevel risk factors, interpersonal and community relationships, and societal structures [18][19][20].…”

Obesity-associated cancer: an immunological perspective

“…However, obesity is a complex variable, and BMI is not always a reliable measure of metabolic health. Schmitz et al suggest that further clarification of the biological-social-environmental feedback loop is required in order to elucidate the combined and independent contributions of race, ethnicity, comorbidities and obesity on cancer survival and adverse treatment effects (159) . This review highlights the critical importance of understanding the obesity-immunity-cancer axis and the fact that obesity driven immunological dysregulation should no longer be ignored when developing immunotherapeutic strategies.…”