Toward Precision Surgery in Rectal Cancer: Integrating Machine Learning for Molecular Subtype Identification and Surgical Planning

Impact of Clinician Linkage on Unequal Access to High-Volume Hospitals for Colorectal Cancer Surgery.

Hypoperfusion is the main cause of anastomotic leakage (AL) following colorectal surgery. The conventional method for evaluating anastomotic perfusion is to observe color change and active bleeding of the resection margin of the intestine and the pulsation of mesenteric vessels. However, the accuracy of this method is low, which may be due to insufficient observation time. A novel surgical procedure that separates the mesentery in advance at the intended transection site can delay the observation of anastomotic perfusion, and can potentially detect more anastomotic sites with insufficient vascular supply and reduce the rate of AL. This study aimed to investigate the effects of a novel surgical procedure on AL following sigmoid colon and rectal cancer surgeries. A total of 343 patients who underwent rectal and sigmoid colon cancer surgeries were included in the study. From August 2021 to June 2022, patients with sigmoid colon or rectal cancer underwent a new surgical procedure of pre-division of the mesentery (PDM) at the intended transection site (PDM group). Patients with colorectal cancer who underwent conventional surgical procedures from August 2018 to July 2021 were categorized as the non-PDM group. Symptomatic AL (SAL) within 30 days and other outcomes were retrospectively analyzed using propensity score matching and compared between the two groups. The incidences of SAL were 1.3% and 11.3% in the PDM and non-PDM groups, respectively. PDM significantly reduced the SAL rate in sigmoid colon and rectal cancer surgeries (P = 0.009). The incidence of total postoperative complications (P < 0.05) was significantly lower in the PDM group than that in the non-PDM group. There were no significant differences between the two groups for operative time (P = 0.662), intraoperative blood loss (P = 0.651), intraoperative blood transfusion (P = 0.316), and intensive care rate (P = 1). The length of postoperative hospital stay (P = 0.010) and first exhaust (P = 0.001) and defecation time (P < 0.05) were shorter in the PDM group than in the non-PDM group. PDM can effectively prevent AL, and this procedure can be safely performed in sigmoid colon and rectal cancer surgeries.

For resectable rectal cancer, surgical treatment must safely meet two objectives. The most important goal is to achieve an R0 tumour resection with adequate circumferential margins and a complete regional...

Since its introduction, laparoscopy has gained more and more consent in colorectal surgery, even if its role in rectal cancer surgery is still controversial and widely debated. The aim of this study is to present the ongoing situation of laparoscopic surgery for rectal cancer by a review of current literature. We performed a systematic search in the electronic databases (PubMed, Web of Science, Scopus, EMBASE) according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. We limited the search until 31 March 2017 and used the following search terms in all possible combinations: rectal cancer, laparoscopy, minimally invasive and open surgery. A total of 66 articles were include in this review, of which 38 were non-randomized trials, 8 were randomized controlled trials (RCTs) performed in a single center, 5 were multicentric RCTs and 15 were meta-analyses. Laparoscopic approach resulted in a faster and better recovery after surgery and has been proven to be equivalent in terms of short-terms outcomes comparing to the open approach. Nevertheless, the findings concerning oncologic safety of minimally invasive approach are still controversial. This should give the rationale to perform new meta-analyses based on the last evi-dences produced. Moreover, even more multicentric RCTs studies, hypothetically designed on new pathological outcomes, should be performed to finally assess if laparoscopy is a valid choice for the treatment of rectal cancer.

PurposeIn surgery for rectal cancer, splenic flexure mobilization is sometimes necessary to ensure a tension-free colorectal anastomosis with adequate blood supply. Splenic flexure mobilization is regarded as a challenging and risky maneuver, but there are no clear indicators of its difficulty in rectal cancer surgery. This study evaluated the impact of clinical and anatomical factors, including splenic flexure height measured qualitatively on the basis of vertebral level using computed tomography, on the difficulty of splenic flexure mobilization during rectal cancer surgery.MethodsThe enrolled patients underwent robotic splenic flexure mobilization during rectal surgery for primary rectal cancer at Shizuoka Cancer Center in Japan between December 2011 and March 2022. All patients were scheduled to undergo splenic flexure mobilization preoperatively, and all procedures were carried out following a standardized approach. Linear regression analysis was conducted to determine the clinical and anatomical factors significantly influencing the operative time of the abdominal phase, which is defined as the duration from lymph node dissection around the inferior mesenteric artery to the mobilization of the sigmoid and descending colon, including the splenic flexure.ResultsThe median operative time for the abdominal phase was 88 min (range, 39–179 min). Univariate analysis revealed that the following variables were significantly correlated with a prolonged abdominal phase: higher body mass index, larger visceral fat area, and higher splenic flexure. In a multiple linear regression analysis, only higher splenic flexure remained significantly associated with a longer abdominal phase (p < 0.01).ConclusionsSplenic flexure height measured on the basis of vertebral level using computed tomography may be useful for predicting the difficulty of robotic splenic flexure mobilization in surgery for rectal cancer.

AimAnastomotic leakage (AL) after colon cancer (CC) and rectal cancer (RC) surgery often requires reintervention. Prevalence and morbidity may change over time with evolutions in treatment strategies and changes in patient characteristics. This nationwide study aimed to evaluate changes in the incidence, risk factors and mortality from AL during the past nine years.MethodsData of CC and RC resections with primary anastomosis were extracted from the Dutch Colorectal Audit (2011–2019). AL was registered if requiring reintervention. Three consecutive cohorts were compared using logistic regression analysis.ResultsIncidence of AL after CC surgery decreased from 6.6% in 2011–2013 to 4.8% in 2017–2019 and increased from 8.6% to 11.9% after RC surgery. In 2011–2013, male sex, ASA ≥3, (y)pT3‐4, neoadjuvant therapy, emergency surgery and multivisceral resection were identified as risk factors for AL after CC surgery. In 2017–2019, only male sex and ASA ≥3 were risk factors for AL. For RC patients, male sex and neoadjuvant therapy were a risk factor for AL in 2011–2013. In 2017–2019, transanal approach was also a risk factor for AL. Postoperative mortality rate after AL was 12% (CC) and 2% (RC) in 2017–2019, without significant changes over time.ConclusionContradictory trends in incidence and mortality for AL were observed among CC and RC surgery with changing risk factors over the past 9 years. High mortality after AL is only observed after CC surgery and remains unchanged. Continued efforts should be made to improve early detection and treatment of AL for these patients.

This study aimed to evaluate the effectiveness and safety of 2D laparoscopy vs 3D laparoscopy for the treatment of colorectal cancer. A literature search was conducted through PubMed, Web of Science, and Embase from their inception to January 2024. Studies investigating different outcomes of colorectal surgery were included. Results are presented as odds ratios (ORs) or mean differences (MDs) with 95% confidence intervals (CIs). The protocol for this review has been registered on PROSPERO (CRD42024504902). A total of 10 publications were retrieved in this article. The 3D group is associated with a significant improvement in intraoperative blood loss (MD = -8.04, 95% CI = -14.18 to -1.89, P = 0.01, I2 = 55%), operative time (MD = -17.33, 95% CI = -29.15 to -5.51, P = 0.004, I2 = 90%), and postoperative hospital stay (MD = -0.23, 95% CI = -0.43 to -0.04, P = 0.02, I2 = 48%) compared to that of patients treated in the 2D group, particularly for rectal cancer patients above three results (MD = -10.36, 95% CI = -15.00 to -5.73, P < 0.001, I2 = 0%), (MD = -18.85, 95% CI = -34.88 to -2.82, P = 0.02, I2 = 57%), and (MD = -0.93, 95% CI = -1.53 to -0.34, P = 0.002, I2 = 0%), respectively. There was no significant statistical difference in the time of pass flatus (MD = -0.14, 95% CI = -0.49 to 0.21, P = 0.44, I2 = 79%) and the number of dissected lymph nodes (MD = 0.36, 95% CI = -0.49 to 1.21, P = 0.41, I2 = 45%), but the 3D group had an earlier postoperative pass flatus for rectal cancer patients (MD = -0.46, 95% CI = -0.66 to -0.27, P<0.001, I2 = 0%) and the more number of dissected lymph nodes for colon cancer patients (MD = 1.54, 95% CI = 0.05 to 3.03, P = 0.04, I2 = 69%) than the 2D group. There was no significant difference in postoperative overall complication (OR = 0.94, 95% CI = 0.67 to 1.31, P = 0.71, I2 = 0%) and anastomotic leakage (OR = 0.93, 95% CI = 0.48 to 1.80, P = 0.83, I2 = 0%) in the two groups, regardless of rectal cancer and colon surgery patients. This meta-analysis demonstrates that 3D laparoscopy could reduce the amount of blood loss, accelerate postoperative pass flatus, and shorten the operation time and postoperative hospital stay over 2D for radical rectal cancer surgery, without obvious advantage for radical colon cancer surgery. Moreover, 3D laparoscopy increases the number of dissected lymph nodes for radical colon cancer surgery but may not be observed in rectal cancer surgery.

BACKGROUNDThree-dimensional (3D) modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models, which more closely resemble the complex environment encountered during surgery. It has been successfully applied to surgical planning and navigation, as well as surgical training and patient education in several surgical specialties, but its uptake lags behind in colorectal surgery. Rectal cancer surgery poses specific challenges due to the complex anatomy of the pelvis, which is difficult to comprehend and visualise.AIMTo review the current and emerging applications of the 3D models, both virtual and physical, in rectal cancer surgery.METHODSMedline/PubMed, Embase and Scopus databases were searched using the keywords “rectal surgery”, “colorectal surgery”, “three-dimensional”, “3D”, “modelling”, “3D printing”, “surgical planning”, “surgical navigation”, “surgical education”, “patient education” to identify the eligible full-text studies published in English between 2001 and 2020. Reference list from each article was manually reviewed to identify additional relevant papers. The conference abstracts, animal and cadaveric studies and studies describing 3D pelvimetry or radiotherapy planning were excluded. Data were extracted from the retrieved manuscripts and summarised in a descriptive way. The manuscript was prepared and revised in accordance with PRISMA 2009 checklist.RESULTSSixteen studies, including 9 feasibility studies, were included in the systematic review. The studies were classified into four categories: feasibility of the use of 3D modelling technology in rectal cancer surgery, preoperative planning and intraoperative navigation, surgical education and surgical device design. Thirteen studies used virtual models, one 3D printed model and 2 both types of models. The construction of virtual and physical models depicting the normal pelvic anatomy and rectal cancer, was shown to be feasible. Within the clinical context, 3D models were used to identify vascular anomalies, for surgical planning and navigation in lateral pelvic wall lymph node dissection and in management of recurrent rectal cancer. Both physical and virtual 3D models were found to be valuable in surgical education, with a preference for 3D printed models. The main limitations of the current technology identified in the studies were related to the restrictions of the segmentation process and the lack of 3D printing materials that could mimic the soft and deformable tissues.CONCLUSION3D modelling technology has potential to be utilised in multiple aspects of rectal cancer surgery, however, it is still at the experimental stage of application in this setting.

Randomized controlled trials have demonstrated that laparoscopic surgery for rectal cancer is safe and can accelerate recovery without compromising oncological outcomes. However, such a surgery is technically demanding, limiting its application in nonspecialized centers. The operational features of a robotic system may facilitate overcoming this limitation. Studies have reported the potential advantages of robotic surgery. However, only a few of them have featured the application of this surgery in patients with advanced rectal cancer undergoing neoadjuvant chemoradiation therapy (nCRT).From January 2012 to April 2015, after undergoing nCRT, 40 patients with mid or low rectal cancer were operated using the robotic approach at our institution. Another 38 patients who were operated using the conventional laparoscopic approach were matched to patients in the robotic group by sex, age, the body mass index, and procedure. All operations were performed by a single surgical team. The clinicopathological characteristics and short-term outcomes of these patients were compared. To assess the effect of the learning curve on the outcomes, patients in the robotic group were further subdivided into 2 groups according to the sequential order of their procedures, with an equal number of patients in each group. Their outcome measures were compared.The robotic and laparoscopic groups were comparable with regard to pretreatment characteristics, rectal resection type, and pathological examination result. After undergoing nCRT, more patients in the robotic group exhibited clinically advanced diseases. The complication rate was similar between the 2 groups. The operation time and the time to the resumption of a soft diet were significantly prolonged in the robotic group. Further analysis revealed that the difference was mainly observed in the first robotic group. No significant difference was observed between the second robotic and laparoscopic groups.Although the robotic approach may offer potential advantages for rectal surgery, comparable short-term outcomes may be achieved when laparoscopic surgery is performed by experienced surgeons. However, our results suggested a shorter learning curve for robotic surgery for rectal cancer, even in patients who exhibited more advanced disease after undergoing nCRT.

First clinical report of the international single-port robotic rectal cancer registry.

Currently, the safety and efficiency of laparoscopic surgery for rectal cancer have been confirmed by large amount of evidences. Laparoscopic surgery has been commonly applied in the treatment for low rectal cancer. Sphincter preservation is a highly concerning issue for patients and surgeons during rectal cancer surgery. Sphincter-preserving surgery should be based on the R0 resection. The article reviews the application of laparoscopic surgery for low rectal cancer and the choice of operations for sphincter-preserving surgery.

See Article on Page 100-107 Total mesorectal excision (TME) was proposed by Heald et al. [1] more than 20 years ago and it is defined as the complete excision of the visceral mesorectal tissue to the level of the levators. The local recurrence rate after rectal cancer surgery has decreased dramatically to below 10% thanks to this TME technique. Currently TME is the gold standard for treatment of rectal cancer. However, if the tumor is located in upper rectum, partial mesorectal excision (PME) down to 5 cm below tumor can be performed. In 1998, Lopez-Kostner et al. [2] from Cleveland clinic insisted that TME is not necessary in case of the upper rectal cancer. And in the same year, Zaheer et al. [3] from Mayo clinic stated that appropriate mesorectal excision during anterior resection when tumor is high in the rectum is likewise consistent with a low rate of local recurrence and good long-term survival. The term tumor-specific mesorectal excision (TSME) was noted first in this article. In the Europe, Maurer et al. [4] from Germany concluded that the rectal cancers of upper third are appropriately treated by PME to 5 cm below the tumor. TSME is defined as the precise perpendicular and circumferential excision of the mesorectum to the level of an appropriate distal resection margin by American Society of Colon and Rectal Surgeons. Law and Chu et al. [5] from Queen Mary's Hospital in Hong Kong compared the patients with TME for mid and lower rectal cancer and PME for upper rectal cancer, where the rectum was transected 4 to 5 cm below the tumor. Due to longer operative times, higher anastomotic leak rates, a more technically demanding surgery and a higher incidence of stoma formation, the authors called for a more selective use of TME. The authors argue that oncologic outcome is not compromised with this approach based on similar cancer-specific survival patterns between TME and PME in this study. This conclusion was confirmed by meta-analysis. Mirnezami et al. [6] examined the long-term oncological impact of anastomotic leakage after rectal cancer surgery using meta-analysis methods. They found that anastomotic leakage has a negative impact on local recurrence after the rectal cancer surgery. A significant association between anastomotic leakage and reduced long-term cancer specific survival was also noted. Junginger and Hermanek [7] reviewed the literature concerning oncologic outcomes after the rectal surgery. The authors recommended PME, if the rectal cancer is located 12 to 16 cm from anal verge. Oncologic outcomes after the rectal cancer surgery can be divided into the long-term survival and the local recurrence rate. Regarding rectal cancer, local recurrence rate is especially important compared to colon cancer. TSME itself and its quality is one of the most important factors to predict the local recurrence and even the long-term survival after rectal cancer surgery. Survival is mainly determined by the occurrence of distant metastasis, but TME seems to improve survival in patients without systemic disease. Therefore, the effort to improve the quality of TME is so crucial to improve oncologic outcomes after rectal cancer surgery. Preoperative concurrent chemoradiotherapy is another important factor to reduce the local failure. Pathologic results, such as distal margin, circumferential radial margin, T and N stage, lymphatic and vascular invasion, neural invasion, are also important factors to influence the oncologic results after TSME. In conclusion, surgeon is one of the most important factors to predicting oncologic outcomes after TME. Individual surgeon should make an effort to improve surgical skill and pathologist can help him with the specimen audit. Nationwide audit program is needed to improve the oncologic results after TME in rectal cancer in South Korea. The other important factor is the preoperative radiotherapy. Preoperative radiotherapy with high quality TME can almost abolish the possibility of local recurrence.

The objective of this study was to examine the relationship between hospital surgical volume and long-term survival in patients with a new diagnosis of colorectal cancer who underwent surgical resection during fiscal years 1991-2000 in the Veterans Affairs (VA) health-care system. This research was a cohort study of patients admitted to all VA hospitals with a new diagnosis of colorectal cancer who underwent surgical resection between October 1990 and September 2000 and followed through September 2001. Overall 5-yr cumulative survival was calculated from Kaplan-Meier estimates, while adjusted risk of death was estimated using a Cox proportional hazards model. Adjustment was made for differences in patient characteristics including comorbidity, receipt of therapy, and year of surgery. We identified 34,888 individuals with a new diagnosis of colorectal cancer in VA hospitals during fiscal years 1991-2000, of whom 22,633 (65%) underwent surgical resection. The majority (98.5%) were men, the mean age was 68 yr, and the two largest race/ethnic groups were whites (75%) and blacks (17%). The 5-yr cumulative survival was greater among those who received surgery in high surgical volume hospitals as defined by 25 or more procedures per year (52.1%) than among those who received surgery in low volume hospitals (48.3%). After adjusting for differences in patient characteristics, comorbidity, receipt of adjuvant therapy, and year of surgery, we found 7% and 11% increases in 5-yr survival for patients with colon and rectal cancers, respectively, who underwent surgical resection in high volume hospitals compared with those who had surgery in low volume hospitals. Greater hospital surgical volume is an independent predictor of prolonged long-term survival following surgery for both colon and rectal cancer in the VA health-care system. The volume-long-term mortality relationship is greater for rectal than for colon cancer patients, perhaps reflecting the fact that surgery for rectal cancer is more technically demanding. Future studies are needed to discover what aspects of clinical management explain these differences.

Objective: The study aimed to describe and compare minimally invasive surgery (MIS) and open surgery for rectal cancer in Peru. Material and methods: A retrospective single-center analysis was performed for all patients who underwent sphincter- sparing surgery for non-metastatic rectal cancer at Instituto Nacional de Enfermedades Neoplásicas in Peru between January 2016 and December 2020. Clinical, perioperative, pathological, and survival outcomes were compared between both groups. A propensity score matching method was used to minimize bias. Results: 162 patients were included in the final analysis. 124 had open surgery and 38 had MIS. Patients, clinical tumour, pathological characteristics, and perioperative were similar between groups after matching. Similar circumferential resection margin (CRM) with optimal quality of the mesorectum (p=1.000) but higher number of lymph nodes resected in open surgery group (p=0.741) was described. The leakage rate was slightly higher in the MIS group (p=0.358) with 10.5%, while the postoperative hospital stay was longer in the open surgery group after matching (p=0.001; OR 95% 5.2 CI: 1.8-15.6). The estimated recurrence-free survival (RFS) and overall survival (OS) at 3 years in open surgery and MIS was 71.8% (95% CI; 0.58-0.89) and 70% (95% CI; 0.56-0.88) (p=0.431) and 77.7% (95% CI; 0.64-0.94) and 88.9% (95% CI; 0.79-0.99) (p=0.5), respectively. Conclusions: Shorter postoperative hospital stay in the minimally invasive surgery group was reported. RFS, OS, and re lar between both groups. This approach is for non-metastatic rectal cancer in referral centers in Peru.

Colorectal cancer is the second most common cause of death from malignant disease in the United Kingdom, with about 20 000 deaths each year. Around one million new cases (9%...