A comprehensive evaluation of 80 consecutive robotic low anterior resections: impact of not mobilizing the splenic flexure alongside low-tie vascular ligation as a standardized technique

Rectal cancer surgery represents challenges due to its location. To overcome them and minimize the risk of anastomosis-related complications, some technical maneuvers or even a diverting ileostomy may be required. One of these technical steps is the mobilization of the splenic flexure (SFM), especially in medium/low rectal cancer. High-tie vascular ligation may be another one. However, the need of these maneuvers may be controversial, as especially SFM may be time-consuming and increase the risk of iatrogenic. The objective is to present the short- and long-term outcomes of a low-tie ligation combined with no SFM in robotic low anterior resection (LAR) for mid- and low rectal cancer as a standardized technique. A retrospective observational single-cohort study was carried out at Reina Sofia University Hospital, Cordoba, Spain. 221 robotic rectal resections between Jul-18th-2018 and Jan-12th-2023 were initially considered. After case selection, 80 consecutive robotic LAR performed by a single surgeon were included. STROBE checklist assessed the methodological quality. Histopathological, morbidity and oncological outcomes were assessed. Anastomotic stricture occurrence and distance to anal verge were evaluated after LAR by rectosigmoidoscopy. Variables related to the ileostomy closure such as time to closure, post-operative complications or hospital stay were also considered. The majority of patients (81.2%) presented a mid-rectal cancer and the rest, lower location (18.8%). All patients had adequate perfusion of the anastomotic stump assessed by indocyanine green. Complete total mesorectal excision was performed in 98.8% of the patients with a lymph node ratio < 0.2 in 91.3%. The anastomotic leakage rate was 5%. One patient (1.5%) presented local recurrence. Anastomosis stricture occurred in 7.5% of the patients. The limitations were small cohort and retrospective design. The non-mobilization of the splenic flexure with a low-tie ligation in robotic LAR is a feasible and safe procedure that does not affect oncological outcomes.

A prospective study of dual-energy computed tomography for differentiating metastatic and non-metastatic lymph nodes of colorectal cancer

Background

Colorectal cancer (CRC) is the third most common malignancy worldwide, and lymph node metastasis is considered to be a risk factor for local recurrence and a poor prognosis in colorectal cancer. However, there remains a lack of reliable and non-invasive biomarkers to identify the lymph node status of CRC patients preoperatively. The purpose of this study was to explore the ability of dual-energy computed tomography (DECT) to differentiate metastatic from non-metastatic lymph nodes in colorectal cancer.

Methods

Seventy-one patients with primary colorectal cancer underwent contrast-enhanced dual-energy computed tomography imaging preoperatively. The colorectal specimen was scanned postoperatively, and lymph nodes were matched to the pathology report. The following dual-energy computed tomography quantitative parameters were analyzed: dual-energy curve slope value (λ_HU), standardized iodine concentration (n△HU), iodine water ratio (nIWR), electron density value (nρ_eff), and effective atom-number (nZ), based on metastatic and non-metastatic lymph node differentiation. Also, sensitivity and specificity analyses were performed using receiver operating characteristic curves.

Results

In all patients, one hundred and fifty lymph nodes, including 66 non-metastatic and 84 metastatic lymph nodes, were matched using the radiological-pathological correlation. Metastatic nodes had significantly greater λ_HU, n△HU, and nIWR values than non-metastatic nodes in both the arterial and venous phases (P<0.01). The area under curve (AUC), sensitivity, and specificity were 0.80, 80%, and 66% for λ_HU; 0.86, 70%, and 95% for n△HU; and 0.88, 71%, and 95% for nIWR in the arterial phase. There was no significant difference in electron density and effective Z values between metastatic and non-metastatic lymph nodes.

Conclusions

DECT quantitative parameters may help differentiate between metastatic and normal lymph nodes in patients with CRC.

Biomarkers and cell-based models to predict the outcome of neoadjuvant therapy for rectal cancer patients

Rectal cancer constitutes approximately one-third of all colorectal cancers and contributes to considerable mortality globally. In contrast to colon cancer, the standard treatment for localized rectal cancer often involves neoadjuvant chemoradiotherapy. Tumour response rates to treatment show substantial inter-patient heterogeneity, indicating a need for treatment stratification. Consequently researchers have attempted to establish new means for predicting tumour response in order to assist in treatment decisions. In this review we have summarized published findings regarding potential biomarkers to predict neoadjuvant treatment response for rectal cancer tumours. In addition, we describe cell-based models that can be utilized both for treatment prediction and for studying the complex mechanisms involved.

Prognostic importance of lymph node count and ratio in rectal cancer after neoadjuvant chemoradiotherapy: Results from a cross-sectional study

BACKGROUND

The aim of this study was to determine the prognostic value of lymph node count (LNC) and lymph node ratio (LNR) in rectal cancer after neoadjuvant chemoradiotherapy (CRT).

METHODS

Patients who underwent neoadjuvant CRT and total mesorectal excision (TME) for Stage I-III rectal cancer were selected from a cross-sectional study including 71 Dutch centres. Primary outcome parameters were disease-free survival (DFS) and overall survival (OS). Prognostic significance of LNC and LNR (cut-off values 0.15, 0.20, 0.30) was tested for different (sub)groups.

RESULTS

From 2095 registered patients, 458 were included, of which 240 patients with LNC < 12 and 218 patients with LNC ≥ 12. LNC was not significantly associated with DFS (p = 0.35) and OS (p = 0.59). In univariable analysis, LNR was significantly associated with DFS and OS in the whole cohort and LNC subgroups, but not in multivariable analysis.

CONCLUSIONS

LNC was not associated with long-term oncological outcome in rectal cancer patients treated with CRT, nor was LNR when corrected for N-stage. However, LNR might be used to identify subgroups of node-positive patients with a favourable outcome.

Lymph Node Ratio as a Prognostic Marker in Rectal Cancer Survival: A Systematic Review and Meta-Analysis

Introduction 

The lymph node ratio (LNR) is defined as the ratio of the number of positive lymph nodes to the total number of nodes retrieved. LNR has recently emerged as a prognostic factor in rectal cancer. The objective of our study was to pool eligible studies to elucidate the prognostic role of LNR on overall survival (OS) and disease-free survival (DFS) in rectal cancer patients using a meta-analysis.

Methods

A systematic database search was performed in MEDLINE and Embase for relevant studies that reported LNR in rectal cancer. Two authors independently screened the relevant articles for selection and data extraction. As a result, a list of such studies and references, published in English up to December 2019, was obtained, and a total of 4,486 node-positive patients in 18 studies were included in this meta-analysis. RevMan software 5.3 (Cochrane Collaboration, the Nordic Cochrane Centre, Copenhagen) was used for conducting all statistical analyses.

Results

A higher LNR was significantly correlated with worse OS [hazard ratio (HR): 2.60; 95% confidence interval (CI): 2.21-3.06; p≤.00001] and DFS (HR: 2.43; 95% CI: 2.11-2.80; p≤.00001) in node-positive rectal cancer patients. Besides, LNR is an independent predictive and prognostic marker of OS and DFS (HR: 2.52; 95% CI: 2.17-2.94; p≤.00001 with I²=0%; p=.32 and HR: 2.63; 95% CI: 2.17-3.18; p≤.00001 with I²=0%; p=.63 respectively, irrespective of lymph nodal harvest).

Conclusions

Our present study demonstrates that LNR is an independent predictor of survival in rectal cancer. LNR should be considered as a parameter in future oncological staging systems. Further well-designed randomized control trials to prospectively assess LNR as an independent predictor of rectal cancer survival are necessary before its application in daily practice.

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.

A Distal Resection Margin of ≤1 mm and Rectal Cancer Recurrence After Sphincter-Preserving Surgery: The Role of a Positive Distal Margin in Rectal Cancer Surgery

BACKGROUND

There is little information about the prognostic value of a microscopically positive distal margin in patients who have rectal cancer.

OBJECTIVE

We aimed to investigate the influence of a distal margin of ≤1 mm on oncologic outcomes after sphincter-preserving resection for rectal cancer.

DESIGN

This is a retrospective cohort study.

SETTINGS

The study was conducted at 2 hospitals.

PATIENTS

A total of 6574 patients underwent anterior resection for rectal cancer from January 1999 to December 2014; 97 (1.5%) patients with a distal margin of ≤1 mm were included in this study. For comparative analyses, patients were matched with 194 patients with a negative distal margin (>1 mm) according to sex, age, BMI, ASA score, neoadjuvant treatment, tumor location, and stage.

MAIN OUTCOME MEASURES

The oncologic outcomes of the 2 groups were compared.

RESULTS

Perineural and lymphovascular invasion rates were significantly higher in patients with a positive distal margin (54.6% vs 28.9%; 67.0% vs 42.8%; both p < 0.001) compared with to patients with negative distal margin. Comparison between microscopically positive and negative distal margin showed worse oncologic outcomes in patients with a microscopically positive distal margin, including 5-year local recurrence rate (24.1% vs 12.0%, p = 0.005); 5-year distant recurrence rate (35.5% vs 20.2%, p = 0.011); 5-year disease-free survival (45.5% vs 69.5%, p < 0.001); and 5-year OS (69.2% vs 79.7%, p = 0.004). Among the 97 patients with a microscopically positive distal margin, the 5-year disease-free survival rate was higher in patients who received adjuvant therapy (52.0% vs 30.7%, p = 0.089).

LIMITATIONS

This is a retrospective study; bias may exist.

CONCLUSIONS

A distal margin of 1 mm is associated with worse oncologic results. Our data indicate the importance of achieving a clear distal margin in the surgical treatment of rectal cancer. Adjuvant therapy should be used in these patients to reduce recurrence. See Video Abstract at http://links.lww.com/DCR/A408.

LODDS is superior to lymph node ratio for the prognosis of node-positive rectal cancer patients treated with preoperative radiotherapy

PURPOSE

Yielding pathologic-lymph node ratio (yp-LNR) was considered to be a better staging system than yp-N stage in rectal cancer patients treated with preoperative radiotherapy (pre-RT). We aimed to compare the predictive ability of yielding pathologic log odds of positive lymph nodes (yp-LODDS) with that of yp-LNR for cancer-specific survival (CSS) in stage III rectal cancer patients treated with pre-RT.

METHODS

We analyzed stage III rectal cancer patients treated with pre-RT in the Surveillance, Epidemiology and End Results (SEER) database. Patients were classified into 4 groups, yp-LNR1 to 4, based on the LNR cutoff points 0.25, 0.50, and 0.75. Subjects were categorized into 5 groups, yp-LODDS1 to yp-LODDS5, based on the LODDS cutoff points -1, 0, 1, and 2. Univariate and multivariate Cox proportional hazards models were performed to analyze the risk factors for survival outcome.

RESULTS

A total of 4,612 patients were included from the SEER database. Patients in the yp-LNR4 group could be further divided into yp-LODDS4 and yp-LODDS5 groups with 5-year CSS of 47.6% and 31.5%, respectively (p&lt;0.001). In the multivariate analysis without yp-LODDS, yp-LNR was an independent prognostic factor (hazard ratio [HR] 2.006, 95% confidence interval [CI] 1.619-2.484, p&lt;0.001). However, after adjusting for yp-LODDS, yp-LNR was no longer associated with CSS (p = 0.393), and yp-LODDS was identified as an independent prognostic factor (HR 1.274, 95% CI 1.069-1.520, p = 0.007).

CONCLUSIONS

The prognostic value of yp-LNR can be confounded by yp-LODDS. In stage III rectal cancer patients treated with pre-RT, yp-LODDS has superior discrimination power over yp-LNR and can more accurately evaluate CSS.

Prognostic Value of Lymph Node Ratio in Locally Advanced Rectal Cancer Patients After Preoperative Chemoradiotherapy Followed by Total Mesorectal Excision

Although the absolute number of positive lymph nodes (LNs) has been established as 1 of the most important prognostic factors in rectal cancers, many researchers have proposed that the lymph node ratio (LNR) may have better predicted outcomes. We conducted a retrospective study to compare the predictive ability of LNR and ypN category in rectal cancer. A total of 264 locally advanced rectal cancer (LARC) patients who underwent preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) between 2005 and 2012 were reviewed. All patients were categorized into 3 groups or patients with metastatic LNs were categorized into 2 groups according to the LNR. The prognostic effect on overall survival (OS) and disease-free survival (DFS) was evaluated. With a median follow-up of 45 months, the OS and DFS were 68.4% and 59.3% for the entire cohort, respectively. The respective 5-year OS and DFS rates for the 3 groups (LNR = 0, 0 < LNR ≤ 0.20, and 0.20 < LNR ≤ 1.0) were as follows: 83.2%, 72.6%, and 49.4% (P < 0.001) and 79.5%, 57.3%, and 33.5% (P < 0.001), respectively. Multivariate analysis revealed that LNR and differentiation, but not the number of positive LNs, had independent prognostic value for OS (hazard ratio [HR] = 2.328, 95% confidence interval [CI]: 1.850-4.526, P < 0.001) and DFS (HR = 3.004, 95% CI: 1.616-5.980, P < 0.001). As for patients with positive LNs, the respective 5-year OS and DFS rates for the 2 groups (0 < LNR ≤ 0.20, and 0.20 < LNR ≤ 1.0) were 72.6% and 49.4% (P < 0.001) and 57.3% and 33.5% (P < 0.001), respectively. Multivariate analysis revealed that only LNR was an independent factor for OS (HR = 3.214, 95% CI: 1.726-5.986, P < 0.001) and DFS (HR = 4.230, 95% CI: 1.825-6.458, P < 0.001). Subgroups analysis demonstrated that the ypN category had no impact on survival whereas increased LNR was a significantly prognostic indicator for worse survival in the LNs < 12 subgroup. LNR is an independent prognostic factor in LARC patients treated with preoperative CRT followed by TME. It may be a better independent staging method than the number of metastatic LNs when <12 LNs are harvested after preoperative CRT.

Clinical parameters predicting pathologic complete response following neoadjuvant chemoradiotherapy for rectal cancer

Introduction

Preoperative chemoradiotherapy (CRT), followed by total mesorectal excision, has become the standard of care for patients with clinical stages II and III rectal cancer. Patients with pathologic complete response (pCR) to preoperative CRT have been reported to have better outcomes than those without pCR. However, the factors that predict the response to neoadjuvant CRT have not been well defined. In this study, we aimed to investigate the impact of clinical parameters on the development of pCR after neoadjuvant chemoradiation for rectal cancer.

Methods

A total of 323 consecutive patients from a single institution who had clinical stage II or III rectal cancer and underwent a long-course neoadjuvant CRT, followed by curative surgery, between 2005 and 2013 were included. Patients were divided into two groups according to their responses to neoadjuvant therapy: the pCR and non-pCR groups. The clinical parameters were analyzed by univariate and multivariate analyses, with pCR as the dependent variable.

Results

Of the 323 patients, 75 (23.2%) achieved pCR. The two groups were comparable in terms of age, sex, body mass index, tumor stage, tumor location, tumor differentiation, radiation dose, and chemotherapy regimen. On multivariate analysis, a pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL [odds ratio (OR) = 2.170, 95% confidence interval (CI) = 1.195–3.939, P = 0.011] and an interval of >7 weeks between the completion of chemoradiation and surgical resection (OR = 2.588, 95% CI = 1.484–4.512, P = 0.001) were significantly associated with an increased rate of pCR.

Conclusions

The pretreatment CEA level and neoadjuvant chemoradiotherapy-surgery interval were independent clinical predictors for achieving pCR. These results may help clinicians predict the prognosis of patients and develop adaptive treatment strategies.

Can induction chemotherapy before concurrent chemoradiation impact circumferential resection margin positivity and survival in low rectal cancers?

BACKGROUND

Distance from anal verge and abdominoperineal resection are risk factors for circumferential resection margin (CRM) positivity in rectal cancer. Induction chemotherapy (IC) before concurrent chemoradiation (CRT) has emerged as a new treatment modification. Impact of IC before concurrent CRT on CRM positivity in low rectal cancer remains to be independently studied. The objective of this study was to determine CRM positivity in low rectal cancer, with and without prior IC, and to identify predictors of disease free and overall survival.

MATERIALS AND METHODS

Patients who underwent surgery for rectal cancer between 2005 and 2011 were retrospectively reviewed and divided into two groups. Group 1 received IC before CRT and Group 2 did not. Demographics, clinicopathological variables and CRM status were compared. Actuarial 5 year disease free survival (DFS), overall survival (OS) and independent predictors of survival were determined.

RESULTS

Patients in the IC group presented with advanced stage (Stage 3=89.2% versus 75.4%) (P=0.02) but a high rate of total mesorectal excision (TME) (100% versus 93.4%) (P=0.01) and sphincter preservation surgery (54.9 % versus 22.9%) (P=0.001). Patients with low rectal cancer who received IC had a significantly low positive CRM rate (9.2% versus 34%) (P=0.002). Actuarial 5 year DFS in IC and no IC groups were 39% and 43% (P=0.9) and 5 year OS were 70% and 47% (P=0.003). Pathological tumor size [HR: 2.2, CI: 1.1-4.5, P=0.01] and nodal involvement [HR: 2, CI: 1.08-4, P=0.02] were independent predictors of relapse while pathological nodal involvement [HR: 2.6, CI: 1.3-4.9, P=0.003] and IC [HR: 0.7, CI: 0.5-0.9, P=0.02] were independent predictors of death.

CONCLUSIONS

In low rectal cancer, induction chemotherapy before CRT may significantly decrease CRM positivity and improve 5 year overall survival.