Oncological outcome of T1 rectal cancer undergoing standard resection and local excision

The value of machine learning based on CT radiomics in the preoperative identification of peripheral nerve invasion in colorectal cancer: a two-center study

BACKGROUND

We aimed to explore the application value of various machine learning (ML) algorithms based on multicenter CT radiomics in identifying peripheral nerve invasion (PNI) of colorectal cancer (CRC).

METHODS

A total of 268 patients with colorectal cancer who underwent CT examination in two hospitals from January 2016 to December 2022 were considered. Imaging and clinicopathological data were collected through the Picture Archiving and Communication System (PACS). The Feature Explorer software (FAE) was used to identify the peripheral nerve invasion of colorectal patients in center 1, and the best feature selection and classification channels were selected. Finally, the best feature selection and classifier pipeline were verified in center 2.

RESULTS

The six-feature models using RFE feature selection and GP classifier had the highest AUC values, which were 0.610, 0.699, and 0.640, respectively. FAE generated a more concise model based on one feature (wavelet-HLL-glszm-LargeAreaHighGrayLevelEmphasis) and achieved AUC values of 0.614 and 0.663 on the validation and test sets, respectively, using the "one standard error" rule. Using ANOVA feature selection, the GP classifier had the best AUC value in a one-feature model, with AUC values of 0.611, 0.663, and 0.643 on the validation, internal test, and external test sets, respectively. Similarly, when using the "one standard error" rule, the model based on one feature (wave-let-HLL-glszm-LargeAreaHighGrayLevelEmphasis) achieved AUC values of 0.614 and 0.663 on the validation and test sets, respectively.

CONCLUSIONS

Combining artificial intelligence and radiomics features is a promising approach for identifying peripheral nerve invasion in colorectal cancer. This innovative technique holds significant potential for clinical medicine, offering broader application prospects in the field.

CRITICAL RELEVANCE STATEMENT

The multi-channel ML method based on CT radiomics has a simple operation process and can be used to assist in the clinical screening of patients with CRC accompanied by PNI.

KEY POINTS

• Multi-channel ML in the identification of peripheral nerve invasion in CRC. • Multi-channel ML method based on CT-radiomics can detect the PNI of CRC. • Early preoperative identification of PNI in CRC is helpful to improve the formulation of treatment strategies and the prognosis of patients.

Long-term efficacy of transanal local excision versus total mesorectal excision after neoadjuvant treatment for rectal cancer: A meta-analysis

AIM

The purpose of this meta-analysis is to compare the long-term efficacy of transanal local excision (TLE) versus total mesorectal excision (TME) following neoadjuvant therapy for rectal cancer.

METHOD

The Web of Science, Pubmed, Medline, Embase, and the Cochrane Library were systematically searched for correlational research. The Newcastle-Ottawa Scale and the Cochrane risk of bias tool were used to assess the quality of cohort studies (CSs) and randomized controlled trials (RCTs), respectively. Statistically analyzed using RevMan5.4.

RESULT

A total of 13 studies, including 3 randomized controlled trials (RCTs) and 10 cohort studies (CSs), involving 1402 patients, were included in the analysis. Of these, 570 patients (40.66%) underwent TLE, while 832 patients (59.34%) underwent TME. In the meta-analysis of CSs, no significant difference was observed between the TLE group and TME group regarding 5-year overall survival (OS) and 5-year disease-free survival (DFS) (P > 0.05). However, the TLE group had a higher rates of local recurrence (LR) [risk ratio (RR) = 1.93, 95%CI (1.18, 3.14), P = 0.008] and a lower rates of 5-years local recurrence-free survival (LRFS) [hazard ratio (HR) = 2.79, 95%CI (1.04, 7.50), P = 0.04] compared to the TME group. In the meta-analysis of RCTs, there was no significant difference observed between the TLE group and TME group in terms of LR, 5-year OS, 5-year DFS, and 5-year disease-specific survival (P > 0.05).

CONCLUSION

After undergoing neoadjuvant therapy, TLE may provide comparable 5-year OS and DFS to TME for rectal cancer. However, neoadjuvant therapy followed by TLE may has a higher LR and lower 5-year LRFS compared to neoadjuvant therapy followed by TME, so patients should be carefully selected. Neoadjuvant therapy followed by TLE may be a suitable option for patients who prioritize postoperative quality of life. However, the effectiveness of this approach requires further research to draw a definitive conclusion.

Computed tomography-based radiomics nomogram for the preoperative prediction of perineural invasion in colorectal cancer: a multicentre study

PURPOSE

To develop and validate a computed tomography (CT) radiomics nomogram from multicentre datasets for preoperative prediction of perineural invasion (PNI) in colorectal cancer.

METHODS

A total of 299 patients with histologically confirmed colorectal cancer from three hospitals were enrolled in this retrospective study. Radiomic features were extracted from the whole tumour volume. The least absolute shrinkage and selection operator logistic regression was applied for feature selection and radiomics signature construction. Finally, a radiomics nomogram combining the radiomics score and clinical predictors was established. The receiver operating characteristic curve and decision curve analysis (DCA) were used to evaluate the predictive performance of the radiomics nomogram in the training cohort, internal validation and external validation cohorts.

RESULTS

Twelve radiomics features extracted from the whole tumour volume were used to construct the radiomics model. The area under the curve (AUC) values of the radiomics model in the training cohort, internal validation cohort, external validation cohort 1, and external validation cohort 2 were 0.82 (0.75-0.90), 0.77 (0.62-0.92), 0.71 (0.56-0.85), and 0.73 (0.60-0.85), respectively. The nomogram, which combined the radiomics score with T category and N category by CT, yielded better performance in the training cohort (AUC = 0.88), internal validation cohort (AUC = 0.80), external validation cohort 1 (AUC = 0.75), and external validation cohort 2 (AUC = 0.76). DCA confirmed the clinical utility of the nomogram.

CONCLUSIONS

The CT-based radiomics nomogram has the potential to accurately predict PNI in patients with colorectal cancer.

Clinical outcome of local treatment and radical resection for pT1 rectal cancer

BACKGROUND

Rectal cancer is mainly cured by radical resection with neoadjuvant chemoradiation or adjuvant chemotherapy. Pathological T1 lesions can be managed by local treatment and radiotherapy thereafter. Lower morbidity is the key benefit of these local treatments. Since nodal metastasis is important for staging, radical resection (RR) is suggested. Rectal cancer has higher surgical morbidity than colon cancer; local treatment has been the preferred choice by patients.

METHODS

We retrospectively enrolled data of 244 patients with pT1 rectal adenocarcinoma. A total of 202 patients (82.8%) underwent RR, including low anterior resection (LAR) and abdomino-perineal resection (APR), and 42 patients (17.2%) underwent LT, including transanal excision and colonoscopic polypectomy.

RESULTS

In our study, seven patients (16.7%) had loco-regional recurrence and distant metastasis from the LT group while eight patients (4.0%) had distant metastasis without loco-regional recurrence from the RR group. The lymph node metastasis rate in RR group was 8.4%. Forty-seven patients (24.2%) underwent LAR with temporary stoma, and its reversal rate was 100%. In the RR group, postoperative complication rate was 10.4% with a mortality rate of 0.5%. Recurrence-free survival (RFS) was 95.7% for RR and 80.2% for LT (P = 0.001), and overall survival (OS) was 93.7% for RR and 70.0% for LT (P = 0.001).

CONCLUSION

This study found that RFS and OS in patients of pT1 rectal adenocarcinoma that had received RR were better than receiving LT. Further adjuvant chemotherapy was possible for some RR patients. A higher recurrence rate after LT must be balanced against the morbidity and mortality associated with RR.

Treatment of clinical T1 rectal cancer in the Netherlands; a population-based overview of clinical practice

INTRODUCTION

Local excision is increasingly used as an alternative treatment for radical surgery in patients with early stage clinical T1 (cT1) rectal cancer. This study provides an overview of incidence, staging accuracy and treatment strategies in patients with cT1 rectal cancer in the Netherlands.

MATERIALS AND METHODS

Patients with cT1 rectal cancer diagnosed between 2005 and 2018 were included from the Netherlands Cancer Registry. An overview per time period (2005-2009, 2010-2014 and 2015-2018) of the incidence and various treatment strategies used, e.g. local excision (LE) or major resection, with/without neoadjuvant treatment (NAT), were given and trends over time were analysed using the Chi Square for Trend test. In addition, accuracy of tumour staging was described, compared and analysed over time.

RESULTS

In total, 3033 patients with cT1 rectal cancer were diagnosed. The incidence of cT1 increased from 540 patients in 2005-2009 to 1643 patients in 2015-2018. There was a significant increased use of LE. In cT1N0/X patients, 9.2% received NAT, 25.5% were treated by total mesorectal excision (TME) and 11.4% received a completion TME (cTME) following prior LE. Overall accuracy in tumour staging (cT1 = pT1) was 77.3%, yet significantly worse in cN1/2 patients, as compared to cN0 patients (44.8% vs 77.9%, respectively, p < 0.001).

CONCLUSION

Over time, there was an increase in the incidence of cT1 tumours. Both the use of neoadjuvant therapy and TME surgery in clinically node negative patients decreased significantly. Clinical accuracy in T1 tumour staging improved over time, but remained significantly worse in clinical node positive patients.

The outcome of transanal endoscopic microsurgery and adjuvant radiotherapy in patients with high-risk T1 rectal cancer

Introduction:

Transanal endoscopic microsurgery (TEM) is considered the technique of choice for adenoma and low-risk T1 rectal cancer. The adequacy of such treatment for high-risk T1 tumours, however, is still controversial. The aim of the study is to evaluate our results with local excision of high-risk T1 cancers.

Materials and Methods:

Demographic, clinical data pertaining to patients undergoing TEM for T1 rectal cancer between 1999 and 2015 was retrospectively collected. Long-term outcomes were assessed for the entire cohort. Patients were classified into two groups: favourable and high-risk cancer features.

Results:

Three hundred and fifty-five TEM procedures were recorded in the study period. Forty-three patients were included in the present study. There were 20 females and 23 males, the median age was 69 ± 9. The median tumour distance from the anal verge was 6 cm (range 1–13 cm). Post-operative histopathology showed well/moderately differentiated T1 adenocarcinoma in 30 patients and poorly differentiated in 13. The overall survival for patients with favourable and high-risk features groups were 93.5% and 77%, respectively, while the local recurrence (LR) was 3.5% and 23.1%, respectively. Nine patients with high-risk features received adjuvant radiotherapy; one (11.1%) of them experienced LR.

Conclusions:

Local excision by TEM augmented by adjuvant radiotherapy may be a feasible alternative for selected patients with high-risk T1 rectal cancer. The addition of radiotherapy seems to decrease the rates of LR.

Local recurrence after local excision of early rectal cancer: a meta-analysis of completion TME, adjuvant (chemo)radiation, or no additional treatment

BACKGROUND

The risks of local recurrence and treatment-related morbidity need to be balanced after local excision of early rectal cancer. The aim of this meta-analysis was to determine oncological outcomes after local excision of pT1-2 rectal cancer followed by no additional treatment (NAT), completion total mesorectal excision (cTME) or adjuvant (chemo)radiotherapy (aCRT).

METHODS

A systematic search was conducted in PubMed, Embase and the Cochrane Library. The primary outcome was local recurrence. Statistical analysis included calculation of the weighted average of proportions.

RESULTS

Some 73 studies comprising 4674 patients were included in the analysis. Sixty-two evaluated NAT, 13 cTME and 28 aCRT. The local recurrence rate for NAT among low-risk pT1 tumours was 6·7 (95 per cent c.i. 4·8 to 9·3) per cent. There were no local recurrences of low-risk pT1 tumours after cTME or aCRT. The local recurrence rate for high-risk pT1 tumours was 13·6 (8·0 to 22·0) per cent for local excision only, 4·1 (1·7 to 9·4) per cent for cTME and 3·9 (2·0 to 7·5) per cent for aCRT. Local recurrence rates for pT2 tumours were 28·9 (22·3 to 36·4) per cent with NAT, 4 (1 to 13) per cent after cTME and 14·7 (11·2 to 19·0) per cent after aCRT.

CONCLUSION

There is a substantial risk of local recurrence in patients who receive no additional treatment after local excision, especially those with high-risk pT1 and pT2 rectal cancer. The lowest recurrence risk is provided by cTME; aCRT has outcomes comparable to those of cTME for high-risk pT1 tumours, but shows a higher risk for pT2 tumours.

Primary local excision of stage 1 rectal cancer is not associated with worse oncological outcomes when compared with major resection

PURPOSE

Primary local excision (PLE) for early rectal cancers is associated with decreased surgical morbidity and mortality compared with major resection (MR). However, it is thought to be associated with poorer oncological outcomes. There is a paucity of data regarding PLE within the Australasian population. We present comparative post-operative and survival outcomes for stage 1 rectal cancers treated with PLE or MR from three Western Australian hospitals.

METHODS

A retrospective analysis was performed on a prospectively maintained database of patients undergoing PLE or MR for stage 1 rectal cancers between February 1996 and May 2019.

RESULTS

Of the 533 patients, 81 underwent PLE. Median post-operative admission was shorter for those undergoing PLE, with no significant difference in post-operative complication rate. Five-year overall survival was greater following MR (89.6% CI 86.1-92.3) compared with PLE (84.6% CI 73.8-91.2; p = 0.0003). There was no significant difference in 5-year cancer-specific survival (MR, 94.4% CI 91.5-96.3; PLE, 95.3% CI 86.0-98.5; p = 0.98) or 5-year disease-free survival (MR, 92.3% CI 89.1-94.7; PLE, 89.1% CI 78.5-94.7; p = 0.36). Local excision provided poorer local tumour control with an inferior 5-year local recurrence rate (MR, 2.16% CI 1.08-4.28; PLE, 10.9% CI 5.30-21.6; p = 0.0002). After controlling for confounders, PLE was significantly associated with worse local recurrence but did not significantly impact overall survival, cancer-specific survival, overall recurrence, or metastatic recurrence.

CONCLUSION

Local excision of early rectal cancer remains a viable alternative, in those unwilling or unable to undergo MR. Patients should be informed that while PLE is associated with poorer local pelvic control, this does not translate to worse survival.

Executive Summary of the American Radium Society Appropriate Use Criteria for Local Excision in Rectal Cancer

The goal of treatment for early stage rectal cancer is to optimize oncologic outcome while minimizing effect of treatment on quality of life. The standard of care treatment for most early rectal cancers is radical surgery alone. Given the morbidity associated with radical surgery, local excision for early rectal cancers has been explored as an alternative approach associated with lower rates of morbidity. The American Radium Society Appropriate Use Criteria presented in this manuscript are evidence-based guidelines for the use of local excision in early stage rectal cancer that include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) used by a multidisciplinary expert panel to rate the appropriateness of imaging and treatment procedures. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. These guidelines are intended for the use of all practitioners and patients who desire information regarding the use of local excision in rectal cancer.

Long-term Transanal Excision Outcomes in Patients With T1 Rectal Cancer: Comparative Analysis of Radical Resection

Purpose

Transanal excision (TAE) is an alternative surgical procedure for early rectal cancer. This study compared long-term TAE outcomes, in terms of survival and local recurrence (LR), with total mesorectal excision (TME) in patients with pathologically confirmed T1 rectal cancer.

Methods

T1 rectal adenocarcinoma patients who underwent surgery from 1990 to 2011 were retrospectively reviewed. Patients that were suspected to have preoperative lymph node metastasis were excluded. Demographics, recurrence, and survival were analyzed based on TAE and TME surgery.

Results

Of 268 individuals, 61 patients (26%) underwent TAE, which was characterized by proximity to the anus, submucosal invasion depth, and lesion infiltration, compared with TME patients (P < 0.001–0.033). During a median follow-up of 10.4 years, 12 patients had systemic and/or LR. Ten-year cancer-specific survival in the TAE and TME groups was not significantly different (98% vs. 100%). However, the 10-year LR rate in the TAE group was greater than that of TME group (10% vs. 0%, P < 0.001). Although 5 of the 6 TAE patients with LR underwent salvage surgery, one of the patients eventually died. The TAE surgical procedure (hazard ratio, 19.066; P = 0.007) was the only independent risk factor for LR.

Conclusion

Although long-term survival after TAE was comparable to that after TME, TAE had a greater recurrence risk than TME. Thus, TAE should only be considered as an alternative surgical option for early rectal cancer in selected patients.

[Treatment strategy for early stage rectal cancer (T1 carcinoma)]

BACKROUND

A common consensus for the definition for early rectal cancer does not exist. This item is used in cases of histological findings including pTis, pT1 or pT2 tumors. The term early rectal cancer is not mentioned in the German S3 guidelines on colorectal cancer. The pTis tumors are located at the mucosa level of the intestinal wall and they have nearly no tendency to develop metastases but pT2 tumors have a high risk of local metastases; therefore, the term early rectal cancer is not adequate for pT2 tumors.

OBJECTIVE

This focus of this article is exclusively on pT1 rectal cancer. Following the histological definition, pT1 tumors of the rectum are located at the level of the mucosa and submucosa of the intestinal wall.

CONCLUSION

With respect to the nature of the tumor (e.g. size, grading, invasion of lymphatic and/or blood vessels, Kikuchi classification) local methods (endoscopic procedure, surgical techniques) or radical resections are recommended. Tumor budding is of increasing interest and importance. Depending on the severity of the tumor budding classification (bd1-bd3) there is an association with a more frequent occurrence of lymph node metastases and should therefore be taken into consideration in treatment decisions in the future.

Histopathological factors help to predict lymph node metastases more efficiently than extra-nodal recurrences in submucosa invading pT1 colorectal cancer

The therapeutic management of patients with endoscopic resection of colorectal cancer invading the submucosa (i.e. pT1 CRC) depends on the balance between the risk of cancer relapse and the risk of surgery-related morbidity and mortality. The aim of our study was to report on the histopathological risk factors predicting lymph node metastases and recurrences in an exhaustive case series comprising every pT1 CRC (of adenocarcinoma subtype only) diagnosed in Finistère (France) during 5-years. For 312 patients with at least 46 months follow-up included in the digestive cancers registry database, histopathological factors required for risk stratification in pT1 CRC were reviewed. Patients were treated by endoscopic resection only (51 cases), surgery only (138 cases), endoscopic resection followed by surgery (102 cases) or transanal resection (21 cases). Lymph node metastases were diagnosed in 19 patients whereas 15 patients had an extra-nodal recurrence (7 local recurrences only, 4 distant metastases only and 4 combining local and distant recurrences). Four patients with distant metastases died of their cancer. Poor tumor differentiation, vascular invasion and high grade tumor budding on HES slides were notably identified as strong risk-factors of lymph node metastases but the prediction of extra-nodal recurrences (local, distant and sometimes fatal) was less obvious, albeit it was more frequent in patients treated by transanal resection than with other treatment strategies. Beyond good performances in predicting lymph node metastases and guiding therapeutic decision in patients with pT1 CRC, our study points that extra-nodal recurrence of cancer is more difficult to predict and requires further investigations.

For Patients with Early Rectal Cancer, Does Local Excision Have an Impact on Recurrence, Survival, and Quality of Life Relative to Radical Resection?

BACKGROUND

The most appropriate treatment for early-stage rectal cancers is controversial. The advantages of local excision regarding morbidity and function must be weighed against poorer oncologic efficacy. This study aimed to clarify further the role for local excision in the treatment of rectal cancer.

METHODS

A systematic review of Medline, SCOPUS, and Cochrane databases was conducted. Relevant studies were selected using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data addressing five key questions about outcomes of local versus radical resection of rectal cancer were analyzed.

RESULTS

The 16 studies identified by this study were mostly retrospective, and none were randomized. Local excision was associated with fewer complications and better functional outcome than radical resection. Of 12 studies evaluating local recurrence, 6 showed a higher local recurrence rate among patients who underwent local excision. Two additional studies showed no increase in local recurrence rate among patients who underwent local excision of T1 lesions but a significantly higher local recurrence rate among those who underwent local excision of T2 lesions. High histologic grade, angiolymphatic invasion, perineural invasion, and depth within submucosa were features associated with a higher risk of local recurrence. In 7 of 15 studies, long-term survival was reduced compared with that of patients who underwent radical resection.

CONCLUSIONS

Although local excision for early-stage rectal cancer is associated with increased local recurrence and decreased overall survival compared with radical resection, local excision may be appropriate for select individuals who have T1 tumors with no adverse pathologic features.

Does transanal local resection increase morbidity for subsequent total mesorectal excision for early rectal cancer?

AIM

Local excision is recommended for early rectal cancer (pT1). Complementary total mesorectal excision (cTME) is warranted when bad pathological features are present. The impact of a prior local resection on the outcome remains unclear. The aim of this study was to assess if prior local excision increases the morbidity of a subsequent cTME compared with primary TME.

METHODS

From 2001 to 2016 all patients who underwent TME after local excision for rectal adenocarcinoma were studied. All were matched (1:1) with patients who underwent primary TME, without neoadjuvant radiochemotherapy. The matching factors included age, sex, body mass index, American Society of Anesthesiologists score and type of surgery. Short-term morbidity and pathological examination of the resected specimen were compared.

RESULTS

Forty-one patients were included (14 women, 34%, mean age 65 ± 11 years), comprising classic transanal excision (66%) and transanal endoscopic microsurgery (34%), and were matched to 41 patients who had primary TME. cTME was significantly longer (315 min ± 87 vs 275 min ± 58, P = 0.03). The overall morbidity was 48.8% in the local excision group vs 31.7% in the control group (P = 0.18). Surgical morbidity was 31.7% vs 26.8% (P = 0.8). Anastomotic related morbidity was similar (local excision 17% vs TME 14.6%, P = 0.84) and the mean length of stay was similar (14 days) in both groups. There was a tendency to a worse quality of mesorectal excision in the cTME group (17% vs 5%, P = 0.15).

CONCLUSION

Local excision prior to TME for early rectal cancer tends to increase overall morbidity and may worsen the quality of the mesorectal plane but should be considered as a surgical approach in select cases.

Local Excision and Endoscopic Resections for Early Rectal Cancer

Radical surgery is considered as the standard treatment for rectal cancer. Transanal local excision has been considered an interesting alternative for the management of selected patients with rectal cancers for many decades. Different approaches had been considered for local excision, from endoscopic submucosal dissection to resections using platforms, such as transanal endoscopic microsurgery or transanal minimally invasive surgery. Identifying the ideal candidate for this approach is crucial, as a local failure after local excision is associated with poor outcomes, even for an initial early rectal tumor. In this article, the diagnostic tools and criteria to select patients for local excision, the different modalities used, and the outcomes are discussed.

Peritoneal perforation is less a complication than an expected event during transanal endoscopic microsurgery: experience from 194 consecutive cases

BACKGROUND

Indications for transanal endoscopic microsurgery (TEM) have been extended to technically challenging tumors, which may be associated with an increased risk of peritoneal perforation (PP). The aim of the present study was to investigate the occurrence, management and outcome of PP in patients having TEM.

METHODS

All the patients who had TEM for rectal adenoma or adenocarcinoma in our unit were included. Patients in whom PP occurred (Group A) were compared to those without PP (Group B).

RESULTS

From 2007 to 2015, 194 TEM (116 men, median age 66 [range 21-100] years) were divided into Groups A (n = 28, 14%) and B (n = 166). The latter group included four patients, in whom a laparoscopy did not confirm suspicion of PP made during TEM. In 2 of 28 patients (7%), the diagnosis of PP was made postoperatively during reoperation for peritonitis. For the 26 other patients (93%), routine exploratory laparoscopy was performed with suture of the peritoneal defect on the pouch of Douglas in 24 cases and a rectal suture alone in 2 cases. Independent predictive factors for PP were: distance from the anal verge >10 cm (OR = 3.6), circumferential tumor (OR = 3.0) and anterior location (OR = 2.7). Hospital stay was significantly longer in Group A (7.5 [3-31] days) than in Group B (4 [1-38] days; p < 0.0001), whereas there was no significant difference regarding postoperative morbidity and recurrence rate.

CONCLUSIONS

Our results suggested that PP is not a very rare event during TEM, especially in anterior, circumferential and/or high rectal tumors. Laparoscopic treatment of PP is feasible and safe. The occurrence of PP is not associated with poor oncologic results.

What is the best tool for transanal endoscopic microsurgery (TEM)? A case-matched study in 74 patients comparing a standard platform and a disposable material

PURPOSE

Transanal endoscopic microsurgery (TEM) is the gold standard for local excision of rectal lesions, but no study exists concerning the best material. The objective was to compare TEM using a disposable material vs a standard platform through a case-matched study.

METHODS

Patients who underwent TEM for rectal neoplasms were identified from prospective databases in two tertiary referral centers and matched according to four criteria (sex, tumor location, size, distance from the anal verge): TEM using a disposable material (GelPoint Applied®; group A) and TEM using a standard TEO® platform (Karl Storz, Tuttlingen, Germany; group B).

RESULTS

A total of 74 patients were included and divided into group A (n = 33) and group B (n = 41). Full-thickness resection was less frequent in group A (85%) than B (100%; p = 0.01). Adenocarcinoma was less frequent in group A than B: 27 vs 42% (p = 0.03). No difference was noted regarding median operative time (53 vs 53 min; p = 0.6) and a peritoneal perforation rate (6 vs 20%; p = 0.17). Median length of stay was shorter in group A than B (4 vs 5 days; p < 0.008). No significant difference was noted for major morbidity (12 vs 10%; p = 0.66), R1 resection (21 vs 10%; p = 0.2), and recurrence rates (8 vs 7%; p = 0.62). No difference was noted for rectal stenosis (3 vs 12%; p = 0.22) and transit disorder rates (12 vs 17%; p = 0.74).

CONCLUSIONS

Our study suggested that TEM can be performed using either a TEO® platform or a disposable material, with similar surgical results. The TEO® platform seems to be superior to obtain full-thickness and R0 resection.

Comparison of trans-anal endoscopic operation and trans-anal excision of rectal tumors

Background

Trans-anal endoscopic operation (TEO) has developed to facilitate proper tumor location and ensure excision safely.

Methods

We reviewed 92 patients enrolled in our database between 2006 and 2014 who were diagnosed with early rectal tumors and who underwent conventional trans-anal excision (TAE) or TEO. Clinical data were collected prospectively to compare safety and feasibility between two techniques.

Results

Ninety-two patients underwent trans-anal local excision for lower rectal tumors. TEO and TAE were performed in 48 and 44 patients, respectively. Age, sex, and comorbidities were similar. There was no significant difference in tumor diameter (1.6 ± 1.68 cm vs. 1.17 ± 1.17, respectively). Tumor height, however, was higher in the TEO (7.46 ± 3 cm) than the TAE group (3.84 ± 1.88 cm, p < 0.001). Four complications, perianal abscess, and two perforations, occurred in the TEO group, whereas no major complications occurred in the TAE. Seven patients (14.6%) underwent TEO underwent a salvage operation compared to only a single patient in TAE group (2.3%, p = 0.039). Eight patients (17.4%) diagnosed with adenocarcinoma developed recurrence, four in each group. Disease-free survival was similar between groups (TEO – 41.8 months, 95% RI 39.4–44.1; TAE 79.7 months, 95% RI 72.2–87.3). However, more TAE patients (n = 7, 15.9%) than TEO patients (n = 2, 4.2%) underwent chemotherapy.

Conclusions

TEO treatment of local rectal tumors is safe and feasible and can achieve an adequate resection margin. Local recurrence was similar in both groups. However, the numbers of salvage operations and minor complications were higher in the TEO group.

•

TEO is treatment modality of choice in addressing lower rectal lesions.

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Evolving of TEO technique facilitate higher standard of academic teaching.

•

TEO has few drawbacks; first, long term learning curve; second, technique is demanding (through single port + narrow space).

•

TEO has promising results in the field of surgical oncology with equivalent results to conventional surgery.

Perineural Invasion is a Strong Prognostic Factor in Colorectal Cancer: A Systematic Review

Perineural invasion (PNI) is a possible route for metastatic spread in various cancer types, including colorectal cancer (CRC). PNI is linked to poor prognosis, but systematic analyses are lacking. This study systematically reviews the frequency and impact of PNI in CRC. A literature search was performed using PubMed database from inception to January 1, 2014. Data were analyzed using Review Manager 5.3. A quality assessment was performed on the basis of modified REMARK criteria. Endpoints were local recurrence (LR), 5-year disease-free survival (5yDFS), 5-year cancer-specific survival (5yCSS), and 5-year overall survival (5yOS). Meta-analysis was performed in terms of risk ratios (RR) and hazard ratios (HR) with 95% confidence interval (95% CI). In this meta-analysis, 58 articles with 22,900 patients were included. PNI was present in 18.2% of tumors. PNI is correlated with increased LR (RR 3.22, 95% CI, 2.33-4.44) and decreased 5yDFS (RR 2.35, 95% CI, 1.66-3.31), 5yCSS (RR 3.61, 95% CI, 2.76-4.72), and 5yOS (RR 2.09, 95% CI, 1.68-2.61). In multivariate analysis PNI remains an independent prognostic factor for 5yDFS, 5yCSS, and 5yOS (HR 2.35, 95% CI, 1.97-3.08; HR 1.91, 95% CI, 1.50-2.42; and HR 1.85, 95% CI, 1.63-2.12, respectively). We confirmed the strong impact of PNI for LR and survival in CRC. The prognostic value of PNI is similar to that of well-established prognostic factors as depth of invasion, differentiation grade, lymph node metastases, and lymphatic and extramural vascular invasion. Therefore, PNI should be one of the factors in the standardized reporting of CRC and might be considered a high-risk feature.

Shifting Paradigms in Minimally Invasive Surgery: Applications of Transanal Natural Orifice Transluminal Endoscopic Surgery in Colorectal Surgery

Since the advent of laparoscopy, minimally invasive techniques such as single port laparoscopy, robotics, endoscopically assisted laparoscopy, and transanal endoscopic surgery continue to revolutionize the field of colorectal surgery. Transanal natural orifice transluminal endoscopic surgery (NOTES) represents a further paradigm shift by combining the advantages of these earlier techniques to reduce the size and number of abdominal incisions and potentially optimize rectal dissection, especially with respect to performance of an oncologically adequate total mesorectal excision (TME) for rectal cancer. Since the first experimental report of transanal rectosigmoid resection in 2007, the potential impact of transanal NOTES in colorectal surgery has been extensively investigated in experimental models and recently transitioned to clinical application. There have been 14 clinical trials of transanal TME (taTME) for rectal cancer that have demonstrated the feasibility and preliminary oncologic safety of this approach in carefully selected patients, with results comparable to outcomes after laparoscopic and open TME, including cumulative intraoperative and postoperative complication rates of 5.5 and 35.5%, respectively, 97.3% rate of complete or near-complete specimens, and 93.6% rate of negative margins. Transanal NOTES has also been safely applied to proctectomy and colectomy for benign indications. The consensus among published series suggests that taTME is most safely performed with transabdominal assistance by surgeons experienced with laparoscopic TME, transanal endoscopic surgery, and sphincter-preserving techniques including intersphincteric resection. Future applications of transanal NOTES may include evolution to a pure endoscopic transanal approach for TME, colectomy, and sentinel lymph node biopsy for rectal cancer, with a potential role for robotic assistance.

ACR Appropriateness Criteria® Local Excision in Early Stage Rectal Cancer

Low anterior resection or abdominoperineal resection are considered standard treatments for early rectal cancer but may be associated with morbidity in selected patients who are candidates for early distal lesions amenable to local excision (LE). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. The panel recognizes the importance of accurate staging to identify patients who may be candidates for a LE approach. Patients who may be candidates for LE alone include those with small, low-lying T1 tumors, without adverse pathologic features. Several surgical approaches can be utilized for LE however none include lymph node evaluation. Adjuvant radiation±chemotherapy may be warranted depending on the risk of nodal metastases. Patients with high-risk T1 tumors, T2 tumors not amenable to radical surgery may also benefit from adjuvant treatment; however, patients with positive margins or T3 lesions should be offered abdominoperineal resection or low anterior resection. Neoadjuvant radiation±chemotherapy followed by LE in higher risk patients results in excellent local control, but it is not clear if this approach reduces recurrence rates over surgery alone.

Practice parameters for early rectal cancer management: Italian Society of Colorectal Surgery (Società Italiana di Chirurgia Colo-Rettale; SICCR) guidelines

The introduction of new technologies for diagnosis and screening programs led to an increasing rate of early detection of colorectal cancer. This, associated with the evolution of endoscopic techniques of local excision, led to the assessment of new strategies to reduce morbidity related to treatment, especially for early rectal cancer (ERC). Nevertheless, the definition of ERC and its staging and treatment algorithm are still under debate. The Italian Society of Colorectal Surgery developed practice guidelines to provide recommendations on the diagnosis, staging and treatment of ERC. A systematic review on the topic was performed by a multidisciplinary group of experts selected based on their clinical and scientific expertise in endoscopy, endoscopic ultrasound, magnetic resonance and surgery, with the aid of an external international audit.

The Role of Transanal Surgery in the Management of T1 Rectal Cancers

The management of T1 rectal cancers is based on finding the balance between optimal oncologic outcomes and acceptable functional results for the patient. While radical resection involving a proctectomy is considered the most oncologically adequate option, its adverse effects on patient reported outcomes makes this a less than ideal choice in certain circumstances. While local excision can circumvent some of the adverse functional outcomes, its inadequacy in assessing metastatic lymph node disease and the subsequent negative impact of untreated positive lymph nodes on patient prognosis is a cause for concern. As a result, the therapeutic strategy has to be based on patient and disease-related factors in order to identify the best treatment choice that maximizes survival benefit and preserves health-related quality of life. After adequate preoperative staging work up, in selected patients with favorable pathological features, local excision can be considered. These cancers can be removed by transanal local excision or transanal endoscopic microsurgery, depending on the location of the cancer and expertise available. While perioperative morbidity is minimal, close postoperative follow-up is essential.

Is there a limit to transanal endoscopic surgery? A comparative study between standard and technically challenging indications among 168 consecutive patients

AIM

To assess the surgical outcome of transanal endoscopic surgery (TES) for rectal neoplasms in technically challenging indications.

METHOD

All patients who underwent TES for a rectal neoplasm from 2007 to 2014 were included. Technically challenging indications included a tumour with (i) diameter ≥ 5 cm, (ii) involving ≥ 50% of the rectal circumference and (iii) located ≥ 10 cm from the anal verge. Patients were divided into three groups according to how many of these features they had, as follows: Group 1, none; Group 2, one; Group 3, two or more.

RESULTS

Of the 168 patients (80 benign and 88 malignant tumours) included in the study, 73 (44%) were in Group 1, 46 (27%) in Group 2 and 49 (29%) in Group 3. There was no difference between Group 1 and Group 2 with regard to peritoneal perforation (P = 0.210), severe postoperative morbidity (P = 0.804), length of hospital stay (P = 0.444), incomplete resection (P = 0.441), piecemeal resection (P = 0.740), locoregional recurrence (P = 0.307) and long-term symptomatic rectal stenosis (P = 0.076). Conversely Group 3 showed significantly impaired results compared with Group 1 with regard to peritoneal perforation (P = 0.003), piecemeal resection (P = 0.005), incomplete resection (P = 0.025), locoregional recurrence (P = 0.035) and long-term symptomatic rectal stenosis (P < 0.001), but no difference in severe postoperative morbidity (P = 0.328).

CONCLUSION

Transanal endoscopic surgery for rectal neoplasms appears to be safe and effective, even in patients presenting with a technically challenging tumours. Although the short- and long-term outcomes after TES are worse in patients with highly challenging tumours, nevertheless the technique should still be considered in patients at high risk of requiring a proctectomy.

Future directions in surgery for colorectal cancer: the evolving role of transanal endoscopic surgery

SUMMARY 

The morbidity associated with radical surgery for rectal cancer has launched a revolution in increasingly less-invasive methods of resection, including a recent resurgence in transanal endoscopic surgical approaches. The next evolution in transanal surgery for rectal cancer is natural orifice translumenal endoscopic surgery (NOTES). To date, 14 series of transanal NOTES total mesorectal excision (TME) for rectal cancer have been published (n = 76). Overall, the intraoperative and postoperative complication rates of 8 and 28%, respectively, compare favorably to those expected from laparoscopic and open TME. Short-term follow-up after NOTES TME has yielded no cancer recurrence in average-risk patients. High-risk patients have cancer recurrence rates similar to those after laparoscopic TME. Overall, these early data support transanal NOTES TME as a safe and viable alternative to conventional TME. Advances in instrumentation, surgical expertise and neoadjuvant treatment may expand current indications for NOTES even further.

Evaluation of the frequency and pattern of local recurrence following intersphincteric resection for ultra-low rectal cancer

INTRODUCTION

Abdomino-perineal resection has been the standard treatment for rectal tumors located ≤5cm from the anal verge. Recently, intersphincteric resection became a valid option which preserves the bowel continuity with better functional outcome.

AIM

Is to evaluate the oncological and functional outcome alongside the associated surgical morbidity in patients with T1-3 rectal cancer, who underwent intersphincteric resection (ISR).

PATIENTS & METHODS

Between the years 2006 and 2011, 55 patients with invasive rectal adenocarcinoma, T1-3 lesions, located 2-5cm from the anal verge underwent ISR with total mesorectal excision. When inevitable, complete. ISR was performed, otherwise partial ISR was done. All T3 patients underwent total meso-rectal excision (TME) while some had lateral lymph node dissection (LND) with concomitant pelvic autonomic nerve preservation (PANP).

RESULTS

Among the 55 patients, 21 (38.1%) patients were T1-2 and 34 (61.9%) patients were T3. The tumor location range was 0-5cm from the anal verge (median 2.3cm). Partial or complete ISR was done for 35 (63.6%) and 20 (36.4%), respectively. Patients were followed for a median of 1.5 years (range 1-4.6 years). The 3 year local recurrence and distant metastasis free rates were 85.2% and 85.6%, respectively. All the 3 local recurrences occurred in T3 patients group, and had positive circumferential resection margins. Overall 3-year disease-free survival was 82.6%; while the overall 3-year survival was 88.7%.

CONCLUSION

Intersphincteric resection with TME does not affect the local recurrence or overall survival rate in early rectal cancer T1-2 & 3, with preservation of bowel continuity and better life quality.

Transanal colorectal resection using natural orifice translumenal endoscopic surgery (NOTES)

The surgical management of rectal cancer has evolved over the past century, with total mesorectal excision (TME) emerging as standard of care. As a result of the morbidity associated with open TME, minimally invasive techniques have become popular. Natural orifice translumenal endoscopic surgery (NOTES) has been held as the next revolution in surgical techniques, offering the possibility of 'incisionless' TME. Early clinical series of transanal TME with laparoscopic assistance (n = 72) are promising, with overall intraoperative and postoperative complication rates of 8.3% and 27.8%, respectively, similar to laparoscopic TME. The mesorectal specimen was intact in all patients, and 94.4% had negative margins. There was no oncological recurrence in average-risk patients at short-term follow up, and 2-year survival rates in high-risk patients were comparable to that after laparoscopic TME. These preliminary studies demonstrate transanal NOTES TME with laparoscopic assistance to be clinically feasible and safe given careful patient selection, surgical expertise, and appropriate procedural training. We are hopeful that with optimization of transanal instruments and surgical techniques, pure transanal NOTES TME will become a viable alternative to open and laparoscopic TME in the future.

Is adjuvant radiotherapy warranted in resected pT1-2 node-positive rectal cancer?

Background

Stage T1-2 rectal cancers are unlikely to have lymph node metastases and neoadjuvant therapy is not routinely administered. Postoperative management is controversial if lymph node metastases are detected in the resected specimen. We studied the outcomes of patients with pT1-2 node-positive rectal cancer in order to determine whether adjuvant radiotherapy was beneficial.

Methods

We conducted a retrospective analysis of 284 patients with pathological T1-2 node-positive rectal cancer from a single institution. Outcomes, including local recurrence (LR), distant metastasis (DM), disease free survival (DFS) and overall survival (OS), were studied in patients with detailed TN staging and different adjuvant treatment modalities.

Results

The overall 5-year LR, DM, DFS and OS rates for all patients were 12.5%, 32.9%, 36.4% and 76.8%, respectively. Local control was inferior among patients who received no adjuvant therapy. Patients could be divided into three risk subsets: Low-risk, T1N1; Intermediate-risk, T2N1 and T1N2; and High-risk, T2N2. The 5-year LR rates were 5.3%, 9.8% and 26.4%, respectively (p = 0.005). In High-risk patients, addition of radiotherapy achieved a 5-year LR rate of 9.1%, compared 34.8% without radiotherapy.

Conclusions

In our study, we provide the detailed outcomes and preliminary survival analysis in a relatively infrequent subset of rectal cancer. Three risk subsets could be identified based on local control for pT1-2 node positive rectal cancer. Postoperative treatment needs to be individualized for patients with pT1-2 node-positive rectal cancer.

When is local excision appropriate for "early" rectal cancer?

Local excision is increasingly performed for “early stage” rectal cancer in the US; however, local recurrence after local excision has become a controversial issue in Western countries. Local recurrence is considered to originate based on the type of tumor and procedure performed, and in surgical margin-positive cases. This review focuses on the inclusion criteria of “early” rectal cancers for local excision from the Western and Japanese points of view. “Early” rectal cancer is defined as T1 cancer in the rectum. Only the tumor grade and depth of invasion are the “high risk” factors which can be evaluated before treatment. T1 cancers with sm1 or submucosal invasion <1,000 μm are considered to be “low risk” tumors with less than 3.2 % nodal involvement, and are considered to be candidates for local excision as the sole curative surgery. Tumors with a poor tumor grade should be excluded from local excision. Digital examination, endoscopy or proctoscopy with biopsy, a barium enema study and endorectal ultrasonography are useful for identifying “low risk” or excluding “high risk” factors preoperatively for a comprehensive diagnosis. The selection of an initial local treatment modality is also considered to be important according to the analysis of the nodal involvement rate after initial local treatment and after radical surgery.

The management of patients with T1 adenocarcinoma of the low rectum: a decision analysis

BACKGROUND

Decision making for patients with T1 adenocarcinoma of the low rectum, when treatment options are limited to a transanal local excision or abdominoperineal resection, is challenging.

OBJECTIVES

The aim of this study was to develop a contemporary decision analysis to assist patients and clinicians in balancing the goals of maximizing life expectancy and quality of life in this situation.

DESIGN

We constructed a Markov-type microsimulation in open-source software. Recurrence rates and quality-of-life parameters were elicited by systematic literature reviews. Sensitivity analyses were performed on key model parameters.

PATIENTS AND SETTING

Our base case for analysis was a 65-year-old man with low-lying T1N0 rectal cancer. We determined the sensitivity of our model for sex, age up to 80, and T stage.

MAIN OUTCOME MEASURES

The main outcome measured was quality-adjusted life-years.

RESULTS

In the base case, selecting transanal local excision over abdominoperineal resection resulted in a loss of 0.53 years of life expectancy but a gain of 0.97 quality-adjusted life-years. One-way sensitivity analysis demonstrated a health state utility value threshold for permanent colostomy of 0.93. This value ranged from 0.88 to 1.0 based on tumor recurrence risk. There were no other model sensitivities.

LIMITATIONS

Some model parameter estimates were based on weak data.

CONCLUSIONS

In our model, transanal local excision was found to be the preferable approach for most patients. An abdominoperineal resection has a 3.5% longer life expectancy, but this advantage is lost when the quality-of-life reduction reported by stoma patients is weighed in. The minority group in whom abdominoperineal resection is preferred are those who are unwilling to sacrifice 7% of their life expectancy to avoid a permanent stoma. This is estimated to be approximately 25% of all patients. The threshold increases to 12% of life expectancy in high-risk tumors. No other factors are found to be relevant to the decision.

The transanal endoscopic microsurgery procedure: standards and extended indications

Transanal endoscopic microsurgery (TEM) was developed in the early 1980s as a minimally invasive technique allowing the resection of benign rectal adenomas. For this indication, TEM was reported to be safe and effective and even exceeded the results compared to classical local excision. Unsurprisingly, the indication expanded to small rectal cancer. There is still much debate, though, whether it is oncologically safe to perform TEM for rectal cancer. Much has been published about the need for proper patient selection, i.e. patients presenting a low-risk T1 rectal cancer seem to be the most adequate subgroup for this technique. Nevertheless, TEM remains controversial concerning high-risk T1 rectal adenocarcinomas and deeper infiltrating tumors. Several retrospective case series and a small prospective study suggest that radiochemotherapy before local excision reduces recurrence to a level comparable with classic radical surgery (total mesorectal excision). However, these studies are collectively limited, and prospective data from larger multicenter trials are awaited. Reports about functional results after TEM have shown that the procedure has no permanent impact on anorectal function. Even if transient anal resting pressure weakening has been repeatedly described, patients do not suffer from any long-term functional sequelae. Nor do they complain of quality of life impairment.