Defining and predicting early recurrence in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

BACKGROUND

The definition of "early recurrence (ER)" after rectal cancer surgery is currently unclear.

OBJECTIVE

To determine an evidence-based cut-off to distinguish early and late recurrence (LR) for patients with rectal cancer and compare the clinicopathological factors between the two groups.

METHODS

Patients who underwent neoadjuvant chemoradiotherapy (nCRT) and radical resection for locally advanced rectal cancer were included. A minimum p-value approach was used to evaluate the optimal cut-off value of recurrence-free survival to divide the patients into ER and LR groups based on overall survival. A logistic regression model was used to assess risk factors for ER.

RESULTS

A total of 763 patients were included, of which 167 (21.9%) experienced recurrence. The optimal cut-off value of recurrence-free survival to differentiate between ER (n = 125, 74.9%) and LR (n = 42, 25.1%) was 24 months (P = 0.000001). The median postrecurrence survival of ER and LR was 12 months and 22 months, respectively (p = 0.028). The most common recurrent sites in patients with ER and LR were lung metastases, the incidence of liver metastases, however, differed considerably in ER and LR (27.2% vs 9.5%, P = 0.019). Risk factors including elevated preoperative carcinoembryonic antigen (CEA), higher ypTNM stage, positive circumferential resection margin (CRM), and perineural invasion were significantly associated with ER.

CONCLUSION

A recurrence-free interval of 24 months is the optimal cut-off value for defining ER versus LR. Elevated preoperative CEA, higher ypTNM staging, positive CRM, and perineural invasion were associated with ER of locally advanced rectal cancer.

Outcome measures in multimodal rectal cancer trials

There is a large variability regarding the definition and choice of primary endpoints in phase 2 and phase 3 multimodal rectal cancer trials, resulting in inconsistency and difficulty of data interpretation. Also, surrogate properties of early and intermediate endpoints have not been systematically assessed. We provide a comprehensive review of clinical and surrogate endpoints used in trials for non-metastatic rectal cancer. The applicability, advantages, and disadvantages of these endpoints are summarised, with recommendations on clinical endpoints for the different phase trials, including limited surgery or non-operative management for organ preservation. We discuss how early and intermediate endpoints, including patient-reported outcomes and involvement of patients in decision making, can be used to guide trial design and facilitate consistency in reporting trial results in rectal cancer.

Three-year outcome after transanal versus laparoscopic total mesorectal excision in locally advanced rectal cancer: a multicenter comparative analysis

Background

For patients with mid and distal rectal cancer, robust evidence on long-term outcome and causal treatment effects of transanal total mesorectal excision (TaTME) is lacking. This multicentre retrospective cohort study aimed to assess whether TaTME reduces locoregional recurrence rate compared to laparoscopic total mesorectal excision (LapTME).

Methods

Consecutive patients with rectal cancer within 12 cm from the anal verge and clinical stage II-III were selected from three institutional databases. Outcome after TaTME (Nov 2011 - Feb 2018) was compared to a historical cohort of patients treated with LapTME (Jan 2000 - Feb 2018) using the inverse probability of treatment weights method. The primary endpoint was three-year locoregional recurrence.

Results

A total of 710 patients were analysed, 344 in the TaTME group and 366 in the LapTME group. At 3 years, cumulative locoregional recurrence rates were 3.6% (95% CI, 1.1–6.1) in the TaTME group and 9.6% (95% CI, 6.5–12.7) in the LapTME group (HR = 0.4; 95% CI, 0.23–0.69; p = 0.001). Three-year cumulative disease-free survival rates were 74.3% (95% CI, 68.8–79.8) and 68.6% (95% CI, 63.7–73.5) (HR = 0.82; 95% CI, 0.65–1.02; p = 0.078) and three-year overall survival 87.2% (95% CI, 82.7–91.7) and 82.2% (95% CI, 78.0–86.2) (HR = 0.74; 95% CI, 0.53–1.03; p = 0.077), respectively. In patients who underwent sphincter preservation procedures, TaTME was associated with a significantly better disease-free survival (HR = 0.78; 95% CI, 0.62–0.98; p = 0.033).

Conclusions

These findings suggest that TaTME may improve locoregional recurrence and disease-free survival rates among patients with mid and distal locally advanced rectal cancer.

Avoidance of Overtreatment of Rectal Cancer by Selective Chemoradiotherapy: Results of the Optimized Surgery and MRI-Based Multimodal Therapy Trial

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) in patients with rectal cancer carries a high risk of adverse effects. The aim of this study was to examine the selective application of nCRT based on patient risk profile, as determined by MRI, to find the optimal range between undertreatment and overtreatment.

STUDY DESIGN

In this prospective multicenter observational study, nCRT before total mesorectal excision (TME) was indicated in high-risk patients with involved or threatened mesorectal fascia (≤1 mm), or cT4 or cT3 carcinomas of the lower rectal third. All other patients received primary surgery.

RESULTS

Of the 1,093 patients, 878 (80.3%) were treated according to the protocol, 526 patients (59.9%) underwent primary surgery, and 352 patients (40.1%) underwent nCRT followed by surgery. The 3-year locoregional recurrence (LR) rate was 3.1%. Of 604 patients with clinical stages II and III, 267 (44.2%) had primary surgery; 337 (55.8%) received nCRT followed by TME. The 3-year LR rate was 3.9%, without significant differences between groups. In patients with clinical stages II and III who underwent primary surgery, 27.3% were diagnosed with pathological stage I.

CONCLUSIONS

The results justify the restriction of nCRT to high-risk patients with rectal cancer classified by pretreatment MRI. Provided that a high-quality MRI diagnosis, TME surgery, and standardized examination of the resected specimen are performed, nCRT, with its adverse effects, costs, and treatment time can be avoided in more than 40% of patients with stage II or III rectal cancer with minimal risk of undertreatment. (clinicaltrials.gov NCT325649).

The Circumferential Resection Margin Is a Prognostic Predictor in Colon Cancer

Objective: This study aimed to investigate the potential value of circumferential resection margin (CRM) in colon cancer prognostics.

Summary Background Data: CRM has been extensively studied as an important prognostic factor in rectal and esophageal cancer, but not in colon cancer.

Methods: Data from 6,681 CRM-positive patients and 25,908 CRM-negative patients diagnosed with colon cancer in 2010–2015 were obtained from the Surveillance, Epidemiology, and End Results database. Statistical analysis methods utilized included the chi-square test, Kaplan-Meier estimates, Cox proportional, and X-tile software analyses.

Results: After propensity score matching, CRM positivity was found to be negatively related with survival (P < 0.001). X-tile software identified 0 and 30 mm as optimal cutoff values (P < 0.001) for prognosis, which was applicable only in stage II–IV patients. A 20 and 33% risk decrease were observed in patients with CRM between 0 and 30 mm [95% confidence interval (CI) = 0.76–0.84], and larger than 30 mm (95% CI = 0.62–0.71), respectively. Chemotherapy strongly benefited prognosis with a hazard ratio of 0.36 (95% CI = 0.34–0.38) for overall survival (OS). Patients with a CRM value of 0–30 mm seemed to benefit most from chemotherapy compared with other groups. CRM and number of regional lymph nodes are independent risk factors, and the latter is a good substitute for CRM in AJCC stage I patients.

Conclusion: CRM positivity is a strong unfavorable survival indicator for colon cancer patients. A better outcome is expected with CRM values larger than 30 mm. This cutoff value only applied to stage II–IV patients. For stage I patients, number of regional lymph nodes is a good substitute to predict survival. Chemotherapy was another favorable prognostic factor, especially for patients with a CRM value between 0 and 30 mm.

Surgery with and without adjuvant radiotherapy is associated with similar survival in T4 colon cancer

AIM

There is little evidence regarding the role of adjuvant radiotherapy for colon cancer. Despite this, national consensus guidelines recommend consideration of radiation for patients with T4 colon cancer. Large comparative studies may be beneficial in clarifying the potential benefit of postoperative radiation for this cohort.

METHOD

We compared the overall survival between patients treated with surgery with and without adjuvant radiation using the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results Program (SEER), as well as disease-specific survival using SEER. Cox proportional hazards models and propensity score matching were used to adjust for relevant confounders.

RESULTS

There were a total of 18 776 patients in the NCDB cohort and 9926 patients in the SEER cohort. After propensity score matching, there was no statistically significant difference in overall mortality between surgery with and without radiation in the NCDB [hazard ratio (HR) 1.11; 95% CI 0.93-1.31; P = 0.25] or in SEER (HR 1.20; 95% CI 0.84-1.72; P = 0.32). Additionally, using SEER, we found no statistically significant difference in disease-specific mortality between these two groups (HR 1.13; 95% CI 0.76-1.67; P = 0.54).

CONCLUSION

Using the NCDB and SEER, we found no statistically significant difference in overall survival or disease-specific survival between patients treated with and without adjuvant radiation. Further studies should evaluate the impact of adjuvant radiotherapy on local control and prevention of recurrence-related morbidity in patients with T4 colon cancer.

The multidisciplinary management of rectal cancer

Rectal cancer treatment has evolved during the past 40 years with the use of a standardized surgical technique for tumour resection: total mesorectal excision. A dramatic reduction in local recurrence rates and improved survival outcomes have been achieved as consequences of a better understanding of the surgical oncology of rectal cancer, and the advent of adjuvant and neoadjuvant treatments to compliment surgery have paved the way for a multidisciplinary approach to disease management. Further improvements in imaging techniques and the ability to identify prognostic factors such as tumour regression, extramural venous invasion and threatened margins have introduced the concept of decision-making based on preoperative staging information. Modern treatment strategies are underpinned by accurate high-resolution imaging guiding both neoadjuvant therapy and precision surgery, followed by meticulous pathological scrutiny identifying the important prognostic factors for adjuvant chemotherapy. Included in these strategies are organ-sparing approaches and watch-and-wait strategies in selected patients. These pathways rely on the close working of interlinked disciplines within a multidisciplinary team. Such multidisciplinary forums are becoming standard in the treatment of rectal cancer across the UK, Europe and, more recently, the USA. This Review examines the essential components of modern-day management of rectal cancer through a multidisciplinary team approach, providing information that is essential for any practising colorectal surgeon to guide the best patient care.

Association of Image-Guided Navigation With Complete Resection Rate in Patients With Locally Advanced Primary and Recurrent Rectal Cancer: A Nonrandomized Controlled Trial

IMPORTANCE

The percentage of tumor-positive surgical resection margin rates in patients treated for locally advanced primary or recurrent rectal cancer is high. Image-guided navigation may improve complete resection rates.

OBJECTIVE

To ascertain whether image-guided navigation during rectal cancer resection improves complete resection rates compared with surgical procedures without navigation.

DESIGN, SETTING, AND PARTICIPANTS

This prospective single-center nonrandomized controlled trial was conducted at the Netherlands Cancer Institute-Antoni van Leeuwenhoek in Amsterdam, the Netherlands. The prospective or navigation cohort included adult patients with locally advanced primary or recurrent rectal cancer who underwent resection with image-guided navigation between February 1, 2016, and September 30, 2019, at the tertiary referral hospital. Clinical results of this cohort were compared with results of the historical cohort, which was composed of adult patients who received rectal cancer resection without image-guided navigation between January 1, 2009, and December 31, 2015.

INTERVENTION

Rectal cancer resection with image-guided navigation.

MAIN OUTCOMES AND MEASURES

The primary end point was the complete resection rate, measured by the amount of tumor-negative resection margin rates. Secondary outcomes were safety and usability of the system. Safety was evaluated by the number of navigation system-associated surgical adverse events. Usability was assessed from responses to a questionnaire completed by the participating surgeons after each procedure.

RESULTS

In total, 33 patients with locally advanced or recurrent rectal cancer were included (23 men [69.7%]; median [interquartile range] age at start of treatment, 61 [55.0-69.0] years). With image-guided navigation, a radical resection (R0) was achieved in 13 of 14 patients (92.9%; 95% CI, 66.1%-99.8%) after primary resection of locally advanced tumors and in 15 of 19 patients (78.9%; 95% CI, 54.4%-94.0%) after resection of recurrent rectal cancer. No navigation system-associated complications occurred before or during surgical procedures. In the historical cohort, 142 patients who underwent resection without image-guided navigation were included (95 men [66.9%]; median [interquartile range] age at start of treatment, 64 [55.0-70.0] years). In these patients, an R0 resection was accomplished in 85 of 101 patients (84.2%) with locally advanced rectal cancer and in 20 of 41 patients (48.8%) with recurrent rectal cancer. A significant difference was found between the navigation and historical cohorts after recurrent rectal cancer resection (21.1% vs 51.2%; P = .047). For locally advanced primary tumor resection, the difference was not significant (7.1% vs 15.8%; P = .69). Surgeons stated in completed questionnaires that the navigation system improved decisiveness and helped with tumor localization.

CONCLUSIONS AND RELEVANCE

Findings of this study suggest that image-guided navigation used during rectal cancer resection is safe and intuitive and may improve tumor-free resection margin rates in recurrent rectal cancer.

TRIAL REGISTRATION

Netherlands Trial Register Identifier: NTR7184.

Response Assessment with MRI after Chemoradiotherapy in Rectal Cancer: Current Evidences

Baseline magnetic resonance imaging (MRI) has become the primary staging modality for surgical plans and stratification of patient populations for more efficient neoadjuvant treatment. Patients who exhibit a complete response to chemoradiotherapy (CRT) may achieve excellent local tumor control and better quality of life with organ-preserving treatments such as local excision or even watch-and-wait management. Therefore, the evaluation of tumor response is a key factor for determining the appropriate treatment following CRT. Although post-CRT MRI is generally accepted as the first-choice method for evaluating treatment response after CRT, its application in the clinical decision process is not fully validated. In this review, we will discuss various oncologic treatment options from radical surgical technique to organ-preservation strategies for achieving better cancer control and improved quality of life following CRT. In addition, the current status of post-CRT MRI in restaging rectal cancer as well as the main imaging features that should be evaluated for treatment planning will also be described for the tailored treatment.

Predictive Factors of Positive Circumferential and Longitudinal Margins in Early T3 Colorectal Cancer Resection

Background

Malignant involvement of circumferential resection margin (CRM) and longitudinal resection margin (LRM) after surgical resection of colorectal cancer (CRC) are associated with higher rates of recurrence and development of distant metastasis. This can influence the overall patient's prognosis. The aim of the current study was to identify pathological factors as predictors for the involvement of resection margins in early T3 CRC. Patients and Methods. Fifty patients radiologically diagnosed to have cT3a/b (CRC) were included in the study. After resection, the pathological examination was performed to identify patients with positive CRM and/or LRM. Relations between the different pathological parameters and the CMR and LRM involvements were assessed.

Results

Positive CRM was present in 17 cases (34%), while positive LRM was found in 6 cases (12%). The involvement of both margins was significantly associated with rectal tumors and tumors with infiltrative gross appearance, grade III, deeper invasion, and positive lymph node metastases. Also, there was a significant association between both margins' positivity and other pathological parameters as signet ring carcinoma, tumor budding, perineural and vascular invasion, high microvessel density (MVD), and sinusoidal vascular pattern, while the presence of necrosis and infiltrative advancing tumor front was significantly associated with CRM involvement only. The depth of tumor invasion and signet ring carcinoma were identified as independent predictor factors for positive CRM and LRM, respectively.

Conclusion

Preoperative identification of these pathological parameters can be a guide to tailor the management plan accordingly.

Transanal total mesorectal excision in the prone jackknife position without being conscious of the size of prostatic enlargement for lower rectal cancer

In 1982, it was demonstrated that a total mesorectal excision alone could achieve low rectal cancer recurrence rates in the pelvis and high disease-free survival rates. Nowadays, the total mesorectal excision is the gold-standard surgery for rectal cancer. Currently, the transanal total mesorectal excision has attracted attention as a promising alternative to the anterior approach. The transanal approach is superior to the anterior approach, because it facilitates total mesorectal excisions of the lower rectum, improves visualization, and shortens the surgical time. Some factors are particularly favorable for the transanal approach, including lesions in the lower third of the rectum, a narrow pelvis, a large tumor, male sex, and a prostatic enlargement. The transanal total mesorectal excision is commonly performed in the Lloyd-Davies position. However, in the Lloyd-Davies position, the sacral bone prevents the mobilized rectum from moving away from the pelvic base. From the perspective of pelvic morphology, we reasoned that, in the prone jackknife position, the mobilized rectum could spontaneously move toward the head, due to gravity, and this would broaden the pelvic surgical field. Consequently, this position could facilitate the transanal total mesorectal excision. Here, we described a transanal total mesorectal excision performed in the prone jackknife position for treating lower rectal cancer with a prostatic enlargement.

Transition from laparoscopic to robotic rectal resection: outcomes and learning curve of the initial 100 cases

Background

Following several landmark trials, laparoscopic rectal resection has reached standard clinical practice. Current literature is undecided on the advantages of robotic rectal resection and little is known on its learning curve. This study aimed to compare the outcomes of the first 100 robotic rectal resections to the laparoscopic approach in a teaching hospital experienced in laparoscopic colorectal surgery.

Methods

A retrospective analysis was conducted of a prospective cohort of all consecutive rectal resections between January 2012 and September 2019 at a single center. All laparoscopic cases were compared to the robotic approach. Outcomes included operative time, morbidity, anastomotic leakage, and hospital stay.

Results

Out of the 326 consecutive resections, 100 were performed robotically and 220 laparoscopically, the remaining 6 open cases were excluded. Median operative time was lower for robotic cases (147 (121–167) versus 162 (120–218) minutes P = 0.024). Overall morbidity was lower in robotic cases (25% versus 50%, P < 0.001), while major morbidity was similar. Anastomotic leakage was observed in 11% (8/70) of robotic and 15% (18/120) of laparoscopic anastomoses, despite more anastomoses in the robotic group (70%, 70/100 versus 55%, 120/220, P = 0.001). Median length of stay was 4 (4–7) days after a robotic and 6 (5–9) days after a laparoscopic procedure.

Discussion

Implementation of a robotic rectal resection program in an experienced laparoscopic surgery center was associated with reduced operative time, length of stay, and fewer complications despite a learning curve.

Improved Outcomes for Rectal Cancer in the Era of Preoperative Chemoradiation and Tailored Mesorectal Excision: A Series of 338 Consecutive Cases

Neoadjuvant chemoradiation (CRT), tailored mesorectal excision, and intraoperative radiotherapy (IORT) have become the leading measures for rectal cancer treatment. The objective of this study was to evaluate early and long-term results of a multimodal treatment model for rectal cancer followed by curative surgery. Prospectively collected hospital records of 338 patients surgically treated for rectal cancer between January 1998 and December 2008 were retrospectively reviewed. Patients with high rectum level cancers and those with middle and low rectum cancers with clinical stage T1 to T2 underwent surgery, whereas those with T3 to T4 and N1 disease at the middle and low rectum received neoadjuvant CRT in 96.2 per cent of cases. Short-course neoadjuvant radiotherapy was not considered for neoadjuvant treatment. Postoperative major complications and mortality rates were 12.7 and 2.3 per cent, respectively. Overall 5-year disease-specific and disease-free survival were 80 and 73.1 per cent, respectively, whereas local recurrence rate was 6.1 per cent. At multivariate analysis, nodal status and circumferential margin status were independently associated with poor survival; local recurrence rates were independently affected by nodal and marginal status and tumor stage. The extent of mesorectal excision should be tailored depending on tumor location and the use of neoadjuvant chemotherapy, combined with IORT in advanced middle and low rectal cancer, leading to remarkable tumor downstaging with excellent prognosis in responding patients.

Transperineal minimally invasive APE: preliminary outcomes in a multicenter cohort

Background

Abdominoperineal excision (APE) for rectal cancer is associated with a relatively high risk of positive margins and postoperative morbidity, particularly related to perineal wound healing problems. It is unknown whether the use of a minimally invasive approach for the perineal part of these procedures can improve postoperative outcomes without oncological compromise. The aim of this study was to evaluate the feasibility of minimally invasive transperineal abdominoperineal excision (TpAPE)

Methods

This multicenter retrospective cohort study included all patients having TpAPE for primary low rectal cancer. The primary endpoint was the intraoperative complication rate. Secondary endpoints included major morbidity (Clavien–Dindo ≥ 3), histopathology results, and perineal wound healing.

Results

A total of 32 TpAPE procedures were performed in five centers. A bilateral extralevator APE (ELAPE) was performed in 17 patients (53%), a unilateral ELAPE in 7 (22%), and an APE in 8 (25%). Intraoperative complications occurred in five cases (16%) and severe postoperative morbidity in three cases (9%). There were no perioperative deaths. A positive margin (R1) was observed in four patients (13%) and specimen perforation occurred in two (6%). The unilateral extralevator TpAPE group had worse specimen quality and a higher proportion of R1 resections than the bilateral ELAPE or standard APE groups. The rate of uncomplicated perineal wound healing was 53% (n = 17) and three patients (9%) required surgical reintervention.

Conclusions

TpAPE seems to be feasible with acceptable perioperative morbidity and a relatively low rate of perineal wound dehiscence, while histopathological outcomes remain suboptimal. Additional evaluation of the viability of this technique is needed in the form of a prospective trial with standardization of the procedure, indication, audit of outcomes and performed by surgeons with vast experience in transanal total mesorectal excision.

Predictors of overall survival following extended radical resections for locally advanced and recurrent pelvic malignancies

PURPOSE

In an era of personalised medicine, there is an overwhelming effort for predicting patients who will benefit from extended radical resections for locally advanced pelvic malignancy. However, there is paucity of data on the effect of comorbidities and postoperative complications on long-term overall survival (OS). The aim of this study was to define predictors of 1-year and 5-year OS.

METHODS

Data were collected from prospective databases at two high-volume institutions specialising in beyond TME surgery for locally advanced and recurrent pelvic malignancies between 1990 and 2015. The primary outcome measures were 1-year and 5-year OS.

RESULTS

A total of 646 consecutive extended radical resections were performed between 1990 and 2015. The majority were female patients (371, 57.4%) and the median age was 63 years (range 19-89 years). One-year OS, primary rectal adenocarcinoma had the best survival while recurrent colon cancer had the worse survival (p = 0.047). The 5-year OS between primary and recurrent cancers were 64.7% and 53%, respectively (p = 0.004). Poor independent prognostic markers for 5-year OS were increasing ASA score, cardiovascular disease, recurrent cancers, ovarian cancers, pulmonary embolus and acute respiratory distress syndrome. A positive survival benefit was demonstrated with preoperative radiotherapy (HR 0.55; 95% CI 0.4-0.75, p < 0.001).

CONCLUSION

Patient comorbidities and specific complications can influence long-term survival following extended radical resections. This study highlights important predictors, enabling clinicians to better inform patients of the potential short- and long-term outcomes in the management of locally advanced and recurrent pelvic malignancy.

The Landmark Series: Management of Lateral Lymph Nodes in Locally Advanced Rectal Cancer

There has historically been a significant divide in the approach to the management of lateral pelvic lymph nodes in patients with rectal cancer. These differing paradigms have developed based upon competing priorities. In the West, the circumferential resection margin has been the main focus because it is a strong predictor of local recurrence, distal recurrence, and survival. This approach was supplemented by radiation and chemotherapy to treat the lateral pelvic lymph nodes and micrometastatic disease. In the East, lateral pelvic lymph nodes are considered to be locoregional; thus, surgical treatment has traditionally included routine dissection of this compartment for low rectal cancers without the use of neoadjuvant chemoradiotherapy. However, neither approach has adequately addressed the important issue of lateral compartment recurrence in patients with clinically evident lateral pelvic lymph node metastasis. The aims of the review were to present the recent key studies and evolution of lateral pelvic lymph node management in locally advanced rectal cancer and secondly to propose a management strategy for the lateral compartment based on the current evidence.

Robotic surgery for rectal cancer as a platform to build on: review of current evidence

Laparoscopy in colorectal surgery reduces the rate of postoperative complications, shortens the length of stay in hospital, and improves the quality of patient care. Despite these established benefits, the technical challenges of rectal resection for cancer have resulted in most operations being performed through open surgery in the USA. Moreover, controversy in the current literature questions the oncologic safety of a laparoscopic approach for rectal cancer. How then can surgeons innovate to overcome the technical challenges while preserving the critical oncological outcomes of high-quality rectal cancer surgery? Robotics may be a platform that allows us to overcome the technical challenges in the pelvis while maintaining both oncological outcomes and the benefits of a minimally invasive technique. Current evidence suggests that the quality of total mesorectal excision, the rates of circumferential margin involvement, and postoperative outcomes are comparable between robotic and laparoscopic surgery. While a robotic approach demonstrates lower conversion rates and reduced surgeon workload, the operative time is longer and initial costs are higher; however, time and future science will determine its true benefits. We review the current state of robotic surgery and its impact on rectal cancer surgery.

Significance of Radial Margin in Patients Undergoing Complete Mesocolic Excision for Colon Cancer

BACKGROUND

Comparable to circumferential resection margin in rectal cancer, radial margin is a potential prognostic factor in colon cancer that has just begun to be studied. No previous studies have investigated the influence of radial margin in the context of complete mesocolic excision.

OBJECTIVE

This study aimed to examine the impact of radial margin on oncologic outcomes after complete mesocolic excision for colon cancer.

DESIGN

We retrospectively reviewed patients with stage I to III colon cancer who underwent curative resection from October 2010 to March 2013.

SETTINGS

This study was conducted using the prospective colorectal cancer registry of Severance hospital.

PATIENTS

A total of 834 consecutive patients who underwent complete mesocolic excision for colon adenocarcinoma were included.

INTERVENTIONS

We assigned patients into 3 groups according to radial margin distance: group A, radial margin ≥2.0 mm; group B, 1.0 ≤ radial margin < 2.0 mm; group C, radial margin <1 mm.

MAIN OUTCOMES AND MEASURES

Overall survival and disease-free survival were estimated.

RESULTS

On adjusted Cox regression analysis, only group C was predictive of reduced overall survival (HR, 1.90; 95% CI, 1.11-3.25; p = 0.018) and disease-free survival (HR, 1.93; 95% CI, 1.28-2.89; p = 0.001). We thereby defined radial margin threatening as radial margin <1 mm. Postoperative 5-fluorouracil (HR, 0.86; 95% CI, 0.35-2.10; p = 0.743) and FOLFOX (HR, 1.23; 95% CI, 0.57-2.64; p = 0.581) chemotherapy did not affect disease-free survival in patients with radial margin threatening.

LIMITATIONS

This study has the limitations inherent in all retrospective, single-institution studies.

CONCLUSIONS

Even with complete mesocolic excision, radial margin <1 mm was an independent predictor of survival and recurrence. This finding suggests that special efforts for obtaining a clear radial margin may be necessary in locally advanced colon cancer. See Video Abstract at http://links.lww.com/DCR/B125. IMPORTANCIA DEL MARGEN RADIAL EN PACIENTES SOMETIDOS A ESCISIÓN MESOCÓLICA COMPLETA PARA CÁNCER DEL COLON: Comparable al margen de resección circunferencial en cáncer rectal, el margen radial en cáncer de colon, es un factor pronóstico potencial, que recientemente comienza a estudiarse. Ningún estudio previo ha investigado la influencia del margen radial, en el contexto de la escisión mesocólica completa.Examinar en cáncer de colon, el impacto del margen radial en los resultados oncológicos, después de la escisión mesocólica completa.Revisión retrospectiva de pacientes con cáncer de colon en estadio I-III, sometidos a resección curativa de octubre 2010 a marzo 2013.Este estudio se realizó utilizando un registro prospectivo de cáncer colorrectal del hospital Severance.Se incluyeron un total de 834 pacientes consecutivos con adenocarcinoma de colon, sometidos a escisión mesocólica completa. Dividimos a los pacientes en 3 grupos según la distancia del margen radial: grupo A, margen radial ≥ 2.0 mm; grupo B, 1.0 ≤ margen radial <2.0 mm; grupo C, margen radial <1 mm.Se estimó la supervivencia general y la supervivencia libre de enfermedad.En el análisis de regresión de Cox ajustado, solo el grupo C fue predictivo de supervivencia global reducida (HR, 1.90; IC 95%, 1.11-3.25; p = 0.018) y supervivencia libre de enfermedad (HR, 1.93; IC 95%, 1.28-2.89; p = 0.001). Definimos como margen radial amenazante, un margen radial <1 mm. La quimioterapia posoperatoria con 5-FU (HR, 0,86; IC 95%, 0,35-2,10; p = 0.743) y FOLFOX (HR, 1,23; IC 95%, 0,57-2,64; p = 0,581), no afectó la supervivencia libre de enfermedad en pacientes con riesgo de margen radial.Este estudio tiene limitaciones inherentes a todos los estudios retrospectivos de una sola institución.Aun con la escisión mesocólica completa, el margen radial <1 mm fue un predictor independiente de supervivencia y recurrencia. Este hallazgo sugiere que pueden ser necesarios esfuerzos especiales para obtener un claro margen radial, en cáncer de colon localmente avanzado. Consulte Video Resumen en http://links.lww.com/DCR/B125.

A Multicenter Matched Comparison of Transanal and Robotic Total Mesorectal Excision for Mid and Low-rectal Adenocarcinoma

OBJECTIVE

To compare the quality of surgical resection of transanal total mesorectal excision (TA-TME) and robotic total mesorectal excision (R-TME).

BACKGROUND

Both TA-TME and R-TME have been advocated to improve the quality of surgery for rectal cancer below 10 cm from the anal verge, but there are little data comparing TA-TME and R-TME.

METHODS

Data of patients undergoing TA-TME or R-TME for rectal cancer below 10 cm from the anal verge and a sphincter-saving procedure from 5 high-volume rectal cancer referral centers between 2011 and 2017 were obtained. Coarsened exact matching was used to create balanced cohorts of TA-TME and R-TME. The main outcome was the incidence of poor-quality surgical resection, defined as a composite measure including incomplete quality of TME, or positive circumferential resection margin (CRM) or distal resection margin (DRM).

RESULTS

Out of a total of 730 patients (277 TA-TME, 453 R-TME), matched groups of 226 TA-TME and 370 R-TME patients were created. These groups were well-balanced. The mean tumor height from the anal verge was 5.6 cm (SD 2.5), and 70% received preoperative radiotherapy. The incidence of poor-quality resection was similar in both groups (TA-TME 6.9% vs R-TME 6.8%; P = 0.954). There were no differences in TME specimen quality (complete or near-complete TA-TME 99.1% vs R-TME 99.2%; P = 0.923) and CRM (5.6% vs 6.0%; P = 0.839). DRM involvement may be higher after TA-TME (1.8% vs 0.3%; P = 0.051).

CONCLUSIONS

High-quality TME for patients with rectal adenocarcinoma of the mid and low rectum can be equally achieved by transanal or robotic approaches in skilled hands, but attention should be paid to the distal margin.

Risk of local recurrence of rectal cancer and circumferential resection margin: population-based cohort study

Background

A circumferential resection margin (CRM) of 1·0 mm or less after rectal cancer surgery is thought to increase the risk of local recurrence (LR). This retrospective population-based study examined how CRM distance affects the LR risk.

Methods

Data from the Swedish Colorectal Cancer Registry were used in a retrospective analysis of rectal cancers resected between 2005 and 2013. The primary endpoint was LR.

Results

A total of 12 146 patients were identified, of whom 8392 were included in the analysis; 739 patients had a CRM of 1·0 mm or less and 7653 had a CRM larger than 1·0 mm. The mean follow-up time was 51 months. There were 66 LRs (8·9 per cent) in the group with a CRM of 1·0 mm or less, and 256 (3·3 per cent) among patients with a CRM larger than 1·0 mm. The LR rate was 17·0 per cent (27 of 159), 6·7 per cent (39 of 580), 1·9 per cent (2 of 103) and 3·4 per cent (254 of 7550) when the CRM was 0, 0·1–1·0, 1·1–1·9 and at least 2·0 mm respectively. The risk of LR among patients with a CRM of 0 mm was higher than that in all other subgroups with a larger CRM (P &lt; 0·050). There was no difference in LR between the subgroups with CRM 1·1–1·9 mm and at least 2·0 mm. LR was diagnosed earlier when the CRM was 1·0 mm or less.

Conclusion

LR risk is related to exact CRM, with the highest risk in patients with a CRM of 0 mm. Close monitoring of patients with no measurable clear margin may allow early detection of LR.

Circumferential Resection Margin as a Hospital Quality Assessment Tool for Rectal Cancer Surgery

BACKGROUND

Circumferential resection margin (CRM) status is an important predictor of outcomes after rectal cancer operation, and is influenced not only by operative technique, but also by incorporation of a multidisciplinary treatment strategy. This study sought to develop a risk-adjusted quality metric based on CRM status to assess hospital-level performance for rectal cancer operation.

STUDY DESIGN

We conducted a retrospective observational cohort study of 58,374 patients with resected stage I to III rectal cancer within 1,303 hospitals who were identified from the National Cancer Database (2010 to 2015). The number of observed cases with a positive CRM (≤ 1 mm) was divided by the risk-adjusted expected number of cases with positive CRM to form the observed-to-expected (O/E) ratio. Secondary endpoint was overall survival.

RESULTS

The overall rate of CRM positivity was 15.9%. Based on the O/E ratio for 1,139 hospitals, 147 (12.9%) and 103 (9.0%) were significantly worse and better performers, respectively. The majority of hospitals (n = 570) performed as expected. Positive CRMs using criteria of 0 mm and 0.1 to 1 mm were associated with a significantly shorter 5-year overall survival of 49% and 63.5% (hazard ratio 1.67; 95% CI, 1.57 to 1.76 and hazard ratio 1.19; 95% CI, 1.12 to 1.26) than negative CRM > 1 mm of 74.1% (all p < 0.001).

CONCLUSIONS

CRM-based O/E ratio is a robust hospital-based quality measure for rectal cancer operation. It allows facilities to compare their performance with that of centers of similar characteristics and helps identify underperforming, at-risk, and high-performing centers. National quality-improvement initiatives for rectal cancer should focus on ensuring high-quality data collection and providing ready access to risk-adjusted comparative metrics.

Correlation Between Endorectal Ultrasound and Magnetic Resonance Imaging for Predicting the Circumferential Resection Margin in Patients With Mid-Low Rectal Cancer Without Preoperative Chemoradiotherapy

OBJECTIVES

To assess the correlation between endorectal ultrasound (ERUS) and magnetic resonance imaging (MRI) in predicting the circumferential resection margin (CRM) status of patients with mid-low rectal cancer without preoperative chemoradiotherapy.

METHODS

Twenty patients with rectal cancer who did not receive preoperative chemoradiotherapy and underwent ERUS and MRI examinations before total mesorectal excision from May 2018 to April 2019 were included in this study. The patient and tumor characteristics, lymph nodes, tumor stages, ERUS and MRI predictors of the CRM status, and postoperative pathologic results were recorded. The closest distance between the deepest portion of lesion invasion and the mesorectal fascia was independently measured on MRI and ERUS images by 2 observers. The observers were blinded to the pathologic results. Measurements from ERUS and MRI were compared.

RESULTS

The mean distance between the distal edge of the lesion and the anal verge was 5.7 cm (range, 3.1-8.1 cm). The ERUS and pathologic evaluations of CRM involvement were consistent in 90% of the cases. The MRI and pathologic evaluations of CRM involvement were concordant in 95% of the cases. The Cohen κ coefficient of ERUS and MRI was 0.608 (P = .007). The correlation coefficient of ERUS and MRI for assessing the closest distance from the edge of cancer invasion to the mesorectal fascia was 0.99 (P = .0005).

CONCLUSIONS

Endorectal ultrasound and MRI assessments of the preoperative CRM status appear to be highly consistent. Endorectal ultrasound can be used as a complementary tool with MRI to predict the CRM status of patients with mid-low rectal cancer without preoperative chemoradiotherapy.

Use of Robotic Technology in the Management of Complex Colorectal Pathology

Use of robotic surgery is increasing in multiple surgical specialties including colorectal. We argue that the improved visualization and better instrumentation outweigh the increased cost and operating room time. However, the indications for its use are not clearly defined. This is especially true in complex pathologies such as rectal cancer and complicated diverticulitis. We explore the limited clinical data on the subject to support or dismiss the use of this currently developing technology.

Robotic Colorectal Surgery

The role of robotics in colon and rectal surgery has been established as an important and effective tool for the surgeon. Its inherent technologies have provided for increased visualization and ease of dissection in the minimally invasive approach to surgery. The value of the robot is apparent in the more challenging aspects of colon and rectal procedures, including the intracorporeal anastomosis for right colectomies and the low pelvic dissection for benign and malignant diseases.

Can better surgical outcomes be obtained in the learning process of robotic rectal cancer surgery? A propensity score-matched comparison between learning phases

BACKGROUND

Although studies of robotic rectal cancer surgery have demonstrated the effects of learning on operation time, comparisons have failed to demonstrate differences in clinicopathological outcomes between unadjusted learning phases. This study aimed to investigate the learning curve of robotic rectal cancer surgery for clinicopathological outcomes and compare surgical outcomes between adjusted learning phases. Study design We enrolled 506 consecutive patients with rectal adenocarcinoma who underwent robotic resection by a single surgeon between 2007 and 2018. Risk-adjusted cumulative sum (RA-CUSUM) for surgical failure was used to analyze the learning curve. Surgical failure was defined as the occurrence of any of the following: conversion to open surgery, severe complications (Clavien-Dindo grade ≥ 3a), insufficient number of harvested lymph nodes (LNs), or R1 resection. Comparisons between learning phases analyzed by RA-CUSUM were performed before and after propensity score matching.

RESULTS

In RA-CUSUM analysis, the learning curve was divided into two learning phases: phase 1 (1st-177th cases, n = 177) and phase 2 (178th-506th cases, n = 329). Before matching, patients in phase 2 had deeper tumor invasion and higher rates of positive LNs on pretreatment images and preoperative chemoradiotherapy. After matching, phase 1 (n = 150) and phase 2 (n = 150) patients exhibited similar clinical characteristics. Phase 2 patients had lower rates of surgical failure overall and these components: conversion to open surgery, severe complications, and insufficient harvested LNs.

CONCLUSIONS

For robotic rectal cancer surgery, surgical outcomes improved after the 177th case. Further studies by other robotic surgeons are required to validate our results.

An observational study of patho-oncological outcomes of various surgical methods in total mesorectal excision for rectal cancer: a single center analysis

BACKGROUND

Total mesorectal excision (TME) with or without neoadjuvant concurrent chemoradiotherapy (CCRT) is the treatment for rectal cancer (RC). Recently, the use of conventional laparoscopic surgery (LS) or robotic-assisted surgery (RS) has been on a steady increase cases. However, various oncological outcomes from different surgical approaches are still under investigation.

METHODS

This is a retrospective observational study comprising 300 consecutive RC patients who underwent various techniques of TME (RS, n = 88; LS, n = 37; Open surgery, n = 175) at a single center of real world data to compare the pathological and oncological outcomes, with a median follow-up of 48 months.

RESULTS

Upon multivariate analysis, histologic grade (P = 0.016), and stage (P < 0.001) were the independent factors of circumferential resection margin (CRM) involvement. The Kaplan-Meier survival analysis determined RS, early pathologic stage, negative CRM involvement, and pathologic complete response to be significantly associated with better overall survival (OS) and disease-free survival (DFS) (all P < 0.05). Multivariable analyses observed the surgical method (P = 0.037), histologic grade (P = 0.006), and CRM involvement (P = 0.043) were the independent factors of DFS, whereas histologic grade (P = 0.011) and pathologic stage (P = 0.022) were the independent prognostic variables of OS.

CONCLUSIONS

This study determined that RS TME is feasible because it has less CRM involvement and better oncological outcomes than the alternatives have. The significant factors influencing CRM and prognosis depended on the histologic grade, tumor depth, and pre-operative CCRT. RS might be an acceptable option owing to the favorable oncological outcomes for patients with RC undergoing TME.

Clinicopathologic Analysis of Lateral Margin Measured by Whole-mount Section in T3 Rectal Cancer

PURPOSE

Total mesorectal excision is a standard technique for rectal cancer. The whole-mount section can encompass the entire specimen, so it is a more appropriate for measuring circumferential margin than conventional section. We analyzed the clinical characteristics and prognosis based on lateral margins measured by whole-mount sections.

MATERIALS AND METHODS

Medical records of patients who were operated on for T3 rectal cancer from 2005 to 2015 were reviewed retrospectively. A total of 154 patients were included. The slides of the whole-mount sections were re-reviewed by a single pathologist.

RESULTS

We divided the groups according to the length of the lateral margin (LM: 1mm, 1.5mm and 2mm). There was significantly frequent lymphovascular invasion and N state was higher when LM was short in all groups. There were more micrometastasis in group LM.

Importance of the neoadjuvant rectal (NAR) score to the outcome of neoadjuvant chemotherapy alone for locally advanced rectal cancer

PURPOSE

The neoadjuvant rectal (NAR) score is a promising indicator of survival after preoperative chemoradiotherapy for rectal cancer. However, its effectiveness after neoadjuvant chemotherapy (NAC) alone has not been fully investigated.

METHODS

We analyzed data retrospectively on 61 patients with rectal cancer, who received NAC followed by surgical resection between 2010 and 2015, and evaluated the impact of the NAR score on survival.

RESULTS

The median NAR score was 14.9. Of the 61 patients, 13, 35, and 13 were classified as having NAR-low (< 8), NAR-intermediate (8-16), and NAR-high (> 16) scores, respectively. The median observation period was 49.0 months. According to the NAR score, the 3-year DFS in the NAR-low group was 100%, which was significantly better than that in the NAR-intermediate (64.8%, p = 0.041), and NAR-high (61.5%, p = 0.018) groups. When the NAR-intermediate and NAR-high groups were investigated as a single high-risk group, the 3-year DFS of the patients who received adjuvant chemotherapy was 88.7%, which was significantly better than that of the patients who did not receive adjuvant chemotherapy (53.3%, p = 0.042).

CONCLUSIONS

The NAR score may predict the DFS and could serve as a favorable indicator of adjuvant chemotherapy after NAC alone.

Open Versus Laparoscopic Versus Robotic Versus Transanal Mesorectal Excision for Rectal Cancer: A Systematic Review and Network Meta-analysis

OBJECTIVE

To compare techniques for rectal cancer resection.

SUMMARY BACKGROUND DATA

Different surgical approaches exist for mesorectal excision.

METHODS

Systematic literature review and Bayesian network meta-analysis performed.

RESULTS

Twenty-nine randomized controlled trials included, reporting on 6237 participants, comparing: open versus laparoscopic versus robotic versus transanal mesorectal excision. No significant differences identified between treatments in intraoperative morbidity, conversion rate, grade III/IV morbidity, reoperation, anastomotic leak, nodes retrieved, involved distal margin, 5-year overall survival, and locoregional recurrence. Operative blood loss was less with laparoscopic surgery compared with open, and with robotic surgery compared with open and laparoscopic. Robotic operative time was longer compared with open, laparoscopic, and transanal. Laparoscopic operative time was longer compared with open. Laparoscopic surgery resulted in lower overall postoperative morbidity and fewer wound infections compared with open. Robotic surgery had fewer wound infections compared with open. Time to defecation was longer with open surgery compared with laparoscopic and robotic. Hospital stay was longer after open surgery compared with laparoscopic and robotic, and after laparoscopic surgery compared with robotic. Laparoscopic surgery resulted in more incomplete or nearly complete mesorectal excisions compared with open, and in more involved circumferential resection margins compared with transanal. Robotic surgery resulted in longer distal resection margins compared with open, laparoscopic, and transanal.

CONCLUSIONS

The different techniques result in comparable perioperative morbidity and long-term survival. The laparoscopic and robotic approaches may improve postoperative recovery, and the open and transanal approaches may improve oncological resection. Technique selection should be based on expected benefits by individual patient.

How to measure tumour response in rectal cancer? An explanation of discrepancies and suggestions for improvement

Various methods categorize tumour response after neoadjuvant therapy, including down-staging and tumour regression grading. Response categories allow comparison of different treatments within clinical trials and predict outcome. A reproducible response categorization could identify subgroups with high or low risk for the most appropriate subsequent treatments, like watch and wait. Lack of standardization and interpretation difficulties currently limit the usability of these approaches. In this review we describe these difficulties for the evaluation of chemoradiation in rectal cancer. An alternative approach of tumour response is based on patterns of residual disease, including fragmentation. We summarise the evidence behind this alternative method of response categorisation, which explains a number of very relevant clinical discrepancies. These issues include differences between downstaging and tumour regression, high local regrowth in advanced tumours during watchful waiting procedures, the importance of resection margins, the limited value of post-treatment biopsies and the relatively poor outcome of patients with a near complete pathological response. Recognition of these patterns of response can allow meaningful development of novel biomarkers in the future.

Margin Positivity in Resectable Esophageal Cancer: Are there Modifiable Risk Factors?

BACKGROUND

Patients with esophageal cancer have poor overall survival, with positive resection margins worsening survival. Margin positivity rates are used as quality measures in other malignancies, but modifiable risk factors are necessary to develop actionable targets for improvement. Our objectives were to (1) evaluate trends in esophageal cancer margin positivity, and (2) identify modifiable patient/hospital factors associated with margin positivity.

METHODS

Patients who underwent esophagectomy from 2004 to 2015 were identified from the National Cancer Database. Trends in margin positivity by time and hospital volume were evaluated using Cochrane-Armitage tests. Associations between patient/hospital factors and margin positivity were assessed by multivariable logistic regression.

RESULTS

Among 29,706 patients who underwent esophagectomy for cancer, 9.37% had positive margins. Margin positivity rates decreased over time (10.62% in 2004 to 8.61% in 2015; p < 0.001). Older patients (≥ 75 years) were more likely to have positive margins [odds ratio (OR) 2.04, 95% confidence interval (CI) 1.42-2.92], as were patients with a Charlson-Deyo Index ≥ 3 (OR 1.84, 95% CI 1.08-3.12). Patients who received neoadjuvant therapy were less likely to have positive margins (OR 0.37, 95% CI 0.29-0.47), while laparoscopic surgical approach was associated with increased margin positivity (OR 1.70, 95% CI 1.40-2.06). As the hospital annual esophagectomy volume increased, margin positivity rates decreased (7.76% in the fourth quartile vs. 11.39% in the first quartile; OR 0.70, 95% CI 0.49-0.99).

CONCLUSIONS

Use of neoadjuvant therapy, surgical approach, and hospital volume are modifiable risk factors for margin positivity in esophageal cancer. These factors should be considered in treatment planning, and margin positivity rates could be considered as a quality measure in esophageal cancer.

Laparoscopic Versus Open Resection for Rectal Cancer: A Noninferiority Meta-analysis of Quality of Surgical Resection Outcomes

OBJECTIVE

To determine whether laparoscopic surgery is noninferior to open surgery for rectal cancer in terms of quality of surgical resection outcomes.

BACKGROUND

Randomized clinical trials (RCTs) have evaluated the oncologic safety of laparoscopic versus open surgery for rectal cancer with conflicting results. Prior meta-analyses comparing these operative approaches in terms of quality of surgical resection aimed to demonstrate if one approach was superior. However, this method is not appropriate and potentially misleading when noninferiority RCTs are included.

METHODS

MEDLINE, EMBASE, and Cochrane were searched to identify RCTs comparing these operative approaches. Risk differences (RDs) were pooled using random-effects meta-analyses. One-sided Z tests were used to determine noninferiority. Noninferiority margins (ΔNI) for circumferential resection margin (CRM), plane of mesorectal excision (PME), distal resection margin (DRM), and a composite outcome ("successful resection") were based on the consensus of 58 worldwide experts.

RESULTS

Fourteen RCTs were included. Laparoscopic resection was noninferior compared with open resection for the rate of positive CRM [RD 0.79%, 90% confidence interval (CI) -0.46 to 2.04, ΔNI = 2.33%, PNI = 0.026], incomplete PME (RD 1.16%, 90% CI -0.27 to 2.59, ΔNI = 2.85%, PNI = 0.025), and positive DRM (RD 0.15%, 90% CI -0.58 to 0.87, ΔNI = 1.28%, PNI = 0.005). For the rate of "successful resection" (RD 6.16%, 90% CI 2.30-10.02), the comparison was inconclusive when using the ΔNI generated by experts (ΔNI = 2.71%, PNI = 0.07), although no consensus was achieved for this ΔNI.

CONCLUSIONS

Laparoscopy was noninferior to open surgery for rectal cancer in terms of individual quality of surgical resection outcomes. These findings are concordant with RCTs demonstrating noninferiority for long-term oncologic outcomes between the 2 approaches.

Oncologic and Perioperative Outcomes of Laparoscopic, Open, and Robotic Approaches for Rectal Cancer Resection: A Multicenter, Propensity Score-Weighted Cohort Study

BACKGROUND

Minimally invasive approaches have been shown to reduce surgical site complications without compromising oncologic outcomes.

OBJECTIVE

The primary aim of this study is to evaluate the rates of successful oncologic resection and postoperative outcomes among laparoscopic, open, and robotic approaches to rectal cancer resection.

DESIGN

This is a multicenter, quasiexperimental cohort study using propensity score weighting.

SETTINGS

Interventions were performed in hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program.

PATIENTS

Adult patients who underwent rectal cancer resection in 2016 were included.

MAIN OUTCOME MEASURES

The primary outcome was a composite variable indicating successful oncologic resection, defined as negative distal and radial margins with at least 12 lymph nodes evaluated.

RESULTS

Among 1028 rectal cancer resections, 206 (20%) were approached laparoscopically, 192 (18.7%) were approached robotically, and 630 (61.3%) were open. After propensity score weighting, there were no significant sociodemographic or preoperative clinical differences among subcohorts. Compared to the laparoscopic approach, open and robotic approaches were associated with a decreased likelihood of successful oncologic resection (ORadj = 0.64; 95% CI, 0.43-0.94 and ORadj = 0.60; 95% CI, 0.37-0.97), and the open approach was associated with an increased likelihood of surgical site complications (ORadj = 2.53; 95% CI, 1.61-3.959). Compared to the laparoscopic approach, the open approach was associated with longer length of stay (6.8 vs 8.6 days, p = 0.002).

LIMITATIONS

This was an observational cohort study using a preexisting clinical data set. Despite adjusted propensity score methodology, unmeasured confounding may contribute to our findings.

CONCLUSIONS

Resections that were approached laparoscopically were more likely to achieve oncologic success. Minimally invasive approaches did not lengthen operative times and provided benefits of reduced surgical site complications and decreased postoperative length of stay. Further studies are needed to clarify clinical outcomes and factors that influence the choice of approach. See Video Abstract at http://links.lww.com/DCR/B70. RESULTADOS ONCOLÓGICOS Y PERIOPERATORIOS DE LOS ABORDAJES LAPAROSCÓPICOS, ABIERTOS Y ROBÓTICOS PARA LA RESECCIÓN DEL CÁNCER RECTAL: UN ESTUDIO DE COHORTE MULTICÉNTRICO Y PONDERADO DEL PUNTAJE DE PROPENSIÓN: Se ha demostrado que los enfoques mínimamente invasivos reducen las complicaciones del sitio quirúrgico sin comprometer los resultados oncológicos.El objetivo principal de este estudio es evaluar las tasas de resección oncológica exitosa y los resultados postoperatorios entre los abordajes laparoscópico, abierto y robótico para la resección del cáncer rectal.Este es un estudio de cohorte cuasi-experimental multicéntrico que utiliza la ponderación de puntaje de propensión.Las intervenciones se realizaron en hospitales que participan en el Programa Nacional de Mejora de la Calidad Quirúrgica del Colegio Americano de Cirujanos.Se incluyeron pacientes adultos que se sometieron a resección de cáncer rectal en 2016.El resultado primario fue una variable compuesta que indicaba una resección oncológica exitosa, definida como márgenes negativos distales y radiales con al menos 12 ganglios linfáticos evaluados.Entre 1,028 resecciones de cáncer rectal, 206 (20%) fueron abordadas por vía laparoscópica, 192 (18.7%) robóticamente y 630 (61.3%) abiertas. Después de ponderar el puntaje de propensión, no hubo diferencias sociodemográficas o clínicas preoperatorias significativas entre las subcohortes. En comparación con el abordaje laparoscópico, los abordajes abiertos y robóticos se asociaron con una menor probabilidad de resección oncológica exitosa (ORadj = 0.64; IC 95%, 0.43-0.94 y ORadj = 0.60; IC 95%, 0.37-0.97), y el abordaje abierto se asoció con una mayor probabilidad de complicaciones del sitio quirúrgico (ORadj = 2.53; IC 95%, 1.61-3.959). En comparación con el abordaje laparoscópico, el abordaje abierto se asoció con una estadía más prolongada (6.8 frente a 8.6 días, p = 0.002).Este fue un estudio de cohorte observacional que utilizó un conjunto de datos clínicos preexistentes. A pesar de la metodología de puntuación de propensión ajustada, la confusión no medida puede contribuir a nuestros hallazgos.Las resecciones que se abordaron por vía laparoscópica tuvieron más probabilidades de lograr el éxito oncológico. Los enfoques mínimamente invasivos no alargaron los tiempos quirúrgicos y proporcionaron beneficios de la reducción de las complicaciones del sitio quirúrgico y la disminución de la duración de la estadía postoperatoria. Se necesitan más estudios para aclarar los resultados clínicos y los factores que influyen en la elección del enfoque. Vea video resumen en http://links.lww.com/DCR/B70.

Compliance With Preoperative Elements of the American Society of Colon and Rectal Surgeons Rectal Cancer Surgery Checklist Improves Pathologic and Postoperative Outcomes

BACKGROUND

In 2016, the American Society of Colon and Rectal Surgeons published a rectal cancer surgery checklist composed of the essential elements of preoperative, intraoperative, and postoperative care for patients undergoing rectal cancer surgery.

OBJECTIVE

The purpose of this study was to assess whether compliance with preoperative checklist elements was associated with improved pathologic and 30-day postoperative outcomes after rectal cancer surgery.

DESIGN

This was a retrospective cohort study.

SETTINGS

The study involved North American hospitals contributing to the American College of Surgeons National Surgical Quality Improvement Program.

PATIENTS

Adult patients who underwent elective rectal cancer surgery from 2016 to 2017 were included.

INTERVENTION

The study encompassed checklist compliance with 6 preoperative elements from the checklist.

MAIN OUTCOME MEASURES

Pathologic outcomes (circumferential resection margin status, distal resection margin status, and adequate lymph node harvest ≥12), 30-day surgical morbidity, and length of stay were measured.

RESULTS

In total, 2217 patients were included in the analysis. Individual compliance with the 6 available preoperative checklist items was variable, including 91.3% for pretreatment documentation of tumor location within the rectum, 86.8% for complete colonoscopy, 84.0% for appropriate preoperative stoma marking, 79.8% for appropriate use of neoadjuvant radiotherapy, 76.6% for locoregional staging, and 70.8% for distant staging. Only 836 patients (37.7%) had all 6 checklist elements complete, whereas 1381 (62.3%) did not. Compared with patients without checklist compliance, patients with checklist compliance were younger (60.0 vs 63.0 y; p < 0.001) but otherwise had similar demographic characteristics. On multivariate regression, checklist compliance was associated with lower odds of circumferential resection margin positivity (OR = 0.47 (95% CI, 0.31-0.71); p < 0.001), higher odds of an adequate lymph node harvest ≥12 (OR = 1.60 (95% CI, 1.29-2.00); p < 0.001), reduced surgical morbidity (OR = 0.78 (95% CI, 0.65-0.95); p = 0.01), and shorter length of stay (β = -0.87 (95% CI, -1.51 to -0.24); p = 0.007). The association between checklist compliance and reduced odds of circumferential resection margin positivity remained on sensitivity analysis (OR = 0.61 (95% CI, 0.42-0.88); p = 0.009) when adjusting for neoadjuvant radiation.

LIMITATIONS

This study was limited by its absence of long-term oncologic data and missing variables.

CONCLUSIONS

Compliance with 6 preoperative elements of the American Society of Colon and Rectal Surgeons rectal cancer surgery checklist was associated with significantly improved pathologic outcomes and reduced postoperative morbidity. See Video Abstract at http://links.lww.com/DCR/B80. EL CUMPLIMIENTO CON LOS ELEMENTOS PREOPERATORIOS DE LA LISTA DE VERIFICACIÓN DE CIRUGÍA PARA CÁNCER RECTAL DE LA SOCIEDAD AMERICANA DE CIRUJANOS DE COLON Y RECTO MEJORA LOS RESULTADOS HISTOPATOLÓGICOS Y POSTOPERATORIOS: En 2016, la Sociedad Americana de Cirujanos de Colon y Recto publicó una lista de verificación de cirugía de cáncer de recto que comprende los elementos esenciales de la atención pre, intra y postoperatoria para pacientes sometidos a cirugía de cáncer de recto.Evaluar si el cumplimiento con los elementos preoperatorios de la lista de verificación se asoció con mejores resultados histopatológicos y postoperatorios a 30 días después de la cirugía de cáncer rectal.Estudio de cohorte retrospectiva.Hospitales norteamericanos que contribuyen al Programa Nacional de Mejora de la Calidad Quirúrgica del Colegio Americano de Cirujanos.Pacientes adultos que se sometieron a cirugía electiva de cáncer rectal entre 2016 y 2017.Cumplimiento de la lista de verificación con seis elementos preoperatorios de la lista de verificación.Resultados histopatológicos (estado del margen de resección circunferencial, estado del margen de resección distal, cosecha adecuada de ganglios linfáticos ≥12), morbilidad quirúrgica a 30 días y duración de la estadía.En total, 2,217 pacientes fueron incluidos en el análisis. El cumplimiento individual de los seis ítems disponibles de la lista de verificación preoperatoria fue variable: 91.3% para la documentación previa al tratamiento de la localización del tumor dentro del recto, 86.8% para colonoscopía completa, 84.0% para el marcado preoperatorio apropiado del sitio de estoma, 79.8% para el uso apropiado de radioterapia neoadyuvante, 76.6 % para estadificación locorregional y 70.8% para estadificación distante. Solo 836 (37.7%) pacientes tenían los seis elementos de la lista de verificación completos, mientras que 1,381 (62.3%) no. En comparación con los pacientes sin cumplimiento de la lista de verificación, los pacientes con cumplimiento de la lista de verificación eran más jóvenes (60.0 vs. 63.0 años, p <0.001), pero por lo demás tenían características demográficas similares. En la regresión multivariada, el cumplimiento de la lista de verificación se asoció con menores probabilidades de positividad en el margen de resección circunferencial (OR = 0.47; IC del 95%: 0.31-0.71, p <0.001), mayores probabilidades de una cosecha adecuada de ganglios linfáticos ≥12 (OR = 1.60, IC 95% 1.29-2.00, p <0.001), menor morbilidad quirúrgica (OR = 0.78, IC 95% 0.65-0.95, p = 0.01) y menor duración de estadía (β = -0.87, IC 95% -1.51 - - 0.24, p = 0.007). La asociación entre el cumplimiento de la lista de verificación y las probabilidades reducidas de positividad del margen de resección circunferencial se mantuvo en el análisis de sensibilidad (OR = 0.61; IC del 95%: 0.42-0.88, p = 0.009) al ser ajustado con radiación neoadyuvante.Ausencia de datos oncológicos a largo plazo y variables faltantes.El cumplimiento de seis elementos preoperatorios de la lista de verificación de cirugía de cáncer rectal de la Sociedad Americana de Cirujanos de Colon y Recto se asoció con resultados histopatológicos significativamente mejores y una menor morbilidad postoperatoria. Vea el resumen en video en http://links.lww.com/DCR/B80.

Using Diffuse Reflectance Spectroscopy to Distinguish Tumor Tissue From Fibrosis in Rectal Cancer Patients as a Guide to Surgery

BACKGROUND AND OBJECTIVES

In patients with rectal cancer who received neoadjuvant (chemo)radiotherapy, fibrosis is induced in and around the tumor area. As tumors and fibrosis have similar visual and tactile feedback, they are hard to distinguish during surgery. To prevent positive resection margins during surgery and spare healthy tissue, it would be of great benefit to have a real-time tissue classification technology that can be used in vivo.

STUDY DESIGN/MATERIALS AND METHODS

In this study diffuse reflectance spectroscopy (DRS) was evaluated for real-time tissue classification of tumor and fibrosis. DRS spectra of fibrosis and tumor were obtained on excised rectal specimens. After normalization using the area under the curve, a support vector machine was trained using a 10-fold cross-validation.

RESULTS

Using spectra of pure tumor tissue and pure fibrosis tissue, we obtained a mean accuracy of 0.88. This decreased to a mean accuracy of 0.61 when tumor measurements were used in which a layer of healthy tissue, mainly fibrosis, was present between the tumor and the measurement surface.

CONCLUSION

It is possible to distinguish pure fibrosis from pure tumor. However, when the measurements on tumor also involve fibrotic tissue, the classification accuracy decreases. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Outcomes in rectal cancer patients undergoing laparoscopic or robotic low anterior resection compared to open: a propensity-matched analysis of the NCDB (2010-2015)

BACKGROUND

Minimally invasive resection of rectal cancer is controversial due to concerns of the oncologic efficacy and the difficulties of a laparoscopic total mesorectal excision (TME).

METHODS

Using the National Cancer Database (NCDB), for the period 2010-2015, perioperative outcomes and overall survival (OS) in patients with rectal cancer who underwent laparoscopic or robotic low anterior resection (LLAR or RLAR) were compared to open LAR (OLAR) after propensity score matching.

RESULTS

26,047 patients underwent LAR: 4062 (16%) RLAR, 9236 (35%) LLAR, and 12,749 (49%) OLAR. Patient and clinical tumor characteristics were similar between groups after matching. The conversion rates among patients undergoing LLAR and RLAR were 15% and 8%, respectively. In matched OLAR and LLAR patients, longitudinal and circumferential resection margins (CRM) were positive in 5.4% and 3.2% (p < 0.001) and 5.5% and 4.1% (p < 0.001); length of stay was 6 and 5 days, (p < 0.001); readmission was required in 6.5% and 7.0% (p = 0.112); OS at 1, 3, and 5 years were 95.5%, 83.7%, and 72.0% and 95.9%, 86.3%, and 76.4%, respectively (p < 0.001). In matched OLAR and RLAR patients, longitudinal and CRM were positive in 5.4% and 3.2% (p < 0.001) and 5.5% and 3.9% (p < 0.001); length of stay was 6 and 5 days (p < 0.001); readmission was required in 6.1% and 7.9%, (p = 0.010); and OS at 1, 3, and 5 years were 96.2%, 86.5%, and 77.1% and 97.5%, 89.4%, and 79.7%, respectively (p = 0.001).

CONCLUSIONS

In this national sample of propensity matched patients with rectal cancer who underwent open, laparoscopic, or robotic sphincter-saving rectal resection, only small differences in terms of resection margin status, length of stay, readmission, and overall survival were revealed. With acknowledgement of the limitations introduced by selection bias, our data indicate that each of the evaluated operative techniques results in acceptable outcomes for patients with rectal cancer.

Rectal Cancer: Staging

The imaging of rectal cancer has evolved noticeably over the past 2 decades, paralleling the advances in therapy. The methods for imaging rectal cancer are increasingly used in clinical practice with the purpose of helping to detect, characterize and stage rectal cancer. In this setting, MR imaging emerged as the most useful imaging method for primary staging of rectal cancer; the present review focuses on the role of MR imaging in this regard.

Locally recurrent rectal cancer: what the radiologist should know

Despite advances in surgical techniques and chemoradiation therapy, recurrent rectal cancer remains a cause of morbidity and mortality. After successful treatment of rectal cancer, patients are typically enrolled in a surveillance strategy that includes imaging as studies have shown improved prognosis when recurrent rectal cancer is detected during imaging surveillance versus based on development of symptoms. Additionally, patients who experience a complete clinical response with chemoradiation therapy may elect to enroll in a "watch-and-wait" strategy that includes imaging surveillance rather than surgical resection. Factors that increase the likelihood of recurrence, patterns of recurrence, and the imaging appearances of recurrent rectal cancer are reviewed with a focus on CT, PET CT, and MR imaging.

Impact of Preoperative Care for Rectal Adenocarcinoma on Pathologic Specimen Quality and Postoperative Morbidity: A NSQIP Analysis

BACKGROUND

Comprehensive and multidisciplinary care are critical in rectal cancer treatment. We sought to determine if completeness of preoperative care was associated with pathologic specimen quality and postoperative morbidity.

STUDY DESIGN

Clinical stage I-III rectal adenocarcinoma patients who underwent elective low anterior resection or abdominoperineal resection were identified from the 2016-2017 American College of Surgeons-National Surgical Quality Improvement Project (ACS-NSQIP) database. The 3 preoperative NSQIP variables (colonoscopy, stoma marking, and neoadjuvant chemoradiation) were used to divide patients into 2 cohorts: complete vs incomplete preoperative care. The primary outcome was a composite higher pathologic specimen quality score (>12 lymph nodes, negative circumferential, and negative distal margins). The secondary outcome was 30-day morbidity. Preoperative characteristics were compared with ANOVAs and chi-square tests. Outcomes measures were evaluated with logistic regression.

RESULTS

We identified 1,125 patients: 591 (52.5%) complete and 534 (47.5%) incomplete. The complete group was younger, had more women, lower-third rectal tumors, clinical stage III disease, and neoadjuvant treatment. The complete group had higher odds of better pathologic specimen quality after adjusting for age, sex, tumor location, stage, and neoadjuvant therapy (adjusted odds ratio [aOR] 1.75, p = 0.001). The complete group had decreased rates of transfusions (odds ratio [OR] 0.47, p < 0.001), postoperative ileus (OR 0.67, p = 0.01), sepsis (OR 0.32, p = 0.01), and readmissions (OR 0.60, p = 0.003). Other complications did not statistically differ between groups.

CONCLUSIONS

Complete preoperative care in rectal adenocarcinoma is associated with higher pathologic specimen quality and reduced postoperative morbidity. This highlights the importance of adherence to guideline-directed care.

Back-Table Fluorescence-Guided Imaging for Circumferential Resection Margin Evaluation Using Bevacizumab-800CW in Patients with Locally Advanced Rectal Cancer

Negative circumferential resection margins (CRM) are the cornerstone for the curative treatment of locally advanced rectal cancer (LARC). However, in up to 18.6% of patients, tumor-positive resection margins are detected on histopathology. In this proof-of-concept study, we investigated the feasibility of optical molecular imaging as a tool for evaluating the CRM directly after surgical resection to improve tumor-negative CRM rates. Methods: LARC patients treated with neoadjuvant chemoradiotherapy received an intravenous bolus injection of 4.5 mg of bevacizumab-800CW, a fluorescent tracer targeting vascular endothelial growth factor A, 2-3 d before surgery (ClinicalTrials.gov identifier: NCT01972373). First, for evaluation of the CRM status, back-table fluorescence-guided imaging (FGI) of the fresh surgical resection specimens (n = 8) was performed. These results were correlated with histopathology results. Second, for determination of the sensitivity and specificity of bevacizumab-800CW for tumor detection, a mean fluorescence intensity cutoff value was determined from the formalin-fixed tissue slices (n = 42; 17 patients). Local bevacizumab-800CW accumulation was evaluated by fluorescence microscopy. Results: Back-table FGI correctly identified a tumor-positive CRM by high fluorescence intensities in 1 of 2 patients (50%) with a tumor-positive CRM. For the other patient, low fluorescence intensities were shown, although (sub)millimeter tumor deposits were present less than 1 mm from the CRM. FGI correctly identified 5 of 6 tumor-negative CRM (83%). The 1 patient with false-positive findings had a marginal negative CRM of only 1.4 mm. Receiver operating characteristic curve analysis of the fluorescence intensities of formalin-fixed tissue slices yielded an optimal mean fluorescence intensity cutoff value for tumor detection of 5,775 (sensitivity of 96.19% and specificity of 80.39%). Bevacizumab-800CW enabled a clear differentiation between tumor and normal tissue up to a microscopic level, with a tumor-to-background ratio of 4.7 ± 2.5 (mean ± SD). Conclusion: In this proof-of-concept study, we showed the potential of back-table FGI for evaluating the CRM status in LARC patients. Optimization of this technique with adaptation of standard operating procedures could change perioperative decision making with regard to extending resections or applying intraoperative radiation therapy in the case of positive CRM.

Tissue diagnosis during colorectal cancer surgery using optical sensing: an in vivo study

Background

In colorectal cancer surgery there is a delicate balance between complete removal of the tumor and sparing as much healthy tissue as possible. Especially in rectal cancer, intraoperative tissue recognition could be of great benefit in preventing positive resection margins and sparing as much healthy tissue as possible. To better guide the surgeon, we evaluated the accuracy of diffuse reflectance spectroscopy (DRS) for tissue characterization during colorectal cancer surgery and determined the added value of DRS when compared to clinical judgement.

Methods

DRS spectra were obtained from fat, healthy colorectal wall and tumor tissue during colorectal cancer surgery and results were compared to histopathology examination of the measurement locations. All spectra were first normalized at 800 nm, thereafter two support vector machines (SVM) were trained using a tenfold cross-validation. With the first SVM fat was separated from healthy colorectal wall and tumor tissue, the second SVM distinguished healthy colorectal wall from tumor tissue.

Results

Patients were included based on preoperative imaging, indicating advanced local stage colorectal cancer. Based on the measurement results of 32 patients, the classification resulted in a mean accuracy for fat, healthy colorectal wall and tumor of 0.92, 0.89 and 0.95 respectively. If the classification threshold was adjusted such that no false negatives were allowed, the percentage of false positive measurement locations by DRS was 25% compared to 69% by clinical judgement.

Conclusion

This study shows the potential of DRS for the use of tissue classification during colorectal cancer surgery. Especially the low false positive rate obtained for a false negative rate of zero shows the added value for the surgeons.

Trail registration This trail was performed under approval from the internal review board committee (Dutch Trail Register NTR5315), registered on 04/13/2015, https://www.trialregister.nl/trial/5175.

Circumferential Resection Margin After Laparoscopic and Open Rectal Resection: A Nationwide Propensity Score Matched Cohort Study

BACKGROUND

Recent studies suggest better oncological results after open versus laparoscopic rectal resection for cancer. The external validity of these results has not been tested on a nationwide basis.

OBJECTIVE

This study aimed to identify risk factors for positive circumferential resection margin in patients undergoing surgery for rectal cancer with special emphasis on surgical approach.

DESIGN

This database study was based on the Danish nationwide colorectal cancer database. To identify risk factors for positive circumferential resection margin, we performed uni- and multivariate logistic regression analyses. To assess the role of surgical approach, a propensity score-matched analysis was performed.

SETTINGS

This study was conducted at public hospitals across Denmark.

PATIENTS

Patients undergoing elective rectal resection from October 2009 through December 2013 were included.

MAIN OUTCOME MEASURES

The primary outcome measured was the risk of a positive circumferential resection margin.

RESULTS

Included in the final analyses were 2721 cases (745 operated on by an open approach; 1976 by laparoscopy). On direct comparison, positive circumferential resection margin occurred more often after open resection (6.3% vs 4.7%; p = 0.047). After multivariate analyses, tumors located low in the rectum, neoadjuvant chemoradiation therapy, increasing T and N stage, tumor fixated in the pelvis, and dissection in the muscularis plane increased the risk of a positive circumferential resection margin. In the propensity score-matched sample (541 exact matched pairs), the laparoscopic approach did not influence the risk of a positive circumferential resection margin (OR, 0.9; 95% CI, 0.6-1.5; p = 0.77).

LIMITATIONS

This was a retrospective review of prospectively collected data, and thereby contained possible selection bias.

CONCLUSIONS

Based on this nationwide database study, and after multivariate and propensity score-matched analyses, there was no increased risk of positive circumferential resection margin after laparoscopic vs open rectal resection. See Video Abstract at http://links.lww.com/DCR/A996. MARGEN DE RESECCIÓN CIRCUNFERENCIAL DESPUÉS DE LA RESECCIÓN RECTAL LAPAROSCÓPICA Y ABIERTA: UN ESTUDIO DE COHORTE DE PUNTUACIÓN DE PROPENSIÓN A NIVEL NACIONAL: Estudios recientes sugieren mejores resultados oncológicos después de la resección rectal abierta versus laparoscópica. La validez de estos resultados no se ha probado a nivel nacional.

OBJETIVO

Identificar los factores de riesgo del margen de resección circunferencial positivo en pacientes sometidos a cirugía por cáncer de recto con especial énfasis en el abordaje quirúrgico. DISEÑO:: Estudio de la base de datos nacional de Dinamarca de cáncer colorrectal. Para identificar los factores de riesgo del margen de resección circunferencial positivo, realizamos análisis de regresión logística uni y multivariable. Para evaluar el papel del abordaje quirúrgico, se realizó un análisis emparejado de puntuación de propensión.

AJUSTES

Hospitales públicos en toda Dinamarca.

PACIENTES

Pacientes sometidos a resección rectal electiva en el período comprendido entre octubre de 2009 y diciembre de 2013.

PRINCIPALES MEDIDAS DE RESULTADOS

Riesgo del margen de resección circunferencial positivo.

RESULTADOS

2721 casos (745 operados por abordaje abierto; 1976 por laparoscopia) se incluyeron en el análisis final. En la comparación directa, el margen de resección circunferencial positivo ocurrió más a frecuentemente, después de la resección abierta (6.3 vs 4.7%; p = 0.047). Posterior a los análisis multivariados, tumores localizados en el recto bajo, quimioterapia con radioterapia neoadyuvante, incremento de etapas T y la N, tumor fijo en pelvis y la disección en el plano muscular, aumentaron el riesgo del margen de resección circunferencial positivo. En la muestra emparejada del puntaje de propensión (541 pares coincidentes exactos), el abordaje laparoscópico no influyó en el riesgo del margen de resección circunferencial positivo (razón de probabilidades (IC 95%) 0.9 (0.6-1.5); p = 0.77).

LIMITACIONES

Revisión retrospectiva de los datos recopilados prospectivamente y por lo tanto, posible sesgo de selección.

CONCLUSIONES

El estudio de la base de datos a nivel nacional y después de los análisis emparejados multivariados y de puntuación de propensión, no hubo un mayor riesgo del margen de resección circunferencial positivo después de la resección laparoscópica versus resección abierta. Vea el Resumen del video en http://links.lww.com/DCR/A996.