CA : A Cancer Journal for Clinicians

ESPEN guidelines on nutrition in cancer patients

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans. CA Cancer J Clin 2012. © 2012 American Cancer Society.

https://acsjournals.onlinelibrary.wiley.com/doi/epdf/10.3322/caac.20140

American Cancer Society guidelines on nutrition and physical activity for cancer prevention

Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in so...

The Role of Selenium in Inflammation and Immunity: From Molecular Mechanisms to Therapeutic Opportunities

Background
This review is an update of the first Cochrane publication on selenium for preventing cancer (Dennert 2011).

Selenium is a metalloid with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers.

Selenium for preventing cancer

Background. No comprehensive systematic review has been published since 1998 about the frequency with which cancer patients use complementary and alternative medicine (CAM). Methods. MEDLINE, AMED, and Embase databases were searched for surveys published until January 2009. Surveys conducted in Australia, Canada, Europe, New Zealand, and the United States with at least 100 adult cancer patients were included. Detailed information on methods and results was independently extracted by 2 reviewers. Methodological quality was assessed using a criteria list developed according to the STROBE guideline. Exploratory random effects metaanalysis and metaregression were applied. Results. Studies from 18 countries (152; >65 000 cancer patients) were included. Heterogeneity of CAM use was high and to some extent explained by differences in survey methods. The combined prevalence for “current use” of CAM across all studies was 40%. The highest was in the United States and the lowest in Italy and the Netherlands. Metaanalysis suggested an increase in CAM use from an estimated 25% in the 1970s and 1980s to more than 32% in the 1990s and to 49% after 2000. Conclusions. The overall prevalence of CAM use found was lower than often claimed. However, there was some evidence that the use has increased considerably over the past years. Therefore, the health care systems ought to implement clear strategies of how to deal with this. To improve the validity and reporting of future surveys, the authors suggest criteria for methodological quality that should be fulfilled and reporting standards that should be required.

https://journals.sagepub.com/doi/pdf/10.1177/1534735411423920

How Many Cancer Patients Use Complementary and Alternative Medicine: A Systematic Review and Metaanalysis

BACKGROUND: Selenium is a trace element essential to humans. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers. OBJECTIVE: Two research questions were addressed in this review: What is the evidence for: 1. an aetiological relationship between selenium exposure and cancer risk in women and men?; 2. the efficacy of selenium supplementation for cancer prevention in women and men? SEARCH STRATEGY: We searched electronic databases and bibliographies of reviews and included publications. SELECTION CRITERIA: We included prospective observational studies to answer research question (a) and randomised controlled trials (RCTs) to answer research question (b). DATA COLLECTION AND ANALYSIS: We conducted random effects meta-analyses of epidemiological data when five or more studies were retrieved for a specific outcome. We made a narrative summary of data from RCTs. MAIN RESULTS: We included 49 prospective observational studies and six RCTs. In epidemiologic data, we found a reduced cancer incidence (summary odds ratio, OR, 0.69; 95% confidence interval, CI, 0.53 to 0.91) and mortality (OR 0.55, 95% CI 0.36 to 0.83) with higher selenium exposure. Cancer risk was more pronouncedly reduced in men (incidence: OR 0.66, 95% CI 0.42 to 1.05) than in women (incidence: OR 0.90, 95% CI 0.45 to 1.77). These findings have potential limitations due to study design, quality and heterogeneity of the data, which complicated the interpretation of the summary statistics. The RCTs found no protective efficacy of selenium yeast supplementation against non-melanoma skin cancer or L-selenomethionine supplementation against prostate cancer. Study results for the prevention of liver cancer with selenium supplements were inconsistent and studies had an unclear risk of bias. The results of the Nutritional Prevention of Cancer Trial (NPCT) and SELECT raised concerns about possible harmful effects of selenium supplements. AUTHORS' CONCLUSIONS: No reliable conclusions can be drawn regarding a causal relationship between low selenium exposure and an increased risk of cancer. Despite evidence for an inverse association between selenium exposure and the risk of some types of cancer, these results should be interpreted with care due to the potential limiting factors of heterogeneity and influences of unknown biases, confounding and effect modification. The effect of selenium supplementation from RCTs yielded inconsistent results. To date, there is no convincing evidence that selenium supplements can prevent cancer in men, women or children.

/pdf/selenium-for-preventing-cancer-5flsjzs95y.pdf

Background
This is an updated version of the original Cochrane review published in Issue 3, 2006. Selenium supplements are frequently used by cancer patients. Selenium is an essential trace element and is involved in antioxidant protection and the redox-regulation in humans. Several adverse effects of radiotherapy and chemotherapy in cancer patients as well as cellular processes that maintain chronic lymphoedema have been linked to oxidative cell processes in the human body. Selenium has been claimed to alleviate side effects of conventional cancer therapy and recently been investigated as a remedy against chemotherapy and radiotherapy-associated side effects and secondary lymphoedema.

Objectives
This review assessed the effects of supplementary selenium on adverse effects of conventional radiotherapy, chemotherapy, or surgery in oncology patients and on quality of life/performance status during and after oncological treatment.

Search methods
The Cochrane Pain, Palliative & Supportive Care Trials Register, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects (DARE), CENTRAL, MEDLINE, EMBASE, SIGLE, Cancerlit, CCMed, the German online register for cancer trials, the ISRCTN, the mRCT, the NCI Clinical Trials register databases were searched and most updated in July 2007.

Selection criteria
Randomised controlled trials (RCTs) of selenium mono-supplements in cancer patients undergoing tumour specific therapy, such as chemotherapy, radiotherapy or surgery.

Data collection and analysis
Two review authors independently checked trials for eligibility, extracted data and assessed trial quality.

Main results
One new included study as well as further participants to a study already included was added to this update involving a further 39 participants. There were a total of three studies included involving 162 participants for this update.

For this review two RCTs were included investigating secondary lymphoedema in 60 women after breast cancer surgery and 20 men and women after head and neck cancer surgery. One ongoing trial with preliminary results of 82 participants was also identified studying radiotherapy induced diarrhoea as a secondary outcome. All studies had considerable drawbacks with regards to quality and reporting.

One study on secondary lymphoedema reported a decreased number of recurrent erysipela infections in the selenium supplementation group compared to placebo. The second study reported a decreased facial swelling in the selenium group in a two-week period following surgical tumour resection. However, results must be interpreted with caution and cannot be generalised to other populations.

The ongoing trial on radiotherapy associated diarrhoea preliminarily reported a lower incidence of diarrhoea in participants receiving selenium supplementation concomitant to pelvic radiation, however, no data were presented. We must await publication of final results to discuss these findings in detail.

No RCTs were found studying the effect of selenium supplementation on other therapy-associated toxicities or quality of life/performance status in cancer patients.

Authors' conclusions
There is insufficient evidence at present that selenium supplementation alleviates the side effects of tumour specific chemotherapy or radiotherapy treatments or that it improves the after-effects of surgery, or improves quality-of-life in cancer patients or reduces secondary lymphoedema. To date, research findings do not provide a basis for any recommendation in favour or against selenium supplementation in cancer patients. Potential hazards of supplementing a trace mineral should be kept in mind. Since the last version of this review, the one new additional study has not provided information to change the conclusions of the original review.

/pdf/selenium-for-alleviating-the-side-effects-of-chemotherapy-b8e2jg775c.pdf

Selenium for alleviating the side effects of chemotherapy, radiotherapy and surgery in cancer patients.

BACKGROUND
Selenium is a trace element essential to humans. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers.


OBJECTIVES
Two research questions were addressed in this review: What is the evidence for1. an aetiological relationship between selenium exposure and cancer risk in women and men?2. the efficacy of selenium supplementation for cancer prevention in women and men?


SEARCH STRATEGY
We searched electronic databases and bibliographies of reviews and included publications.


SELECTION CRITERIA
We included prospective observational studies to answer research question (a) and randomised controlled trials (RCTs) to answer research question (b).


DATA COLLECTION AND ANALYSIS
We conducted random effects meta-analyses of epidemiological data when five or more studies were retrieved for a specific outcome. We made a narrative summary of data from RCTs.


MAIN RESULTS
We included 49 prospective observational studies and six RCTs. In epidemiologic data, we found a reduced cancer incidence (summary odds ratio (OR) 0.69 (95% confidence interval (CI) 0.53 to 0.91) and mortality (OR 0.55, 95% CI 0.36 to 0.83) with higher selenium exposure. Cancer risk was more pronouncedly reduced in men (incidence: OR 0.66, 95% CI 0.42 to 1.05) than in women (incidence: OR 0.90, 95% CI 0.45 to 1.77). These findings have potential limitations due to study design, quality and heterogeneity of the data, which complicated the interpretation of the summary statistics.The RCTs found no protective efficacy of selenium yeast supplementation against non-melanoma skin cancer or L-selenomethionine supplementation against prostate cancer. Study results for the prevention of liver cancer with selenium supplements were inconsistent and studies had an unclear risk of bias. The results of the Nutritional Prevention of Cancer Trial (NPCT) and SELECT raised concerns about possible harmful effects of selenium supplements.


AUTHORS' CONCLUSIONS
No reliable conclusions can be drawn regarding a causal relationship between low selenium exposure and an increased risk of cancer. Despite evidence for an inverse association between selenium exposure and the risk of some types of cancer, these results should be interpreted with care due to the potential limiting factors of heterogeneity and influences of unknown biases, confounding and effect modification.The effect of selenium supplementation from RCTs yielded inconsistent results. To date, there is no convincing evidence that selenium supplements can prevent cancer in men, women or children.

/pdf/selenium-for-preventing-cancer-review-information-ewyr9fnh7x.pdf

Gabriele Dennert

Papers

How Many Cancer Patients Use Complementary and Alternative Medicine: A Systematic Review and Metaanalysis

Selenium for preventing cancer

Selenium for preventing cancer

Selenium for alleviating the side effects of chemotherapy, radiotherapy and surgery in cancer patients.

Selenium for preventing cancer.Review information