Studies have reported conflicting results on the association between body mass index (BMI) and prognosis of colorectal cancer. Therefore, we have conducted a meta-analysis of prospective studies, ...which examined the association of pre- and post-diagnostic BMI with colorectal cancer-specific mortality and all-cause mortality in patients with colorectal cancer. We searched Medline and EMBASE database published between 1970 and September 2014. A total of 508 articles were identified, of which 16 prospective cohort studies were included for the current meta-analysis. The analysis included 58,917 patients who were followed up over a period ranging from 4.9 to 20 years (median: 9.9 years). We found that being underweight before cancer diagnosis was associated with increased all-cause mortality (Relative risk RR: 1.63, 95% CI: 1.18-2.23, p < 0.01) and being obese (BMI ≥ 30 kg/m(2)) before cancer diagnosis was associated with increased colorectal cancer-specific mortality (RR: 1.22, 95% CI: 1.003-1.35, p < 0.01) and all-cause mortality (RR: 1.25, 95% CI: 1.14-1.36, p < 0.01). On the other hand, being underweight (RR: 1.33, 95% CI: 1.20-1.47, p < 0.01), obese (RR: 1.08, 95% CI: 1.03-1.3, p < 0.01), and class II/III obese (BMI ≥ 35 kg/m(2); RR: 1.13, 95% CI: 1.04-1.23, p < 0.01) after diagnosis were associated with significantly increased all-cause mortality. Being obese prior to diagnosis of colorectal cancer was associated with increased colorectal cancer-specific mortality and all-cause mortality, whereas being obese after diagnosis was associated with increased all-cause mortality. The associations with being underweight may reflect reverse causation. Maintaining a healthy body weight should be discussed with colorectal cancer survivors.
This review summarizes the evidence regarding physical activity and diet after colorectal cancer diagnosis in relation to quality of life, disease recurrence, and survival. There have been extensive ...reports on adiposity, inactivity, and certain diets, particularly those high in red and processed meats, and increased risk of colorectal cancer. Only in the past decade have data emerged on how such lifestyle factors are associated with outcomes in colorectal cancer survivors. Prospective observational studies have consistently reported that physical activity after colorectal cancer diagnosis reduces mortality. A meta-analysis estimated that each 15 metabolic equivalent task-hour per week increase in physical activity after colorectal cancer diagnosis was associated with a 38% lower risk of mortality. No randomized controlled trials have been completed to confirm that physical activity lowers risk of mortality among colorectal cancer survivors; however, trials have shown that physical activity, including structured exercise, is safe for colorectal cancer survivors (localized to metastatic stage, during and after treatment) and improves cardiorespiratory fitness and physical function. In addition, prospective observational studies have suggested that a Western dietary pattern, high carbohydrate intake, and consuming sugar-sweetened beverages after diagnosis may increase risk of colorectal cancer recurrence and mortality, but these data are limited to single analyses from one of two US cohorts. Additional data from prospective studies and randomized controlled trials are needed. Nonetheless, on the basis of the available evidence, it is reasonable to counsel colorectal cancer survivors to engage in regular physical activity and limit consumption of refined carbohydrates, red and processed meats, and sugar-sweetened beverages.
To provide guidance on exercise, diet, and weight management during active cancer treatment in adults.
A systematic review of the literature identified systematic reviews and randomized controlled ...trials evaluating the impact of aerobic and resistance exercise, specific diets and foods, and intentional weight loss and avoidance of weight gain in adults during cancer treatment, on quality of life, treatment toxicity, and cancer control. PubMed and the Cochrane Library were searched from January 2000 to May 2021. ASCO convened an Expert Panel to review the evidence and formulate recommendations.
The evidence base consisted of 52 systematic reviews (42 for exercise, nine for diet, and one for weight management), and an additional 23 randomized controlled trials. The most commonly studied types of cancer were breast, prostate, lung, and colorectal. Exercise during cancer treatment led to improvements in cardiorespiratory fitness, strength, fatigue, and other patient-reported outcomes. Preoperative exercise in patients with lung cancer led to a reduction in postoperative length of hospital stay and complications. Neutropenic diets did not decrease risk of infection during cancer treatment.
Oncology providers should recommend regular aerobic and resistance exercise during active treatment with curative intent and may recommend preoperative exercise for patients undergoing surgery for lung cancer. Neutropenic diets are not recommended to prevent infection in patients with cancer during active treatment. Evidence for other dietary and weight loss interventions during cancer treatment was very limited. The guideline discusses special considerations, such as exercise in individuals with advanced cancer, and highlights the critical need for more research in this area, particularly regarding diet and weight loss interventions during cancer treatment.Additional information is available at www.asco.org/supportive-care-guidelines.
Large-scale genomic characterization of tumors from prospective cohort studies may yield new insights into cancer pathogenesis. We performed whole-exome sequencing of 619 incident colorectal cancers ...(CRCs) and integrated the results with tumor immunity, pathology, and survival data. We identified recurrently mutated genes in CRC, such as BCL9L, RBM10, CTCF, and KLF5, that were not previously appreciated in this disease. Furthermore, we investigated the genomic correlates of immune-cell infiltration and found that higher neoantigen load was positively associated with overall lymphocytic infiltration, tumor-infiltrating lymphocytes (TILs), memory T cells, and CRC-specific survival. The association with TILs was evident even within microsatellite-stable tumors. We also found positive selection of mutations in HLA genes and other components of the antigen-processing machinery in TIL-rich tumors. These results may inform immunotherapeutic approaches in CRC. More generally, this study demonstrates a framework for future integrative molecular epidemiology research in colorectal and other malignancies.
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•Whole-exome sequencing of 619 colorectal cancers with clinicopathologic annotations•Discovery of significantly mutated genes in colorectal cancer•Neoantigen load correlation with infiltrating lymphocytes and memory T cells•Positive selection for HLA mutations in immune-cell-infiltrated tumors
Through whole-exome sequencing of annotated colorectal tumors, Giannakis et al. identify additional colorectal cancer driver genes and correlate high neoantigen load with increased lymphocytic infiltration and improved survival. They also find positive selection for HLA mutations in immune-cell-infiltrated tumors. These results may inform immunotherapeutic approaches in colorectal cancer.
The overall 5‐year relative survival rate for all cancers combined is now 68%, and there are over 16.9 million survivors in the United States. Evidence from laboratory and observational studies ...suggests that factors such as diet, physical activity, and obesity may affect risk for recurrence and overall survival after a cancer diagnosis. The purpose of this American Cancer Society guideline is to provide evidence‐based, cancer‐specific recommendations for anthropometric parameters, physical activity, diet, and alcohol intake for reducing recurrence and cancer‐specific and overall mortality. The audiences for this guideline are health care providers caring for cancer survivors as well as cancer survivors and their families. The guideline is intended to serve as a resource for informing American Cancer Society programs, health policy, and the media. Sources of evidence that form the basis of this guideline are systematic literature reviews, meta‐analyses, pooled analyses of cohort studies, and large randomized clinical trials published since 2012. Recommendations for nutrition and physical activity during cancer treatment, informed by current practice, large cancer care organizations, and reviews of other expert bodies, are also presented. To provide additional context for the guidelines, the authors also include information on the relationship between health‐related behaviors and comorbidities, long‐term sequelae and patient‐reported outcomes, and health disparities, with attention to enabling survivors' ability to adhere to recommendations. Approaches to meet survivors' needs are addressed as well as clinical care coordination and resources for nutrition and physical activity counseling after a cancer diagnosis.
To develop recommendations for adjuvant therapy for patients with resected stage II colon cancer.
ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop ...recommendations for clinical practice.
Twenty-one observational studies and six randomized controlled trials met the systematic review inclusion criteria.
Adjuvant chemotherapy (ACT) is not routinely recommended for patients with stage II colon cancer who are not in a high-risk subgroup. Patients with T4 tumors are at higher risk of recurrence and should be offered ACT, whereas patients with other high-risk factors, including sampling of fewer than 12 lymph nodes in the surgical specimen, perineural or lymphovascular invasion, poorly or undifferentiated tumor grade, intestinal obstruction, tumor perforation, or grade BD3 tumor budding, may be offered ACT. The addition of oxaliplatin to fluoropyrimidine-based ACT is not routinely recommended, but may be offered as a result of shared decision making. Patients with mismatch repair deficiency/microsatellite instability tumors should not be routinely offered ACT; if the combination of mismatch repair deficiency/microsatellite instability and high-risk factors results in a decision to offer ACT, oxaliplatin-containing chemotherapy is recommended. Duration of oxaliplatin-containing chemotherapy is also addressed, with recommendations for 3 or 6 months of treatment with capecitabine and oxaliplatin or fluorouracil, leucovorin, and oxaliplatin, with decision making informed by key evidence of 5-year disease-free survival in each treatment subgroup and the rate of adverse events, including peripheral neuropathy.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.
BRAF mutation in colorectal cancer is associated with microsatellite instability (MSI) through its relationship with high-level CpG island methylator phenotype (CIMP) and MLH1 promoter methylation. ...MSI and BRAF mutation analyses are routinely used for familial cancer risk assessment. To clarify clinical outcome associations of combined MSI/BRAF subgroups, we investigated survival in 1253 rectal and colon cancer patients within the Nurses' Health Study and Health Professionals Follow-up Study with available data on clinical and other molecular features, including CIMP, LINE-1 hypomethylation, and KRAS and PIK3CA mutations. Compared with the majority subtype of microsatellite stable (MSS)/BRAF-wild-type, MSS/BRAF-mutant, MSI-high/BRAF-mutant, and MSI-high/BRAF-wild-type subtypes showed multivariable colorectal cancer-specific mortality hazard ratios of 1.60 (95% confidence interval CI =1.12 to 2.28; P = .009), 0.48 (95% CI = 0.27 to 0.87; P = .02), and 0.25 (95% CI = 0.12 to 0.52; P < .001), respectively. No evidence existed for a differential prognostic role of BRAF mutation by MSI status (P(interaction) > .50). Combined BRAF/MSI status in colorectal cancer is a tumor molecular biomarker for prognosic risk stratification.
Body composition may partially explain the U-shaped association between body mass index (BMI) and colorectal cancer survival.
Muscle and adiposity at colorectal cancer diagnosis and survival were ...examined in a retrospective cohort using Kaplan-Meier curves, multivariable Cox regression, and restricted cubic splines in 3,262 early-stage (I-III) male (50%) and female (50%) patients. Sarcopenia was defined using optimal stratification and sex- and BMI-specific cut points. High adiposity was defined as the highest tertile of sex-specific total adipose tissue (TAT). Primary outcomes were overall mortality and colorectal cancer-specific mortality (CRCsM).
Slightly over 42% patients were sarcopenic. During 5.8 years of follow-up, 788 deaths occurred, including 433 from colorectal cancer. Sarcopenic patients had a 27% HR, 1.27; 95% confidence interval (CI), 1.09-1.48 higher risk of overall mortality than those who were not sarcopenic. Females with both low muscle and high adiposity had a 64% higher risk of overall mortality (HR, 1.64; 95% CI, 1.05-2.57) than females with adequate muscle and lower adiposity. The lowest risk of overall mortality was seen in patients with a BMI between 25 and <30 kg/m
, a range associated with the greatest number of patients (58.6%) who were not at increased risk of overall mortality due to either low muscle or high adiposity.
Sarcopenia is prevalent among patients with non-metastatic colorectal cancer, and should, along with adiposity be a standard oncological marker.
Our findings suggest a biologic explanation for the obesity paradox in colorectal cancer and refute the notion that the association between overweight and lower mortality is due solely to methodologic biases.
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The American Society of Clinical Oncology (ASCO) has a policy and set of procedures for endorsing recent clinical practice guidelines that have been developed by other professional organizations.
The ...Cancer Care Ontario (CCO) Guideline on Follow-up Care, Surveillance Protocol, and Secondary Prevention Measures for Survivors of Colorectal Cancer was reviewed by ASCO for methodologic rigor and considered for endorsement.
The ASCO Panel concurred with the CCO recommendations and recommended endorsement, with the addition of several qualifying statements.
Surveillance should be guided by presumed risk of recurrence and functional status of the patient (important within the first 2 to 4 years). Medical history, physical examination, and carcinoembryonic antigen testing should be performed every 3 to 6 months for 5 years. Patients at higher risk of recurrence should be considered for testing in the more frequent end of the range. A computed tomography scan (abdominal and chest) is recommended annually for 3 years, in most cases. Positron emission tomography scans should not be used for surveillance outside of a clinical trial. A surveillance colonoscopy should be performed 1 year after the initial surgery and then every 5 years, dictated by the findings of the previous one. If a colonoscopy was not preformed before diagnosis, it should be done after completion of adjuvant therapy (before 1 year). Secondary prevention (maintaining a healthy body weight and active lifestyle) is recommended. If a patient is not a candidate for surgery or systemic therapy because of severe comorbid conditions, surveillance tests should not be performed. A treatment plan from the specialist should have clear directions on appropriate follow-up by a nonspecialist.
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