Excess body weight, as defined by the body mass index (BMI), has been associated with several diseases and includes subjects who are overweight (BMI≥25–29.9 kg/m ² ) or obese (BMI≥30 kg/m ² ). Overweight and obesity constitute the fifth leading risk for overall mortality, accounting for at least 2.8 million adult deaths each year. In addition around 11% of colorectal cancer (CRC) cases have been attributed to overweight and obesity in Europe. Epidemiological data suggest that obesity is associated with a 30–70% increased risk of colon cancer in men, whereas the association is less consistent in women. Similar trends exist for colorectal adenoma, although the risk appears lower. Visceral fat, or abdominal obesity, seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m ² increase in BMI confers additional risk (HR 1.03). Obesity might be associated with worse cancer outcomes, such as recurrence of the primary cancer or mortality. Several factors, including reduced sensitivity to antiangiogenic-therapeutic regimens, might explain these differences. Except for wound infection, obesity has no significant impact on surgical procedures. The underlying mechanisms linking obesity to CRC are still a matter of debate, but metabolic syndrome, insulin resistance and modifications in levels of adipocytokines seem to be of great importance. Other biological factors such as the gut microbita or bile acids are emerging. Many questions still remain unanswered: should preventive strategies specifically target obese patients? Is the risk of cancer great enough to propose prophylactic bariatric surgery in certain patients with obesity?

Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, also called statins, are commonly prescribed medications that lower serum cholesterol and decrease cardiac morbidity and mortality. They also possess beneficial effects beyond their cholesterol-lowering properties. Preclinical data suggest statins exhibit pleiotropic antineoplastic effects in a variety of tumours, but clinical studies have provided conflicting data as to whether statins influence the risk of cancer. The biological underpinning of potential effects of statins in colorectal cancer and their role in its prevention or as adjuvant therapy are reviewed. Following a meta-analysis of both randomised clinical trials and epidemiological studies, it is concluded that available clinical data only support a modest, although statistically significant, protective effect of statins in colorectal cancer. Statins may impact on outcomes by decreasing the invasiveness or metastatic properties of colorectal cancer. The data supporting these hypotheses, however, are few and further studies are required to better assess these hypotheses. Statins may also exert a beneficial effect on colorectal cancer by sensitising the tumour to chemotherapeutic agents. Further research is needed to better define the role of statins in overcoming chemoresistance. The combination of statins with other drugs, such as low-dose aspirin or safer non-steroidal anti-inflammatory medications, may be useful in both the prevention and treatment of colorectal cancer.

Summary: Background: Obesity is a growing global public health problem. More than half the European and North American population is overweight or obese. Colon and rectum cancers are still the second leading cause of cancer death worldwide, and epidemiological data support an association between obesity and colorectal cancers (CRCs).Aim: To review the literature on CRC epidemiology in obese subjects, assessing the effects of obesity, including childhood or maternal obesity, on CRC, diagnosis, management, and prognosis, and discussing targeted prophylactic measures.Method: We searched PubMed for obesity/overweight/metabolic syndrome and CRC. Other key words included ‘staging’, ‘screening’, ‘treatment’, ‘weight loss’, ‘bariatric surgery’ and ‘chemotherapy’.Results: In Europe, about 11% of CRCs are attributed to overweight and obesity. Epidemiological data suggest that obesity is associated with a 30%–70% increased risk of colon cancer in men, the association being less consistent in women. Visceral fat or abdominal obesity seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m² increase in body mass index confers more risk (hazard ratio 1.03). Obesity might increase the likelihood of recurrence or mortality of the primary cancer and may affect initial management, including accurate staging. The risk maybe confounded by different factors, including lower adherence to organised CRC screening programmes. It is unclear whether bariatric surgery helps reduce rectal cancer risk.Conclusions: Despite a growing body of evidence linking obesity to CRC, many questions remain unanswered, including whether we should screen patients with obesity earlier or propose prophylactic bariatric surgery for certain patients with obesity.

Colorectal cancer (CRC) is one of the most common and lethal malignancies in Western countries. Its development is a multistep process that spans more than 15 years, thereby providing an opportunity for prevention and early detection. The high incidence and mortality rates emphasise the need for prevention and screening. Many countries have therefore introduced CRC screening programmes. It is expected, and preliminary evidence in some countries suggests, that this screening effort will decrease CRC-related mortality rates. CRC prevention involves a healthy lifestyle and chemoprevention—more specifically, oral chemoprevention that can interfere with progression from a normal colonic mucosa to adenocarcinoma. This preventive effect is important for individuals with a genetic predisposition, but also in the general population. The ideal chemopreventive agent, or combination of agents, remains unknown, especially when considering safety during long-term use. This review evaluates the evidence across 80 meta-analyses of interventional and observational studies of CRC prevention using medications, vitamins, supplements and dietary factors. This review suggests that the following factors are associated with a decreased incidence of CRC: aspirin, non-steroidal anti-inflammatory drugs, magnesium, folate, a high consumption of fruits and vegetables, fibre and dairy products. An increased incidence of CRC was observed with frequent alcohol or meat consumption. No evidence of a protective effect for tea, coffee, garlic, fish and soy products was found. The level of evidence is moderate for aspirin, β-carotene and selenium, but is low or very low for all other exposures or interventions.

The value of variant-adapted vaccines that are capable of inducing a higher and broader immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at booster vaccination is currently being evaluated.^1-4 We conducted a multicenter, randomized, single-blind trial to assess the immunogenicity and safety of two adjuvanted recombinant vaccines and the messenger RNA (mRNA) vaccine BNT162b2 (Pfizer–BioNTech) administered as a booster (ClinicalTrials.gov number, NCT05124171; EudraCT number, 2021-004550-33).