Does body mass index impact the number of LNs harvested and influence long-term survival rate in patients with stage III colon cancer?

Post-diagnosis adiposity and colorectal cancer prognosis: A Global Cancer Update Programme (CUP Global) systematic literature review and meta-analysis

The adiposity influence on colorectal cancer prognosis remains poorly characterised. We performed a systematic review and meta-analysis on post-diagnosis adiposity measures (body mass index [BMI], waist circumference, waist-to-hip ratio, weight) or their changes and colorectal cancer outcomes. PubMed and Embase were searched through 28 February 2022. Random-effects meta-analyses were conducted when at least three studies had sufficient information. The quality of evidence was interpreted and graded by the Global Cancer Update Programme (CUP Global) independent Expert Committee on Cancer Survivorship and Expert Panel. We reviewed 124 observational studies (85 publications). Meta-analyses were possible for BMI and all-cause mortality, colorectal cancer-specific mortality, and cancer recurrence/disease-free survival. Non-linear meta-analysis indicated a reverse J-shaped association between BMI and colorectal cancer outcomes (nadir at BMI 28 kg/m2). The highest risk, relative to the nadir, was observed at both ends of the BMI distribution (18 and 38 kg/m2), namely 60% and 23% higher risk for all-cause mortality; 95% and 26% for colorectal cancer-specific mortality; and 37% and 24% for cancer recurrence/disease-free survival, respectively. The higher risk with low BMI was attenuated in secondary analyses of RCTs (compared to cohort studies), among studies with longer follow-up, and in women suggesting potential methodological limitations and/or altered physiological state. Descriptively synthesised studies on other adiposity-outcome associations of interest were limited in number and methodological quality. All the associations were graded as limited (likelihood of causality: no conclusion) due to potential methodological limitations (reverse causation, confounding, selection bias). Additional well-designed observational studies and interventional trials are needed to provide further clarification.

Body mass index, weight change, and cancer prognosis: a meta-analysis and systematic review of 73 cohort studies

BACKGROUND

Identifying the association between body mass index (BMI) or weight change and cancer prognosis is essential for the development of effective cancer treatments. We aimed to assess the strength and validity of the evidence of the association between BMI or weight change and cancer prognosis by a systematic evaluation and meta-analysis of relevant cohort studies.

METHODS

We systematically searched the PubMed, Web of Science, EconLit, Embase, Food Sciences and Technology Abstracts, PsycINFO, and Cochrane databases for literature published up to July 2023. Inclusion criteria were cohort studies with BMI or weight change as an exposure factor, cancer as a diagnostic outcome, and data type as an unadjusted hazard ratio (HR) or headcount ratio. Random- or fixed-effects models were used to calculate the pooled HR along with the 95% confidence interval (CI).

RESULTS

Seventy-three cohort studies were included in the meta-analysis. Compared with normal weight, overweight or obesity was a risk factor for overall survival (OS) in patients with breast cancer (HR 1.37, 95% CI 1.22-1.53; P < 0.0001), while obesity was a protective factor for OS in patients with gastrointestinal tumors (HR 0.67, 95% CI 0.56-0.80; P < 0.0001) and lung cancer (HR 0.67, 95% CI 0.48-0.92; P = 0.01) compared with patients without obesity. Compared with normal weight, underweight was a risk factor for OS in patients with breast cancer (HR 1.15, 95% CI 0.98-1.35; P = 0.08), gastrointestinal tumors (HR 1.54, 95% CI 1.32-1.80; P < 0.0001), and lung cancer (HR 1.28, 95% CI 1.22-1.35; P < 0.0001). Compared with nonweight change, weight loss was a risk factor for OS in patients with gastrointestinal cancer.

CONCLUSIONS

Based on the results of the meta-analysis, we concluded that BMI, weight change, and tumor prognosis were significantly correlated. These findings may provide a more reliable argument for the development of more effective oncology treatment protocols.

Systematic review and meta-analysis of factors which reduce the length of stay associated with elective laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy is a safe ambulatory procedure in appropriately selected patients; however, day case rates remain low. The objective of this systematic review and meta-analysis was to identify interventions which are effective in reducing the length of stay (LOS) or improving the day case rate for elective laparoscopic cholecystectomy.

METHODS

Comparative English-language studies describing perioperative interventions applicable to elective laparoscopic cholecystectomy in adult patients and their impact on LOS or day case rate were included.

RESULTS

Quantitative data were available for meta-analysis from 80 studies of 10,615 patients. There were an additional 17 studies included for systematic review. The included studies evaluated 14 peri-operative interventions. Implementation of a formal day case care pathway was associated with a significantly shorter LOS (MD = 24.9 h, 95% CI, 18.7-31.2, p < 0.001) and an improved day case rate (OR = 3.5; 95% CI, 1.5-8.1, p = 0.005). Use of non-steroidal anti-inflammatories, dexamethasone and prophylactic antibiotics were associated with smaller reductions in LOS.

CONCLUSION

Care pathway implementation demonstrated a significant impact on LOS and day case rates. A limited effect was noted for smaller independent interventions. In order to achieve optimal day case targets, a greater understanding of the effective elements of a care pathway and local barriers to implementation is required.

Obesity and Cancer Treatment Outcomes: Interpreting the Complex Evidence

A wealth of epidemiological evidence, combined with plausible biological mechanisms, present a convincing argument for a causal relationship between excess adiposity, commonly approximated as body mass index (BMI, kg/m²), and incident cancer risk. Beyond this relationship, there are a number of challenges posed in the context of interpreting whether being overweight (BMI 25.0-29.9 kg/m²) or obese (BMI ≥ 30.0 kg/m²) adversely influences disease progression, cancer mortality and survival. Elevated BMI (≥ 25.0 kg/m²) may influence treatment selection of, for example, the approach to surgery; the choice of chemotherapy dosing; the inclusion of patients into randomised clinical trials. Furthermore, the technical challenges posed by an elevated BMI may adversely affect surgical outcomes, for example, morbidity (increasing the risk of surgical site infections), reduced lymph node harvest (and subsequent risk of under-staging and under-treatment) and increased risk of margin positivity. Suboptimal chemotherapy dosing, associated with capping chemotherapy in obese patients as an attempt to avoid excess toxicity, might be a driver of poor prognostic outcomes. By contrast, the efficacy of immune checkpoint inhibition may be enhanced in patients who are obese, although in turn, this observation might be due to reverse causality. So, a central research question is whether being overweight or obese adversely affects outcomes either directly through effects of cancer biology or whether adverse outcomes are mediated through indirect pathways. A further dimension to this complex relationship is the obesity paradox, a phenomenon where being overweight or obese is associated with improved survival where the reverse is expected. In this overview, we describe a framework for evaluating methodological problems such as selection bias, confounding and reverse causality, which may contribute to spurious interpretations. Future studies will need to focus on prospective studies with well-considered methodology in order to improve the interpretation of causality.

Lymph node retrieval after colorectal cancer surgery: a comparative study of the efficacy between the conventional manual method and a new fat dissolution method

PURPOSE

This study compared the efficacy of two different methods for lymph node (LN) searching after colorectal cancer surgery: the fat dissolution and the conventional manual method.

METHODS

For the fat dissolution method, we used a commercially available solution of collagenase and lipase (FD group). The primary endpoint was the number of identified LNs in the FD group compared to an historical control (control group) after adjusting by propensity score matching.

RESULTS

Using 37 matched patients from each group, we identified 20.6 ± 7.2 LNs using the fat dissolution method compared to 13.5 ± 5.9 using the conventional method (t test, P < 0.01). Three patients in the FD group received an inappropriate LN examination in terms of number, while the number of the retrieved LNs was < 12 in 12 patients in the control group. The mean diameter of LNs without metastasis was 3.2 ± 1.9 mm in the FD group, and 40% of metastasis cases were found in LNs < 5 mm in diameter. A pathological examination confirmed that using the fat resolution method did not change the morphological or immunochemical staining findings.

CONCLUSION

We demonstrated that fat dissolution had a positive impact on the number of retrieved LNs after colorectal cancer surgery without disturbing the microscopic observation.

Factors affecting retrieval of 12 or more lymph nodes in pT1 colorectal cancers

Objective

The aim of this study was to identify clinicopathological factors that affect the number of lymph nodes (LNs) (12 or more) retrieved from patients with colorectal cancer (CRC), particularly those with pathologic T1 (pT1) disease.

Methods

From 429 CRC patients, 75 pT1 cancers were identified and digitally scanned. Binary logistic regression analysis was performed to identify the clinicopathological factors affecting the number of LNs retrieved from all 429 patients and from the subset of patients with pT1 CRC.

Results

For the 429 patients, the mean number of harvested LNs per specimen was 20 (median, 19). The number of retrieved LNs was independently associated with maximum tumor diameter > 2.3 cm and right-sided tumor location. The mean number of LNs retrieved from the 75 patients with pT1 CRC was 14 (median, 15); retrieval of 12 or more LNs from this group was independently associated with maximum tumor diameter > 14.1 mm.

Conclusion

The number of LNs retrieved from patients with CRC was associated with maximum tumor diameter and right-sided tumor location. For patients with pT1 CRC, maximum tumor diameter was independently associated with the harvesting of 12 or more LNs.

Meta-analysis of Histological Margin Positivity in the Prediction of Recurrence After Crohn's Resection

BACKGROUND

Despite significant advances in the medical management of Crohn's disease, many patients will require intestinal resection during their lifetime. It is disappointing that many will also develop disease recurrence.

OBJECTIVES

The current study utilizes meta-analytical techniques to determine the effect of positive histological margins at the time of index resection on disease recurrence.

DATA SOURCES

Embase, Medline, PubMed, PubMed Central, and Cochrane databases were searched using a Boolean search algorithm for articles published up to August 2017.

STUDY SELECTION

Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

MAIN OUTCOME MEASURES

Databases were searched for studies reporting the outcomes for patients with Crohn's disease undergoing primary resection that correlated resection margin status with disease recurrence. Results were reported as pooled ORs with 95% CI.

RESULTS

A total of 176 citations were reviewed; 18 studies comprising 1833 patients were ultimately included in the analysis, with a mean rate of histopathological margin positivity of 41.7 ± 17.4% and a pooled mean follow-up of 69 ± 39 months. Histopathological margin positivity was associated with a higher rate of overall recurrence (OR, 1.7; 95% CI, 1.3-2.1; p < 0.001), clinical recurrence (OR, 1.7; 95% CI, 1.0-2.8; p = 0.04), and anastomotic recurrence (OR, 1.6; 95% CI, 1.0-2.3; p = 0.03). In studies reporting plexitis specifically at the resection margin, there was an increase in recurrence (OR, 2.3; 95% CI, 1.1-4.9; p = 0.02).

LIMITATIONS

The definitions of histological margin positivity and postoperative recurrence vary between the studies and follow-up durations vary.

CONCLUSIONS

The presence of involved histological margins at the time of index resection in Crohn's disease is associated with recurrence, and plexitis shows promise as a marker of more aggressive disease. Further studies with homogeneity of histopathological and recurrence reporting are required.

The effect of increased body mass index values on surgical outcomes after radical resection for low rectal cancer

PURPOSES

This study aimed to explore the effect of increased body mass index (BMI) values (overweight: BMI ≥ 25-30 kg/m²; obese: BMI ≥ 30 kg/m²) on surgical outcomes after radical resection for low rectal cancer (LRC).

METHODS

Patients with LRC who underwent radical surgery from January 2009 to December 2013 were included. The patients were divided into three groups according to their BMI values (control group: BMI < 25 kg/m²; overweight group: BMI 25 to < 30 kg/m²; obese group: BMI ≥ 30 kg/m²). The patients' clinicopathological characteristics and survival data were collected and analyzed.

RESULTS

A total of 792 patients were enrolled in this study finally (control, n = 624; overweight, n = 147; obese, n = 21). The baseline characteristics of the three groups were similar. We found that an increased BMI was associated with a longer operative time (P < 0.001) and length of postoperative hospital stay (P = 0.032). Patients with increased BMI values had a significantly higher incidence of postoperative complications, including pulmonary infection (P = 0.008), anastomotic leakage (P = 0.029), allergy (P = 0.017) and incisional hernia (P = 0.045). The limited data showed that the pathological outcomes of the three groups did not differ to a statistically significant extent. A multivariate analysis showed that increased BMI was not associated with poorer OS or DFS.

CONCLUSION

In LRC resection, an increased BMI was associated with a longer operative time, postoperative hospital stay, and an increased number of postoperative complications. However, it did not contribute to poorer pathological or survival outcomes.

Lymph node ratio is an independent prognostic factor for rectal cancer after neoadjuvant therapy: A meta-analysis

OBJECTIVE

With neoadjuvant therapy increasingly used in advanced rectal cancer, the lymph node ratio (LNR) has been strongly considered to indicate cancer-specific survival in recent years, and a comprehensive evaluation of a large number of studies is deficient. The objective of our study is to pool enough eligible studies to assess the relationship between LNR and prognosis of advanced rectal cancer after neoadjuvant therapy.

METHODS

A systematic search was done in the PubMed and EmBase databases (through 1 March 2017) that reported LNR in colorectal cancer after neoadjuvant therapy. The first two authors independently conducted the study selection and data extraction. All statistical analyses were conducted using STATA 13.0 (College Station, Texas).

RESULTS

Thirteen studies with 4023 participants were included in the meta-analysis, and all were published after 2011. A high LNR was assessed to be a predictor of poor overall survival in rectal cancer after neoadjuvant therapy (HR: 2.94, 95% CI:1.97 to 3.91, P < 0.001). Similarly, a high LNR was related to poor disease-free survival (HR: 2.83, 95% CI: 1.82 to 3.85, P < 0.001). With respect to recurrence, the HRs of 3.25, 1.93, and 2.11 also showed a strong relationship between high LNR and poor local, distant, and total recurrences.

CONCLUSIONS

Our present study demonstrates that a high LNR can predict poor survival in advanced rectal cancer. We suggest well-designed clinical trials to prospectively assess LNR as an independent predictor of rectal cancer survival.

Lymph node retrieval after dissolution of surrounding adipose tissue for pathological examination of colorectal cancer

Examination of >12 lymph nodes (LNs) is important for the diagnostic accuracy of nodal status following resection of colorectal cancer. In the present study, the efficacy of a fat dissolution technique for LN retrieval was evaluated using resected colon and rectum mesentery. First, the resected mesentery was searched for LNs by inspection and palpation immediately after surgery. Subsequently, fat dissolution liquid was applied to the remnant fat and the LN search was repeated. The primary endpoint was whether the second assessment would increase the number of evaluated LNs. Recruitment of 20 patients was planned. The study was conducted after institutional review board approval and written informed consent was obtained. Among 20 participants, 1 patient was excluded because LN dissection was not performed. The median number of LNs identified at the first and second assessments was 13 and 6, respectively, producing a significant increase in total LNs evaluated (13 vs. 20, respectively; P<0.01; paired t-test). One positive node was identified among the additionally identified LNs (0.9%, 1/107). The second assessment increased the number of LNs assessed to >12 in 4 patients, and although staging was not changed, the treatment was potentially altered in 2 stage II patients. The maximum diameter of the additionally obtained LNs was significantly smaller compared with those from the first assessment (4 vs. 7.7 mm, respectively; P<0.01; Wilcoxon signed-rank test). After the fat dissolution technique, the tumor cells were satisfactorily stained by carcinoembryonic antigen and cytokeratin-20. In conclusion, applying fat dissolution liquid to the remnant adipose tissue of the mesentery of the colon and rectum identified additional LNs. This method should be considered when insufficient LNs are identified after conventional LN retrieval.

Factors associated with short recurrence-free survival in completely resected colon cancer

Background: Several factors could affect disease recurrence in surgically resected colon cancer. While the role of certain factors such as cancer stage and grade is well established, the role of other factors (e.g., histological subtypes) is yet to be determined.

Objective:Therefore, we conducted a study to evaluate the impact of several factors in recurrence-free survival (RFS) in patients who were disease free following surgical resection of the colon cancer.

Design/Methods: Data were collected for patients with Stage I–III colon cancer who underwent complete surgical resection of the tumor between January 2010 and December 2015 in our institution. A total of 90 subjects met the inclusion criteria and were included in the study. The following factors were collected at the time of surgical resection of the colonic tumor: patient’s age, gender, colon cancer stage, grade and histological subtype, body mass index, hemoglobin A1c, and smoking history.

Results: A total of 28 patients (31%) developed recurrence and had a mean follow-up time of 19.8 months (range: 2–54.4 months). Median RFS was 54.4 months with a 5-year RFS of 49%. Advanced colonic cancer stage and mucinous histological subtype were associated with shorter RFS with an HR of 2.37, 95% CI = 1.38–4.06, and 95% CI = 1.02–5.90, respectively. Current smokers or those who quit less than 15 years earlier tended to have worse RFS with an HR of 2.47, 95% CI = 0.98–6.27.

Conclusion: Advanced colon cancer stage and mucinous histological subtype are independent risk factors for cancer recurrence and shorter RFS in completely resected colonic tumor.

Meta-analysis of the clinicopathological characteristics and peri-operative outcomes of colorectal cancer in obese patients

BACKGROUND

The effect of obesity on the clinicopathological characteristics of colorectal cancer (CRC) has not been clearly characterized. This meta-analysis assesses the pathological and perioperative outcomes of obese patients undergoing surgical resection for CRC.

METHODS

Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies reporting outcomes for obese and non-obese patients undergoing primary CRC resection, based on body-mass index measurement. Results were reported as mean differences or pooled odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

A total of 2183 citations were reviewed; 29 studies comprising 56,293 patients were ultimately included in the analysis, with an obesity rate of 19.3%. Obese patients with colorectal cancer were more often female (OR 1.2, 95% CI 1.1-1.2, p<0.001) but there was no difference in the proportion of rectal cancers, T4 tumours, tumour differentiation or margin positivity. Obese patients were significantly more likely to have lymph node metastases (OR 1.2, 95% CI 1.1-1.2, p<0.001), have a lower nodal yield, were associated with a longer duration of surgery, more blood loss and conversions to open surgery (OR 2.6, 95% CI 1.6-4.0, p<0.001) but with no difference in length of stay or post-operative mortality.

CONCLUSION

This meta-analysis demonstrates that obese patients undergoing resection for CRC are more likely to have node positive disease, longer surgery and higher failure rates of minimally invasive approaches. The challenges of colorectal cancer resection in obese patients are emphasized.

Lymph node retrieval in colorectal cancer: determining factors and prognostic significance

PURPOSE

The study aimed to analyze clinicopathological factors that determine the extent of lymph node retrieval and to evaluate its prognostic impact in patients with colorectal cancer (CRC).

METHODS

The number of retrieved lymph nodes was analyzed in 381 CRC specimens. Lymph node count was related to different clinicopathological variables by binary logistic regression. Progression-free survival (PFS) and cancer-specific survival (CSS) were determined using the Kaplan-Meier method and Cox regression models.

RESULTS

The median number of retrieved lymph nodes was 20 (mean 21 ± 10, range 1-65) in right-sided, 13 (16 ± 10, 1-66) in left-sided, and 15 (18 ± 11, 3-64) in rectal tumors. The number of retrieved lymph nodes was independently associated with T-classification (p < 0.001), N-classification (p = 0.014), and tumor size (p = 0.005) as well as right-sided tumor location (p = 0.012). There was no association with age, sex, tumor grade, mismatch-repair status, and lymph or blood vessel invasion. The longer the surgical specimen, the higher were the numbers of retrieved and positive lymph nodes (p < 0.001, respectively). In patients with locally advanced (T3/T4) tumors (n = 283), analysis of more than 12 lymph nodes was independently associated with PFS (HR = 0.63, p = 0.025) and CSS (HR = 0.54, p = 0.004). In the subset of T3/T4 N0 patients (n = 130), analysis of more than 12 lymph nodes similarly proved to be an independent predictor of outcome (PFS, HR = 0.48, p = 0.046; OS, HR = 0.41, p = 0.026).

CONCLUSION

The number of retrieved lymph nodes is associated with higher tumor stage, tumor size, and right-sided location. Low lymph node count indicates adverse outcome in patients with locally advanced (T3/T4) disease.

Body mass index and colorectal cancer prognosis: a systematic review and meta-analysis

Colorectal cancer is one of the most common cancers worldwide. However, it is unclear what influence body mass index (BMI) has on colorectal cancer prognosis. We conducted a systematic review and meta-analysis of observational studies to examine the association of BMI with colorectal cancer outcomes. We searched MEDLINE and EMBASE databases from inception to February 2015 and references of identified articles. We selected observational studies that reported all-cause mortality, colorectal cancer-specific mortality, recurrence and disease-free survival according to BMI category. Random-effects meta-analyses were conducted to combine estimates. We included 18 observational studies. Obese patients had an increased risk of all-cause mortality [relative risk (RR) 1.14; 95 % confidence interval (CI) 1.07-1.21], cancer-specific mortality (RR 1.14; 95 % CI 1.05-1.24), recurrence (RR 1.07; 95 % CI 1.02-1.13) and worse disease-free survival (RR 1.07; 95 % CI 1.01-1.13). Underweight patients also had an increased risk of all-cause mortality (RR 1.43; 95 % CI 1.26-1.62), cancer-specific mortality (RR 1.50; 95 % CI 1.20-1.87), recurrence (RR 1.13; 95 % CI 1.05-1.21) and worse disease-free survival (RR 1.27; 95 % CI 1.13-1.43). Overweight patients had no increased risk for any of the outcomes studied. Both obese and underweight patients with colorectal cancer have an increased risk of all-cause mortality, cancer-specific mortality, disease recurrence and worse disease-free survival compared to normal weight patients.

Non-surgical factors influencing lymph node yield in colon cancer

There are numerous factors which can affect the lymph node (LN) yield in colon cancer specimens. The aim of this paper was to identify both modifiable and non-modifiable factors that have been demonstrated to affect colonic resection specimen LN yield and to summarise the pertinent literature on these topics. A literature review of PubMed was performed to identify the potential factors which may influence the LN yield in colon cancer resection specimens. The terms used for the search were: LN, lymphadenectomy, LN yield, LN harvest, LN number, colon cancer and colorectal cancer. Both non-modifiable and modifiable factors were identified. The review identified fifteen non-surgical factors: (13 non-modifiable, 2 modifiable) which may influence LN yield. LN yield is frequently reduced in older, obese patients and those with male sex and increased in patients with right sided, large, and poorly differentiated tumours. Patient ethnicity and lower socioeconomic class may negatively influence LN yield. Pre-operative tumour tattooing appears to increase LN yield. There are many factors that potentially influence the LN yield, although the strength of the association between the two varies greatly. Perfecting oncological resection and pathological analysis remain the cornerstones to achieving good quality and quantity LN yields in patients with colon cancer.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

Association between body mass index and mortality for colorectal cancer survivors: overall and by tumor molecular phenotype

BACKGROUND

Microsatellite instability (MSI) and BRAF mutation status are associated with colorectal cancer survival, whereas the role of body mass index (BMI) is less clear. We evaluated the association between BMI and colorectal cancer survival, overall and by strata of MSI, BRAF mutation, sex, and other factors.

METHODS

This study included 5,615 men and women diagnosed with invasive colorectal cancer who were followed for mortality (maximum: 14.7 years; mean: 5.9 years). Prediagnosis BMI was derived from self-reported weight approximately one year before diagnosis and height. Tumor MSI and BRAF mutation status were available for 4,131 and 4,414 persons, respectively. Multivariable hazard ratios (HR) and 95% confidence intervals (CI) were estimated from delayed-entry Cox proportional hazards models.

RESULTS

In multivariable models, high prediagnosis BMI was associated with higher risk of all-cause mortality in both sexes (per 5-kg/m(2); HR, 1.10; 95% CI, 1.06-1.15), with similar associations stratified by sex (Pinteraction: 0.41), colon versus rectum (Pinteraction: 0.86), MSI status (Pinteraction: 0.84), and BRAF mutation status (Pinteraction: 0.28). In joint models, with MS-stable/MSI-low and normal BMI as the reference group, risk of death was higher for MS-stable/MSI-low and obese BMI (HR, 1.32; P value: 0.0002), not statistically significantly lower for MSI-high and normal BMI (HR, 0.86; P value: 0.29), and approximately the same for MSI-high and obese BMI (HR, 1.00; P value: 0.98).

CONCLUSIONS

High prediagnosis BMI was associated with increased mortality; this association was consistent across participant subgroups, including strata of tumor molecular phenotype.

IMPACT

High BMI may attenuate the survival benefit otherwise observed with MSI-high tumors.

Colorectal cancer and lymph nodes: The obsession with the number 12

Lymphadenectomy of colorectal cancer is a decisive factor for the prognostic and therapeutic staging of the patient. For over 15 years, we have asked ourselves if the minimum number of 12 examined lymph nodes (LNs) was sufficient for the prevention of understaging. The debate is certainly still open if we consider that a limit of 12 LNs is still not the gold standard mainly because the research methodology of the first studies has been criticized. Moreover many authors report that to date both in the United States and Europe the number “12” target is uncommon, not adequate, or accessible only in highly specialised centres. It should however be noted that both the pressing nature of the debate and the dissemination of guidelines have been responsible for a trend that has allowed for a general increase in the number of LNs examined. There are different variables that can affect the retrieval of LNs. Some, like the surgeon, the surgery, and the pathology exam, are without question modifiable; however, other both patient and disease-related variables are non-modifiable and pose the question of whether the minimum number of examined LNs must be individually assigned. The lymph nodal ratio, the sentinel LNs and the study of the biological aspects of the tumor could find valid application in this field in the near future.

Qualitative and quantitative issues of lymph nodes as prognostic factor in colon cancer

For patients undergoing curative resections for colon cancer, the nodal status represents the strongest prognostic factor, yet at the same time the most disputed issue as well. Consequently, the qualitative and quantitative aspects of lymph node evaluation are thus being scrutinized beyond the blunt distinction between 'node positive' (pN+) and 'node negative' (pN0) disease. Controversy ranges from a minimal or 'least-unit' strategy as exemplified by the 'sentinel node' to a maximally invasive or 'all inclusive' approach by extensive surgery. Ranging between these two extremes of node sampling strategies are factors of quantitative and qualitative value, which may be subject to modification. Qualitative issues may include aspects of lymph node harvest reflected by surgeon, pathologist and even hospital performance, which all may be subject to modification. However, patient's age, gender and genotype may be non-modifiable, yet influence node sample. Quantitative issues may reflect the balance between absolute numbers and models investigating the relationships of positive to negative nodes (lymph node ratio; log odds of positive lymph nodes). This review provides an updated overview of the current controversies and a state-of-the-art perspective on the qualitative and quantitative aspects of using lymph nodes as a prognostic marker in colon cancer.