Management of early rectal cancer

Grades of Poorly Differentiated Clusters are Associated with Lymph Node and the Tumour, Node and Metastasis Stages in Colorectal Carcinoma

Background

Colorectal carcinoma (CRC) is the third most common cancer globally. In Malaysia, CRC is most prevalent among males and the second most common cancer among females. The CRC arises mainly from the adenocarcinoma sequence. Poorly differentiated clusters (PDCs) and tumour budding (TB) are believed to represent sequential steps in tumour growth. Therefore, this study analysed the association between PDC grades with clinicopathological and demographic characteristics of CRC.

Methods

A total of 47 CRC cases previously diagnosed by histopathological examination were reviewed for the presence of PDCs and graded accordingly. The association between PDC grades with clinicopathological and demographic characteristics was statistically analysed.

Results

Out of the 47 cases with PDCs, most of them were of grade 3 (G3) (n = 27, 57.4%), followed by grade 2 (G2) (n = 13, 27.7%) and grade 1 (G1) (n = 7, 14.9%). Higher PDC grades (G2 and G3) were mainly observed in higher tumour stage (T); T3 (n = 26, 83.9%), T4 (n = 12, 92.3%), N1 (n = 20, 86.9%), N2 (n = 15, 100%). In addition, there was a significant association between PDC grades with the nodal stage (N) (P = 0.013) and the tumour, node and metastasis (TNM) stages (P = 0.012).

Conclusion

The PDC grades are useful for assessing the disease prognosis in CRC. A statistically significant association between PDC grades with N and TNM stages suggested that PDC grades are potential predictive parameters for invasive and metastatic risks in CRC.

[Prognostic histological markers in colorectal cancer]

BACKGROUND

Colon carcinomas are among the most common malignant tumors worldwide. The critical evaluation of different therapy options is particularly relevant. On the one hand, colon carcinomas more often occur at an older age, on the other hand patients with colon carcinomas often live for decades after initial diagnosis - it is just as important to avoid overtreatment as it is to avoid undertreatment, which shortens the patient's life span. Prognostically effective biomarkers are decision-making tools. There are clinical, molecular, and histological prognostic markers-the latter are presented in this paper.

AIM OF THE WORK

To present the current state of knowledge on morphologically determinable prognostic markers in colon cancer.

MATERIALS AND METHOD

Literature search in PubMed and Medline.

CONCLUSIONS

In their daily work, pathologists identify highly relevant prognostic markers that are essential for therapeutic decisions. These markers must be communicated to the clinical colleague. The most important and longest-known prognostic markers are staging (TNM), including local resection status, lymph node involvement and number on the surgical specimen, vascular invasion, perineural sheath infiltration, and histomorphologic growth pattern determination (e.g., micropapillary colon carcinoma is associated with a very unfavorable prognosis). Recently, tumor budding has been added, which has practical applications especially in endoscopically applied pT1 carcinomas ("malignant polyps").

[Transanal Tumor Resection: Indication, Surgical Technique and Management of Complications]

Transanal resection procedures are special operations for the minimally invasive treatment of rectal tumours. Apart from benign tumours, this procedure is suitable for the excision of low-risk T1 rectal carcinomas, if these can be completely removed (R0 resection). With stringent patient selection, very good oncological results are achieved. Various international trials are currently evaluating whether local resection procedures are oncologically sufficient if there is a complete or near complete response after neoadjuvant radio-/chemotherapy. Numerous studies have shown that the functional results and the postoperative quality of life after local resection are excellent, especially considering the well-known functional deficits of alternative operations, such as low anterior or abdominoperineal resection.Severe complications are very rare. Most complications, such as urinary retention or subfebrile temperatures, are minor in nature. Suture line dehiscences are usually clinically unremarkable. Major complications comprise significant haemorrhage and the opening of the peritoneal cavity. The latter must be recognized intraoperatively and can usually be managed by primary suture. Infection, abscess formation, rectovaginal fistula, injury of the prostate or even urethra are extremely rare complications.

Complex Procedures in Transanal Endoscopic Microsurgery: Intraperitoneal Entry, Ultra Large Rectal Tumors, High Lesions, and Resection in the Anal Canal

Transanal endoscopic microsurgery (TEM) allows the local excision of rectal tumors and achieves lower morbidity and mortality rates than total mesorectal excision. TEM can treat lesions up to 18 to 20 cm from the anal verge, obtaining good oncological results in T1 stage cancers and preserving sphincter function. TEM is technically demanding. Large lesions (>5 cm), those with high risk of perforation into the peritoneal cavity, those in the upper rectum or the rectosigmoid junction, and those in the anal canal are specially challenging. Primary suture after peritoneal perforation during TEM is safe and it does not necessarily require the creation of a protective stoma. We recommend closing the wall defect in all cases to avoid the risk of inadvertent perforation. It is important to identify these complex lesions promptly to transfer them to reference centers. This article summarizes complex procedures in TEM.

Patient and pathological predictors of management strategy for malignant polyps following polypectomy: a systematic review and meta-analysis

PURPOSE

Malignant polyps present a treatment dilemma for clinicians and patients. This meta-analysis sought to identify the factors that predicted the management strategy for patients diagnosed with a malignant polyp.

METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane Collaboration prognostic studies guidelines. Reports from 1985 onwards were included, data on patient and pathological factors were extracted and random effects meta-analysis models were used.

RESULTS

Fifteen studies were included. Seven studies evaluated lymphovascular invasion (LVI). The odds of surgery were significantly higher in malignant polyps with LVI (OR 2.20, 95% CI 1.36-3.55). Ten studies revealed the odds of surgery were significantly higher with positive polypectomy margins (OR 8.09, 95% CI 4.88-13.40). Tumour differentiation was compared in eight studies. There were significantly lower odds of surgery in malignant polyps with well/moderate differentiation compared with poor differentiation (OR 0.31, 95% CI 0.21-0.46). There were non-significant trends favouring surgical resection in younger patients, males and Haggitt 4/Kikuchi Sm3 lesions. There was considerable heterogeneity in the meta-analyses for the variables age, gender, polyp morphology and Haggitt/Kikuchi level (I² > 75%).

CONCLUSION

This meta-analysis has demonstrated that LVI, positive polypectomy resection margins, and poor tumour differentiation significantly predict malignant polypectomy patients who underwent subsequent surgery. Age and gender were important factors predicting management, but not consistently across studies, whilst polyp morphology and Haggitt/Kikuchi levels did not significantly predict the management strategy. Further research may assist in understanding the management preferences.

Completion surgery vs. primary TME for early rectal cancer: a national study

PURPOSE

While local excision by transanal endoscopic microsurgery (TEM) or transanal minimally invasive surgery (TAMIS) is an option for low-risk early rectal cancers, inaccuracies in preoperative staging may be revealed only upon histopathological evaluation of the resected specimen, demanding completion surgery (CS) by formal resection. The aim of this study was to evaluate the results of CS in a national cohort.

METHOD

This was a retrospective analysis of national registry data, identifying and comparing all Norwegian patients who, without prior radiochemotherapy, underwent local excision by TEM or TAMIS and subsequent CS, or a primary total mesorectal excision (pTME), for early rectal cancer during 2000-2017. Primary endpoints were 5-year overall and disease-free survival, 5-year local and distant recurrence, and the rate of R0 resection at completion surgery. The secondary endpoint was the rate of permanent stoma.

RESULTS

Forty-nine patients received CS, and 1098 underwent pTME. There was no difference in overall survival (OR 0.73, 95% CI 0.27-2.01), disease-free survival (OR 0.72, 95% CI 0.32-1.63), local recurrence (OR 1.08, 95% CI 0.14-8.27) or distant recurrence (OR 0.67, 95% CI 0.21-2.18). In the CS group, 53% had a permanent stoma vs. 32% in the pTME group (P = 0.002); however, the difference was not significant when adjusted for age, sex, and tumor level (OR 2.17, 0.95-5.02).

CONCLUSIONS

Oncological results were similar in the two groups. However, there may be an increased risk for a permanent stoma in the CS group.

Adjuvant chemoradiotherapy versus radical surgery after transanal endoscopic microsurgery for intermediate pathological risk early rectal cancer: A single-center experience with long-term surveillance

BACKGROUND

The choice of subsequent treatment for intermediate-risk rectal tumors after transanal endoscopic microsurgery between adjuvant chemoradiotherapy and total mesorectal excision is controversial. The present study aimed to compare survival and functional outcome between these 2 strategies.

METHODS

This retrospective study included intermediate-risk patients with early rectal cancer after transanal endoscopic microsurgery in our center between 2010 and 2017. Patients were divided into adjuvant treatment and total mesorectal excision groups. Intermediate risk was defined as pT1 with lymphovascular invasion, poor differentiation, or large diameter (3-5 cm) or pT2 with small diameter (<3 cm). The study was based on follow-up data on survival and results from distributed validated scales for functional outcome.

RESULTS

Postoperative overall survival and disease-free survival were comparable between the groups (P = .619 and P = .712, respectively). Pathological T stage was an independent risk factor for disease-free survival (hazard ratio 3.09, 95% confidence interval 1.66-4.18, P = .044). Anorectal symptoms, such as buttock pain, were significantly prevalent in the total mesorectal excision group (P = .030). In addition, the total mesorectal excision group presented with poorer bowel function, including stool urgency (P < .001), bowel frequency (P = .016), severity of low anterior resection syndrome (P = .039) and total low anterior resection syndrome score (P = .040). Except for a lower score of vaginal lubrication in the total mesorectal excision versus the adjuvant treatment group, sexual function was similar between the groups.

CONCLUSION

Similar to total mesorectal excision, adjuvant chemoradiotherapy is an alternative option for intermediate-risk early rectal cancer after transanal endoscopic microsurgery and is associated with similar survival outcomes and better bowel function.

A Meta-analysis of Transanal Endoscopic Microsurgery versus Total Mesorectal Excision in the Treatment of Rectal Cancer

Background  Transanal endoscopic microsurgery (TEMS) has been suggested as an alternative to total mesorectal excision (TME) in the treatment of early rectal cancers. The extended role of TEMS for higher stage rectal cancers after neoadjuvant therapy is also experimented. The aim of this meta-analysis was to compare the oncological outcomes and report on the evidence-based clinical supremacy of either technique.

Methods  Medline, Embase, and Cochrane databases were searched for the randomized controlled trials comparing the oncological and perioperative outcomes of TEMS and a radical TME. A local recurrence and postoperative complications were analyzed as primary end points. Intraoperative blood loss, operation time, and duration of hospital stay were compared as secondary end points.

Results  There was no statistical difference in the local recurrence or postoperative complications with a risk ratio of 1.898 and 0.753 and p -values of 0.296 and 0.306, respectively, for TEMS and TME. A marked statistical significance in favor of TEMS was observed for secondary end points. There was standard difference in means of −4.697, −6.940, and −5.685 with p -values of 0.001, 0.005, and 0.001 for blood loss, operation time, and hospital stay, respectively.

Conclusion  TEMS procedure is a viable alternative to TME in the treatment of early rectal cancers. An extended role of TEMS after neoadjuvant therapy may also be offered to a selected group of patients. TME surgery remains the standard of care in more advanced rectal cancers.

Preoperative Diagnostic Uncertainty in T2-T3 Rectal Adenomas and T1-T2 Adenocarcinomas and a Therapeutic Dilemma: Transanal Endoscopic Surgery, or Total Mesorectal Excision?

BACKGROUND

Endorectal ultrasound and rectal magnetic resonance are sometimes unable to differentiate between stages T2 and T3 in rectal adenomas that are possible adenocarcinomas, or between stages T1 and T2 in rectal adenocarcinomas. These cases of diagnostic uncertainty raise a therapeutic dilemma: transanal endoscopic surgery (TES) or total mesorectal excision (TME)?

METHODS

An observational study of a cohort of 803 patients who underwent TES from 2004 to 2021. Patients operated on for adenoma (group I) and low-grade T1 adenocarcinoma (group II) were included. The variables related to uncertain diagnosis, and to the definitive pathological diagnosis of adenocarcinoma stage higher than T1, were analyzed.

RESULTS

A total of 638 patients were included. Group I comprised 529 patients, 113 (21.4%) with uncertain diagnosis. Seventeen (15%) eventually had a pathological diagnosis of adenocarcinoma higher than T1. However, the variable diagnostic uncertainty was a risk factor for adenocarcinoma above T1 (OR 2.3, 95% CI 1.1-4.7). Group II included 109 patients, eight with uncertain diagnosis (7.3%). Two patients presented a definitive pathological diagnosis of adenocarcinoma above T1.

CONCLUSIONS

On the strength of these data, we recommend TES as the initial indication in cases of diagnostic uncertainty. Multicenter studies with larger samples for both groups should now be performed to further assess this strategy of initiating treatment with TES.

Long-term outcomes of endoscopic submucosal dissection and transanal endoscopic microsurgery for the treatment of rectal tumors

BACKGROUND AND AIM

Endoscopic submucosal dissection and transanal endoscopic microsurgery are good options for the treatment of rectal adenomas and early rectal carcinomas, but whether long-term outcomes of these procedures are comparable is not known. The aim of this study was to address this question.

METHODS

A retrospective single-center study evaluating 98 consecutive procedures between June 2008 and December 2017 was performed in a tertiary cancer center. Consecutive patients who had undergone either endoscopic submucosal resection or transanal endoscopic microsurgery for rectal adenomas and early rectal carcinomas were evaluated, and long-term recurrence and complication rates were compared.

RESULTS

Both groups were similar regarding sex, age, preoperative surgical risk, and en bloc resection rate (95.7% in the endoscopic and 100% in the surgical group, P = 0.81). Mean follow-up period was 37.6 months. Lesions resected endoscopically were significantly larger (68.5 mm) than those resected by transanal resection (44.5 mm), P = 0.003. Curative resections occurred in 97.2% of endoscopic resections and 85.2% of the surgical ones (P = 0.04). Comparing resections that fulfilled histologic curative criteria, there were no recurrences in the endoscopic group (out of 69 cases) and two recurrences in the transanal group (8.3% of 24 cases), P = 0.06. Late complications occurred in 12.7% of endoscopic procedures and 25.9% of surgical procedures (P = 0.13).

CONCLUSIONS

In our experience, endoscopic submucosal resection seems to have advantages over transanal endoscopic microsurgery, with similar en bloc resection rate and lower rate of late complications and recurrences. Multicenter randomized controlled trials are needed to support our findings.

Completion Surgery in Unfavorable Rectal Cancer after Transanal Endoscopic Microsurgery: Does It Achieve Satisfactory Sphincter Preservation, Quality of Total Mesorectal Excision Specimen, and Long-term Oncological Outcomes?

BACKGROUND

Unfavorable adenocarcinoma after transanal endoscopic microsurgery requires "completion surgery" with total mesorectal excision. The literature on this procedure is very limited.

OBJECTIVE

This study aims to assess the percentage of transanal endoscopic microsurgery that will require completion surgery.

DESIGN

This is an observational study with prospective data collection and retrospective analysis from patients who were operated on consecutively.

SETTINGS

The study was conducted at a single academic institution.

PATIENTS

Patients undergoing transanal endoscopic microsurgery from June 2004 to December 2018 who later required total mesorectal excision were included.

MAIN OUTCOME MEASURES

All the patients followed the same protocol: preoperative study, indication of transanal endoscopic microsurgery with curative intent, performance of transanal endoscopic microsurgery, and completion surgery indication 3 to 4 weeks after transanal endoscopic microsurgery.

RESULTS

Seven hundred seventy-four patients underwent transanal endoscopic microsurgery, 622 with curative intent (group I: adenoma, 517; group II: adenocarcinoma, 105). Completion surgery was indicated in 64 of 622 (10.3%) patients: group I, 40 of 517 (7.7%) and group II, 24 of 105 (22.9%). After applying exclusion criteria, completion surgery was performed in 55 patients (8.8%). Abdominoperineal resection was performed in 23 (45.1%); the initial lesion was within 6 cm of the anal verge in 19 of these 23 (82.6%). The clinical morbidity rate (Clavien Dindo> II) was 3 of 51 (5.9%). Total mesorectal excision was graded as complete in 42 of 49 (85.7%). The circumferential resection margin was tumor-free in 47 of 50 (94%). Median follow-up was 58 months. Local recurrence was recorded in 2 of 51 (3.9%) and systemic recurrence was recorded in 7 of 51 (13.7%); 5-year disease-free survival was 86%.

LIMITATIONS

The limitations are defined by the study's observational design and the retrospective analysis.

CONCLUSION

The indication of completion surgery after transanal endoscopic microsurgery is low, but is higher in the indication of adenocarcinoma. Compared with initial total mesorectal excision, completion surgery requires a higher rate of abdominoperineal resection, but has similar postoperative morbidity, total mesorectal excision quality, and oncological results. See Video Abstract at http://links.lww.com/DCR/B423.

CIRUGA COMPLEMENTARIA EN CNCER DE RECTO DESFAVORABLE DESPUS DE UNA TEM SE OBTIENE SATISFACTORIAMENTE PRESERVACIN DEL ESFNTER, CALIDAD DE MUESTRA DE ETM Y RESULTADOS ONCOLGICOS A LARGO PLAZO

ANTECEDENTES:El adenocarcinoma con evolución desfavorable luego de una de microcirugía endoscópica transanal (TEM) requiere "cirugía de finalización" con la excisión total del mesorecto. La literatura sobre este procedimiento es muy limitada.OBJETIVO:Evaluar el porcentaje de microcirugía endoscópica transanal que requerió cirugía completa.DISEÑO:Estudio observacional con recolección prospectiva de datos y análisis retrospectivo de pacientes operados consecutivamente.AJUSTES:El estudio se realizó en una sola institución académica.PACIENTES:Aquellos pacientes sometidos a microcirugía endoscópica transanal desde junio de 2004 hasta diciembre de 2018 que luego requirieron excisón toztal del mesorecto.PRINCIPALES MEDIDAS DE RESULTADO:Todos los pacientes siguieron el mismo protocolo: estudio preoperatorio, indicación de microcirugía endoscópica transanal con intención curativa, realización de microcirugía endoscópica transanal e indicación de cirugía complementaria 3-4 semanas después de la microcirugía endoscópica transanal.RESULTADOS:Setecientos setenta y cuatro pacientes fueron sometidos a microcirugía endoscópica transanal, 622 con intención curativa (grupo I, adenoma: 517, grupo II, adenocarcinoma: 105). la cirugía complementaria fué indicada en 64/622 (10.3%), grupo I: 40/517 (7.7%) y grupo II 24/105 (22.9%). Después de aplicar los criterios de exclusión, la cirugía complementaria se realizó en 55 pacientes (8,8%). La resección abdominoperineal fué realizada en 23 (45,1%); en 19 de estos casos 23 (82,6%) la lesión inicial se encontraba dentro los 6 cm del margen anal. La tasa de morbilidad clínica (Clavien-Dindo > II) fue de 3/51 (5,9%). La excisión total del mesorecto se calificó como completa en 42/49 (85,7%). El margen de resección circunferencial se encontraba libre de tumor en 47/50 (94%). La mediana de seguimiento fue de 58 meses. La recurrencia local se registró en 2/51 (3.9%) y la recurrencia sistémica en 7/51 (13.7%); La supervivencia libre de enfermedad a 5 años fue del 86%.LIMITACIONES:Todas definidas por el diseño observacional y el análisis retrospectivo del mismo.CONCLUSIÓN:La indicación de completar la cirugía después de una TEM es baja, pero es más alta cuando la indicación es por adenocarcinoma. En comparación con la excisión total del mesorecto inicial, la cirugía complementaria requiere una tasa más alta de resección abdominoperineal, pero tiene una morbilidad postoperatoria, una calidad de excisión total del mesorecto y resultados oncológicos similares. ConsulteVideo Resumen en http://links.lww.com/DCR/B423. (Traducción-Dr. Xavier Delgadillo).

Poorly differentiated clusters in colorectal cancer: a current review and implications for future practice

Poorly differentiated clusters (PDC), defined as small groups of ≥5 tumour cells without glandular differentiation, have gained recent attention as a promising prognostic factor in colorectal cancer (CRC). Numerous studies have shown PDC to be significantly associated with other adverse histopathological features and worse clinical outcomes. PDC may hold particular promise in stage II colon cancer, where risk stratification plays a critical role in patient selection for adjuvant chemotherapy. In addition, emerging evidence suggests that PDC can predict lymph node metastasis in endoscopically resected pT1 CRC, potentially helping the selection of patients for oncological resection. In 'head-to-head' comparisons, PDC grade has consistently outperformed conventional histological grading systems both in terms of risk stratification and reproducibility. With a number of large-scale studies now available, this review evaluates the evidence regarding the prognostic significance of PDC, considers its relationship with other emerging invasive front prognostic markers (such as tumour budding and stroma type), assesses its 'practice readiness', addressing issues such as interobserver reproducibility, scoring methodologies and special histological subtypes (e.g. micropapillary and mucinous carcinoma), and draws attention to ongoing challenges and areas in need of further study. Finally, emerging data on the role of PDC in non-colorectal cancers are briefly considered.

Shear Wave Elastography in Rectal Cancer Staging, Compared with Endorectal Ultrasonography and Magnetic Resonance Imaging

The goal of the study described here was to investigate the value of shear wave elastography (SWE) in pre-operative staging of rectal cancer. Fifty-five patients with rectal cancer underwent pre-operative conventional endorectal ultrasonography (ERUS), SWE and enhanced magnetic resonance imaging (MRI) examinations. Pathologic results were used as the gold standard for cancer staging. The concordance rate with pathologic stage by ERUS and MRI and the stiffness values measured by SWE for tumors in different stages were compared. The concordance rates for cancer staging were 72.7% and 70.9% for conventional ERUS and enhanced MRI, respectively; the difference was not significant (p > 0.05). SWE indicated that the mean and maximum stiffness values of the tumors increased with advance in stage. The differences in stiffness values between T1 and T2, T1 and T3-4, as well as T2 and T3-4, were all statistically significant (p < 0.001). When the maximum stiffness values of 65.0 and 90.7 kPa are used for the diagnosis of T1, T2 and local advanced rectal cancer, the concordance rate of cancer staging was 85.5%, which was slightly higher than those of ERUS and MRI, although the difference was not statistically significant (p > 0.05). SWE is useful in judging the depth of invasion of rectal tumors. The value of tumor stiffness can provide a quantifiable indicator for pre-operative diagnosis of cancer staging and can be used as a supplement to conventional ERUS. Further studies with larger sample sizes are needed.

Surgical or endoscopic management of malignant colon polyps

BACKGROUND

To evaluate indications for colectomy in T1 polyps and possible risk factors for lymph node metastasis.

METHODS

Between 2004 and 2017, 40 patients underwent colectomy after endoscopic removal of malignant polyps with T1 carcinoma. Resection was done based on at least one of the unfavourable histopathological criteria. We collected and prospectively studied histopathologic features, short-term results and the benefit-risk balance. Complications were assessed by Clavien-Dindo classification.

RESULTS

Twenty-five patients (62.5%) underwent laparoscopic bowel resection. Twenty-nine patients (63.0%) had more than two unfavourable criteria in the polyp that justified colorectal resection. Thirty-five patients (76%) had G2 (moderately differentiated) cancer, 11 (24%) had G1 (well-differentiated). Five patients (12.5%) had lymph node metastases and one (2.5%) had residual adenocarcinoma. All five patients with lymph node metastasis had G2 cancer. Nine patients (22.5%) had residual adenoma. Overall complications were identified in six (15.0%) patients. Oncologic benefit (or risk factors for lymph node metastasis) was significantly associated with polyp size ≥18 mm (P = 0.006), lymphovascular invasion (P = 0.05) and budding (P = 0.02).

CONCLUSIONS

Female gender, lymphovascular invasion, desmoplastic reaction, criteria for surgery ≥2 and polyp size ≥18 mm were all in complex significant risk factors for lymph node metastasis in T1 colorectal cancer. Acting as a single factor, these variables had no effect to increased risk of metastasis.

Histopathological Significance and Prognostic Impact of Tumor Budding in Colorectal Cancer

Background: Colorectal cancer (CRC) is a heterogeneous disease with a complex etiology. New prognostic factors need to be investigated. Our present focus is on histopathological significance and prognostic impact of tumor budding in CRC. Material and Methods: A total of 60 treatment-naive consecutive patients undergoing surgical resection of CRCs during the period of January 2011 to December 2013 were included in the study. Details of each related to their demographic and tumor profile were recorded. Hematoxylin and Eosin (H and E) and pan-cytokeratin details of each “case” immunohistochemically stained sections were examined for tumor budding assessment along with clinical features. Results: The most frequent site of involvement was the rectosigmoid and sigmoid colon (31.6%). The majority of the cases were moderately differentiated (75%), showed tumor invasion into the pericolic/subserosal fat (66.6%) and stage III (38.3%). Nodal involvement was present in 47%. Correlations between tumor budding and nodal involvement (p-value 0.039) and AJCC stage (p-value 0.021) were found to be statistically significant. Conclusion: Tumor budding is a promising and powerful predictor of lymph nodal metastasis and a higher stage of tumor and can be used as a marker for high-risk CRC. Routine H and E staining aided by cytokeratin immunostaining allows reproducible grading of tumor budding in CRC cases.

Transanal endoscopic surgery is effective and safe after endoscopic polypectomy of potentially malignant rectal polyps with questionable margins

AIM

To determine the percentage of residual lesion observed in the pathology study of transanal endoscopic surgery (TEM) specimens after endoscopic polypectomy of malignant rectal polyps with questionable margins, and the need for further surgery. Secondary aims: to determine the morbidity and mortality associated with this procedure and to identify the percentage of recurrence after excision by TEM.

METHODS

Observational study with prospective data collection of all patients undergoing TEM after endoscopic polypectomy for malignant rectal polyps or non-invasive high-grade neoplasia, from January 2004 to December 2016. An en bloc full-thickness wall excision of the scar was performed. Variables recorded: histology of TEM specimen, 30-day morbidity and mortality according to the Clavien-Dindo classification, need for salvage surgery and recurrence.

RESULTS

Fifty out of 690 patients undergoing TEM during the study period (36 adenocarcinomas, five non-invasive high-grade neoplasias and 9 neuroendocrine tumors) were included. Post-surgery histology showed residual lesion in 21 (42%) patients: 7 neuroendocrine tumors, 10 adenomas and 4 adenocarcinomas (two pT1, one pT2 and one pT3). The pT2 and pT3 patients (4%) underwent salvage surgery. No recurrence was observed, and mean follow-up was 29.1Â ± 21.6 months. The 30-day morbidity rate was 14%, but 4/7 with Clavien-Dindo grade I.

CONCLUSIONS

After endoscopic polypectomy of malignant rectal polyps with questionable margins, the presence of residual lesion in the pathology study of transanal resection specimens is high. TEM with full-thickness resection of these lesions is an appropriate treatment, allowing disease control and achieving minimal morbidity.

Robotic transanal minimally invasive surgery (TAMIS) for local excision of rectal lesions with the da Vinci Xi (dVXi): technical considerations and video vignette

Robotic transanal minimally invasive surgery (TAMIS) (RT) represents a compelling new alternative capable of overcoming the limitations of conventional TAMIS for the local excision of rectal lesions. We describe our RT technique using the dVXi™ (Intuitive Surgical, Sunnyvale, CA, USA) which we have used to efficiently and completely excise eight cases of rectal lesions which were not endoscopically resectable. We also include a video vignette of the procedure. With the patient in the prone jackknife position, we insert a GelPOINT™ Path Transanal Access Platform (Applied Medical, Rancho Santa Margarita, CA, USA) in combination with the dVXi and AirSeal™ insufflation system (Conmed, Niagara. Falls, ON, Canada). Our technique aims to be ergonomically efficient to minimise docking difficulties and to reduce instrument clash in the limited space, whilst maximising the capabilities of the dVXi for RT. At 3-month endoscopic follow-up, no evidence of recurrence was detected in any of the eight patients. RT is safe, feasible and has advantages over conventional laparoscopic TAMIS (LT). Our described technique addresses some of the long-standing challenges of LT and the novel RT. The immediate challenge to its widespread use remains the cost, expertise and availability.

Long-term results of transanal endoscopic microsurgery after endoscopic polypectomy of malignant rectal adenoma

BACKGROUND

There is no consensus on the treatment and prognosis of malignant rectal polyps. The aim of the present study was to determine the role of transanal endoscopic microsurgery (TEM) after endoscopic complete polypectomy of malignant rectal adenomas with long-term follow-up.

METHODS

Of 105 patients with pT1 rectal carcinoma in 32 patients TEM followed complete endoscopic polypectomy while 73 had primary TEM. Local recurrence (LR), distant metastasis, overall and cancer-specific survival were determined by the Kaplan-Meier method.

RESULTS

Median follow-up was 9.1 years. In 32 patients with TEM following complete polypectomy no residual cancer was found. LR occurred in 3/28 (11%) patients with low-risk carcinoma (pT1 G1/2/X, L0/X, R0) and in 1/4 (25%) with high-risk carcinoma (pT1 G3/4 or L1). After primary TEM with complete resection (minimal distance >1 mm) LR occurred in 6/60 (10%) with low-risk carcinoma. After incomplete TEM resection (minimal distance ≤1 mm) LR occurred in 3/8 (38%) patients with low-risk and in 1/5 (20%) patients with high-risk carcinoma. Grading was the only significant risk factor for LR after endoscopic polypectomy followed by TEM (p = 0.002). At all outcomes did not differ between postpolypectomy TEM and primary TEM.

CONCLUSIONS

Patients with malignant rectal polyps removed by endoscopic polypectomy have a substantial risk of LR even if TEM of polyp site is cancer free. Risk of LR depends on tumor characteristics. In low-risk carcinoma long-term follow-up is necessary. The high LR rate in patients with high-risk rectal carcinoma restricts the use of TEM alone.

Analysis of local recurrences after transanal endoscopic microsurgery for low risk rectal carcinoma

AIM

Rates of local recurrence (LR) after transanal endoscopic microsurgery (TEM) for rectal carcinoma vary; the reasons remain unclear. We analyzed LR after TEM for low-risk pT1 (G1/2/X, L0/X) rectal carcinoma to investigate the influence of completeness of resection and occult lymph node metastasis on risk of LR.

METHOD

LR location and stage, completeness of resection of primary carcinoma (minimal distance between tumor and resection line ≤1 mm vs >1 mm), and incidence of involved lymph nodes in resected LR specimens were collected, and tumor characteristics of LR were compared with primary carcinoma. Distant metastasis and overall and cancer-specific survival were determined.

RESULTS

LR developed in 14 patients; in 2/4 with R1/X resection, in 3/8 (38%) with clear margins (R0) but a minimal distance of ≤1 mm, and in 9/88 (10%) with formally complete resection. Six of nine patients with formally complete resection underwent radical surgery for LR; in five out of these six, lymph nodes were not involved. In 5/14 patients, LR was poorly differentiated compared to primary carcinoma. Main LR causes were incomplete tumor resection or tumor persistence after formally complete resection. Overall (p = 0.008) and cancer-specific (p < 0.001) survival was lower in LR patients compared to non-LR patients, even if lymph nodes were uninvolved.

CONCLUSIONS

The results suggest that most LRs after TEM for low-risk rectal cancer were caused by residual tumor at the previous excision site and not by undetected lymph node metastases. By improved standardization of surgical techniques to ensure complete resection of carcinomas and thorough pathological assessments, most LRs seem to be avoidable.

Is the assessment of submucosal invasion still useful in the management of early rectal cancer? A study of 91 consecutive patients

AIM

The only studies on the prognosis of T1 tumours are old and investigate colic and rectal cancers. Very few studies use Kikuchi's classification (of dividing submucosa into three strata) to evaluate the depth of the submucosal invasion. This study aimed to assess the pathological risk factors for lymph node metastasis (LNM), and the pathological and oncological results of patients with early rectal cancer (ERC, pT1 tumour).

METHOD

Between 2000 and 2014, 91 consecutive patients undergoing surgery [primary total mesorectal excision (TME) or local excision (LE) alone, or LE followed by TME] for ERC were included.

RESULTS

Eighteen patients underwent LE, 22 underwent LE followed by TME and 51 underwent primary total TME. After TME (n = 73), 16 (23%) patients had LNM. The LNM rate was 15% for Sm1 tumours, 14% for Sm2 tumours and 30% for Sm3 tumours. In multivariate analysis, lymphovascular invasion (P = 0.027) and high tumour budding (P = 0.037) were the only independent factors predictive of LNM. The depth of submucosal invasion was not associated with an increased risk of LNM. After a mean follow up of 56 ± 46 months, 5-year overall survival, specific survival and disease-free survival were, respectively, 82%, 93% and 75%. No significant difference of survival was found according to the depth of submucosal invasion or to the surgical management.

CONCLUSION

Histological features seem to be stronger risk factors for LNM than depth of submucosal invasion. Considering the LNM rate, TME should be discussed after LE in terms of one of these pathological criteria.

The Ferguson Operating Anoscope for Resection of T1 Rectal Cancer

The Ferguson Operating Anoscope (FOA) is a surgical instrument, which can facilitate transanal excision of appropriate rectal tumors within 15 cm of the anal verge. Previous work showed low recurrence (4.3%) for favorable T1 tumors (no lymphovascular invasion, well/moderate differentiation, negative margins). This follow-up study evaluates outcomes in rectal cancer excised with FOA at a tertiary care center. T1 rectal cancer patients were identified in a prospectively maintained database. Tumor pathology and patient characteristics were reviewed. Primary outcomes include tumor recurrence and patient and disease-free survival. Secondary outcomes are quality of excision (intact specimen). Twenty-eight patients had pathologic stage T1 rectal cancer (average 8 ± 2.6 cm from the anal verge). Final path demonstrated 14 per cent to be well differentiated, 82 per cent moderately differentiated, and 93 per cent without angiolymphatic invasion. All specimens removed were intact. One patient had a true local recurrence and underwent a salvage operation 24 months after her index operation. Patient survival was 96.4 per cent (n = one death from primary lung cancer) at median follow-up 64 ± 35 months. With appropriate tumor selection and quality of initial resection, FOA has demonstrated utility in achieving optimal oncologic resection of T1 rectal tumors.

Postoperative complications in the treatment of rectal neoplasia by transanal endoscopic microsurgery: a prospective study of risk factors and time course

PURPOSE

Transanal endoscopic microsurgery (TEM) is a safe and efficient minimally invasive treatment for rectal benign and early malignant neoplasia, but postoperative complications may be severe. We aimed to evaluate the risk factors related to the incidence, severity, and time course of postoperative complications of TEM.

METHODS

This is a prospective study of postoperative complications in 53 patients (>18 years old) with benign or early rectal neoplasia who underwent TEM with curative intention or, for higher stages, palliation. Outcome measures included age, sex, American Society of Anesthesiologists score, neoadjuvant chemoradiotherapy, lesion height and size, pathologic margins, tumor histology, and suture type.

RESULTS

Overall morbidity was 50 %. Temporary fecal incontinence was the most frequent complication (17.3 %). Complication rates of Clavien-Dindo grades I and II were 21.1 % and those of grades III and IV 3.8 %. Of patients with complications, more had lesions under the first rectal valve than over the first valve (61.54 % vs 38.46 %, p = 0.04). Patients submitted to chemoradiotherapy had a 24-fold greater chance of presenting grade II complications (p = 0.002). When the surgical defect was treated using the TEM device to perform the suture, the chance of having grade III complications was reduced 16-fold (p = 0.04). Fifty-three percent of complications occurred in the first 10 days and 95 % within 20 days.

CONCLUSIONS

Postoperative complications after transanal endoscopic microsurgery for the treatment of rectal neoplasia are frequent, acceptable, and usually controllable with pharmacologic treatment. Over time the nature of complications is continuous, centered on the first 20 days after surgery.

Poorly differentiated clusters (PDC) in colorectal cancer: what is and ought to be known

Background

The counting of poorly differentiated clusters of 5 or more cancer cells lacking a gland-like structure in a tumor mass has recently been identified among the histological features predictive of poor prognosis in colorectal cancer.

Main body

Poorly differentiated clusters can easily be recognized in the histological sections of colorectal cancer routinely stained with haematoxylin and eosin. Despite some limitations related to specimen fragmentation, counting can also be assessed in endoscopic biopsies. Based on the number of poorly differentiated clusters that appear under a microscopic field of a ×20 objective lens (i.e., a microscopic field with a major axis of 1 mm), colorectal cancer can be graded into malignancies as follows: tumors with <5 clusters as grade 1, tumors with 5 to 9 clusters as grade 2, and tumors with ≥10 clusters as grade 3. High poorly differentiated cluster counts are significantly associated with peri-neural and lympho-vascular invasion, the presence of nodal metastases or micrometastases, as well as shorter overall and progression free survival to colorectal cancer.

Conclusion

The morphological aspects and clinical relevance of poorly differentiated clusters counting in colorectal cancer are discussed in this review.

Features of Late Recurrence Following Transanal Local Excision for Early Rectal Cancer

BACKGROUND

Transanal local excision has recently received attention as an alternative to radical surgery for early rectal cancer. Recurrence usually occurs within 5 years after surgery, but recurrences later than this have also been reported.

OBJECTIVE

The aim of this study was to investigate the incidence and risk factors of recurrence in patients who have early rectal cancer 10 years after transanal local excision.

DESIGN

Patients with early rectal cancer who underwent transanal local excision from October 1994 to December 2010 were retrospectively reviewed. We reviewed the demographics and clinicopathologic features of primary lesions and analyzed the incidence and risk factors of recurrence.

SETTINGS

This investigation was conducted at a tertiary university hospital.

PATIENTS

A total of 295 patients who underwent transanal local excision for pTis (n = 155) or pT1 (n = 140) early rectal cancer were included in the analysis.

INTERVENTION

Transanal local excision was performed for each patient to excise primary rectal lesions.

MAIN OUTCOME MEASURES

The primary end point of this study was the incidence of recurrence, especially late recurrence. The secondary end point was risk factors for recurrence.

RESULTS

The 10-year cumulative local recurrence rate was 6.7% in pTis and 18.0% in pT1 patients. The rate of late local recurrence was 2.8% in pTis and 3.7% in pT1 patients. There was no evidence of late systemic recurrence 5 years after transanal local excision. In pT1 patients, a higher risk of recurrence was associated with an invasion depth of sm3, the presence of lymphovascular invasion, and a positive resection margin.

LIMITATION

The main limitation of this study is its retrospective nature.

CONCLUSIONS

Late recurrence can occur in patients with early rectal cancer who have undergone transanal local excision. Transanal local excision can be performed in selective patients with biologically favorable tumors, and 10-year postoperative surveillance should be considered for these patients.

Low rectal cancer: Sphincter preserving techniques-selection of patients, techniques and outcomes

Low rectal cancer is traditionally treated by abdominoperineal resection. In recent years, several new techniques for the treatment of very low rectal cancer patients aiming to preserve the gastrointestinal continuity and to improve both the oncological as well as the functional outcomes, have been emerged. Literature suggest that when the intersphincteric resection is applied in T1-3 tumors located within 30-35 mm from the anal verge, is technically feasible, safe, with equal oncological outcomes compared to conventional surgery and acceptable quality of life. The Anterior Perineal PlanE for Ultra-low Anterior Resection technique, is not disrupting the sphincters, but carries a high complication rate, while the reports on the oncological and functional outcomes are limited. Transanal Endoscopic MicroSurgery (TEM) and TransAnal Minimally Invasive Surgery (TAMIS) should represent the treatment of choice for T1 rectal tumors, with specific criteria according to the NCCN guidelines and favorable pathologic features. Alternatively to the standard conventional surgery, neoadjuvant chemo-radiotherapy followed by TEM or TAMIS seems promising for tumors of a local stage T1sm2-3 or T2. Transanal Total Mesorectal Excision should be performed only when a board approved protocol is available by colorectal surgeons with extensive experience in minimally invasive and transanal endoscopic surgery.

[Management of complications in anal and transanal tumor surgery]

Anal and transanal tumor operations are safe and are associated with a very low morbidity. Perianal and anal lesions as well as low rectal tumors can be excised by direct exposure using an anal retractor. For lesions situated in the middle or upper third of the rectum, special instrumentation, such as transanal endoscopic microsurgery (TEM) and transanal endoscopic operation (TEO) should be used to avoid unnecessary R1 resections. Fatal complications are extremely rare and most complications, such as urinary retention or temporary subfebrile temperatures, are minor. Suture line dehiscences are usually clinically unremarkable. Major complications comprise significant hemorrhage and opening of the peritoneal cavity. The latter must be recognized intraoperatively and can usually be managed by primary suturing. Infections, abscess formation, rectovaginal fistula, injury of the prostate or even urethra are extremely rare complications.

The multidisciplinary approach to the treatment of rectal cancer: 2015 update

The multidisciplinary approach to the management of rectal cancer continues to evolve with developments in surgery, radiation therapy as well as systemic chemotherapy. Refinement of surgical techniques to improve organ preservation, selective use of neoadjuvant (or adjuvant) therapies, improvements in staging modalities and emerging criteria for the selection of tailored therapies are some of the advancements made over the last three decades. In addition, neoadjuvant treatment alternatives, multimodality sequencing and adaptive therapies based on treatment response continue to be a subject of clinical investigation. The current article reviews the salient topics related to the multidisciplinary treatment of resectable rectal cancer.

Toxicity studies of coumarin 6-encapsulated polystyrene nanospheres conjugated with peanut agglutinin and poly(N-vinylacetamide) as a colonoscopic imaging agent in rats

We are investigating an imaging agent that detects early-stage primary colorectal cancer on the mucosal surface in real time under colonoscopic observation. The imaging agent, which is named the nanobeacon, is fluorescent nanospheres conjugated with peanut agglutinin and poly(N-vinylacetamide). Its potential use as an imaging tool for colorectal cancer has been thoroughly validated in numerous studies. Here, toxicities of the nanobeacon were assessed in rats. The nanobeacon was prepared according to the synthetic manner which is being established as the Good Manufacturing Practice-guided production. The rat study was performed in accordance with Good Laboratory Practice regulations. No nanobeacon treatment-related toxicity was observed. The no observable adverse effect levels (NOAEL) of the nanobeacon in 7-day consecutive oral administration and single intrarectal administration were estimated to be more than 1000mg/kg/day and 50mg/kg/day, respectively. We concluded that the nanobeacon could be developed as a safe diagnostic agent for colonoscopy applications.

FROM THE CLINICAL EDITOR

Colon cancer remains a major cause of death. Early detection can result in early treatment and thus survival. In this article, the authors tested potential systemic toxicity of coumarin 6-encapsulated polystyrene nanospheres conjugated with peanut agglutinin (PNA) and poly(N-vinylacetamide) (PNVA), which had been shown to bind specifically to colonic cancer cells and thus very promising in colonoscopic detection of cancer cells.

Combined endorectal ultrasonography and strain elastography for the staging of early rectal cancer

AIM

Strain elastography is a novel approach to rectal tumour evaluation. The primary aim of this study was to correlate elastography to pT stages of rectal tumours and to assess the ability of the method to differentiate rectal adenomas (pT0) from early rectal cancer (pT1-2). Secondary aims were to compare elastography with endorectal ultrasonography (ERUS) and to propose a combined strain elastography and ERUS staging algorithm.

METHOD

In all, 120 consecutive patients with a suspected rectal tumour were examined in this staging study. Patients receiving surgery without neoadjuvant radiotherapy were included (n = 59). All patients were examined with ERUS and elastography. Treatment decisions were made by multidisciplinary team (MDT) assessment, without considering the strain elastography examination.

RESULTS

Histopathology identified 21 adenomas, 13 pT1, 9 pT2, 15 pT3 and one pT4. Mean elastography strain ratios were predictive of T stage (P = 0.01). Differentiation of adenomas from early rectal cancer (pT1-2) had sensitivity, specificity and accuracy of 0.82, 0.86 and 0.84 for elastography and 0.82, 0.62 and 0.72 for ERUS. A combined staging algorithm was developed to identify tumours eligible for local resection. Based on MDT evaluation 32% of tumours later identified as pT0 or pT1 were treated with total mesorectal excision, even though a local excision might have sufficed. Combined ERUS and elastography evaluation would have significantly reduced this number to 9% (P = 0.008).

CONCLUSION

Elastography may improve the staging of adenomas and early rectal cancer compared with ERUS alone. Combined ERUS and elastography assessment is likely to further improve the selection of patients for local resection.

[Is it radical enough? Transanal endoscopic microsurgery for the treatment of rectal neoplasia -- clinicopathological viewpoint]

The transanal endoscopic microsurgery (TEM) provides lower relapse and complication rate for the the surgical treatment of the neoplasms of the middle and lower third of the rectum in selected cases. Hence, it can be an alternative method of the conventional approaches, if it does not compromise oncological radicality. The TEM procedure has been started at the 1st Department of Surgery, Semmelweis University in the fall of 2013. In this short study we have evaluated the clinicopathological characteristics of patients undergoing TEM between September 2013 and September 2014. Fourty-four patients were included in our retrospective analysis. 12 patients had low grade adenoma, 14 patients had high grade adenoma, 17 patients had invasive adenocarcinoma, while one was operated for a neuroendocrine tumor. There was no difference in the size of neoplasms between the low and high grade adenomas or adenocarcinomas (p = 0.210), tumors below the size of 30 mm or over 30 mm displayed no significant difference either (p = 0.424). The surgical margins were free of tumor in 41 cases (95.3%). In 13 out of 44 cases the preoperative histology proposed a lower grade neoplasm than the final report (p < 0.001). These results demonstrate that the surgical treatment of large adenomas with TEM technique, which involves excision of the whole bowel wall, is more appropriate than the fractionated removal or polypectomy supplemented by mucosectomy. The pT2 stage tumours might be subjected to the TEM method in selected cases (e.g. following neoadjuvant treatment or palliative care), but this has to be confirmed with prospecively evaluated large series clinical studies which are currently ongoing.

Sphincter preservation in distal CT2N0 rectal cancer after preoperative chemoradiotherapy

BACKGROUND

Preoperative chemoradiotherapy is usually not indicated for cT2N0 rectal cancer. Abdominoperineal resection is the standard treatment for distal rectal tumors. The aim of the study was to evaluate the actual sphincter-preservation rate in patients with distal cT2N0 rectal cancer given neoadjuvant chemoradiotherapy.

METHODS

Data were retrospectively collected for all patients who were diagnosed with distal cT2N0 rectal cancer at a tertiary medical center in 2000-2008 and received chemoradiotherapy followed by surgery (5-7 weeks later).

RESULTS

Thirty-three patients (22 male) of median age 65 years (range, 32-88) were identified. Tumor distance from the anal verge ranged from 0 to 5 cm. R0 resection with sphincter preservation was accomplished in 22 patients (66%), with a 22% pathological complete response rate. Median follow-up time was 62 months (range 7-120). There were no local failures. Crude disease-free and overall survival were 82% and 86%, respectively. Factors associated with sphincter preservation were tumor location (OR=0.58, p=0.02, 95% CI=0.37-0.91) and pathological downstaging (OR=7.8, p=0.02, 95% CI=1.35-45.85). Chemoradiotherapy was well tolerated.

CONCLUSION

High rates of sphincter preservation can be achieved after preoperative chemoradiotherapy for distal cT2N0 rectal cancer, with tolerable toxicity, without compromising oncological outcome.

Transanal endoscopic surgery in rectal cancer

Total mesorectal excision (TME) is the standard treatment for rectal cancer, but complications are frequent and rates of morbidity, mortality and genitourinary alterations are high. Transanal endoscopic microsurgery (TEM) allows preservation of the anal sphincters and, via its vision system through a rectoscope, allows access to rectal tumors located as far as 20 cm from the anal verge. The capacity of local surgery to cure rectal cancer depends on the risk of lymph node invasion. This means that correct preoperative staging of the rectal tumor is necessary. Currently, local surgery is indicated for rectal adenomas and adenocarcinomas invading the submucosa, but not beyond (T1). Here we describe the standard technique for TEM, the different types of equipment used, and the technical limitations of this approach. TEM to remove rectal adenoma should be performed in the same way as if the lesion were an adenocarcinoma, due to the high percentage of infiltrating adenocarcinomas in these lesions. In spite of the generally good results with T1, some authors have published surprisingly high recurrence rates; this is due to the existence of two types of lesions, tumors with good and poor prognosis, divided according to histological and surgical factors. The standard treatment for rectal adenocarcinoma T2N0M0 is TME without adjuvant therapy. In this type of adenocarcinoma, local surgery obtains the best results when complete pathological response has been achieved with previous chemoradiotherapy. The results with chemoradiotherapy and TEM are encouraging, but the scientific evidence remains limited at present.

Depth and lateral spread of microscopic residual rectal cancer after neoadjuvant chemoradiation: implications for treatment decisions

AIM

The aim of this study was to determine the distribution of residual tumour within the bowel wall in relation to residual mucosal abnormalities (RMAs) and surrounding normal mucosa in patients with rectal cancer who underwent neoadjuvant chemoradiation followed by curative surgery.

METHOD

Archived pathological slides from a cohort of 60 patients with residual tumour were retrieved. The incidence, distance and depth of tumour spread (ypT) under RMAs and adjacent normal mucosa were reviewed and recorded.

RESULTS

Histological sections containing both RMA and adjacent normal mucosa were available for 45 of 60 patients with ypT1 (n = 6), ypT2 (n = 18) and ypT3 (n = 21) disease. The maximal depth of invasion, as measured by ypT stage, was found underneath the RMA in 44 of 45 (98%) patients. Microscopic tumour spread lateral to the RMA and under adjacent normal mucosa was found in 32 of 45 (71%) patients. The median and maximum distances of lateral spread for ypT1 tumours were 0 and 4 mm; for ypT2 were 2.5 and 9 mm; and for ypT3 were 4 and 9 mm respectively.

CONCLUSION

Lateral tumour spread under normal mucosa adjacent to RMAs is a common finding and extended up to 9 mm in this study. The epicentre for maximum depth of invasion was directly underneath the RMAs in nearly all cases. These data have clinical and technical implications if local excision is to be considered.

Specificity of lectin-immobilized fluorescent nanospheres for colorectal tumors in a mouse model which better resembles the clinical disease

We have been investigating an imaging agent that enables real-time and accurate diagnosis of early colorectal cancer at the intestinal mucosa by colonoscopy. The imaging agent is peanut agglutinin-immobilized polystyrene nanospheres with surface poly(N-vinylacetamide) chains encapsulating coumarin 6. Intracolonically-administered lectin-immobilized fluorescent nanospheres detect tumor-derived changes through molecular recognition of lectin for the terminal sugar of cancer-specific antigens on the mucosal surface. The focus of the present study was to evaluate imaging abilities of the nanospheres in animal models that reflect clinical environments. We previously developed an orthotopic mouse model with human colorectal tumors growing on the mucosa of the descending colon to better resemble the clinical disease. The entire colon of the mice in the exposed abdomen was monitored in real time with an in vivo imaging apparatus. Fluorescence from the nanospheres was observed along the entire descending colon after intracolonical administration from the anus. When the luminal side of the colon was washed with phosphate-buffered saline, most of the nanospheres were flushed. However, fluorescence persisted in areas where cancer cells were implanted. Histological evaluation demonstrated that tumors were present in the mucosal epithelia where the nanospheres fluoresced. In contrast, no fluorescence was observed when control mice, without tumors were tested. The lectin-immobilized fluorescent nanospheres were tumor-specific and remained bound to tumors even after vigorous washing. The nanospheres nonspecifically bound to normal mucosa were easily removed through mild washing. These results indicate that the nanospheres combined with colonoscopy, will be a clinically-valuable diagnostic tool for early-stage primary colon carcinoma.

Oncologic colorectal resection after endoscopic treatment of malignant polyps: does endoscopy have an adverse effect on oncologic and surgical outcomes?

BACKGROUND

Early colorectal cancer is increasingly treated by endoscopic removal. In cases of incomplete resection or high-risk carcinoma, additional surgery is necessary.

OBJECTIVE

To evaluate the frequency of subsequent oncologic surgery after endoscopic resection of colorectal cancer, the rate of lymph node metastasis, residual cancer, and morbidity and mortality rates of the operation. Any eventual adverse effect of the prior endoscopic therapy on the surgical and oncologic outcome was assessed.

DESIGN

Retrospective review of prospectively collected data.

SETTING

University hospital.

PATIENTS

Sixty-six consecutive patients with incomplete endoscopic treatment and need for additional surgery between 2004 and 2011.

INTERVENTION

The data of these patients were compared with those of a group of patients with surgery for early colorectal cancer during the same period without prior endoscopic resection as the control group.

MAIN OUTCOME MEASUREMENTS

Rate of lymph node metastasis and residual cancer, perioperative morbidity and mortality.

RESULTS

The lymph node metastasis rate after oncologic resection was 8.6%, and the residual cancer rate was 41%. Risk factors for residual cancer were macroscopic incomplete resection (P < .0001), positive resection margins (P = .03), and piecemeal resection (P = .004). No mortality was observed. Perioperative morbidity, mortality, and oncologic outcome were not significantly different in the group with prior endoscopic resection compared with the primarily operated group.

LIMITATIONS

Retrospective study.

CONCLUSION

Endoscopic treatment of malignant polyps does not worsen surgical and oncologic outcomes in cases of subsequent surgery. Because mortality and morbidity are low, oncologic resection generally should be done in the presence of risk factors for residual cancer.

Transanal endoscopic microsurgery with 3-D (TEM) or high-definition 2-D transanal endoscopic operation (TEO) for rectal tumors. A prospective, randomized clinical trial

PURPOSE

Transanal endoscopic microsurgery (TEM) is a three-dimensional viewing endoscopic system procedure which provides access to rectal tumors through a rectoscope. Two-dimensional transanal endoscopic operation (TEO), with the introduction of high-definition vision, achieves results that are comparable to those of the classical TEM. The main aim of the study was to compare the effectiveness of TEO and TEM systems in a prospective, randomized clinical trial.

STUDY POPULATION

patients meeting inclusion criteria for diagnosis of rectal tumors with curative intent. Sample size, 36 patients. Patients were randomized to receive one of the two procedures. Study variables recorded were the following: preoperative data (time taken to assemble equipment, surgical time, quality of pneumorectum), postoperative morbidity and mortality, pathology study of the tumors, and economic analysis.

RESULTS

Thirty-six patients were analyzed according to intention to treat. Two patients were excluded. The final per-protocol analysis was 34 patients. There were no significant differences in the preoperative or operative variables, quality of pneumorectum, postoperative variables, or pathology results. A trend toward benefit was observed in favor of TEO in time required for assembly, surgical suture time, and total surgical time though the differences were not statistically significant. Statistically significant differences were found in terms of the total cost of the procedure, with mean costs of 2,031 <euro> ± 440 for TEO and 2,603 <euro> ± 507 for TEM (95% CI 218.15-926.486 <euro>, p = 0.003).

CONCLUSION

No technical or clinical differences were observed between the results obtained with the two systems except lower cost with TEO.

Poorly differentiated clusters (PDCs) as a novel histological predictor of nodal metastases in pT1 colorectal cancer

The practical use of histological factors such as submucosal (SM) invasion depth, poor differentiation, presence of lymphovascular invasion (LVI) and tumour budding to establish the risk of nodal dissemination in pT1 colorectal cancer (CRC) is limited by their low standardization and high inter-observer variability. It was recently suggested that the presence in CRC histological sections of poorly differentiated clusters (PDCs), defined as ≥5 cancer cells with no gland formation, may predict the metastatic potential of CRC. In addition, PDC assessment was shown to be more reproducible than the evaluation of the other aforementioned histological predictors. Hence, in this study, we investigated and compared the predictive value of PDC and other histological parameters on the risk of nodal involvement in pT1 CRC. The presence of PDC, SM invasion depth ≥1,000 μm and LVI was significantly associated with N+ status in pT1 CRC (P < 0.0001). Among these parameters, SM invasion depth had the highest sensitivity to identify N+ pT1 CRC but with the lowest specificity. When the analysis was restricted to CRCs with SM invasion depth ≥1,000 μm, the presence of PDC was the only independent risk factor for nodal metastases and allowed the identification of 87.5 % of N+ cancers. In conclusion, in this study, we demonstrate that the presence of PDC is associated with the metastatic potential of pT1 CRC. The combination of this parameter with SM invasion depth may allow identifying most of the pT1 CRC with nodal metastases.

Imaging assessment of early rectal cancer

Early rectal cancer (ERC) is defined as invasive adenocarcinoma spreading into, but not beyond, the submucosa or muscularis propria-that is a Dukes'A: T1N0 or T2N0 tumour in the tumour node metastasis (TNM) classification (Taylor et al. 2008). Among these tumours it is suggested that the most superficial T1 tumours least likely to metastasize to local lymph nodes than adenocarcinoma invading deeper where the rich lymphatic and venous plexuses within the submucosa provide a mechanism for tumour spread beyond the rectum. Currently, only about 10 % of patients presenting symptomatically with rectal cancer are diagnosed with early disease; however, up to 30 % of screen detected cancers are being identified as Dukes'A. Thus, the overall detection of early stage tumours is likely to increase following greater implementation in screening programs. The goal of this invited review is to provide recommendations based on the consensus discussion on the information from preoperative imaging that is of relevance for clinical decision-making for patients with early rectal cancer.

T1 colorectal cancer: poor histological grading is predictive of lymph-node metastases

INTRODUCTION

After complete local excision of pT1 colorectal cancers, prediction of the absence of lymph-node involvement represents an interesting perspective in order to avoid unnecessary additional radical surgery, reducing morbidity, mortality and costs of care. We aimed to identify independent risk factors predictive of nodal involvement in pT1 colorectal cancer patients.

METHODS

Data regarding depth of submucosal invasion, histological grading, tumour budding and lymphovascular invasion in a consecutive series of 48 pT1 surgically resected colorectal cancers have been retrospectively collected and related to the nodal status.

RESULTS

A 12.5% rate of nodal involvement has been found. The poor differentiation was found as the only independent predictor of nodal metastases in pT1 colorectal cancer (p = 0.01).

CONCLUSIONS

Poor differentiation was the only independent significant predictor of nodal involvement in pT1 colorectal tumours. Our and literature's data confirm that risk factors must be prospectively collected and reported; further genetic and epigenetic predictive factors have to be investigated in order to carefully evaluate the needing of major surgery for pT1 colorectal 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.