The Impact of Body Mass Index on the Clinicopathological and Prognostic Factors of Colorectal Cancer in Saudi Arabia

Association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

Clinical practice guidelines recommend retrieving at least 12 lymph nodes for correct staging in colorectal cancer. However, it is difficult to retrieve adequate lymph nodes because of various factors. We aimed to evaluate the association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer.

DESIGN

Systematic review and meta-analysis of primary studies.

DATA SOURCES

PubMed, Embase, Cochrane and Web of Science were searched from January 2016 to June 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that evaluated the association between retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer were included.

DATA EXTRACTION AND SYNTHESIS

OR with 95% conference intervals was extracted and pooled.

RESULTS

A total of 54 studies containing 2 05 821 patients were included in this meta-analysis. The results showed that fewer nodes were retrieved from elderly patients (OR=0.70, 95% CI (0.54 to 0.90), p=0.005), and from tumours located in the left colon than in the right colon (OR=0.43, 95% CI (0.33 to 0.56), p<0.001). More lymph nodes were obtained from females than males (OR=1.15, 95% CI (1.04 to 1.28), p=0.006), from the advanced T stage (T3+T4) than T1+T2 stage (OR=1.57, 95% CI (1.25 to 1.97), p<0.001) and from the N2 stage than N0 stage (OR=1.32, 95% CI (1.15 to 1.51), p<0.001). Body mass index, ethnicity, N1 stage, M stage, tumour differentiation and lymph-vascular invasion were not significantly associated with the lymph node yield.

CONCLUSIONS

The study results suggest that clinicians have an increased opportunity to retrieve sufficient lymph nodes for accurate pathological staging to guide treatment decisions in patients with colorectal cancer who are young, female, with tumours located in the right colon, advanced T stage and N2 stage.

Assessment of Body Mass Index, Polygenic Risk Score, and Development of Colorectal Cancer

IMPORTANCE

Excess weight, the prevalence of which is high and increasing in many countries, is linked to multiple adverse health outcomes, including increased colorectal cancer (CRC) risk. Better communication of health risks associated with excess weight might support efforts of prevention.

OBJECTIVE

To evaluate the individual and joint associations of body mass index (BMI) and polygenic risk with CRC, to assess potential interactions among them, and to quantify by how much increased polygenic risk for CRC can be offset by having a BMI within reference range.

DESIGN, SETTING, AND PARTICIPANTS

This population-based case-control study was conducted in the Rhine-Neckar region of southwest Germany, with recruitment from 2003 to 2017. Participants with both risk factor and genetic information were included for analysis. Data analysis was conducted from December 8, 2021, to February 17, 2022.

EXPOSURES

BMI was calculated as self-reported weight in kilograms approximately 10 years before diagnosis or interview and current height in meters squared. A polygenic risk score (PRS) was built based on 140 CRC-related risk loci.

MAIN OUTCOMES AND MEASURES

Individual and joint associations of BMI and PRS with CRC were estimated using multiple logistic regression. Associations of excess weight with CRC were quantified by adjusted odds ratios (aORs) and genetic risk equivalents (GREs), the equivalent outcomes conveyed by defined differences in PRS percentiles.

RESULTS

Among 9169 participants (median [IQR] age, 69 [62-76] years; 5589 [61.0%] male participants) included, 5053 had CRC and 4116 did not. BMI of 30 or greater was associated with higher odds of having CRC compared with BMI less than 25 (aOR, 1.71; 95% CI, 1.49-1.97), independent of PRS levels (P for interaction = .45). Participants with BMI of 30 or greater and a PRS in the highest tertile had higher odds of CRC compared with participants with BMI less than 25 and a PRS in the lowest tertile (aOR, 3.82; 95% CI, 3.03-4.82). The estimated association of BMI greater than 30 with CRC risk was equivalent to that of having a 41 (95% CI, 29-53)-percentile higher PRS. BMI of 30 or greater was particularly associated with stage IV CRC (aOR, 2.21; 95% CI, 1.71-2.84).

CONCLUSIONS AND RELEVANCE

These findings suggest that excess weight was associated with CRC regardless of PRS levels. The association of having a BMI within reference range may be similar to that of having a substantially lower polygenic risk for CRC.

Exploring the Inflammatory Pathogenesis of Colorectal Cancer

Colorectal cancer is one of the most commonly diagnosed cancers worldwide. Traditionally, mechanisms of colorectal cancer formation have focused on genetic alterations including chromosomal damage and microsatellite instability. In recent years, there has been a growing body of evidence supporting the role of inflammation in colorectal cancer formation. Multiple cytokines, immune cells such T cells and macrophages, and other immune mediators have been identified in pathways leading to the initiation, growth, and metastasis of colorectal cancer. Outside the previously explored mechanisms and pathways leading to colorectal cancer, initiatives have been shifted to further study the role of inflammation in pathogenesis. Inflammatory pathways have also been linked to some traditional risk factors of colorectal cancer such as obesity, smoking and diabetes, as well as more novel associations such as the gut microbiome, the gut mycobiome and exosomes. In this review, we will explore the roles of obesity and diet, smoking, diabetes, the microbiome, the mycobiome and exosomes in colorectal cancer, with a specific focus on the underlying inflammatory and metabolic pathways involved. We will also investigate how the study of colon cancer from an inflammatory background not only creates a more holistic and inclusive understanding of this disease, but also creates unique opportunities for prevention, early diagnosis and therapy.