Circumferential Resection Margin Involvement Research Articles

Comparative Outcomes of Robotic Versus Open Proctectomy for Rectal Cancer at High Risk of Positive Circumferential Resection Margin.

Concerns persist regarding the effectiveness of robotic proctectomy when compared with open proctectomy for locally advanced rectal cancer with a high risk of circumferential resection margin involvement. Comparison of surrogate cancer outcomes following robotic versus open proctectomy in this subpopulation. Retrospective cohort study. Three academic hospitals (Mayo Clinic Arizona, Florida, and Rochester) through the Mayo Data Explorer platform. Patients at high risk of circumferential resection margin involvement were selected based on the magnetic resonance imaging-based definition from Mercury I and II trials. Rate of pathologic circumferential resection margin involvement (≤1 mm), mesorectal grading, rate of distal margin involvement. Out of 413 patients, 125 (30%) underwent open and 288 (70%) robotic proctectomy. Open proctectomy was significantly associated with a greater proportion of cT4 tumors (39.3% vs. 24.8%, p = 0.021), multivisceral/concomitant resections (40.8% vs. 18.4%, p < 0.001) and less frequent total neoadjuvant therapy use (17.1% vs. 47.1%, p = 0.001). Robotic proctectomy was less commonly associated with pathologic circumferential resection margin involvement (7.3% vs. 17.6%, p = 0.002), including after adjustment for cT stage, neoadjuvant therapy, and multivisceral resection (OR 0.326, 95% CI, 0.157-0.670, p = 0.002). Propensity score-matching on 66 patients per group and related multivariable analysis no longer indicated any reduction of circumferential positive margin rate associated with robotic surgery (p = 0.86 and p = 0.18). Mesorectal grading was comparable (incomplete mesorectum in 6% RP patients vs. 11.8% OP patients, p = 0.327). All cases had negative distal resection margins. Retrospective design. In patients with locally advanced rectal cancer at high risk of circumferential resection margin involvement, robotic proctectomy is an effective approach and could be pursued when technically possible as an alternative to open proctectomy. See Video Abstract.

The mode of circumferential margin involvement in rectal cancer determines its impact on outcomes: A population-based study

BackgroundThe clinical value of different modes of CRM involvement in rectal cancer patients is unclear. This study aims to determine the clinical impact of different modes of circumferential resection margin (CRM) involvement in patients with a locally advanced rectal carcinoma. Patients and methodsA cohort of patients who were diagnosed with stage III rectal cancer between June 2014 and June 2020 was selected from the prospective Dutch nationwide pathology databank (PALGA). Histopathological and clinical data were analyzed according to the nature of CRM involvement (via primary tumor invasion, lymph node metastasis, tumor deposit, multiple factors) and analyses on recurrence and overall survival (OS) were performed. Results3020 patients were included, of whom 12.4 % had a positive CRM. The majority of these patients (63.2 %) had CRM involvement by primary tumor invasion and in 9 % of patients multiple factors caused the positive CRM. The rates of local recurrence and distant metastasis were related to the nature of the CRM involvement, with lowest rate for lymph node metastasis and highest rate for multiple factors. On multivariate analysis, CRM involvement by primary tumor invasion, tumor deposits and multiple factors, but not by lymph node metastasis, were associated with poor OS. ConclusionThis nationwide population based study highlights the clinical importance of reporting the nature of CRM involvement in rectal cancer patients. Lymph node metastasis involving the CRM does not bear the same risks for local recurrence, distant metastases and OS as CRM involvement by primary tumor invasion or CRM involvement by multiple factors.

A comparison of whole-mount and conventional sections for pathological mesorectal extension and circumferential resection margin assessment after total mesorectal excision

IntroductionThe objective of the study is to compare 2 techniques for histological handling of rectal cancer specimens, namely whole-mount in a large block vs conventional sampling using small blocks, for mesorectal pathological assessment of circumferential resection margin status and depth of tumor invasion into the mesorectal fat. MethodsThis is a prospective study including 27 total mesorectal excision specimens of rectal cancer from patients treated for primary rectal carcinoma between 2020 and 2022 in a specialized multidisciplinary Colorectal Unit. For each total mesorectal excision specimen, 2 contiguous representative tumoral slices were selected and comparatively analyzed with whole-mount and small blocks macroscopic dissection techniques, enabling comparison between them in the same surgical specimen. The agreement between the 2 techniques to assess the distance of the tumor from the circumferential resection margin as well as the depth of tumor invasion was evaluated with the Student’s t-test for paired samples, Pearson’s correlation coefficient, and the Bland-Altman method comparison analysis. ResultsComplete mesorectal excision was observed in 8% of cases. Circumferential resection margin involvement was observed in only one case (4 %). The whole-mount and small block techniques obtained similar results when we assessed the distance to the circumferential resection margin (t-test P = 0.8, r = 0.92) and the depth of mesorectal infiltration (t-test P = 0.6, r = 0.95). ConclusionsBoth gross dissection techniques (whole-mount vs multiple small cassettes) are equivalent and reliable to assess the distance to circumferential resection margin and the depth of mesorectal infiltration in the mesorectal fat in rectal cancer staging.

Tailoring rectal cancer surgery: Surgical approaches and anatomical insights during deep pelvic dissection for optimal outcomes in low‐lying rectal cancer

AbstractThis review article explores advanced surgical approaches and anatomical insights for tailoring rectal cancer surgery, particularly focusing on low‐lying rectal cancer. With the evolution of imaging technologies, precise preoperative planning has become possible, enhancing the visualization of anatomy surrounding the rectum and enabling more accurate assessments of circumferential resection margin (CRM) involvement. The article emphasizes the dynamic nature of rectal cancer treatment, advocating for individualized surgical planning based on comprehensive preoperative imaging and intraoperative assessment. This approach aims to optimize patient care by integrating recent advancements and anatomical insights into clinical practice for the management of low‐lying rectal cancer. Particularly, the article discusses the importance of customizing the excision of Denonvilliers' fascia (DVF) based on tumor characteristics for optimal oncologic and functional outcomes, especially for anteriorly located tumors. It highlights the need for precise dissection techniques to ensure a negative CRM while preserving critical anatomical structures. Additionally, the review addresses the surgical management of tumors at the anorectal ring and introduces the Gate Approach for deep anterolateral pelvic dissection. Special attention is given to tumors impacting the membranous and prostate urethra, emphasizing tailored surgical approaches to balance complete tumor resection with the preservation of urogenital functions.

Pelvic Diameter is not Associated with Positive Circumferential Resection Margin in Rectal Cancer: Retrospective Analysis of 78 Cases

Abstract Objective To identify if there is an association between pelvic entry and pelvic outlet diameters with increased positive circumferential resection margin (CRM) in rectal cancer. Introduction Positive CRM in rectal cancer is a major predictor for local and distant recurrence. Pelvic diameters may be related to the difficulty of dissection, as well as intrinsic tumor characteristics such as tumor size, location, distance from the anal margin, and T stage, which may compromise the integrity of the mesorectum and circumferential margin involvement. Methods A retrospective review of the patient's medical records who underwent surgical resection of rectal adenocarcinoma from January 2012 to June 2022 was performed. The patient's preoperative staging, operative characteristics, and histopathologic outcomes were gathered from the medical records. Preoperative MRI scanning was done in all patients. MRI pelvimetry was done by two observers. CRM involvement was recorded as stated in the pathology report. Pelvimetry variables were dichotomized according to their mean values for correlation analysis. The odds ratio (OR) was calculated from a binary logistics regression model to assess the relation between the positive CRM and the independent variables. Results A total of 78 patients were included in this study. A positive CRM was reported in 10 patients (12.8%). BMI &gt;27.4 + 6.6 (p = 0.02), positive extramural vascular invasion (p = 0.027), positive CRM by MRI scanning (p = 0.004), and anal sphincter involvement (p = 0.03) were associated with positive CRM. Pelvimetry values were not associated with a positive CRM. Conclusion No association was found between the pelvic diameters measured by MRI pelvimetry with a positive CRM.

A comparison of whole-mount and conventional sections for pathological mesorectal extension and circumferential resection margin assessment after total mesorectal excision

IntroductionThe objective of the study is to compare 2 techniques for histological handling of rectal cancer specimens, namely whole-mount in a large block vs conventional sampling using small blocks, for mesorectal pathological assessment of circumferential resection margin status and depth of tumor invasion into the mesorectal fat. MethodsThis is a prospective study including 27 total mesorectal excision specimens of rectal cancer from patients treated for primary rectal carcinoma between 2020 and 2022 in a specialized multidisciplinary Colorectal Unit. For each total mesorectal excision specimen, 2 contiguous representative tumoral slices were selected and comparatively analyzed with whole-mount and small blocks macroscopic dissection techniques, enabling comparison between them in the same surgical specimen. The agreement between the 2 techniques to assess the distance of the tumor from the circumferential resection margin as well as the depth of tumor invasion was evaluated with the Student’s t-test for paired samples, Pearson’s correlation coefficient, and the Bland-Altman method comparison analysis. ResultsComplete mesorectal excision was observed in 8% of cases. Circumferential resection margin involvement was observed in only one case (4 %). The whole-mount and small block techniques obtained similar results when we assessed the distance to the circumferential resection margin (t-test P = 0.8, r = 0.92) and the depth of mesorectal infiltration (t-test P = 0.6, r = 0.95). ConclusionsBoth gross dissection techniques (whole-mount vs multiple small cassettes) are equivalent and reliable to assess the distance to circumferential resection margin and the depth of mesorectal infiltration in the mesorectal fat in rectal cancer staging.

Impact of visceral fat area on short-term outcomes in robotic surgery for mid and low rectal cancer.

Rectal cancer is one of the most prevalent cancers that arise in the digestive tract. The purpose of this retrospective study was to investigate the impact of visceral fat area (VFA) on postoperative outcomes in mid and low rectal cancer patients undergoing robotic surgery (RS). Data were collected on patients who underwent robotic anterior rectal resection in a single center from December 2019 to October 2023. Clinical pathology information was analyzed. Statistical analysis was done on the computed tomography (CT) imaging data. A total of 277 patients were included in the study, including 121 cases with visceral obesity (VO) and 156 cases without VO. There was no statistically significant disparity in the lymph node dissection count, blood loss, duration of hospitalization, time to first liquid diet, early postoperative complications, histopathologic specimen indices (quality of TME and CRM involvement rate), and or the rate of conversion to open surgery between VO and non-VO group (P>0.05). Nevertheless, the group of individuals with VO experienced a lengthier duration of surgery (P<0.001) and a delayed time until the first passage of flatus (P<0.001) in comparison to the group without VO. The study suggests that VO does not significantly impact early complications or the quality of surgical outcomes in mid and low rectal cancer patients undergoing robotic surgery. The findings support the continued use of RS as an optimal strategy for technically demanding patients.

Total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC): Real-world experience from a tertiary Asian cancer center.

39 Background: Multiple studies of TNT for LARC have shown improved pathological complete response (pCR) rate and disease-free survival (DFS). However, real-world data in Asia is limited. Methods: Patients (pts) diagnosed with LARC at National University Cancer Institute, Singapore were discussed at a multidisciplinary tumor board. Patients were eligible for TNT if they had cT2/3N+ or cT4Nany, threatened circumferential resection margin (CRM) and adequate organ function. TNT protocol was systemic chemotherapy with 5-6 cycles of mFOLFOX6 (5-fluorouracil, leucovorin, oxaliplatin) or 3-4 cycles of XELOX (capecitabine, oxaliplatin) followed by short- or long-course chemoradiation (CRT), then 3 cycles of mFOLFOX6 or 2 cycles of XELOX. Clinical outcomes included rates of clinical complete response (cCR), pCR, surgery type, R0 resection and DFS. Baseline pt demographics, laboratory results and tumor characteristics were analyzed against these outcomes. Results: 173/205 pts who were diagnosed with rectal cancer between February 2020 and November 2022 had LARC and 47 received TNT. Median age was 65 (range: 33-79), 68.1% male, 78.7% were Chinese, 19.2% had cT4 tumors, 87.2% node positive and 80.9% had CRM involvement. Median tumor distance from anal verge was 6cm (range: 1-15cm) on colonoscopy and 5cm (range: 2-12cm) on magnetic resonance imaging. 95.7% received XELOX, 87.0% had long-course CRT and 83.0% completed all cycles of systemic chemotherapy and CRT. 44.7% had dose reduction of systemic therapy and 4.3% required emergent surgery due to local complications during TNT. After TNT completion, 7 pts did not pursue surgery – 3 achieved cCR (6.4%) and adopted a watch-and-wait approach, 2 had disease progression (PD), and 2 declined. Of those who underwent surgery, 75.0% had sphincter-preserving surgery and 85.0% achieved R0 resection. 2.1% (n =1) achieved pCR. Rates of tumour regression grade (TRG) 0, 1, 2, 3 were 7.5%, 15.0%, 67.5% and 10.0%, respectively. After a median follow up of 21.7 months (range: 9.3 – 41.6 months), 21.3% (n = 10) had disease recurrence and 14.9% (n=7; 5 from PD, 1 from surgery-related complication, 1 unrelated to treatment) passed away. 1-year DFS rate was 88.7% (95% CI 75.0% - 95.2%). Conclusions: This is the first Asian study reporting real-world data of TNT for LARC since its wide-scale adoption. pCR rates appear lower than reported studies. Understanding the limitation of retrospective studies, further analysis is ongoing to determine if factors other than sequence of modality can contribute to the observed findings.

Circumferential resection margin positivity due to direct or indirect tumour involvement in rectal cancer - a call for better stratification.

A positive circumferential resection margin (CRM) after rectal cancer surgery, which can be the result of direct or indirect tumour involvement, has consistently been associated with increased local recurrence and poorer survival. However, little is known of the differential impact of the mode of tumour involvement on outcomes. 1460 consecutive patients undergoing rectal cancer resection between 2003 and 2018 were retrospectively assessed. Histopathology reports for patients with a positive CRM were reviewed to determine cases of direct (R1-tumour) or indirect tumour involvement (R1-other). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis. The role of the mode of CRM positivity was examined by univariate and multivariate Cox proportional hazards models. Eighty-five patients had an R1 resection due to CRM involvement (5.8%). Of those, 69 were due to direct tumour involvement, while 16 were from indirect causes. Kaplan-Meier analysis revealed that R1-other was associated with increased OS (hazard ratio 0.40, log-rank P = 0.006) and DFS (P = 0.043). Multivariate regression confirmed that the mode of CRM positivity was an independent predictor of OS. More interestingly, the patterns of recurrence were different between the two groups, with R1-tumour leading to significantly more local recurrence (P = 0.04). Our data strongly suggests that direct tumour involvement of the CRM confers worse prognosis after rectal cancer surgery. Importantly, differences in the site and frequency of recurrences make a case for better stratification of patients with a positive CRM to guide treatment decisions.

Impact of robotic total mesorectal excision upon pathology metrics in overweight males with low rectal cancer: a pooled analysis of 836 cases.

The aim of this pooled analysis was to evaluate the impact of robotic total mesorectal excision (TME) on pathology metrics in Male Overweight patients with Low rectal cancer (MOL). This was a multicenter retrospective pooled analysis of data. Two groups were defined: MOL (Male, Overweight, Low rectal cancer) and non-MOL. Overweight was defined as BMI ≥ 25kg/m2. Low rectal cancer was defined as cancer within 6cm from the anal verge. The primary endpoints of this study were histopathological metrics, namely circumferential resection margin (CRM) (mm), CRM involvement rate (%), and the quality of TME. Circumferential resection margin (CRM) was involved if < 1mm. 836 (106 MOL and 730 non-MOL) patients that underwent robotic TME by six surgeons over 3years were compared. No significant differences in demographics and perioperative variables were found, except for operating time, distal margin, and number of lymph nodes harvested. CRM involvement rate did not significantly differ (7.5% vs. 5.5%, p = 0.395). Mean CRM was statistically significantly narrower in MOL patients (6.6 vs. 7.7mm, p = 0.04). Quality of TME did not differ. Distance of tumor from the anal verge was the only independent predictor of CRM involvement. Robotic TME may provide optimal pathology metrics in overweight males with low rectal cancer. Although CRM was a few millimeters narrower in MOL, the values were within the range of uninvolved margins making the difference statistically significant, but not clinically. Being MOL was not a risk factor for involvement of circumferential resection margin.

Recurrence Patterns and Risk Factors after Curative Resection for Colorectal Cancer: Insights for Postoperative Surveillance Strategies.

This study aimed to assess recurrence patterns and related risk factors following curative resection of colorectal cancer (CRC). This retrospective observational study was conducted at a tertiary care center, including 2622 patients with stage I-III CRC who underwent curative resection between 2008 and 2018. Hazard rates of recurrence were calculated using a hazard function. The primary outcome was the peak recurrence time after curative resection and secondary outcomes were prognostic factors associated with recurrence. Over a median follow-up period of 53 months, the overall, locoregional and systemic recurrence rates were 8.9%, 0.7%, and 8.5%, respectively. Recurrence rates were significantly higher for rectal cancer (14.9% overall, 4.4% locoregionally, and 12.3% systemically) than for colon cancer (all p < 0.001). The peak recurrence time was 11 months, with variations in hazard rates and curves depending on the tumor location, stage, and risk factors. Patients with AL or CRM involvement exhibited a distinct pattern, with a high hazard rate in the early postoperative period. Understanding these recurrence patterns and risk factors is crucial for establishing effective postoperative surveillance strategies. Our findings suggested that short-interval surveillance should be considered during the first 2 years post-surgery, particularly for high-risk patients who should receive early attention.

Comparing perioperative and oncological outcomes of transanal and laparoscopic total mesorectal excision for rectal cancer: a meta-analysis of randomized controlled trials and prospective studies.

Meta-analysis of the results of transanal total mesorectal excision (taTME) and laparoscopic TME (laTME) regarding perioperative and oncological outcomes have been conducted. Due to the lack of high-quality randomized controlled trials (RCTs) and prospective studies in the included literature, the conclusions are unreliable. This study included RCTs and prospective studies for analysis to obtain more reliable conclusions. Systematic searches of the PubMed, Embase, and Cochrane Library databases were conducted up to June 2023. To assess the quality, the Cochrane quality assessment tool and the Newcastle-Ottawa Scale were employed. The perioperative and oncological outcomes were then analyzed. The I2 statistic was used to evaluate statistical heterogeneity and sensitivity analyses was conducted. A total of 22 studies, comprising 5056 patients, were included in the analysis, of which 6 were RCTs and 16 were prospective studies. The conversion rate in the taTME group was significantly lower than that in the laTME group (OR 0.14, 95% CI 0.09 to 0.22, P < 0.01), and the circumferential resection margin (CRM) was longer (MD 0.99mm, 95% CI 0.66 to 1.32mm, P < 0.01), with a lower rate of positive CRM involvement (OR 0.68, 95% CI 0.47 to 0.97, P = 0.03). No statistically significant differences were found in terms of the operation time, intraoperative blood loss, complications, anastomotic leakage, uroschesis, obstruction, secondary operation, hospital stay, urethral injury, readmission, mortality rate within 30days, mesorectal resection quality, number of harvested lymph nodes, distal resection margin (DRM), positive DRM, local recurrence, and distance recurrence (P > 0.05). According to the findings of this meta-analysis, which is based on RCTs and prospective studies, taTME appears to have an advantage over laTME in terms of conversion rate and CRM involvement.

Development and validation of a prognostic nomogram for rectal cancer patients who underwent surgical resection.

Objective: The purpose of this study was to develop and validate a nomogram model for the prediction of survival outcome in rectal cancer patients who underwent surgical resection. Methods: A total of 9,919 consecutive patients were retrospectively identified using the Surveillance, Epidemiology, and End Results (SEER) database. Significant prognostic factors were determined by the univariate and multivariate Cox analysis. The nomogram model for the prediction of cancer-specific survival (CSS) in rectal cancer patients were developed based on these prognostic variables, and its predictive power was assessed by the concordance index (C-index). Calibration curves were plotted to evaluate the associations between predicted probabilities and actual observations. The internal and external cohort were used to further validate the predictive performance of the prognostic nomogram. Results: All patients from the SEER database were randomly split into a training cohort (n = 6,944) and an internal validation cohort (n = 2,975). The baseline characteristics of two cohorts was comparable. Independent prognostic factors were identified as age, pT stage, lymph node metastasis, serum CEA level, tumor size, differentiation type, perineural invasion, circumferential resection margin involvement and inadequate lymph node yield. In the training cohort, the C-index of the nomogram was 0.719 (95% CI: 0.696-0.742), which was significantly higher than that of the TNM staging system (C-index: 0.606, 95% CI: 0.583-0.629). The nomogram had a C-index of 0.726 (95% CI: 0.691-0.761) for the internal validation cohort, indicating a good predictive power. In addition, an independent cohort composed of 202 rectal cancer patients from our institution were enrolled as the external validation. Compared with the TNM staging system (C-index: 0.573, 95% CI: 0.492-0.654), the prognostic nomogram still showed a better predictive performance, with the C-index of 0.704 (95% CI: 0.626-0.782). Calibration plots showed a good consistency between predicted probability and the actual observation in the training and two validation cohorts. Conclusion: The nomogram showed an excellent predictive ability for survival outcome of rectal cancer patients, and it might provide an accurate prognostic stratification and help clinicians determine individualized treatment strategies.

The role of magnetic resonance tumour regression grade in the prediction of regression and survival of rectal adenocarcinoma after long-course chemoradiotherapy: a cohort study.

Between 2011 and 2016, patients with rectal cancer who underwent LCCRT and had post-LCCRT MRI were included in the study. Both mrTRG and pTRG were dichotomised into good responders (mrTRG 1-3 and pTRG 0-1) and poor responders (mrTRG 4-5 and pTRG 2-3). Correlation between mrTRG and pTRG was assessed with Cohen κ analysis. Survival analysis was performed with Kaplan-Meier test and Cox proportional hazard models. There were 59 patients included in this study. There were significant reductions in anal sphincter and circumferential resection margin involvement in post-LCCRT MRI. Fair agreement was found between mrTRG and pTRG (κ=0.345). Sensitivity, specificity and accuracy of mrTRG 1-3 to predict good pathological response were 100%, 46.3% and 62.7%, respectively. On survival analysis, mrTRG 1-3 was not associated with improved overall survival and recurrence-free survival. While there is fair agreement in correlation between mrTRG and pTRG, MRI remains an objective, noninvasive assessment of tumour response. Further studies are required to improve the ability of mrTRG to predict good responders to LCCRT and evaluate its role as a prognostic marker for survival.

Supine bottom-up extralevator abdominoperineal excision for anorectal adenocarcinoma is not inferior to standard approach and may be thus safely performed.

Extralevator abdominoperineal excision (APE) for rectal carcinoma has been described in order to improve pathological and oncological results compared to standard APE. To obtain the same oncological advantages as extralevator APE, we have previously described a new procedure starting by a perineal approach: the supine bottom-up APE. Our objective is to compare oncological and surgical outcomes between the supine bottom-up APE and the standard APE. All patients with low rectal adenocarcinoma requiring APE were retrospectively included and divided into 2 groups: supine bottom-up APE (Group A) and standard APE (Group B). From 2008 to 2016, 61 patients were divided into Groups A (n = 30) and B (n = 31). Postoperative outcomes and median length of stay were similar between groups. Patients from Group A had a significantly longer distal margin (30 [8-120] vs. 20 [1.5-60] mm, p = 0.04) and higher number of harvested lymph nodes (14.5 [0-33] vs. 11 [5-25], p = 0.03) than those from Group B. Circumferential resection margin involvement was similar between groups (28 vs. 22%, p = 0.6), whereas tumors from Group A were significantly larger and more frequently classified as T4 than those from Group B. Operative time was significantly shorter in Group A (437.5 [285-655] minutes) than in Group B (537.5 [361-721] minutes, p = 0.0009). At the end of follow-up, local recurrence occurred in 7 and 16% of patients from Groups A and B (p = 0.68). Three-year overall and disease-free survival rates were similar between groups (87 vs. 90%, p = 0.62 and 61 vs. 63%, p = 0.88, respectively). Our findings suggest that supine bottom-up APE doesn't impair surgical outcomes, pathological results, overall and disease-free survivals in comparison with standard APE. This new procedure may be thus safely performed and decrease the operative time. Further randomized multicentric studies are required to confirm these results.

The impact of resection margin distance on survival and recurrence in pancreatic ductal adenocarcinoma in a retrospective cohort analysis.

The prognostic effect of resection margin status following pancreatoduodenectomy for pancreatic ductal adenocarcinoma (PDAC) remains controversial, even with the implementation of standardized pathological assessment. We therefore investigated the impact of resection margin (RM) status and RM distance in curative resected PDAC on overall survival (OS), disease-free survival (DFS) and recurrence. 108 patients were retrieved from a prospectively maintained database of a certified pancreatic cancer center. Distribution and relationships between circumferential resection margin (CRM) involvement (CRM≤1mm; CRM>1mm; CRM≥2mm) and their prognostic impact on OS and DFS were assessed using Kaplan-Meier statistics and the Log-Rank test. Multivariate logistic regression was used explain the development of a recurrence 12 months after surgery. 63 out of 108 patients had medial RM and 32 posterior RM involvement. There was no significant difference in OS and DFS between CRM≤1mm and CRM>1mm resections. Clearance at the medial margin of ≥2mm had an impact on OS and DFS, (RM≥2mm vs. RM<2mm: median OS 29.8 vs 16.8 months, median DFS 19.6 vs. 10.3 months). Multivariate analysis demonstrated that age, medial RM ≥2mm, lymph node status and chemotherapy were prognostic factors for OS and DFS. Posterior RM had no influence on OS or DFS. Not all RM seem to have the same impact on OS and DFS, and a clearance of 1mm for definition of a negative RM (i.e. CRM>1mm) seems not sufficient. Future studies should include more patients to stratify for potential confounders we could not account for. This study was registered with the German Clinical Trials Registry (reference number DRKS0017425).

The AUGIS Survival Predictor: Prediction of Long-Term and Conditional Survival After Esophagectomy Using Random Survival Forests.

The aim of this study was to develop a predictive model for overall survival after esophagectomy using pre/postoperative clinical data and machine learning. For patients with esophageal cancer, accurately predicting long-term survival after esophagectomy is challenging. This study investigated survival prediction after esophagectomy using a RandomSurvival Forest (RSF) model derived from routine data from a large, well-curated, national dataset. Patients diagnosed with esophageal adenocarcinoma or squamous cell carcinoma between 2012 and 2018 in England and Wales who underwent an esophagectomy were included. Prediction models for overall survival were developed using the RSF method and Cox regression from 41 patient and disease characteristics. Calibration and discrimination (time-dependent area under the curve) were validated internally using bootstrap resampling. The study analyzed 6399 patients, with 2625 deaths during follow-up. Median follow-up was 41 months. Overall survival was 47.1% at 5 years. The final RSF model included 14 variables and had excellent discrimination with a 5-year time-dependent area under the receiver operator curve of 83.9% [95% confidence interval (CI) 82.6%-84.9%], compared to 82.3% (95% CI 81.1%-83.3%) for the Cox model. The most important variables were lymph node involvement, pT stage, circumferential resection margin involvement (tumor at < 1 mm from cut edge) and age. There was a wide range of survival estimates even within TNM staging groups, with quintiles of prediction within Stage 3b ranging from 12.2% to 44.7% survival at 5 years. An RSF model for long-term survival after esophagectomy exhibited excellent discrimination and well-calibrated predictions. At a patient level, it provides more accuracy than TNM staging alone and could help in the delivery of tailored treatment and follow-up.

Benefits of Adjuvant Chemotherapy for Clinical T3-4N0 Rectal Cancer After Preoperative Chemoradiotherapy.

While the guidelines for adjuvant chemotherapy (AC) for colon cancer are relatively standardized, those for early rectal cancer are still lacking. We therefore evaluated the role of AC in clinical stage II rectal cancer treatment after preoperative chemoradiotherapy (CRT). Patients diagnosed with early rectal cancer (defined by clinical stage T3/4, N0) who completed CRT followed by surgery were enrolled in this retrospective study. To evaluate the role of AC, we analyzed the risk of recurrence and survival based on clinicopathologic parameters and adjuvant chemotherapy. Of the 112 patients, 11 patients (9.8%) experienced recurrence and five patients (4.8%) died. In a multivariate analysis, circumferential resection margin involvement (CRM+) on magnetic resonance imaging at diagnosis, CRM involvement following neoadjuvant therapy (ypCRM+), tumor regression grade (≤G1) and no-AC were considered poor prognostic factors for recurrence free survival (RFS). In addition, ypCRM+ and no-AC were associated with poor overall survival (OS) in the multivariate analysis. AC including 5-FU monotherapy demonstrated the benefits of reduced recurrence and prolonged survival in clinical stage II rectal cancer, even in pathologic stage following neoadjuvant therapy (ypStage) 0-I. Further prospective studies are needed to verify the benefit of each regimen of AC and the development of a method that can accurately predict CRM status before surgery, and a vigorous treatment that can induce CRM non-involvement (CRM-) should be considered even in early stages of rectal cancer.

Diagnostic Performance of Rectal CT for Staging Rectal Cancer: Comparison with Rectal MRI and Histopathology.

To compare the diagnostic performance of rectal CT with that of high-resolution rectal MRI and histopathology in assessing rectal cancer. Sixty-seven patients with rectal cancer who underwent rectal CT with rectal distension using sonographic gel and high-resolution MRI were enrolled in this study. The distance from the anal verge/anorectal junction, distance to the mesorectal fascia (MRF), extramural depth (EMD), extramesorectal lymph node (LN) involvement, extramural venous invasion (EMVI), and T/N stages in rectal CT/MRI were analyzed by two gastrointestinal radiologists. The CT findings of 20 patients who underwent radical surgery without concurrent chemoradiotherapy were compared using histopathology. Interclass correlations and kappa statistics were used. The distance from the anal verge/anorectal junction showed an excellent intraclass correlation between CT and MRI for both reviewers. For EMD, the distance to the MRF, presence of LNs, extramesorectal LN metastasis, EMVI, T stage, and intermodality kappa or weighted kappa values between CT and MRI showed excellent agreement. Among the 20 patients who underwent radical surgery, T staging, circumferential resection margin involvement, EMVI, and LN metastasis on rectal CT showed acceptable concordance rates with histopathology. Dedicated rectal CT may be on par with rectal MRI in providing critical information to patients with rectal cancer.

Can CT Pelvimetry Be Used to Predict Circumferential Resection Margin Positivity in Laparoscopic Resection of Middle and Lower Rectum Cancer?

Background Previous studies have shown that pelvimetry can be valuable in predicting surgical difficulties in rectal cancer operations. However, its usability in predicting circumferential resection margin (CRM) involvement remains debatable. This study investigated the factors affecting CRM status and the importance of computed tomography (CT) pelvimetry in predicting CRM involvement in laparoscopic resection of middle and lower rectal cancer. Methodology In this study, we retrospectively investigated the data of 111 patients who underwent a laparoscopic operation for middle and lower rectum cancer at Ankara University Faculty of Medicine, Department of Surgical Oncology between January 2014 and January 2020. The predictive value of CT pelvimetry and other variables on the CRM statuswas analyzed. Results The following four pelvic parameters differed significantly between the genders: transverse diameter of the pelvic inlet (p = 0.024), anteroposterior diameter of the pelvic outlet (p = 0.003), transverse diameter of the pelvic outlet (p < 0.001), and pelvic depth (p < 0.001). The effect of pelvic anatomic parameters on CRM involvement was not found to be significant. It was found that tumor height from the anal verge (p = 0.004), tumor size (p < 0.001), and gender (p = 0.033) were significant risk factors for CRM involvement. Survival was poor in patients with male gender (p = 0.032), perineural invasion (p < 0.001), and grade 3 tumor. Conclusions In this study, no benefit was found in predicting CRM positivity from CT pelvimetry in the laparoscopic resection of middle and lower rectal cancer. Besides, tumor height from the anal verge, tumor size, and gender were important factors for CRM positivity. Although our study sheds light on this issue, prospective randomized studies with larger sample sizes are needed.